Largest and heaviest animals#Mollusks (Mollusca)

The heaviest living animals are all whales. Since no scale can accommodate the whole body of a large whale, most have been weighed by parts.

File:Marine megafauna Infographic.jpg showing the size of marine megafauna.]]

File:Blue Whale 001 body bw.jpg is the heaviest living animal.]]

The heaviest land animals are all mammals. The African elephant is now listed as two species, the African bush elephant and the African forest elephant, as they are now generally considered to be two separate species.[https://web.archive.org/web/20101224161928/http://news.nationalgeographic.com/news/2010/12/101222-african-elephants-two-species-new-science/ African Elephant Really Two Wildly Different Species]. News.nationalgeographic.com (22 December 2010)

{{main|List of largest mammals}}

File:Rhino sizes English.png (dark grey) compared to a human and other rhinos (though one study suggests Palaeoloxodon namadicus may have been a larger land mammal)]]

The blue whale is the largest mammal of all time, with the longest known specimen being {{convert|33|m|ft|1|abbr=on}} long and the heaviest weighted specimen being 190 tonnes.{{cite web | url=https://www.guinnessworldrecords.com/world-records/largest-mammal | title=Largest mammal }}{{cite web | url=http://animaldiversity.org/accounts/Balaenoptera_musculus/ | title=Balaenoptera musculus (Blue whale) | website=Animal Diversity Web }} The extinct whale species Perucetus colossus was shorter than the blue whale, at {{convert|17.0|–|20.1|m|ft|sp=us}} but it is estimated to have rivaled or surpassed it in weight, at 85–340 tonnes. At the highest estimates, this would make Perucetus the heaviest known animal in history., although more recent estimates put it at a more moderate 60 to 113 tonnes.

The largest land mammal extant today is the African bush elephant. The largest extinct land mammal known was long considered to be Paraceratherium orgosensis, a rhinoceros relative thought to have stood up to {{convert|4.8|m|ft|1|abbr=on}} tall, measured over {{convert|7.4|m|ft|1|abbr=on}} long and may have weighed about 17 tonnes.{{Cite journal | doi = 10.1111/j.1096-3642.1993.tb02560.x| title = The largest land mammal ever imagined| journal = Zoological Journal of the Linnean Society| volume = 108| pages = 85–101| year = 1993| last = Fortelius | first = M.; Kappelman, J. }} In 2015, a study suggested that the extinct elephant Palaeoloxodon namadicus may have been the largest land mammal ever, based on a fragmentary femur estimated to belong to an individual with maximum weight of 22 tonnes. This author also suggested that the extinct mastodon "Mammut" borsoni may have rivalled P. namadicus in size.{{Cite news|url=http://mentalfloss.com/article/66361/ancient-elephant-may-have-been-biggest-land-mammal-ever|title=An Ancient Elephant May Have Been Biggest Land Mammal Ever|date=17 July 2015|access-date=21 April 2017|language=en}}{{Cite journal | last1 = Larramendi | first1 = A. | year = 2016 | title = Shoulder height, body mass and shape of proboscideans | journal = Acta Palaeontologica Polonica | volume = 61 | doi = 10.4202/app.00136.2014 | s2cid = 2092950 | url = https://www.app.pan.pl/archive/published/app61/app001362014.pdf | doi-access = free }}

File:Lisowicia Size Comparison.svg, likely the biggest non-mammal synapsid ever, compared to a human]]

The Late Triassic Lisowicia bojani, from what is now southern Poland, probably was the largest of all non-mammalian synapsids (most of which became extinct 250 million years ago), at {{convert|4.5|m|ft|abbr=on}} in length, {{convert|2.6|m|ft|abbr=on}} in height and {{cvt|9|t|lb}} in weight. However, one study suggested a more conservative weight of 4.87 tonnes to 7.02 tonnes for the adult taxon, with an average body mass of 5.88 tonnes.{{Cite journal|last1=Romano|first1=Marco|last2=Manucci|first2=Fabio|date=14 June 2019|title=Resizing Lisowicia bojani: volumetric body mass estimate and 3D reconstruction of the giant Late Triassic dicynodont|journal=Historical Biology|volume=33|issue=4|pages=474–479|doi=10.1080/08912963.2019.1631819|s2cid=196679837|issn=0891-2963|doi-access=free}} The largest carnivorous synapsid was Anteosaurus at {{convert|5|–|6|m|ft|abbr=on}} and {{convert|500|–|600|kg|lb|abbr=on}}.[http://palaeos.com/vertebrates/therapsida/anteosauridae.html#Anteosaurus Anteosaurus]. Palaeos.com

;Caseasaurs (Caseasauria)

:The herbivorous Alierasaurus was the largest caseid and the largest amniote to have lived at the time, with an estimated length around {{cvt|6-7|m|0}}.{{Cite journal |last1=Romano |first1=Marco |last2=Citton |first2=Paolo |last3=Maganuco |first3=Simone |last4=Sacchi |first4=Eva |last5=Caratelli |first5=Martina |last6=Ronchi |first6=Ausonio |last7=Nicosia |first7=Umberto |date=2019 |editor-last=Somerville |editor-first=I. D. |title=New basal synapsid discovery at the P outcrop of Torre del Porticciolo (A lghero, I taly) |url=https://onlinelibrary.wiley.com/doi/10.1002/gj.3250 |journal=Geological Journal |language=en |volume=54 |issue=3 |pages=1554–1566 |doi=10.1002/gj.3250 |s2cid=133755506 |issn=0072-1050|url-access=subscription }} Another huge caseasaur is Cotylorhynchus hancocki, with an estimated length and weight of at least {{cvt|6|m|0}}{{Cite web|url=http://permian.stratigraphy.org/files/20180825094514307.pdf|archive-url=https://web.archive.org/web/20181203104036/http://permian.stratigraphy.org/files/20180825094514307.pdf|url-status=live|archive-date=3 December 2018|title=Permian Stratigraphy – International Commission on Stratigraphy International Union of Geological Sciences|access-date=15 September 2022}} and more than {{cvt|500|kg}}.{{Cite journal|title=The Oldest Caseid Synapsid from the Late Pennsylvanian of Kansas, and the Evolution of Herbivory in Terrestrial Vertebrates|first1=Robert R.|last1=Reisz|first2=Jörg|last2=Fröbisch|date=16 April 2014|journal=PLOS One |volume=9|issue=4|pages = e94518|doi=10.1371/journal.pone.0094518|pmid=24739998|pmc=3989228|bibcode = 2014PLoSO...994518R|doi-access=free}}

;Sphenacodontids (Sphenacodontidae)

:The biggest carnivorous synapsid of Early Permian was Dimetrodon, which could reach {{cvt|4.6|m|0}} and {{cvt|250|kg}}.{{cite journal |last=Berman |first=D.S. |author2=Reisz, R.R. |author3=Martens, T. |author4= Henrici, A.C. |year=2001 |title=A new species of Dimetrodon (Synapsida: Sphenacodontidae) from the Lower Permian of Germany records first occurrence of genus outside of North America |journal=Canadian Journal of Earth Sciences |volume=38|issue=5 |pages=803–812 |doi=10.1139/cjes-38-5-803 |url=http://www.stuartsumida.com/BIOL680-09/BermanEtAl2001.pdf|bibcode=2001CaJES..38..803B }} The largest members of the genus Dimetrodon were also the world's first fully terrestrial apex predators.{{Cite journal|title=Hidden dental diversity in the oldest terrestrial apex predator Dimetrodon|first1=Kirstin S.|last1=Brink|first2=Robert R.|last2=Reisz|date=16 October 2014|journal=Nature Communications|volume=5|pages=3269|doi=10.1038/ncomms4269|pmid=24509889|bibcode = 2014NatCo...5.3269B|doi-access=free}}

;Tappenosaurids (Tappenosauridae)

:The Middle Permian Tappenosaurus was estimated at {{cvt|5.5|m}} in length which is comparable in size with the largest dinocephalians.{{cite journal |last=Olson |first=E.C. |year=1955 |title=Parallelism in the evolution of the Permian reptilian faunas of the Old and New Worlds |journal=Fieldiana |volume=37 |issue=13 |pages=395 |url=https://archive.org/stream/parallelisminevo3713olso#page/n5/mode/2up |access-date=15 September 2022}}

;Therapsids (Therapsida)

:The plant-eating dicynodont Lisowicia bojani is the largest-known of all non-mammalian synapsids, at {{cvt|4.5|m}} and {{cvt|9000|kg}}.{{cite news |last=St. Fleur |first=Nicholas |title=An Elephant-Size Relative of Mammals That Grazed Alongside Dinosaurs |url=https://www.nytimes.com/2019/01/04/science/dicynodonts-fossils-poland.html |date=4 January 2019 |work=The New York Times |access-date=7 January 2019 }}{{cite journal |last1=Sulej |first1=Tomasz |last2=Niedzwiedzki |first2=Grzegorz |title=An elephant-sized Late Triassic synapsid with erect limbs |date=4 January 2019 |journal=Science |volume=363 |issue=6422 |pages=78–80 |doi=10.1126/science.aal4853|pmid=30467179 |bibcode=2019Sci...363...78S |doi-access=free }}{{cite web |author= |title=Gigantic mammal 'cousin' discovered |url=https://www.sciencedaily.com/releases/2018/11/181123134400.htm |date=23 November 2018 |work=Science Daily |access-date=7 January 2019 }} The largest carnivorous therapsid was the aforementioned Anteosaurus from what is now South Africa during Middle Permian epoch. It reached {{convert|5|–|6|m|ft|abbr=on}} long, and about {{convert|500|–|600|kg|lb|abbr=on}} in weight.

{{main|List of largest reptiles}}

File:SaltwaterCrocodile('Maximo').jpg is the largest living reptile.]]

The largest living reptile, a representative of the order Crocodilia, is the saltwater crocodile (Crocodylus porosus) of Southern Asia and Australia, with adult males being typically {{convert|3.9|–|5.5|m|ft|abbr=on}} long. The largest confirmed saltwater crocodile on record was {{convert|6.32|m|ft|1|abbr=on}} long, and weighed about {{convert|1,360|kg|lb|abbr=on}}. Unconfirmed reports of much larger crocodiles exist, but examinations of incomplete remains have never suggested a length greater than {{convert|7|m|ft|abbr=on}}.[http://www.flmnh.ufl.edu/cnhc/cbd-faq-q2.htm Crocodilian Biology Database – FAQ – Which is the largest species of crocodile?] Flmnh.ufl.edu Also, a living specimen estimated at {{convert|7|m|ft|abbr=on}} and {{convert|2,000|kg|lb|abbr=on}} has been accepted by the Guinness Book of World Records.[http://news.boloji.com/200701/00800.htm Boloji.com – A Study in Diversity] {{Webarchive|url=https://web.archive.org/web/20101230162011/http://news.boloji.com/200701/00800.htm |date=30 December 2010 }}. News.boloji.com However, due to the difficulty of trapping and measuring a very large living crocodile, the accuracy of these dimensions has yet to be verified. A specimen named Lolong caught alive in the Philippines in 2011 (died February 2013) was found to have measured {{convert|6.17|m|ft|abbr=on}} in length.{{cite web|title="Lolong" holds world record as largest croc in the world |url=http://www.pawb.gov.ph/index.php?option=com_content&view=article&id=480:lolong-holds-world-record-as-largest-croc-in-the-world&catid=22:news&Itemid=131 |work=Protected Areas and Wildlife Bureau |access-date=23 June 2012 |date=17 November 2011 |url-status=dead|archive-url=https://web.archive.org/web/20120419075200/http://www.pawb.gov.ph/index.php?option=com_content&view=article&id=480%3Alolong-holds-world-record-as-largest-croc-in-the-world&catid=22%3Anews&Itemid=131 |archive-date=19 April 2012 }}{{cite web|last=Britton|first=Adam|title=Accurate length measurement for Lolong|url=http://crocodilian.blogspot.com.au/2011/11/accurate-length-measurement-for-lolong.html|work=Croc Blog|access-date=23 June 2012|date=12 November 2011|archive-date=26 January 2016|archive-url=https://web.archive.org/web/20160126054039/http://crocodilian.blogspot.com.au/2011/11/accurate-length-measurement-for-lolong.html|url-status=dead}}{{cite news|title=NatGeo team confirms Lolong the croc is world's longest|url=http://www.gmanetwork.com/news/story/237992/news/nation/natgeo-team-confirms-lolong-the-croc-is-world-s-longest|access-date=23 June 2012|publisher=GMA News Online|date=9 November 2011}}{{cite news|title=Philippine town claims world's largest crocodile title|url=https://www.telegraph.co.uk/earth/wildlife/8879042/Philippine-town-claims-worlds-largest-crocodile-title.html|archive-url=https://web.archive.org/web/20111110145205/http://www.telegraph.co.uk/earth/wildlife/8879042/Philippine-town-claims-worlds-largest-crocodile-title.html|url-status=dead|archive-date=10 November 2011|access-date=23 June 2012|newspaper=The Telegraph|date=9 November 2011}}{{cite news|title='Lolong' claims world's largest croc title |url=http://www.abs-cbnnews.com/nation/regions/11/09/11/lolong-claims-worlds-largest-croc-title |access-date=23 June 2012 |publisher=ABS-CBNnews.com |date=9 November 2011 |agency=Agence France-Presse |url-status=dead |archive-url=https://web.archive.org/web/20150104023240/http://www.abs-cbnnews.com/nation/regions/11/09/11/lolong-claims-worlds-largest-croc-title |archive-date= 4 January 2015 }}

The Komodo dragon (Varanus komodoensis), also known as the "Komodo monitor", is a large species of lizard found in the Indonesian islands of Komodo, Rinca, Flores, Gili Motang, Nusa kode and Padar. A member of the monitor lizard family (Varanidae), it is the largest living species of lizard, growing to a maximum length of more than {{convert|3|m|ft|abbr=off}} in rare cases and weighing up to approximately {{convert|166|kg|lb|abbr=off}}.{{cite journal|author=Ciofi, Claudio|date=March 1999 |journal=Scientific American|volume=280|issue=3|pages=84–91 |title=The Komodo Dragon|doi=10.1038/scientificamerican0399-84|bibcode=1999SciAm.280c..84C}}

Nevertheless, current extant reptiles are still dwarfed by their prehistoric ancestors. The largest non-dinosaurian terrestrial reptile to have ever lived were crocodilomorphs such as Deinosuchus, Sarcosuchus and Purussaurus, each have weight varying between 5-10 metric tons.{{cite book |title=King of the Crocodylians: The Paleobiology of Deinosuchus |last=Schwimmer |first=David R. |publisher=Indiana University Press |pages=42–63 |chapter=The Size of Deinosuchus |year=2002 |url=https://books.google.com/books?id=0OsPJnC4CCwC |isbn=978-0-253-34087-0}}{{cite journal|title=Femoral dimensions and body size of Alligator mississippiensis: estimating the size of extinct mesoeucrocodylians|journal=Journal of Vertebrate Paleontology|year=2005|volume=25|issue=2|author=Farlow|doi=10.1671/0272-4634(2005)025[0354:FDABSO]2.0.CO;2|display-authors=etal|pages=354–369|s2cid=49386389 }}{{Cite journal |last1=Paiva |first1=Ana Laura S. |last2=Godoy |first2=Pedro L. |last3=Souza |first3=Ray B. B. |last4=Klein |first4=Wilfried |last5=Hsiou |first5=Annie S. |date=13 August 2022 |title=Body size estimation of Caimaninae specimens from the miocene of South America |journal=Journal of South American Earth Sciences |volume=118 |language=en |pages=103970 |doi=10.1016/j.jsames.2022.103970 |bibcode=2022JSAES.11803970P |s2cid=251560425 |issn=0895-9811|doi-access=free }} The largest snake to have ever lived was Titanoboa which could grow up to {{convert|12.8|–|14.3|m|ft|abbr=on}} and weigh up to {{convert|730|-|1,135|kg|lb|abbr=on}}.{{cite journal|first1=A. |last1=Feldman |first2=N. |last2=Sabath |first3=R.A. |last3=Pyron |first4=I. |last4=Mayrose |first5=S. |last5=Meiri |year=2016|title=Body sizes and diversification rates of lizards, snakes, amphisbaenians and the tuatara|journal=Global Ecology and Biogeography|volume=25|issue=2|pages=187–197|doi=10.1111/geb.12398|bibcode=2016GloEB..25..187F |s2cid=25049185}}{{citation |last1=Head |first1=Jason |last2=Bloch |first2=Jonathan |last3=Moreno Bernal |first3=Jorge |last4=Rincón Burbano |first4=Aldo Fernando |last5=Bourque |first5=Jason |year=2013 |title=Cranial osteology, body size, systematics, and ecology of the giant Paleocene snake Titanoboa cerrejonensis |url=https://www.researchgate.net/publication/280610583 |publisher=Society of Vertebrate Paleontology |pages=140–141 |accessdate=22 May 2017}} Prehistoric marine reptiles from the Mesozoic were even larger. Archelon was the largest testudines, being around {{cvt|4.6|m|ft}} long from head to tail and {{cvt|2.2|-|3.2|MT|ST}} in weight.{{cite journal|last1=Derstler|first1=K.|first2=A. D.|last2=Leitch|first3=P. L.|last3=Larson|first4=C.|last4=Finsley|first5=L.|last5=Hill|year=1993|title=The World's Largest Turtles - The Vienna Archelon (4.6 m) and the Dallas Protostega (4.2 m), Upper Cretaceous of South Dakota and Texas|journal=Journal of Vertebrate Paleontology|volume=13|number=3|page=33A}} Mosasaurus hoffmanni was the largest squamate lizard to have ever lived, with a length of {{convert|11|m|ft|sp=us}} and a body mass of {{convert|10|MT|ST}}{{cite journal|author1=Fedrico Fanti|author2=Andrea Cau|author3=Alessandra Negri|title=A giant mosasaur (Reptilia, Squamata) with an unusually twisted dentition from the Argille Scagliose Complex (late Campanian) of Northern Italy|year=2014|journal=Cretaceous Research|volume=49|issue=2014|pages=91–104|doi=10.1016/j.cretres.2014.01.003|bibcode=2014CrRes..49...91F |url=https://www.disva.univpm.it/sites/www.disva.univpm.it/files/disva/news_dipartimento/cretaceus%20research.pdf}} However, the largest reptiles, period, were the shastasaurids, specifically Ichthyotitan, which approached lengths rivalling to exceeding those of a blue whale, at around {{convert|26|–|35|m|ft|abbr=on}} in length.

The following is a list of the largest living reptile species ranked by average weight, which is dominated by the crocodilians. Unlike mammals, birds, or fish, the mass of large reptiles is frequently poorly documented and many are subject to conjecture and estimation.

{{Main|Dinosaur size}}

{{see also|Largest prehistoric animals}}

File:Bruhathkayosaurus matleyi updated.png, potentially the largest animal to have walked the earth.]]

[[File:Longest dinosaur by clade.svg|alt=|thumb|320x320px|A human and the longest known dinosaurs of the five major clades. Each grid section represents 1 square meter.

{{legend|#B3464A|Sauropoda (Supersaurus vivianae)}}

{{legend|#CC48CC|Ornithopoda (Shantungosaurus giganteus)}}

{{legend|#58BD67|Theropoda (Spinosaurus aegyptiacus)}}

{{legend|#F59331|Thyreophora (Stegosaurus ungulatus)}}

{{legend|#73A9D5|Marginocephalia (Triceratops prorsus)}}]]

Dinosaurs are now extinct, except for birds, which are theropods.{{citation needed|date=October 2024}}

;Sauropods (Sauropoda)

:The largest dinosaurs, and the largest animals to ever live on land, were the plant-eating, long-necked Sauropoda. The tallest and heaviest sauropod known from a complete skeleton is a specimen of an immature Giraffatitan discovered in Tanzania between 1907 and 1912, now mounted in the Museum für Naturkunde of Berlin. It is {{convert|12-13.27|m|ft|abbr=on}} tall and weighed 23.3–39.5 tonnes.{{cite journal|last=Mazzetta|first=G.V.|title=Giants and bizarres: Body size of some southern South American Cretaceous dinosaurs.|journal=Historical Biology|year=2004|pages=1–13|display-authors=etal|doi=10.1080/08912960410001715132|volume=16|issue=2–4|bibcode=2004HBio...16...71M |citeseerx=10.1.1.694.1650|s2cid=56028251 }}{{cite news|last=Janensch|first=W.|title=The skeleton reconstruction of Brachiosaurus brancai.|year=1950|pages=97–103}}{{cite journal | last1 = Paul | first1 = G.S. | year = 1988 | title = The brachiosaur giants of the Morrison and Tendaguru with a description of a new subgenus, Giraffatitan, and a comparison of the world's largest dinosaurs | journal = Hunteria | volume = 2 | issue = 3| pages = 1–14 }}{{Cite journal | doi = 10.1371/journal.pbio.1001853| title = Rates of dinosaur body mass evolution indicate 170 million years of sustained ecological innovation on the avian stem lineage| journal = PLOS Biology| volume = 12| issue = 5| pages = e1001853| year = 2014| last1 = Benson | first1 = R. B. J. | last2 = Campione | first2 = N. S. E. | last3 = Carrano | first3 = M. T. | last4 = Mannion | first4 = P. D. | last5 = Sullivan | first5 = C. | last6 = Upchurch | first6 = P. | last7 = Evans | first7 = D. C. | pmid=24802911 | pmc=4011683| doi-access = free}}{{cite journal | last1 = Taylor | first1 = M.P. | year = 2009 | title = A re-evaluation of Brachiosaurus altithorax Riggs 1903 (Dinosauria, Sauropod) and its generic separation from Giraffatitan brancai (Janensch 1914) | url = http://www.miketaylor.org.uk/dino/pubs/taylor2009/Taylor2009-brachiosaurus-and-giraffatitan.pdf | journal = Journal of Vertebrate Paleontology | volume = 29 | issue = 3| pages = 787–806 | doi=10.1671/039.029.0309| bibcode = 2009JVPal..29..787T | s2cid = 15220647 }}{{Cite news|url=https://www.museumfuernaturkunde.berlin/en/museum/ausstellungen/world-dinosaurs|title=The World of Dinosaurs|work=Museum für Naturkunde|access-date=18 November 2018|language=en}} The longest is a {{convert|25|m|ft|abbr=on}} long specimen of Diplodocus discovered in Wyoming, and mounted in Pittsburgh's Carnegie Natural History Museum in 1907. A Patagotitan specimen found in Argentina in 2014 is estimated to have been {{convert|37-40|m|ft|abbr=on}} long and {{convert|20|m|ft|abbr=on}} tall, with a weight of 69–77 tonnes.{{cite news|url=https://www.bbc.com/news/science-environment-27441156|title=BBC News - 'Biggest dinosaur ever' discovered|newspaper=BBC News|access-date=30 September 2014|date=17 May 2014|last1=Morgan|first1=James}}{{Cite news|url=https://www.bbc.com/news/science-environment-40889321|title=Giant dinosaur slims down ... a bit|date=10 August 2017|work=BBC News|access-date=18 November 2018|language=en-GB}}

:There were larger sauropods, but they are known only from a few bones. The current record-holders include Argentinosaurus, which may have weighed 100 tonnes; Supersaurus which might have reached {{convert|34|m|ft|abbr=on}} in length and Sauroposeidon which might have been {{convert|18|m|ft|abbr=on}} tall. Some abnormal specimens such as specimen BYU 9024 of the Barosaurus/Supersaurus genus could reach an astounding 45-50 meters long,{{Cite book|last1=Benton|first1=Michael|date=31 October 2023 |title=Dinosaur Behavior: An Illustrated Guide|publisher=Princeton University Press|language=en |isbn=9780691244297|pages=94–95}} with mass varying from the 'modest' 60-66 tons to the more immense 92-120 tons. Two other such sauropods include Bruhathkayosaurus and Maraapunisaurus (formally Amphicoelias). Both are known only from fragments that no longer exist. Bruhathkayosaurus might have been between {{convert|40|–|45|m|ft|abbr=on}} in length and 175–220 tonnes in weight according to some estimates, with recent estimates placing it between 110 and 170 tons.Mortimer, M. (2001), [http://dml.cmnh.org/2001Jun/msg00665.html "Re: Bruhathkayosaurus"] {{Webarchive|url=https://web.archive.org/web/20170522105714/http://dml.cmnh.org/2001Jun/msg00665.html |date=22 May 2017 }}, discussion group, The Dinosaur Mailing List, 19 June 2001. Accessed 23 May 2008.{{Cite journal |last1=Paul |first1=Gregory S. |last2=Larramendi |first2=Asier |date=11 April 2023 |title=Body mass estimate of Bruhathkayosaurus and other fragmentary sauropod remains suggest the largest land animals were about as big as the greatest whales |journal=Lethaia |language=en |volume=56 |issue=2 |pages=1–11 |doi=10.18261/let.56.2.5 |bibcode=2023Letha..56..2.5P |s2cid=259782734 |issn=0024-1164|doi-access=free }} Maraapunisaurus might have been approximately 35–40 m long and weighed 80–120 tonnes or more.{{Cite journal|last=Paul|first=Gregory S.|date=2019|title=Determining the largest known land animal: A critical comparison of differing methods for restoring the volume and mass of extinct animals|url=http://www.gspauldino.com/Titanomass.pdf|journal=Annals of the Carnegie Museum|volume=85|issue=4|pages=335–358|doi=10.2992/007.085.0403|bibcode=2019AnCM...85..335P |s2cid=210840060}} Each of these two 'super-sauropods' would have easily rivalled the largest blue whale in size.

;Theropods (Theropoda)

:The largest theropod known from a nearly complete skeleton is the most complete Tyrannosaurus rex specimen, nicknamed "Sue", which was discovered in South Dakota in 1990 and now mounted in the Field Museum of Chicago at a total length of {{convert|12.3|m|ft|abbr=on}}. Body mass estimates have reached over 9,500 kg,{{cite journal |title=A computational analysis of limb and body dimensions in Tyrannosaurus rex with implications for locomotion, ontogeny, and growth |journal=PLOS One |year=2011 |last1=Hutchinson |first1=John R. |last2=Bates |first2=Karl T. |last3=Molnar |first3=Julia |last4=Allen |first4=Vivian |last5=Makovicky |first5=Peter J. |volume=6 |issue=10 |pages=1–20 |doi=10.1371/journal.pone.0026037 |bibcode=2011PLoSO...626037H |pmid=22022500 |pmc=3192160|doi-access=free }} though other figures, such as Hartman's 2013 estimate of 8,400 kg,{{cite web |url= http://www.skeletaldrawing.com/home/mass-estimates-north-vs-south-redux772013 |title=Mass estimates: North vs South redux |last=Hartman |first=Scott |date=7 July 2013 |access-date=17 August 2015 }} have been lower.

:Another giant theropod is Spinosaurus aegyptiacus from the mid-Cretaceous of North Africa. Size estimates have been fluctuating far more over the years, with length estimates ranging from 12.6 to 18 m and mass estimates from 7 to 20.9 t.{{cite journal |title=New information on the skull of the enigmatic theropod Spinosaurus, with remarks on its size and affinities |journal=Journal of Vertebrate Paleontology |year=2005 |last1=Dal Sasso |first1=Christiano |last2=Maganuco |first2=Simone |last3=Buffetaut |first3=Eric |last4=Mendez |first4=Marco A. |volume=25 |issue=4 |pages=888–896 |url=http://www.reocities.com/Athens/bridge/4602/spinoskull.pdf |access-date=17 August 2015 |doi=10.1671/0272-4634(2005)025[0888:niotso]2.0.co;2 |s2cid=85702490 |archive-url=https://web.archive.org/web/20110429015542/http://reocities.com/Athens/bridge/4602/spinoskull.pdf |archive-date=29 April 2011 |url-status=dead }}{{cite journal |last=Therrien |first=F. |author2=Henderson, D.M. |year=2007 |title=My theropod is bigger than yours ... or not: estimating body size from skull length in theropods |journal=Journal of Vertebrate Paleontology |volume=27 |issue=1 |pages=108–115 |doi=10.1671/0272-4634(2007)27[108:MTIBTY]2.0.CO;2 |s2cid=86025320 |issn=0272-4634}} Recent findings favor a length exceeding 15 m {{cite journal|last1=Ibrahim|first1=Nizar|author-link=Nizar Ibrahim|last2=Sereno|first2=Paul C.|last3=Dal Sasso|first3=Christiano|last4=Maganuco|first4=Simone|display-authors=etal|year=2014|title=Semiaquatic adaptations in a giant predatory dinosaur|url=https://researchportal.port.ac.uk/portal/en/publications/semiaquatic-adaptations-in-a-giant-predatory-dinosaur(8f11a1ce-3265-4b3b-8c81-6f576856a87f).html|journal=Science|volume=345|issue=6204|pages=1613–1616|bibcode=2014Sci...345.1613I|doi=10.1126/science.1258750|pmid=25213375|s2cid=34421257|doi-access=free}} and a body mass of 7.5 tons.{{cite web|url=http://paulsereno.uchicago.edu/discoveries/spinosaurus_aegyptiacus/|title=Discoveries - Paul Sereno - Paleontologist - The University of Chicago|website=paulsereno.uchicago.edu|access-date=14 June 2017}}

:Other contenders known from partial skeletons include Giganotosaurus carolinii (est. 12.2–13.2 m and 6-13.8 tonnes) and Carcharodontosaurus saharicus (est. 12-13.3 m and 6.2-15.1 tonnes).{{cite journal | last1 = Coria | first1 = R. A. | last2 = Salgado | first2 = L. | year = 1995 | title = A new giant carnivorous dinosaur from the Cretaceous of Patagonia. | journal = Nature | volume = 377 | issue = 6546| pages = 225–226 | doi=10.1038/377224a0| bibcode = 1995Natur.377..224C | s2cid = 30701725 }}Coria, R. A. and Currie, P. J. (2006). "A new carcharodontosaurid (Dinosauria, Theropoda) from the Upper Cretaceous of Argentina". Geodiversitas, 28 (1): 71–118. [http://www.mnhn.fr/museum/front/medias/publication/7653_g06n1a4.pdf pdf link] {{webarchive |url=https://web.archive.org/web/20131002120231/http://www.mnhn.fr/museum/front/medias/publication/7653_g06n1a4.pdf |date=2 October 2013 }}Holtz, Thomas R. Jr. (2012) Dinosaurs: The Most Complete, Up-to-Date Encyclopedia for Dinosaur Lovers of All Ages, [http://www.geol.umd.edu/~tholtz/dinoappendix/HoltzappendixWinter2011.pdf Winter 2011 Appendix].{{Cite journal | last1 = Sereno | first1 = P. C. | last2 = Dutheil | first2 = D. B. | last3 = Iarochene | first3 = M. | last4 = Larsson | first4 = H. C. E. | last5 = Lyon | first5 = G. H. | last6 = Magwene | first6 = P. M. | last7 = Sidor | first7 = C. A. | last8 = Varricchio | first8 = D. J. | last9 = Wilson | first9 = J. A. | doi = 10.1126/science.272.5264.986 | title = Predatory dinosaurs from the Sahara and Late Cretaceous faunal differentiation | journal = Science | volume = 272 | issue = 5264 | pages = 986–991 | year = 1996 | pmid = 8662584| bibcode = 1996Sci...272..986S | s2cid = 39658297 | url = http://doc.rero.ch/record/13893/files/PAL_E831.pdf }}{{cite journal | doi = 10.1671/0272-4634(2001)021[0051:ANMTCA]2.0.CO;2 | last1 = Seebacher | first1 = F. | year = 2001 | title = A new method to calculate allometric length-mass relationships of dinosaurs | journal = Journal of Vertebrate Paleontology | volume = 21 | issue = 1| pages = 51–60 | issn = 0272-4634 | citeseerx = 10.1.1.462.255 | s2cid = 53446536 }}

:The largest extant theropod is the common ostrich (see birds, below).

;Armored dinosaurs (Thyreophora)

:The largest thyreophorans were Ankylosaurus and Stegosaurus, from the Late Cretaceous and Late Jurassic periods (respectively) of what is now North America, both measuring up to {{convert|9|m|ft|abbr=on}} in length and estimated to weigh up to 6 tonnes.[http://www.chemistrydaily.com/chemistry/Stegosaurus Chemistry - Stegosaurus]. Chemistrydaily.com {{webarchive |url=https://web.archive.org/web/20160126054040/http://www.chemistrydaily.com/chemistry/Stegosaurus |date=26 January 2016 }}[http://www.sciencekids.co.nz/sciencefacts/dinosaurs/ankylosaurus.html Ankylosaurus Facts]. sciencekids.co.nz

;Ornithopods (Ornithopoda)

:The largest ornithopods were the hadrosaurids Shantungosaurus, a late Cretaceous dinosaur found in the Shandong Peninsula of China, and Magnapaulia from the late Cretaceous of North America. Both species are known from fragmentary remains but are estimated to have reached over {{convert|15|m|ft|abbr=on}} in length{{Cite journal | last1 = Zhao | first1 = M. Z. | last2 = Zhang | first2 = H. Z. | doi = 10.1007/s10114-005-0808-x | title = The weighted transience and recurrence of Markov processes | journal = Acta Mathematica Sinica, English Series | volume = 23 | pages = 111–126 | year = 2006 | s2cid = 119700784 }}{{cite journal|last=Morris |first=William J. |year=1981 |title=A new species of hadrosaurian dinosaur from the Upper Cretaceous of Baja California: Lambeosaurus laticaudus |jstor=1304231|journal=Journal of Paleontology |volume=55 |issue=2 |pages=453–462}} and were likely the heaviest non-sauropod dinosaurs, estimated at over 23 tonnes.

;Ceratopsians (Ceratopsia)

:The largest ceratopsians were Triceratops and its ancestor Eotriceratops from the late Cretaceous of North America. Both estimated to have reached about {{convert|9|m|ft|abbr=on}} in length{{cite book|title=The Horned Dinosaurs|year=1996|author=Dodson, P.|publisher=Princeton University Press, Princeton, New Jersey|isbn=978-0-691-02882-8|url=https://archive.org/details/horneddinosaursn00dods_0}} and weighed 12 tonnes.{{Cite journal | last1 = Alexander | first1 = R. M. | doi = 10.1111/j.1096-3642.1985.tb00871.x | title = Mechanics of posture and gait of some large dinosaurs | journal = Zoological Journal of the Linnean Society | volume = 83 | pages = 1–25| year = 1985 }}{{Cite journal | last1 = Wu | first1 = X. C. | last2 = Brinkman | first2 = D. B. | last3 = Eberth | first3 = D. A. | last4 = Braman | first4 = D. R. | title = A new ceratopsid dinosaur (Ornithischia) from the uppermost Horseshoe Canyon Formation (upper Maastrichtian), Alberta, Canada | doi = 10.1139/E07-011 | journal = Canadian Journal of Earth Sciences | volume = 44 | issue = 9 | pages = 1243–1265 | year = 2007 | bibcode = 2007CaJES..44.1243W }}

{{main|List of largest birds}}

File:Strauss m Tanzania.jpg is the largest living bird.]]

The largest living bird, a member of the Struthioniformes, is the common ostrich (Struthio camelus), from the plains of Africa. A large male ostrich can reach a height of {{convert|2.8|m|ft|abbr=on}} and weigh over {{convert|156|kg|lb|abbr=on}}.[http://www.birding.com/birdrecords1.asp birding.com] records {{webarchive |url=https://web.archive.org/web/20070302004911/http://www.birding.com/birdrecords1.asp |date=2 March 2007 }} A mass of {{convert|200|kg|lb|abbr=on}} has been cited for the common ostrich but no wild ostriches of this weight have been verified.[http://www.avianmedicine.net/ampa/48.pdf Avian Medicine: Principles and Application]. avianmedicine.net {{webarchive |url=https://web.archive.org/web/20090419061330/http://www.avianmedicine.net/ampa/48.pdf |date=19 April 2009 }} Eggs laid by the ostrich can weigh {{convert|1.4|kg|lb|abbr=on}} and are the largest eggs in the world today.{{Citation needed|date=January 2021}}

The largest bird in the fossil record may be the extinct elephant birds (Aepyornithidae) of Madagascar, which were related to the kiwis. Aepyornis exceeded {{convert|3|m|ft|abbr=on}} in height and {{convert|500|kg|lb|abbr=on}}, while Vorombe could reach a similar height and a mass of {{convert|732|kg|lb|abbr=on}}.{{cite journal|last1= Hansford|first1=J. P.|last2= Turvey|first2=S. T.|title= Unexpected diversity within the extinct elephant birds (Aves: Aepyornithidae) and a new identity for the world's largest bird|journal= Royal Society Open Science|volume= 5|issue= 9|date= 26 September 2018|page= 181295|doi=10.1098/rsos.181295|pmc= 6170582|pmid= 30839722|bibcode=2018RSOS....581295H}} The last of the elephant birds became extinct about 300 years ago. Of almost exactly the same upper proportions as the largest elephant birds was Dromornis stirtoni of Australia, part of a 26,000-year-old group called mihirungs of the family Dromornithidae.Murray, Peter F.; Vickers-Rich, Patricia (2004). Magnificent Mihirungs: The Colossal Flightless Birds of the Australian Dreamtime. Indiana University Press. {{ISBN|978-0-253-34282-9}} The largest carnivorous bird was Brontornis, an extinct flightless bird from South America which reached a weight of {{convert|350|to|400|kg|lb|abbr=on}} and a height of about {{convert|2.8|m|ftin|abbr=on}}.Alvarenga, H.; Chiappe, L.; Bertelle, S. (3 May 2011), Phorusrhacids: the Terror Birds, in Dyke, G.; Kaiser, G., Living Dinosaurs: The Evolutionary History of Modern Birds, Wiley, pp. 187–208, {{ISBN|978-0-470-65666-2}} The tallest carnivorous bird was Kelenken, which could reach 3 to 3.2 meters in height and 220 to 250 kilograms. The tallest bird ever was the giant moa (Dinornis maximus), part of the moa family of New Zealand that went extinct around 1500 AD. This particular species of moa stood up to {{convert|3.7|m|ft|abbr=on}} tall, but weighed about half as much as a large elephant bird or mihirung due to its comparatively slender frame.

The heaviest bird ever capable of flight was Argentavis magnificens, the largest member of the now extinct family Teratornithidae, found in Miocene-aged fossil beds of Argentina, with a wingspan up to {{convert|5.5|m|ft|abbr=on}}, a length of up to {{convert|1.25|m|ft|abbr=on}}, a height on the ground of up to {{convert|1.75|m|ft|abbr=on}} and a body weight of at least {{convert|71|kg|lb|abbr=on}}.{{Cite journal | last1 = Chatterjee | first1 = S. | last2 = Templin | first2 = R. J. | last3 = Campbell | first3 = K. E. | doi = 10.1073/pnas.0702040104 | title = The aerodynamics of Argentavis, the world's largest flying bird from the Miocene of Argentina | journal = Proceedings of the National Academy of Sciences | volume = 104 | issue = 30 | pages = 12398–12403 | year = 2007 | pmid = 17609382| pmc = 1906724| bibcode = 2007PNAS..10412398C | doi-access = free }}{{cite journal|title=Flight performance of the largest volant bird|first=Daniel T.|last=Ksepka|date=22 July 2014|journal=Proceedings of the National Academy of Sciences|volume=111|issue=29|pages=10624–10629|doi=10.1073/pnas.1320297111|pmid=25002475|pmc=4115518|bibcode=2014PNAS..11110624K|doi-access=free}} Pelagornis sandersi is thought to have had an even larger wingspan of about {{convert|6.1|-|7.4|m|ft|abbr=on}}, but is only about {{convert|22|-|40|kg|lb|abbr=on}}, half the mass of the former.{{cite web|url=http://www.ibtimes.co.uk/pelagornis-sandersi-worlds-biggest-bird-was-twice-big-albatross-24ft-wingspan-1455666|title=Pelagornis Sandersi: World's Biggest Bird Was Twice as Big as Albatross with 24ft Wingspan|first=Hannah|last=Osborne|date=7 July 2014|website=International Business Times|access-date=14 June 2017}}

The following is a list of the heaviest living bird species based on maximum reported or reliable mass, but average weight is also given for comparison. These species are almost all flightless, which allows for these particular birds to have denser bones and heavier bodies. Flightless birds comprise less than 2% of all living bird species.{{Citation needed|date=January 2021}}

File:Andrias japonicus cropped.jpg, the largest living amphibian.]]

The largest living amphibian is the South China giant salamander (Andrias sligoi). Formerly considered conspecific with the Chinese giant salamander (A. davidianus), the maximum size of this nearly human-sized river-dweller is {{convert|64|kg|lb|abbr=on}} and almost {{convert|1.83|m|ft|abbr=on}}. Before amniotes became the dominant tetrapods, several giant amphibian proto-tetrapods existed and were certainly the dominant animals in their ecosystems. The largest known was the crocodile-like Prionosuchus, which reached a length of {{convert|9|m|ft|abbr=on}}.{{cite journal|author1=Cox, C. B. |author2=Hutchinson, P. |year=1991 |title=Fishes and amphibians from the Late Permian Pedrado Fogo Formation of northern Brazil |journal=Palaeontology |volume=34 |pages=561–573 |id={{INIST|19854877}} |url=http://palaeontology.palass-pubs.org/pdf/Vol%2034/Pages%20561-573.pdf |url-status=usurped |archive-url=https://web.archive.org/web/20120324051815/http://palaeontology.palass-pubs.org/pdf/Vol%2034/Pages%20561-573.pdf |archive-date=24 March 2012 }}

;Frogs (Anura)

File:Cane-toad.jpg ranks as the largest toad in the world.]]

:The largest member of the largest order of amphibians is the African goliath frog (Conraua goliath). The maximum size this species is verified to attain is a weight of {{convert|3.8|kg|lb|abbr=on}} and a snout-to-vent length of {{convert|39|cm|in|abbr=on}}. The largest of the toads is the cane toad (Rhinella marina). This infamous, often invasive species can grow to maximum mass of {{convert|2.65|kg|lb|abbr=on}} and measure a maximum of {{convert|33|cm|in|abbr=on}} from snout-to-vent. Rivaling the previous two species, the African bullfrog (Pyxicephalus adspersus) can range up to a weight of {{convert|2|kg|lb|abbr=on}} and {{convert|25.5|cm|in|abbr=on}} from snout to vent.[http://www.honoluluzoo.org/african_bullfrog.htm African Bullfrog]. Honoluluzoo.org {{webarchive |url=https://web.archive.org/web/20110903062023/http://www.honoluluzoo.org/african_bullfrog.htm |date=3 September 2011 }} Another large frog is the largest frog in North America, the American bullfrog, which can reach weights of up to {{convert|0.8|kg|lb|abbr=on}} and snout-to-vent-length (SVL) of {{convert|20|cm|in|abbr=on}}. However, the toad Beelzebufo ampinga, found in fossil from the Cretaceous era in what is now Madagascar, was estimated to grow to {{convert|41|cm|in|abbr=on}} long and weigh up to {{convert|4.5|kg|lb|abbr=on}}, making it the largest frog ever known.[https://web.archive.org/web/20080220010642/http://news.nationalgeographic.com/news/2008/02/080218-giant-frog.html Giant "Frog From Hell" Fossil Found in Madagascar]. News.nationalgeographic.com (28 October 2010) But in more recent studies, animals of this species have been estimated to have grown to at least {{convert|23.2|cm|in|1|abbr=on}} (snout-vent length), which is around the size a modern African bullfrog can reach.{{cite journal |last1=Evans |first1=Susan E. |last2=Groenke |first2=Joseph R. |last3=Jones |first3=Marc E. H. |last4=Turner |first4=Alan H. |last5=Krause |first5=David W. |title=New Material of Beelzebufo, a Hyperossified Frog (Amphibia: Anura) from the Late Cretaceous of Madagascar |journal=PLOS One |date=28 January 2014 |volume=9 |issue=1 |pages=e87236 |doi=10.1371/journal.pone.0087236 |pmid=24489877 |pmc=3905036 |bibcode=2014PLoSO...987236E |doi-access=free }} The largest tree frog is the Australasian white-lipped tree frog (Litoria infrafrenata), the females of which can reach a length of {{convert|14|cm|in|abbr=on}} from snout to vent and can weigh up to {{convert|115|g|oz|abbr=on}}.[http://www.theanimalfiles.com/amphibians/frogs/white_lipped_tree_frog.html White Lipped Tree Frog]. The Animal Files The family Leptodactylidae, one of the most diverse anuran families, also has some very large members. The largest is the Surinam horned frog (Ceratophrys cornuta), which can reach {{convert|20|cm|in|abbr=on}} in length from snout to vent and weigh up to {{convert|0.48|kg|lb|abbr=on}}.[http://bullafina.com/video/videos/dCN4QaGtDoE/1/1/-leptodactylidae/Surinam-horned-frog-(Ceratophrys-cornuta) Surinam horned frog (Ceratophrys cornuta) – Videos Peru – Peru Videos]. Bullafina.com (11 June 2008) {{dead link|date=May 2016|bot=medic}}{{cbignore|bot=medic}} While not quite as large as Ceratophrys cornuta, Leptodactylus pentadactylus is often heavier; it can reach {{convert|18.5|cm|in|abbr=on}} long and weigh {{convert|0.60|kg|lb|abbr=off}}. The largest dendrobatid is the Colombian golden poison frog (Phyllobates terribilis), which can attain a length of {{convert|6|cm|in|abbr=on}} and nearly {{convert|28.3|g|oz|abbr=on}}.[https://web.archive.org/web/20100207174351/http://animals.nationalgeographic.com/animals/amphibians/golden-poison-dart-frog/ Golden Poison Dart Frogs, Golden Poison Dart Frog Pictures, Golden Poison Dart Frog Facts]. Animals.nationalgeographic.com Most frogs are classified under the suborder Neobatrachia, although nearly 200 species are part of the suborder Mesobatrachia, or ancient frogs. The largest of these are the little-known Brachytarsophrys or Karin Hills frogs, of South Asia, which can grow to a maximum snout-to-vent length of {{convert|17|cm|in|abbr=on}} and a maximum weight of {{convert|0.54|kg|lb|abbr=on}}.Zweifel, Richard G. (1998). Cogger, H. G. and Zweifel, R. G. ed. Encyclopedia of Reptiles and Amphibians. San Diego: Academic Press. {{ISBN|0-12-178560-2}}.

;Caecilians (Gymnophiona)

:The largest of the worm-like caecilians is the Colombian Thompson's caecilian (Caecilia thompsoni), which reaches a length of {{convert|1.5|m|ft|abbr=on}}, a width of about {{convert|4.6|cm|in|abbr=on}} and can weigh up to about {{convert|1|kg|lb|abbr=on}}.

;Salamanders (Urodela)

:Besides the previously mentioned Chinese and South China giant salamanders, the closely related Japanese giant salamander (Andrias japonicus) is also sometimes cited as the largest living amphibian, but salamanders of a greater size than {{convert|1.53|m|ft|abbr=on}} and {{convert|36|kg|lb|abbr=on}} have never been verified for this species. Another giant of the amphibian world is the North American hellbender (Cryptobranchus alleganiensis), which can measure up to {{convert|0.76|m|ft|abbr=on}}. The recently described reticulated siren of the southeastern United States rivals the hellbender in size, although it is more lean in build.{{cite web|url=https://blogs.scientificamerican.com/extinction-countdown/swampy-thing-the-giant-new-salamander-species-discovered-in-florida-and-alabama/|title=Swampy Thing: The Giant New Salamander Species Discovered in Florida and Alabama|last=Platt|first=John R.|website=Scientific American Blog Network|language=en|access-date=19 December 2018}} The largest of the newts is the Iberian ribbed newt (Pleurodeles waltl), which can grow up to {{convert|30|cm|in|abbr=on}} in length.{{usurped|1=[https://web.archive.org/web/20080720131540/http://www.buzzle.com/articles/the-largest-newt-as-a-pet.html The Largest Newt As a Pet]}}. Buzzle.com

{{main|List of largest fish}}

{{further|Tunicata}}

The largest tunicate is Synoicum pulmonaria, found at depths of {{convert|20|and|40|m|ft|0}}, and are up to {{convert|14|cm|in}} in diameter. It is also present in the northwestern Atlantic Ocean, around the coasts of Greenland and Newfoundland, but is less common here than in the east, and occurs only at depths between {{convert|10|and|13|m|ft|0}}.{{cite web |url=http://doris.ffessm.fr/fiche2.asp?fiche_numero=2797 |title=Synoicum pulmonaria (Ellis & Solander, 1786) |author1=André, Frédéric |author2=Tourenne, Murielle |author3=Foveau, Aurélie |date=8 August 2011 |publisher=DORIS |language=fr |access-date=26 July 2015}}

;Entergonas (Enterogona)

:The largest entergona is Synoicum pulmonaria it is usually found at depths between about {{convert|20|and|40|m|ft|0}} and can grow to over a metre (yard) in length. It is also present in the northwestern Atlantic Ocean, around the coasts of Greenland and Newfoundland, but is less common here than in the east, and occurs only at depths between {{convert|10|and|13|m|ft|0}}.

;Pleurogonas (Pleurogona)

:The largest pleurogona is Pyura pachydermatina.{{cite journal |author1=Lambert, Gretchen |author2=Lambert, Charles C. |year=1996 |title=Spicule Formation in the New Zealand Ascidian Pyura pachydermatina (Chordata, Ascidiacea) |journal=Connective Tissue Research |volume=34 |issue=4 |pages=263–269 |doi=10.3109/03008209609005270|pmid=9084635 }} In colour it is off-white or a garish shade of reddish-purple. The stalk is two thirds to three quarters the length of the whole animal which helps distinguish it from certain invasive tunicates not native to New Zealand such as Styela clava and Pyura stolonifera.{{cite web |url=http://www.biosecurity.govt.nz/pests/pyura |title=Pyura |work=Biosecurity in New Zealand |publisher=Ministry for Primary Industries, New Zealand Government |access-date=19 April 2013 |archive-url=https://web.archive.org/web/20130209200618/http://www.biosecurity.govt.nz/pests/pyura |archive-date=9 February 2013 |url-status=dead }} It is one of the largest species of tunicates and can grow to over a metre (yard) in length.{{cite book |title=Invertebrate Zoology |edition=7th |last1=Ruppert |first1=Edward E. |last2=Fox |first2=Richard, S. |last3=Barnes |first3=Robert D. |year=2004 |publisher=Cengage Learning |isbn=978-81-315-0104-7 |page=941 }}

;Aspiraculates (Aspiraculata)

:The largest aspiraculate is Oligotrema large and surrounded by six large lobes; the cloacal syphon is small. They live exclusively in deep water and range in size from less than one inch (2 cm) to 2.4 inches (6 cm).

File:Pyrosoma_atlanticum.JPG is the largest thaliacean.]]

The largest thaliacean, Pyrosoma atlanticum, is cylindrical and can grow up to {{convert|60|cm|ft|abbr=off}} long and 4–6 cm wide. The constituent zooids form a rigid tube, which may be pale pink, yellowish, or bluish. One end of the tube is narrower and is closed, while the other is open and has a strong diaphragm. The outer surface or test is gelatinised and dimpled with backward-pointing, blunt processes. The individual zooids are up to {{cvt|8.5|mm|in}} long and have a broad, rounded branchial sac with gill slits. Along the side of the branchial sac runs the endostyle, which produces mucus filters. Water is moved through the gill slits into the centre of the cylinder by cilia pulsating rhythmically. Plankton and other food particles are caught in mucus filters in the processes as the colony is propelled through the water. P. atlanticum is bioluminescent and can generate a brilliant blue-green light when stimulated.[http://species-identification.org/species.php?species_group=zmns&id=588 Pyrosoma atlanticum] Marine Species Identification Portal. Retrieved 11 November 2011.

;Doliolida (Doliolida)

:The largest doliolida is Doliolida [http://www.marinespecies.org/aphia.php?p=taxdetails&id=137212 Doliolida] World Register of Marine Species. Retrieved 17 November 2011. The doliolid body is small, typically 1–2 cm long, and barrel-shaped; it features two wide siphons, one at the front and the other at the back end, and eight or nine circular muscle strands reminiscent of barrel bands. Like all tunicates, they are filter feeders. They are free-floating; the same forced flow of water through their bodies with which they gather plankton is used for propulsion - not unlike a tiny ramjet engine. Doliolids are capable of quick movement. They have a complicated lifecycle consisting of sexual and asexual generations. They are nearly exclusively tropical animals, although a few species are found as far north as northern California.{{Citation needed|date=January 2021}}

;Salps (Salpida)

:The largest salp is Cyclosalpa bakeri {{convert|15|cm|in|abbr=on}}s) long. There are openings at the anterior and posterior ends of the cylinder which can be opened or closed as needed. The bodies have seven transverse bands of muscle interspersed by white, translucent patches. A stolon grows from near the endostyle (an elongated glandular structure producing mucus for trapping food particles). The stolon is a ribbon-like organ on which a batch of aggregate forms of the animal are produced by budding. The aggregate is the second, colonial form of the salp and is also gelatinous, transparent and flabby. It takes the shape of a radial whorl of individuals up to about {{convert|20|cm|in|abbr=on}} in diameter. It is formed of approximately 12 zooids linked side by side in a shape that resembles a crown.[http://jellieszone.com/pelagic-tunicates/cyclosalpa-bakeri/ Cyclosalpa bakeri - Ritter, 1905] {{Webarchive|url=https://web.archive.org/web/20160321094842/http://jellieszone.com/pelagic-tunicates/cyclosalpa-bakeri/ |date=21 March 2016 }} JelliesZone, by David Wrobel. Retrieved 10 April 2016.[http://jellieszone.com/pelagic-tunicates/ Pelagic Tunicates] {{Webarchive|url=https://web.archive.org/web/20160623020144/http://jellieszone.com/pelagic-tunicates/ |date=23 June 2016 }} JelliesZone, by David Wrobel. Retrieved 10 April 2016. are largest thetyses: Thetys vagina Individuals can reach up to {{convert|30|cm|in|abbr=on}} long.{{Citation needed|date=January 2021}}

;Larvaceans (Larvacea)

:The largest larvacean is Appendicularia {{convert|1|cm|abbr=on}} in body length (excluding the tail).{{Citation needed|date=January 2021}}

{{further|Leptocardii}}

The largest lancelet is the European lancelet (Branchiostoma lanceolatum) "primitive fish". It can grow up to {{convert|6|cm|in|abbr=on}} long.[http://species-identification.org/species.php?species_group=zmns&id=589 Branchiostoma lanceolatum] Marine Species Information Portal. Retrieved 14 November 2011.

Image:Reef1118 - Flickr - NOAA Photo Library.jpg is the longest known echinoderm.]]

The largest species of echinoderm in terms of bulk is probably the starfish species Thromidia gigas, of the class Asteroidea, which reaches a weight of over {{convert|6|kg|lb|abbr=on}},{{cite web |url=http://echinoblog.blogspot.fr/2008/07/what-are-worlds-largest-starfish.html |title=What Are the World's LARGEST Starfish? |last1=Mah |first1=Christopher |date= 27 July 2008|website=The Echinoblog }} but it might be beaten by some giant sea cucumbers such as Thelenota anax. However, at a maximum span of {{convert|63|cm|in|abbr=on}}, Thromidia gigas is quite a bit shorter than some other echinoderms. The longest echinoderm known is the conspicuous sea cucumber Synapta maculata, with a slender body that can extend up to {{convert|3|m|ft|abbr=on}}. In comparison, the biggest sea star is the brisingid sea star Midgardia xandaros, reaching a span of {{convert|1.4|m|ft|abbr=on}}, despite being quite slender. Evasterias echinosoma is another giant echinoderm and can measure up to {{convert|1|m|ft|abbr=on}} across and weigh {{convert|5.1|kg|lb|abbr=on}}.

;Crinoids (Crinoidea)

:The largest species of crinoid is the unstalked feather-star Heliometra glacialis, reaching a total width of {{convert|78|cm|in|abbr=on}} and an individual arm length of {{convert|35|cm|in|abbr=on}}. A width of {{convert|91.4|cm|in|abbr=on}} was claimed for one unstalked feather-star but is not confirmed. The genus Metacrinus has a stalk span of {{convert|61|cm|in|abbr=on}} but, due to its bulk and multiple arms, it is heavier than Heliometra. In the past, crinoids grew much larger, and stalk lengths up to {{convert|40|m|ft|abbr=on}} have been found in the fossil record.Ponsonby, David and Dussart, George The Anatomy of the Sea, Raincoast Books (2005) {{ISBN|0-8118-4633-4}} p. 129

;Sea urchins and allies (Echinoidea)

:The largest sea urchin is the species Sperosoma giganteum from the deep northwest Pacific Ocean, which can reach a shell width of about {{convert|30|cm|in|abbr=on}}.{{cite book|title=Echinoderms - Starfish, Urchins, and Other Echinoderms|author=Gilpin, D.|year=2006|page=[https://archive.org/details/starfishurchinso0000gilp/page/41 41]|publisher=Capstone |isbn=978-0-7565-1611-6|url=https://archive.org/details/starfishurchinso0000gilp/page/41}} Another deep sea species Hygrosoma hoplacantha is only slightly smaller. The largest species found along the North America coast is the Pacific red sea urchin (Mesocentrotus franciscanus) where the shell can reach {{convert|19|cm|in|abbr=on}}.{{cite web|title=Strongylocentrotus franciscanus|url=http://animaldiversity.org/accounts/Strongylocentrotus_franciscanus/|publisher=Animal Diversity Web|access-date=2 December 2016}} If the spines enter into count, the biggest species may be a Diadematidae like Diadema setosum, with a test up to {{convert|10|cm|in|abbr=on}} only, but its spines can reach up to {{convert|30|cm|in|abbr=on}} in length.{{cite web|title=Long-spined black sea urchin|url=http://www.wildsingapore.com/wildfacts/echinodermata/echinoidea/urchin/diadema.htm|publisher=Wild Singapore|access-date=2 December 2016}}

;Sea cucumbers (Holothuroidea)

:The bulkiest species of sea cucumber are Stichopus variegatus and Thelenota anax, weighing several pounds, being about {{convert|21|cm|in|abbr=on}} in diameter, and reaching a length of {{convert|1|m|ft|abbr=on}} when fully extended. Synapta maculata can reach an extended length of {{convert|3|m|ft|abbr=on}}, but is extremely slender (3-5cm) and weigh much less than Stichopodids.

;Brittle stars (Ophiuroidea)

:The largest known specimen of brittle star is the basket star Astrotoma agassizii. This species can grow to have a span of {{convert|1|m|ft|abbr=on}}. Sometimes, Gorgonocephalus stimpsoni is considered the largest but the maximum this species is can measure {{convert|70|cm|in|abbr=on}} and a disk diameter of about {{convert|14.3|cm|in|abbr=on}}. Outside from euryalids, the biggest ophiurid brittle star may be Ophiopsammus maculata (6–7 inches).{{cite web |url=http://echinoblog.blogspot.fr/2009/04/the-worlds-biggest-brittle-stars.html |title=The World's BIGGEST Brittle Stars! |last1=Mah |first1=Christopher |date= 27 April 2009|website=The Echinoblog }}

;Sea stars (Asteroidea)

:The heaviest sea star is Thromidia gigas from the Indo-Pacific, which can surpass {{convert|6|kg|lb|abbr=on}} in weight, but only has a diameter of about {{convert|65|cm|ft|abbr=on}}. Despite its relatively small disk and weight, the long slender arms of Midgardia xandaros from the Gulf of California makes it the sea star with the largest diameter at about {{convert|4.5|ft|m|abbr=on|order=flip}}. Mithrodia clavigera may also become wider than {{convert|1|m|in|abbr=on}} in some cases, with stout arms.{{citation needed|date=December 2016}}

{{further|Platyhelminthes}}

;Monogenean flatworms (Monogenea)

:The largest known members of this group of very small parasites are among the genus of capsalids, Listrocephalos, reaching a length of {{convert|2|cm|in|abbr=on}}.{{cite journal|url=http://www.actaparasitologica.pan.pl/archive/PDF/Kearn.pdf|title=Neoentobdella gen. nov for species of Entobdella Blainville in Lamarck, 1818 (Monogenea, Capsalidae, Entobdellinae) from stingray hosts, with descriptions of two new species|journal=Acta Parasitologica|year= 2005|volume=50|issue=1|pages=32–48}}

;Flukes (Trematoda)

:The largest known species of fluke is Fasciolopsis buski, which most often attacks humans and livestock. One of these flukes can be up to {{convert|7.5|cm|in|abbr=on}} long and {{convert|2|cm|in|abbr=on}} thick.[http://dpd.cdc.gov/dpdx/html/Fasciolopsiasis.htm DPDx – Fasciolopsiasis]. Dpd.cdc.gov {{webarchive |url=https://web.archive.org/web/20110927063213/http://dpd.cdc.gov/dpdx/html/Fasciolopsiasis.htm |date=27 September 2011 }}

;Tapeworms (Cestoda)

:The largest known species of tapeworm is the whale tapeworm, Polygonoporus giganticus, which can grow to over {{convert|30|m|ft|abbr=on}}.[https://web.archive.org/web/20080627143218/http://www.time.com/time/magazine/article/0,9171,809356-1,00.html The Persistent Parasites]. Time (8 April 1957)Hargis, William J. [http://spo.nwr.noaa.gov/tr25opt.pdf Parasitology and pathology of marine organisms of the world ocean] {{Webarchive|url=https://web.archive.org/web/20111015132455/http://spo.nwr.noaa.gov/tr25opt.pdf |date=15 October 2011 }}. National Oceanic and Atmospheric Administration (1985)

The largest arrow worms is Parasagitta setosa rows to a maximum length of {{convert|14|mm|2|abbr=on}}, its tail being up to a quarter of this length.

The largest of the segmented worms (including earthworms, leeches, and polychaetes) is the African giant earthworm (Microchaetus rappi). Although it averages about {{convert|1.36|m|ft|abbr=on}} in length, this huge worm can reach a length of as much as {{convert|6.7|m|ft|abbr=on}} and can weigh over {{convert|1.5|kg|lb|abbr=on}}.[http://www.wormdigest.org/index.php?option=com_content&task=view&id=102&Itemid=2 The Mighty Worm]. Worm Digest (2 October 2005) {{webarchive |url=https://web.archive.org/web/20090219141951/http://www.wormdigest.org/index.php?option=com_content&task=view&id=102&Itemid=2 |date=19 February 2009 }} Only the giant Gippsland earthworm, Megascolides australis, and a few giant polychaetes, including the notorious Eunice aphroditois, reach nearly comparable sizes, reaching {{convert|4|and|3.6|m|ft|abbr=on}}, respectively.

The largest nemertean is the bootlace worm, Lineus longissimus. A specimen found washed ashore on a beach in St. Andrews, Scotland in 1864 was recorded at a length of {{convert|55|m|ft|abbr=on}}.Carwardine, M. 1995. The Guinness Book of Animal Records. Guinness Publishing. p. 232.

File:Giant squid melb aquarium03.jpg.]]

Both the largest mollusks and the largest of all invertebrates (in terms of mass) are the largest squids. The colossal squid (Mesonychoteuthis hamiltoni) is projected to be the largest invertebrate.[https://web.archive.org/web/20070225081846/http://news.nationalgeographic.com/news/2007/02/070222-squid-pictures.html Photo in the News: Colossal Squid Caught off Antarctica]. News.nationalgeographic.com (28 October 2010) Current estimates put its maximum size at {{convert|12|to|14|m|ft|abbr=on}} long and {{convert|750|kg|lb|abbr=on}},{{cite web|url=http://www.unmuseum.org/colossalsquid.htm|title=The UnMuseum - The Colossal Squid|website=www.unmuseum.org|access-date=14 June 2017}} based on analysis of smaller specimens. In 2007, authorities in New Zealand announced the capture of the largest known colossal squid specimen. It was initially thought to be {{convert|10|m|ft|abbr=on}} and {{convert|450|kg|lb|abbr=on}}. It was later measured at {{convert|4.2|m|ft|abbr=on}} long and {{convert|495|kg|lb|abbr=on}} in weight. The mantle was {{convert|2.5|m|ft|abbr=on}} long when measured.Kathy Marks. [http://www.nzherald.co.nz/section/1/story.cfm?c_id=1&objectid=10430435 NZ's colossal squid to be microwaved] {{Webarchive|url=https://web.archive.org/web/20070929125549/http://www.nzherald.co.nz/section/1/story.cfm?c_id=1&objectid=10430435 |date=29 September 2007 }}. The New Zealand Herald (23 March 2007){{cite web|url=http://squid.tepapa.govt.nz/the-squid-files/article/how-big-is-the-colossal-squid|archive-url=https://web.archive.org/web/20081217062907/http://squid.tepapa.govt.nz/the-squid-files/article/how-big-is-the-colossal-squid|url-status=dead|archive-date=17 December 2008|website=Te papa|title=How big is the colossal squid?}}

The giant squid (Architeuthis dux) was previously thought to be the largest squid, and while it is less massive and has a smaller mantle than the colossal squid, it may exceed the colossal squid in overall length including tentacles. One giant squid specimen that washed ashore in 1878 in Newfoundland reportedly measured {{convert|16.8|m|ft|abbr=on}} in total length (from the tip of the mantle to the end of the long tentacles), head and body length {{convert|6.1|m|ft|abbr=on}}, {{convert|4.6|m|ft|abbr=on}} in circumference at the thickest part of mantle, and weighed about {{convert|900|kg|lb|abbr=on}}. This specimen is still often cited as the largest invertebrate that has ever been examined.[http://marinebio.org/species.asp?id=156 Giant Squids, Architeuthis dux]. Marinebio.org[https://web.archive.org/web/20100116185537/http://animals.nationalgeographic.com/animals/invertebrates/giant-squid Giant Squid, Giant Squid Pictures, Giant Squid Facts]. Animals.nationalgeographic.com (4 December 2006) However, no animals approaching this size have been scientifically documented and, according to giant squid expert Steve O'Shea, such lengths were likely achieved by greatly stretching the two tentacles like elastic bands.O'Shea, S. 2003. [http://www.tonmo.com/science/public/giantsquidfacts.php "Giant Squid and Colossal Squid Fact Sheet".] The Octopus News Magazine Online.

;Aplacophorans (Aplacophora)

:The largest known of these worm-like, shell-less mollusks are represented in the genus Epimenia, which can reach {{convert|30|cm|in|abbr=on}} long. Most aplacophorans are less than {{convert|5|cm|in|abbr=on}} long.{{Cite journal | last1 = Salvini-Plawen | first1 = L. V. | title = Systematic Revision of the Epimeniidae (Mollusca: Solenogastres) | doi = 10.1093/mollus/63.2.131 | journal = Journal of Molluscan Studies | volume = 63 | issue = 2 | pages = 131–155 | year = 1997 | doi-access = free }}

;Chitons (Polyplacophora)

:The largest of the chitons is the gumboot chiton, Cryptochiton stelleri, which can reach a length of {{convert|33|cm|in|abbr=on}} and weigh over {{convert|2|kg|lb|abbr=on}}.[https://www.adfg.alaska.gov/static/species/speciesinfo/_aknhp/Gumboot_Chiton.pdf Gumboot Chiton]. alaska.gov

File:Giant clam black&white komodo.jpg, the largest bivalve]]

;Bivalves (Bivalvia)

:The largest of the bivalve mollusks is the giant clam, Tridacna gigas. Although even larger sizes have been reported for this passive animal, the top verified size was for a specimen from the Great Barrier Reef. This creature weighed {{convert|270|kg|lb|abbr=on}}, had an axial length of {{convert|1.14|m|ft|abbr=on}} and depth of {{convert|0.75|m|ft|abbr=on}}. The largest bivalve ever was Platyceramus platinus, a Cretaceous giant that reached an axial length of up to 3 m (nearly 10 ft).{{Cite journal | last1 = Kauffman | first1 = E. G. | last2 = Harries | first2 = P. J. | last3 = Meyer | first3 = C. | last4 = Villamil | first4 = T. | last5 = Arango | first5 = C. | last6 = Jaecks | first6 = G. | title = Paleoecology of Giant Inoceramidae (Platyceramus) on a Santonian (Cretaceous) Seafloor in Colorado | journal = Journal of Paleontology | volume = 81 | pages = 64–81 | year = 2007 | doi = 10.1666/0022-3360(2007)81[64:POGIPO]2.0.CO;2 | s2cid = 130048023 }}

;Gastropods (Gastropoda)

:The "largest" of this most diverse and successful mollusk class of slugs and snails can be defined in various ways.

:The living gastropod species that has the largest (longest) shell is Syrinx aruanus with a maximum shell length of {{convert|0.91|m|ft|abbr=on}}, a weight of {{convert|18|kg|lb|abbr=on}} and a width of {{convert|96|cm|in|abbr=on}}.John D. Taylor and Emily A. Glover. [https://web.archive.org/web/20110721184302/http://wamuseum.com.au/dampier/documents/pdf/taylor-glovergiants.pdf Food of giants – field observations on the diet of Syrinx aruanus (Linnaeus, 1758) (Turbinellidae) the largest living gastropod], in F. E. Wells, D. I. Walker and D. S. Jones (eds.) 2003. The Marine Flora and Fauna of Dampier, Western Australia. Western Australian Museum, Perth.[http://largestfastestsmartest.co.uk/largest-insects-in-the-world-giant-african-snail/ Largest snails in the world – Giant African snail]. largestfastestsmartest.co.uk Another giant species is Melo amphora, which in a 1974 specimen from Western Australia, measured {{convert|0.71|m|ft|abbr=on}} long, had a maximum girth of {{convert|0.97|m|ft|abbr=on}} and weighed {{convert|16|kg|lb|abbr=on}}.

:The largest shell-less gastropod is the giant black sea hare (Aplysia vaccaria) at {{convert|0.99|m|ft|abbr=on}} in length and almost {{convert|14|kg|lb|abbr=on}} in weight.

:The largest of the land snails is the giant African snail (Achatina achatina) at up to {{convert|1|kg|lb|abbr=on}} and {{convert|35|cm|in|abbr=on}} long.

;Cephalopods (Cephalopoda)

:(See Cephalopod size.) While generally much smaller than the giant Architeuthis and Mesonychoteuthis, the largest of the octopuses, the giant Pacific octopus (Enteroctopus dofleini), can grow to be very large. The largest confirmed weight of a giant octopus is {{convert|74|kg|lb|abbr=on}},{{cite thesis |last1=Cosgrove |first1=James Albert |title=Aspects of the natural history of Octopus dofleini, the giant Pacific octopus |date=1987 |hdl=1828/12155 |hdl-access=free }} with a {{convert|7|m|ft|abbr=on}} arm span (with the tentacles fully extended) and a head-to-tentacle-tip length of {{convert|3.9|m|ft|abbr=on}}.[Octopus – Species].{{full citation needed|date=November 2021}} Specimens have been reported up to {{convert|125|kg|lb|abbr=on}} but are unverified. A weight of 10 - 50kg is a much more common size.

;Tusk Shell (Scaphopoda)

• The largest tusk shell Fissidentalium metivieri class range in length {{convert|0.5-18|cm|abbr=on}}

File:Placentonema gigantissima from Dailey 1985.png, the largest roundworm]]

The largest roundworm, Placentonema gigantissima,{{cite journal |last1=Gubanov |first1=NM |title=Гигантская нематода из плаценты китообразных Placentonema gigantissima nov. gen., nov. sp |trans-title=Giant nematoda from the placenta of Cetacea; Placentonema gigantissima nov. gen., nov. sp |language=ru |journal=Doklady Akademii Nauk SSSR |date=21 April 1951 |volume=77 |issue=6 |pages=1123–1125 |pmid=14822893 |url=http://www.mactode.com/page21/files/Placentonema_gigantissima.pdf |archive-url=https://web.archive.org/web/20131215144805/http://www.mactode.com/page21/files/Placentonema_gigantissima.pdf |archive-date=15 December 2013 }} is a parasite found in the placentas of sperm whales which can reach up to {{convert|9|m|ft|abbr=on}} in length.[http://www.nhc.ed.ac.uk/index.php?page=24.25.333.369 Natural History Collections: Nematoda]. Nhc.ed.ac.uk

The largest velvet worm known is Solórzano's velvet worm (Peripatus solorzanoi). An adult female was recorded to have a body length of 22 cm (approximately 8.7 in).{{cite journal|last1=Morera-Brenes|first1=B.|last2=Monge-Nájera|first2=J.|title=A new giant species of placented worm and the mechanism by which onychophorans weave their nets (Onychophora: Peripatidae)|journal=Revista de Biología Tropical|date=2010|volume=58|issue=4|pages=1127–1142|doi=10.15517/rbt.v58i4.5398|pmid=21246983|arxiv=1511.00983|s2cid=6456946}}

File:Echiniscoides_sigismundi.jpg, the largest water bear]]

The largest tardigrade is Echiniscoides sigismundi, which is less than {{convert|2|mm|in|abbr=on}} long. Typical tardigrades are about {{convert|0.5|mm|in|abbr=on}} long. Only the larger tardigrades are visible to the naked eye, but since they're also transparent, magnification is needed to see them.

File:Japanese spider crab.jpg.]]

The largest arthropod known to have existed is the eurypterid (sea scorpion) Jaekelopterus, reaching up to {{convert|2.5|m|ft|abbr=on}} in body length, followed by the millipede relative Arthropleura at around {{convert|2.1|m|ft|abbr=on}} in length.{{Cite journal | last1 = Tetlie | first1 = O. E. | last2 = Poschmann | first2 = M. | last3 = Braddy | first3 = S. J. | doi = 10.1098/rsbl.2007.0491 | title = Giant claw reveals the largest ever arthropod | journal = Biology Letters | volume = 4 | issue = 1 | pages = 106–109 | year = 2008 | pmid = 18029297| pmc =2412931 }}

Among living arthropods, the Japanese spider crab (Macrocheira kaempferi) is the largest in overall size, the record specimen, caught in 1921, had an extended arm span of {{convert|3.8|m|ft|abbr=on}} and weighed about {{convert|19|kg|lb|abbr=on}}. The heaviest is the American lobster (Homarus americanus), the largest verified specimen, caught in 1977 off of Nova Scotia weighed {{convert|20|kg|lb|abbr=on}} and its body length was {{convert|1.1|m|ft|abbr=on}}. The largest land arthropod and the largest land invertebrate is the coconut crab (Birgus latro), up to {{convert|40|cm|ft|abbr=on}} long and weighing up to {{convert|4|kg|lb|abbr=on}} on average. Its legs may span {{convert|1|m|ft|abbr=on}}.

Both spiders and scorpions include contenders for the largest arachnids.

File:Heteropoda maxima 1.jpg]]

;Spiders (Araneae)

:The largest species of arachnid by length is probably the giant huntsman spider (Heteropoda maxima) of Laos, which in 2008 replaced the Goliath birdeater (Theraphosa blondi) of northern South America as the largest known spider by leg-span.{{cite web|url=http://wwf.panda.org/what_we_do/where_we_work/greatermekong/discovering_the_greater_mekong/species/new_species/first_contact/|title=First Contact|website=panda.org|access-date=14 June 2017|archive-url=https://web.archive.org/web/20170224124106/http://wwf.panda.org/what_we_do/where_we_work/greatermekong/discovering_the_greater_mekong/species/new_species/first_contact/|archive-date=24 February 2017|url-status=dead}} However the most massive arachnids, of comparable dimensions and possibly even greater mass, are the Chaco golden knee (Grammostola pulchripes), and the Brazilian salmon pink (Lasiodora parahybana). The huntsman spider may span up to {{convert|29|cm|in|abbr=on}} across the legs, while in the New World tarantulas like Theraphosa can range up to {{convert|26|cm|in|abbr=on}}. In Grammostola, Theraphosa and Lasiodora, the weight is projected to be up to at least {{convert|150|g|oz|abbr=on}} and body length is up to {{convert|10|cm|in|abbr=on}}.[https://web.archive.org/web/20090305114809/http://library.thinkquest.org/C007974/2_4tar.htm Poisonous Animals: Tarantula (Grammostola, Phrixothrichus)]. Library.thinkquest.org

;Scorpions (Scorpiones)

:The largest of the scorpions is the species Heterometrus swammerdami of the Indian subcontinent, which have a maximum length of {{convert|29.2|cm|in|abbr=on}} and weigh around {{convert|60|g|oz|abbr=on}}. Another extremely large scorpion is the African emperor scorpion (Pandinus imperator), which can weigh {{convert|57|g|oz|abbr=on}} but is not known to exceed a length of {{convert|23|cm|in|abbr=on}}. However, they were dwarfed by Pulmonoscorpius kirktonensis, a giant extinct species of scorpion from Scotland, at an estimated length of {{convert|0.7|m|ft|abbr=on}},{{Cite journal |last=Jeram |first=Andrew J. |date=1993 |title=Scorpions from the Viséan of East Kirkton, West Lothian, Scotland, with a revision of the infraorder Mesoscorpionina |url=https://www.cambridge.org/core/journals/earth-and-environmental-science-transactions-of-royal-society-of-edinburgh/article/abs/scorpions-from-the-visean-of-east-kirkton-west-lothian-scotland-with-a-revision-of-the-infraorder-mesoscorpionina/4FE8E1C63AD52A4CC48528B1B7A541C4 |journal=Earth and Environmental Science Transactions of the Royal Society of Edinburgh |language=en |volume=84 |issue=3–4 |pages=283–299 |doi=10.1017/S0263593300006106 |bibcode=1993EESTR..84..283J |s2cid=131416804 |issn=1755-6929|url-access=subscription }} and the aquatic Brontoscorpio, at up to {{convert|94|cm|ft|abbr=on}} which is only known from a free finger.{{cite journal|jstor=1302906|title=Brontoscorpio anglicus: A Gigantic Lower Paleozoic Scorpion from Central England| author= Erik N. Kjellesvig-Waering|journal=Journal of Paleontology|year= 1972|volume=46|issue=1|pages=39–42}}

;Pseudoscorpions (Pseudoscorpiones)

: The largest pseudoscorpion is Garypus titanius, from Ascension island, which can be {{convert|12|mm|in|abbr=on}} long.{{Cite book |author=Jan Beccaloni |year=2009 |title=Arachnids |publisher=Natural History Museum |isbn=978-0-520-26140-2 |chapter=Pseudoscorpiones |page=271}}

File:Giant Acorn Barnacle, Morro Bay, CA, USA imported from iNaturalist photo 254509873.jpg]]

The largest known thecostracan Facetotecta y-larvae are Hansenocaris cristalabri, about 0.5 millimeters long

;Barnacles and allies (Cirripedia)

:The largest barnacle is Balanus nubilus, reaching a diameter of {{cvt|15|cm|0}} and a height of up to {{cvt|30|cm}},{{Cite web |url=http://www.wavelengthmagazine.com/1997/fm97view.html |title=View from on top: mine's bigger than yours! |last=Richard |first=Martin |year=1997 |website=WaveLength Magazine |archive-url=https://web.archive.org/web/20160303171454/http://www.wavelengthmagazine.com/1997/fm97view.html |archive-date=3 March 2016 |url-status=dead |access-date=18 April 2018}} and containing the largest known muscle fibres.{{cite journal |journal=Science |year=1963 |volume=139 |issue=3549 |pages=49–50 |doi=10.1126/science.139.3549.49 |title=Giant muscle fibers in a barnacle, Balanus nubilus Darwin |author=Graham Hoyle & Thomas Smyth Jr. |pmid=17752025|s2cid=11926059 }}

The largest crustacean is the Tasmanian giant crab (Pseudocarcinus gigas), with a weight of {{convert|13|kg}} and a carapace width of up to {{convert|46|cm}}. It is the only species in the genus Pseudocarcinus.{{cite journal|journal=Raffles Bulletin of Zoology |year=2008 |volume=17 |pages=1–286 |title=Systema Brachyurorum: Part I. An annotated checklist of extant Brachyuran crabs of the world |author1=P. K. L. Ng |author2=D. Guinot |author3=P. J. F. Davie |url=http://rmbr.nus.edu.sg/rbz/biblio/s17/s17rbz.pdf |url-status=dead |archive-url=https://web.archive.org/web/20110606061453/http://rmbr.nus.edu.sg/rbz/biblio/s17/s17rbz.pdf |archive-date=6 June 2011 }} Males reach more than twice the size of females.{{cite book |author1=D. R. Currie |author2=T. M. Ward |year=2009 |url=http://www.sardi.sa.gov.au/__data/assets/pdf_file/0019/109522/No_345_SA_Giant_Crab_Fishery_Assessment_Report_2007_08Final_Report_published_alias.pdf |title=South Australian Giant Crab (Pseudocarcinus gigas) Fishery |id=Fishery Assessment Report for PIRSA |publisher=South Australian Research and Development Institute |access-date=9 December 2013}} At a length of up to {{convert|40|cm}}, Lysiosquillina maculata is the largest mantis shrimp in the world.{{cite web |url=http://www.ucmp.berkeley.edu/arthropoda/crustacea/malacostraca/eumalacostraca/royslist/species.php?name=l_maculata |author=Roy Caldwell |publisher=University of California Museum of Paleontology |title=Species: Lysiosquillina maculata |work=Roy's List of Stomatopods for the Aquarium |access-date=14 February 2009}} Tasmanian giant freshwater crayfish (Astacopsis gouldi) {{convert|5|kg}} in weight and over {{convert|80|cm}} long have been known in the past, but now, even individuals over {{convert|2|kg}} are rare.{{cite web |url=http://www.environment.gov.au/biodiversity/threatened/publications/lobster.html |title=Tasmanian Giant Freshwater Lobster (Astacopsis gouldi) |publisher=Department of the Environment, Water, Heritage and the Arts |date=9 February 2007 |access-date=16 March 2010}} The species is only found in Tasmanian rivers flowing north into the Bass Strait below {{convert|400|m}} above sea level, and is listed as an endangered species on the IUCN Red List.{{Cite iucn | author = T. Walsh | author2 = N. Doran |name-list-style=amp | title = Astacopsis gouldi | volume = 2010 | page = e.T2190A9337732 | date = 2010 | doi = 10.2305/IUCN.UK.2010-3.RLTS.T2190A9337732.en }}

;Branchiopods (Branchiopoda)

:The largest of these primarily freshwater crustaceans is probably Branchinecta gigas, which can reach a length {{convert|10|cm|in|abbr=on}}.[https://www.britannica.com/EBchecked/topic/77560/Branchinecta-gigas Branchinecta gigas (crustacean)]. Britannica Online Encyclopaedia

;Barnacles and allies (Maxillopoda)

:The largest species is Pennella balaenopterae, a copepod and ectoparasite specialising in parasitising marine mammals. The maximum size attained is 32 cm (about 13 in).[http://animaldiversity.ummz.umich.edu/site/accounts/information/Pennella_balaenopterae.html Pennella balaenopterae]. Animaldiversity.ummz.umich.edu The largest of the barnacles is the giant acorn barnacle, Balanus nubilis, reaching {{convert|7|cm|in|abbr=on}} in diameter and {{convert|12.7|cm|in|abbr=on}} high.[http://aquarium.org/exhibits/sandy-shores/animals/giant-acorn-barnacle Giant Acorn Barnacle]. Oregon Coast Aquarium {{webarchive |url=https://web.archive.org/web/20111009022416/http://aquarium.org/exhibits/sandy-shores/animals/giant-acorn-barnacle |date=9 October 2011 }}

;Ostracods (Ostracoda)

:The largest living representative of these small and little-known but numerous crustaceans is the species Gigantocypris australis females of which reaching a maximum length of {{convert|3|cm|in|abbr=on}}.

;Amphipods, isopods, and allies (Peracarida)File:giant isopod.jpg]]

:The largest species is the giant isopod (Bathynomus pergiganteus), which can reach a length of 45 cm (18 inches) and a weight of 1.7 kg (3.7 lb).Knight, J.D. [http://www.seasky.org/deep-sea/giant-isopod.html Giant Isopod – Deep Sea Creatures on Sea and Sky]. Seasky.org

;Remipedes (Remipedia)

:The largest of these cave-dwelling crustaceans is the species Godzillius robustus, at up to {{convert|4.5|cm|in|abbr=on}}.[http://www.crustacea.net/crustace/remipedia/www/robustus.htm Remipedia: Species – robustus, Godzillius]. Crustacea.net (2 October 2002)

The four modern horseshoe crabs are of roughly the same sizes, with females measuring up to {{convert|60|cm|ft|abbr=on}} in length and {{convert|5|kg|lb|abbr=on}} in weight.[http://marinebio.org/species.asp?id=281 Horseshoe Crabs, Limulus polyphemus at]. Marinebio.org

The largest of the sea spiders is the deep-sea species Colossendeis colossea, attaining a leg span of nearly {{convert|60|cm|ft|abbr=on}}.[http://www.encyclopedia.com/topic/Sea_spiders.aspx Sea spiders Facts, information, pictures]. work=Encyclopedia.com (22 October 2004)

Some of these extinct marine arthropods exceeded {{convert|60|cm|in|abbr=on}} in length. A nearly complete specimen of Isotelus rex from Manitoba attained a length over {{convert|70|cm|in|abbr=on}}, and an Ogyginus forteyi from Portugal was almost as long. Fragments of trilobites suggest even larger record sizes. An isolated pygidium of Hungioides bohemicus implies that the full animal was {{convert|90|cm|in|abbr=on}} long.{{Cite journal | journal = Geology | title = Giant trilobites and trilobite clusters from the Ordovician of Portugal | first5 = M. | volume = 37 | pages = 443–446 | doi = 10.1130/G25513A.1 | year = 2009 | last1 = Gutierrez-Marco | last5 = Valerio | last2 = Sa | first1 = J. C. | first2 = A. A. | last3 = Garcia-Bellido | last4 = Rabano | first3 = D. C. | first4 = I. | issue = 5| bibcode = 2009Geo....37..443G }}[http://dsc.discovery.com/news/2009/05/07/trilobites-fossil.html Giant Trilobites in Portugal Could Be Biggest Portugal – Discovery News]. Dsc.discovery.com (7 May 2009). {{webarchive |url=https://web.archive.org/web/20090510084620/http://dsc.discovery.com/news/2009/05/07/trilobites-fossil.html |date=10 May 2009 }}

;Centipedes (Chilopoda)

File:Scolopendra gigantea (1).jpg]]

:The biggest of the centipedes is Scolopendra gigantea of the neotropics, reaching a length of {{convert|33|cm|in|abbr=on}}.[http://www.arachnoboards.com/ab/showthread.php?13259-Scolopendra-gigantea Scolopendra gigantea]. Arachnoboards.com (13 August 2003)

;Millipedes (Diplopoda)

:Two species of millipede both reach a very large size: Archispirostreptus gigas of East Africa and Scaphistostreptus seychellarum, endemic to the Seychelles islands. Both of these species can slightly exceed a length of {{convert|28|cm|in|abbr=on}} and measure over {{convert|2|cm|in|abbr=on}} in diameter. though both of them pale in comparison to the largest known millipede known as the Arthropleura, a gigantic prehistoric specimen that reached nearly {{convert|189|cm|in|abbr=on}}.

;Symphylans (Symphyla)

:The largest known symphylan is Hanseniella magna, originating in Tasmanian caves, which can reach lengths from {{convert|25|mm|in|abbr=on}} up to {{convert|30|mm|in|abbr=on}}.{{cite book|last=Minelli|first=Alessandro|title=Encyclopedia of Biodiversity|date=2001|isbn=978-0122268656|pages=291–303|chapter-url=http://enviro.doe.gov.my/lib/digital/1385476273-3-s2.0-B0122268652002042-main.pdf|author2=Sergei I. Golovatch|editor=Simon A. Levin|chapter=Myriapods|publisher=Academic Press |url-status=dead|archive-url=https://web.archive.org/web/20140221184104/http://enviro.doe.gov.my/lib/digital/1385476273-3-s2.0-B0122268652002042-main.pdf|archive-date=21 February 2014}}

File:Goliathus goliatus dos.jpg]]

Insects, a class of Arthropoda, are easily the most numerous class of organisms, with over one million identified species, and probably many undescribed species. The heaviest insect is almost certainly a species of beetle, which incidentally is the most species-rich order of organisms. Although heavyweight giant wetas (Deinacrida heteracantha) are known, the elephant beetles of Central and South America, (Megasoma elephas) and (M. actaeon), the Titan beetle (Titanus giganteus) of the neotropical rainforest or the Goliath beetles, (Goliathus goliatus) and (G. regius), of Africa's rainforest are thought to reach a higher weight.{{cite web |url=http://entnemdept.ufl.edu/walker/ufbir/chapters/chapter_30.shtml |title=Largest |access-date=10 June 2009 |url-status=bot: unknown |archive-url=https://web.archive.org/web/20110718140051/http://entnemdept.ufl.edu/walker/ufbir/chapters/chapter_30.shtml |archive-date=18 July 2011 }}(2011). source: The University of Florida Book of Insect Records {{cite web |url=http://entnemdept.ufl.edu/walker/ufbir/chapters/chapter_30.shtml |title=Largest |access-date=10 June 2009 |url-status=dead |archive-url=https://web.archive.org/web/20140820232404/http://entnemdept.ufl.edu/walker/ufbir/chapters/chapter_30.shtml |archive-date=20 August 2014 }} The most frequently crowned are the Goliath beetles, the top known size of which is at least {{convert|100|g|oz|abbr=on}} and {{convert|11.5|cm|in|abbr=on}}. The elephant beetles and titan beetle can reach greater lengths than the Goliath, at up to {{convert|13.1|and|15.2|cm|in|abbr=on}}, respectively, but this is in part thanks to their rather large horns. The Goliath beetle's wingspan can range up to {{convert|25|cm|in|abbr=on}}.

Some moths and butterflies have much larger areas than the heaviest beetles, but weigh a fraction as much.

The longest insects are the stick insects, see below.

Representatives of the extinct dragonfly-like order Meganisoptera, such as the Carboniferous Meganeura monyi of what is now France and the Permian Meganeuropsis permiana of what is now North America, are the largest insect species known to have existed. These creatures had a wingspan of some {{convert|75|cm|in|abbr=on}} and a mass of over {{convert|1|lb|g}}, making them about the size of a crow.

;Cockroaches and termites (Blattodea)

File:MP - Macropanesthia rhinoceros 2.jpg]]

:The largest cockroach by body mass is the Australian giant burrowing cockroach (Macropanesthia rhinoceros), also known as the rhinoceros cockroach. This species can attain a length of {{convert|8.3|cm|in|abbr=on}} and a weight of {{convert|36|g|oz|abbr=on}}. It does not have wings.[http://www.abc.net.au/creaturefeatures/facts/cockroach.htm Creature Features – Giant Burrowing Cockroach] {{Webarchive|url=https://web.archive.org/web/20140218184323/http://www.abc.net.au/creaturefeatures/facts/cockroach.htm |date=18 February 2014}}. Abc.net.au The Brazilian giant cockroach (Blaberus giganteus) of the neotropics reaches greater sizes of up to 10 cm in length and 15 cm in wingspan, although it is not as massive and heavy as the burrowing species. The termites, traditionally classified in their own order (Isoptera), have recently been re-considered to belong in Blattodea. The largest of the termites is the African species Macrotermes bellicosus. The queen of this species can attain a length of {{convert|14|cm|in|abbr=on}} and breadth of {{convert|5.5|cm|in|abbr=on}} across the abdomen; other adults, on the other hand, are about a third of the size.

;Beetles (Coleoptera)

:The beetles are the largest order of organisms on earth, with about 400,000 species so far identified. The most massive species are the Goliathus, Megasoma and Titanus beetles already mentioned. Another fairly large species is the Hercules beetle (Dynastes hercules) of the neotropic rainforest with a maximum overall length of at least {{convert|19|cm|in|abbr=on}} including the extremely long pronotal horn. The weight in this species does not exceed {{convert|16.5|g|oz|abbr=on}}. The longest overall beetle is a species of longhorn beetle, Batocera wallacei, from New Guinea, which can attain a length of {{convert|26.6|cm|in|abbr=on}}, about {{convert|19|cm|in|abbr=on}} of which is comprised by the long antennae.

;Earwigs (Dermaptera)

:Since 1798, the largest of the earwigs has been the Saint Helena giant earwig (Labidura herculeana), endemic to the island of its name, measuring up to {{convert|8|cm|in|abbr=on}} in length.[http://www.earwigs-online.de/Lherculeana/Lherculeana.html The Giant Earwig of St. Helena Labidura herculeana]. Earwig Research Centre. Earwigs-online.de As of 2014, with the declaring of the organism extinct by the IUCN,{{Cite journal|last1=Pryce|first1=David|last2=Liza White (Environment and Natural Resources Directorate|first2=St Helena Government)|date=22 August 2014|title=IUCN Red List of Threatened Species: Labidura herculeana|url=https://www.iucnredlist.org/en|journal=IUCN Red List of Threatened Species}} this may no longer be the case, although some believe a small number individuals are still extant.{{Cite web|date=19 November 2014|title=Gone for good: world's largest earwig declared extinct|url=https://news.mongabay.com/2014/11/gone-for-good-worlds-largest-earwig-declared-extinct/|access-date=12 October 2021|website=Mongabay Environmental News|language=en-US}}

;True flies (Diptera)

File:Merry Beach Insect.jpg, the largest fly]]

:The largest species of this order, which includes the common housefly, is the neotropical species Gauromydas heros, which can reach a length of {{convert|6|cm|in|frac=8|abbr=on}} and a wingspan of {{convert|10|cm|in|abbr=on}}. Species of crane fly, the largest of which is Holorusia brobdignagius, can attain a length of {{convert|23|cm|in|abbr=on}} but are extremely slender and much lighter in weight than Gauromydas.

;Mayflies (Ephemeroptera)

:The largest mayflies are members of the genus Proboscidoplocia from Madagascar. These insects can reach a length of {{convert|7|cm|in|abbr=on}}.[http://biofreshblog.wordpress.com/2011/05/24/madagascan-mayfly-hyper-diversity/ Madagascan mayfly hyper-diversity]. The BioFresh blog (24 May 2011)

;True bugs (Hemiptera)

File:Giantwaterbug.jpg walking over land]]

:The largest species of this diverse order is usually listed as the giant water bug in the genus Lethocerus, with L. maximus from the Neotropics being the absolutely largest.P. J. Perez-Goodwyn (2006). "Taxonomic revision of the subfamily Lethocerinae Lauck & Menke (Heteroptera: Belostomatidae)". Stuttgarter Beiträge zur Naturkunde: A (Biologie). 695: 1–71. They can surpass {{convert|12|cm|in|abbr=on}} in length,Haddad Jr; Schwartz; Schwartz; and Carvalho (2010). "Bites Caused by Giant Water Bugs Belonging to Belostomatidae Family (Hemiptera, Heteroptera) in Humans: A Report of Seven Cases". Wilderness & Environmental Medicine 21: 130–133. with some suggesting that the maximum size is {{convert|15|cm|in|abbr=on}}.BBC News (26 May 2011). [https://www.bbc.co.uk/nature/13500857 Giant water bug photographed devouring baby turtle.] Retrieved 27 August 2014. It is more slender and less heavy than most other insects of this size (principally the huge beetles). The largest cicada is Megapomponia imperatoria, which has a head-body length of about {{convert|7|cm|in|abbr=on}} and a wingspan of {{convert|18|-|20|cm|in|0|abbr=on}}.Burton, Maurice; Burton, Robert (2002). International Wildlife Encyclopedia. 4, Chickaree - crabs (3rd ed.). Tarrytown, NY: Marshall Cavendish Corporation. p. 455. {{ISBN|0-7614-7270-3}}Flindt, R. (2006). Amazing Numbers in Biology, p. 10. {{ISBN|978-3540301462}} The cicadas of the genus Tacua can also grow to comparably large sizes. The largest type of aphid is the giant oak aphid (Stomaphis quercus), which can reach an overall length of {{convert|2|cm|in|abbr=on}}.[https://web.archive.org/web/20131229012106/http://www.telegraph.co.uk/earth/wildlife/3302722/Giant-Oak-Aphid-hunt-is-on.html Giant Oak Aphid hunt is on]. The Telegraph (8 August 2007) The biggest species of leafhopper is Ledromorpha planirostris, which can reach a length of {{convert|2.8|cm|in|abbr=on}}.[http://bugs.bio.usyd.edu.au/learning/resources/Entomology/internalAnatomy/imagePages/Ledromorpha_planirostris.html Ledromorpha planirostris] {{Webarchive|url=https://web.archive.org/web/20120514143854/http://bugs.bio.usyd.edu.au/learning/resources/Entomology/internalAnatomy/imagePages/Ledromorpha_planirostris.html |date=14 May 2012 }}. Bugs.bio.usyd.edu.auFile:Stavenn Megachile pluto.jpg, the largest bee.]]

;Ants and allies (Hymenoptera)

:The largest of the ants, and the heaviest species of the order, are the females of the African Dorylus helvolus, reaching a length of {{convert|5.1|cm|in|abbr=on}} and a weight of {{convert|8.5|g|oz|abbr=on}}. The ant that averages the largest for the mean size within the whole colony is a ponerine ant, Dinoponera gigantea, from South America, averaging up to {{convert|3.3|cm|in|abbr=on}} from the mandibles to the end of abdomen. Workers of the bulldog ant (Myrmecia brevinoda) of Australia are up to {{convert|3.7|cm|in|abbr=on}} in total length, although much of this is from their extremely large mandibles. The largest of the bee species, also in the order Hymenoptera, is Megachile pluto of Indonesia, the females of which can be {{convert|3.8|cm|in|abbr=on}} long, with a {{convert|6.3|cm|in|abbr=on}} wingspan. Nearly as large, the carpenter bees can range up to {{convert|2.53|cm|in|abbr=on}}. The largest wasp is probably the so-called tarantula hawk species Pepsis pulszkyi of South America, at up to {{convert|6.8|cm|in|abbr=on}} long and {{convert|11.6|cm|in|abbr=on}} wingspan, although many other Pepsis approach a similar size. The giant scarab-hunting wasp Megascolia procer may rival the largest tarantula hawks in weight and wingspan, though its body is not as long.

;Moths and allies (Lepidoptera)File:MP - Ornithoptera alexandrae 3.jpg.]]

:The Hercules moth (Coscinocera hercules), in the family Saturniidae, is endemic to New Guinea and northern Australia, and its wings have the largest documented surface area (300 square centimeters) of any living insect,Robert G. Foottit & Peter H. Adler. 2009. Insect Biodiversity: Science and Society. Blackwell Publishing Ltd. {{ISBN|978-1-405-15142-9}}Rainier Flindt. 2006. Amazing Numbers in Biology. Springer-Verlag, Berlin. {{ISBN|3-540-30146-1}} and a maximum wingspan which is confirmed to {{convert|28|cm|in|abbr=on}} while unconfirmed specimens have spanned up to {{convert|35.5|cm|in|abbr=on}}. The largest species overall is often claimed to be either the Queen Alexandra's birdwing (Ornithoptera alexandrae), a butterfly from Papua New Guinea, or the Atlas moth (Attacus atlas), a moth from Southeast Asia. Both of these species can reach a length of {{convert|8|cm|in|abbr=on}}, a wingspan of {{convert|28|cm|in|abbr=on}} and a weight of {{convert|12|g|oz|abbr=on}}. One Atlas moth allegedly had a wingspan of {{convert|30|cm|in|abbr=on}} but this measurement was not verified. The larvae in the previous species can weigh up to {{convert|58|and|54|g|oz|abbr=on}}, respectively. The white witch (Thysania agrippina) of Central and South America, has the largest recorded wingspan of the order, and indeed of any living insect. The verified record-sized Thysania spanned {{convert|30.8|cm|in|abbr=on}} across the wings, although specimens have been reported to {{convert|36|cm|in|abbr=on}}. The heaviest mature moths have been cited in the giant carpenter moth (Xyleutes boisduvali) of Australia, which has weighed up to {{convert|20|g|oz|abbr=on}} although the species does not surpass {{convert|25.5|cm|in|abbr=on}} in wingspan.

;Mantises (Mantodea)

:The largest species of this order is Toxodera denticulata from Java, which has been measured up to {{convert|20|cm|in|abbr=on}} in overall length.[http://www.bugsincyberspace.com/mantis.php Live Pet Mantis Hobby] {{Webarchive|url=https://web.archive.org/web/20201204172355/http://www.bugsincyberspace.com/mantis.php |date=4 December 2020 }}. Bugsincyberspace.com However, an undescribed species from the Cameroon jungle is allegedly much larger than any other mantis and may rival the larger stick insects for the longest living insect.{{cite book|author=Craig Glenday|title=Guinness World Records 2009|url=https://books.google.com/books?id=aHYt0RNSDfgC&pg=PA53|year=2009|publisher=Random House Digital, Inc.|isbn=978-0-553-59256-6|page=53}} Among widespread mantis species, the largest is the Chinese mantis (Tenodera aridifolia). The females of this species can attain a length of up to {{convert|10.6|cm|in|abbr=on}}.

;Scorpionflies (Mecoptera)

:The largest scorpionfly, the common scorpionfly (Panorpa communis), can reach a body length of about {{convert|30|mm}}.{{Cite web|url=http://www.uksafari.com/scorpionfly.htm|title=Scorpion Flies - Panorpa communis - UK Safari|website=www.uksafari.com}}

;Alderflies and allies (Megaloptera)

:This relatively small insect order includes some rather large species, many of which are noticeable for their elongated, imposing mandibles. The dobsonflies reach the greatest sizes of the order and can range up to {{convert|12.5|cm|in|abbr=on}} in length.[http://www.realmonstrosities.com/2011/01/dobsonfly.html Dobsonfly]. Real Monstrosities (26 January 2011)

;Net-winged insects (Neuroptera)

File:Nymphes myrmeleonides 4.jpg]]

:These flying insects reach their largest size in Palparellus voeltzkowi, which can have a wingspan over {{convert|16|cm|in|abbr=on}}.[http://researcharchive.calacademy.org/research/entomology/Entomology_Resources/Faunal_Projects/EPHP/htm/Palpares%20voeltzkowi.htm Palparellus voeltzkowi (Kolbe, 1906)]. Researcharchive.calacademy.org The largest lacewing is the "blue eyes lacewing" (Nymphes myrmeleonides) of Australia, which can measure up to {{convert|4|cm|in|abbr=on}} in length and span {{convert|11|cm|in|abbr=on}} across the wings.[http://bio-ditrl.sunsite.ualberta.ca/detail/?P_MNO=5221 Bio-Ditrl], Department of Biological Sciences, University of Alberta {{webarchive |url=https://web.archive.org/web/20110706210325/http://bio-ditrl.sunsite.ualberta.ca/detail/?P_MNO=5221 |date=6 July 2011 }} Some forms of this ancient order could grow extremely large during the Jurassic period.{{cite journal|author=Michael S. Engel|year=2005|title=A remarkable kalligrammatid lacewing from the Upper Jurassic of Kazakhstan (Neuroptera: Kalligrammatidae)|journal= Transactions of the Kansas Academy of Science|volume=108 |issue=1|pages= 59–62|jstor=3628206|doi=10.1660/0022-8443(2005)108[0059:arklft]2.0.co;2|s2cid=86240200 }} Found in the Early Cretaceous sedimentary rocks, Makarkinia adamsi had wings nearly {{convert|14|-|16|cm|in|abbr=on}} in length, implying a wingspan similar to the present-day largest moths.{{Cite journal|last1=Bechly |first1=G. |last2=Makarkin |first2=V. N. |year=2016 |title=A new gigantic lacewing species (Insecta: Neuroptera) from the Lower Cretaceous of Brazil confirms the occurrence of Kalligrammatidae in the Americas |journal=Cretaceous Research |volume=58 |pages=135–140 |doi=10.1016/j.cretres.2015.10.014 |bibcode=2016CrRes..58..135B }}

;Dragonflies and damselflies (Odonata)

:The largest species of Odonata is the damselfly Megaloprepus caerulatus of the neotropics, attaining a size of as much as {{convert|19|cm|in|abbr=on}} across the wings and a body length of over {{convert|12|cm|in|abbr=on}}. The largest species of dragonfly is Tetracanthagyna plagiata of Southeast Asia, spanning up to {{convert|17.6|cm|in|abbr=on}} and measuring up to {{convert|11.8|cm|in|abbr=on}} long; while bulkier and heavier than Megaloprepus (at up to {{convert|7|g|oz|abbr=on}}), it is smaller in its linear dimensions.

;Grasshoppers and allies (Orthoptera)

File:knights.weta.750pix.jpg]]

:The largest of this widespread, varied complex of insects are the giant wetas of New Zealand, which is now split among 12 species. The largest of these is the Little Barrier Island giant weta (Deinacrida heteracantha), the largest specimen was weighed at {{convert|71.3|g|oz|abbr=on}}, one of the largest insect weights ever known. These heavyweight insects can be over {{convert|9|cm|in|abbr=on}} long. The largest grasshopper species is often considered to be the Australian giant grasshopper (Valanga irregularis), which ranges up to {{convert|9|cm|in|abbr=on}} in length.[http://www.brisbaneinsects.com/brisbane_grasshoppers/GiantGrassH.htm Giant Grasshoppers – The largest grasshopper – Valanga irregularis]. Brisbaneinsects.com The American eastern lubber grasshopper (Romalea guttata) can allegedly range up to {{convert|10|cm|in|abbr=on}} in length.[http://www.wildflorida.com/wildlife/insects/Eastern_Lubber_Grasshopper.php Eastern Lubber Grasshopper – Florida eco travel guide] {{Webarchive|url=https://web.archive.org/web/20241118022951/https://wildflorida.com/wildlife/insects/Eastern_Lubber_Grasshopper.php |date=18 November 2024 }}. Wildflorida.com However, the greatest grasshopper sizes known, to {{convert|12|cm|in|abbr=on}}, have been cited in the South American giant grasshopper (Tropidacris violaceus). The longest members of this order (although much lighter than the giant wetas) is the katydid Macrolyristes corporalis of Southeast Asia which can range up to {{convert|21.5|cm|in|abbr=on}} with its long legs extended and can have a wingspan of {{convert|20|cm|in|abbr=on}}.[http://www.hmns.org/cockerell-butterfly-center/our-residents/giant-long-legged-katydid/ Giant Long-Legged Katydid] {{Webarchive|url=https://web.archive.org/web/20160307194338/http://www.hmns.org/cockerell-butterfly-center/our-residents/giant-long-legged-katydid/ |date=7 March 2016}}. Hmns.org

;Stick insects (Phasmatodea)

:The longest known stick insects are also the longest known insects, notably species in the tribe Pharnaciini, but they are generally relatively lightweight because of their slender shape. The longest is an unnamed species of Phryganistria discovered in China in 2016, where a specimen held at the Insect Museum of West China in Chengdu has a total length of {{cvt|62.4|cm|in}}.{{cite web|url= http://news.xinhuanet.com/english/2016-05/05/c_135336786.htm |archive-url= https://web.archive.org/web/20160508170315/http://news.xinhuanet.com/english/2016-05/05/c_135336786.htm |url-status= dead |archive-date= 8 May 2016 |title=Longest Insect discovered in China}} The second-longest species is the Australian Ctenomorpha gargantua, females of which have been measured at over {{cvt|60|cm|in}} in total length.{{cite book |last1=Brock |first1=Paul D. |last2=Hasenpusch |first2=Jack W. |date=2009 |title=The Complete Field Guide to Stick and Leaf Insects of Australia |url=https://books.google.com/books?id=x1Qx40oGXJ8C |publisher=CSIRO Publishing |page=106 |isbn=9780643094185}} Other very large species, formerly believed to be longest but now considered third longest is Sadyattes chani; a specimen held in the Natural History Museum in London has a total length of {{cvt|56.7|cm|in}}.{{cite web|url= http://www.nhm.ac.uk/about-us/news/2008/october/worlds-longest-insect-revealed.html |title= World's longest insect revealed |accessdate=16 October 2008 |publisher=Natural History Museum |date=16 October 2008 |url-status=dead |archiveurl= https://web.archive.org/web/20081019104055/http://www.nhm.ac.uk/about-us/news/2008/october/worlds-longest-insect-revealed.html |archivedate=19 October 2008}}Seow-Choen, F. (1995). "The longest insect in the world". Malayan Nature Journal. 48: 12. These measurements are, however, with the front legs fully extended; it has a body length measuring {{cvt|35.7|cm|in}}.{{cite journal|author1=Hennemann, F.H. |author2=Conle, O.V. |name-list-style=amp |title=Revision of Oriental Phasmatodea: The tribe Pharnaciini Günther, 1953, including the description of the world's longest insect, and a survey of the family Phasmatidae Gray, 1835 with keys to the subfamilies and tribes (Phasmatodea: "Anareolatae": Phasmatidae) |journal=Zootaxa |volume=1906 |pages=1–316 |publisher=Magnolia Press |location=Auckland, New Zealand |issn=1175-5326|url= http://www.mapress.com/zootaxa/2008/f/z01906p316f.pdf |accessdate=16 October 2008 |date=October 2008|doi=10.11646/zootaxa.1906.1.1 }} Another very large species is Phobaeticus kirbyi where the total length (including extended legs) is up to {{cvt|54.6|cm|in}} and the body alone up to {{cvt|32.8|cm|in}}.Brock, P.D. 1999. The amazing world of stick and leaf-insects. Cravitz Printing Co., Essex, England. Another of the longest insect in terms of total length is Phobaeticus serratipes of Malaysia and Singapore, measuring up to {{convert|55.5|cm|in|abbr=on}}.{{Cite journal|last1 = Seow-Choen|first1 = F.|year = 1995|title = The longest insect in the world|journal = Malayan Nat.|volume = 48|page = 12}} Another extremely long stick insect is Pharnacia maxima, which measured {{convert|51|cm|in|abbr=on}} with its legs extended. The spiny stick insect (Heteropteryx dilatata) of Malaysia does not reach the extreme lengths of its cousins, the body reaching up to {{convert|16|cm|in|abbr=on}} long, but it is much bulkier. The largest Heteropteryx weighed about {{convert|65|g|oz|abbr=on}} and was {{convert|3.5|cm|in|abbr=on}} wide across the thickest part of the body.

;Stoneflies (Plecoptera)File:Pteronarcys californica 2544.jpg]]

:The largest species of stonefly is Pteronarcys californica of western North America, a species favored by fishermen as lures. This species can attain a length of {{convert|5|cm|in|abbr=on}} and a wingspan of over {{convert|9.5|cm|in|abbr=on}}.[http://blog.riverwoodfliesonline.com/?p=403 Pteronarcys californica – aka Giant Stonefly or Giant Salmonfly]. Riverwood Blog – Fly Fishing Gear & Guided Fishing Trips in Oregon (20 April 2009) {{webarchive |url=https://web.archive.org/web/20120402122239/http://blog.riverwoodfliesonline.com/?p=403 |date=2 April 2012 }}

;Caddisflies (Trichoptera)

:The largest of the small, moth-like caddisflies is Eubasilissa maclachlani. This species can range up to {{convert|7|cm|in|abbr=on}} across the wings.[http://www.diptera.info/forum/viewthread.php?thread_id=27607 Diptera. info – Discussion Forum: The LARGEST caddisfly of the world].

;Lice (Phthiraptera)

:These insects, which live parasitically on other animals, are as a rule quite small. The largest known species is the hog louse, Haematopinus suis, a sucking louse that lives on large livestock like pigs and cattle. It can range up to {{convert|6|mm|in|abbr=on}} in length.[http://animaldiversity.ummz.umich.edu/site/accounts/information/Haematopinus_suis.html ADW: Haematopinus suis: Information]. Animaldiversity.ummz.umich.edu

;Booklice (Psocoptera)

:The largest of this order of very small insects are the barklice of the genus Psocus, the top size of which is about {{convert|10|mm|in|abbr=on}}.[http://www.brc.ac.uk/schemes/barkfly/introduction.htm National Barkfly (Outdoor Psocoptera) Recording Scheme]. Brc.ac.uk

;Fleas (Siphonaptera)

:The largest species of flea is Hystrichopsylla schefferi. This parasite is known exclusively from the fur of the mountain beaver (Aplodontia rufa) and can reach a length of {{convert|12|mm|in|abbr=on}}.

;Thrips (Thysanoptera)

:Members of the genus Phasmothrips are the largest kinds of thrips. The maximum size these species attain is approximately {{convert|13|mm|in|abbr=on}} in length.[http://www.paulsquiz.com/biology-mainmenu-208/203-trivia-quiz-resources/42-biology/698-list-of-largest-insects List of largest insects]. Paulsquiz.com {{webarchive | url = https://web.archive.org/web/20150714170015/http://www.paulsquiz.com/biology-mainmenu-208/trivia-quiz-resources/biology/list-of-largest-insects |date=14 July 2015 }}

;Angel insects (Zoraptera)

:The largest angel insect species, Hubbard's angel insect (Zorotypus hubbardi), grows up to {{convert|3|mm|in|2|abbr=on}} in length.{{cite book|author1=Foottit, Robert G.|author2=Adler, Peter H.|title=Insect Biodiversity: Science and Society |url=https://books.google.com/books?id=5FhUDwAAQBAJ&pg=PA199 |year=2018 |publisher=Wiley |isbn=978-1-118-94560-5 |pages=199–207}}{{cite web |url=http://tolweb.org/Zoraptera |title=Zoraptera |author=Engel, Michael S.|year=2005 |publisher=Tree of Life Web Project |access-date=9 March 2019}}

;Silverfish and allies (Zygentoma)

:The largest extant silverfish is Acrotelsa collaris, at up to {{convert|18|mm|in|1|abbr=on}}.Molero-Baltanás R, Mitchell A, Gaju-Ricart M, Robla J. Worldwide revision of synanthropic silverfish (Insecta: Zygentoma: Lepismatidae) combining morphological and molecular data. J Insect Sci. 2024 May 1;24(3):1. doi: 10.1093/jisesa/ieae045. PMID: 38703100; PMCID: PMC11069193

File:Cyanea kils.jpg, one of the longest extant animals]]

The lion's mane jellyfish (Cyanea capillata) is the largest cnidarian species, of the class Scyphozoa. The largest known specimen of this giant, found washed up on the shore of Massachusetts Bay in 1870,[https://web.archive.org/web/20100530112100/http://www.waterford-today.ie/index.php?option=com_content&task=view&id=933&Itemid=10177&ed=68 Rare sighting of a lion's mane jellyfish in Tramore Bay]. waterford-today.ie{{cite web|url=http://www.jellyfishfacts.net/mane-jellyfish.html|title=Lion's Mane Jellyfish|website=jellyfishfacts.net|access-date=14 June 2017|archive-date=26 October 2020|archive-url=https://web.archive.org/web/20201026032804/http://www.jellyfishfacts.net/mane-jellyfish.html|url-status=dead}} had a bell diameter of {{convert|2.5|m|ft|abbr=on}}, a weight of {{convert|150|kg|lb|abbr=on}}. The tentacles of this specimen were as long as {{convert|37|m|ft|abbr=on}} and were projected to have a tentacular spread of about {{convert|75|m|ft|abbr=on}} making it one of the longest extant animals.

;Corals and sea anemones (Anthozoa)

:The largest individual species are the sea-anemones of the genus Discoma, which can attain a mouth disc diameter of {{convert|60|cm|ft|abbr=on}}.[http://www.northrup.org/photos/sea-anemone/ Sea Anemones, Sea Anemone Pictures] {{Webarchive|url=https://web.archive.org/web/20170116211002/http://www.northrup.org/photos/sea-anemone/ |date=16 January 2017 }}. Northrup.org Longer, but much less massive overall, are the anemones of the genus Ceriantharia, at up to {{convert|2|m|ft|abbr=on}} tall.[http://www.seawater.no/fauna/cnidaria/Ceriantharia.html Tube Anemones – Ceriantharia]. Seawater.no

Communities of coral can be truly massive, a single colony of the genus Porites can be over {{convert|10|m|ft|abbr=on}}, even though the individual polyps are quite small. In 2024, the largest ever was found off Malaulalo island in the Solomon Islands, a clonal colony of Pavona clavus over 32 by 34 meters — the size of two basketball courts.{{cite news |last1=Kuta |first1=Sarah |date=14 November 2024 |title=See Staggering Photos of the World's Largest Coral, Newly Discovered by Scientists in the Pacific Ocean |url=https://www.smithsonianmag.com/smart-news/see-staggering-photos-of-the-worlds-largest-coral-newly-discovered-by-scientists-in-the-pacific-ocean-180985474/ |work=Smithsonian |access-date=18 November 2024}}{{cite news |last1=Jones |first1=Benji |date=14 November 2024 |title=Scientists just discovered a sea creature as large as two basketball courts. Here's what it looks like. |url=https://www.vox.com/down-to-earth/384668/worlds-largest-coral-discovered-solomon-islands |work=Vox |access-date=18 November 2024}}

;Hydrozoans (Hydrozoa)

:The colonial siphonophore Praya dubia can attain lengths of {{convert|40|–|50|m|ft|abbr=on}}.[http://www.lifesci.ucsb.edu/~biolum/organism/pictures/praya.html Praya picture]. Lifesci.ucsb.edu The Portuguese man o' war's (Physalia physalis) tentacles can attain a length of up to {{convert|50|m|ft|abbr=on}}.[https://web.archive.org/web/20100118144115/http://animals.nationalgeographic.com/animals/invertebrates/portuguese-man-of-war Portuguese Man-of-Wars, Portuguese Man-of-War Pictures, Portuguese Man-of-War Facts]. Animals.nationalgeographic.com On 6 April 2020 the Schmidt Ocean Institute announced the discovery of a giant Apolemia siphonophore in submarine canyons near Ningaloo Coast, measuring {{convert|15|m|ft|abbr=off}} diameter with a ring approximately {{convert|47|m|ft|abbr=off}} long, claiming it was possibly the largest siphonophore ever recorded.{{Cite web|url=https://interestingengineering.com/longest-giant-stringy-sea-creature-ever-recorded-looks-like-it-belongs-in-outer-space|title=Longest Giant Stringy Sea Creature Ever Recorded Looks like It Belongs in Outer Space|date=9 April 2020|website=interestingengineering.com|language=en-US|access-date=10 April 2020}}{{cite news |author=Schmidt Ocean Institute |title=New species discovered during exploration of abyssal deep sea canyons off Ningaloo |url=https://www.eurekalert.org/pub_releases/2020-04/soi-nsd040920.php |date=9 April 2020 |work=EurekAlert! |access-date=12 April 2020 |archive-date=12 April 2020 |archive-url=https://web.archive.org/web/20200412013927/https://www.eurekalert.org/pub_releases/2020-04/soi-nsd040920.php |url-status=dead }} Stygiomedusa, {{efn|{{etymology|grc|Στύγιος (Stúgios)|Stygian,| |Μέδουσα (Médousa)|Medusa,| |γιγάντεια (gigánteia)|gigantic}}}} commonly known as the giant phantom jelly, is the only species in the monotypic genus of deep sea jellyfish, Stygiomedusa. It is in the Ulmaridae family.{{cite book |last=Browne |first=Edward T. |editor-last=Bell |editor-first=Jeffrey |date=1907 |title=Natural History: Voyage of the S.S. Discovery under Capt. R.F. Scott |chapter=Coelentera |series=Zoology and Botany |volume=5 |publisher=Biodiversity Heritage Library |oclc=727233164 |doi=10.5962/bhl.title.18281 |page=57 |url=https://www.biodiversitylibrary.org/page/17270097#254 |access-date=19 August 2015}} With only around 110 sightings in 110 years, it is rarely seen, but is believed to be widespread throughout the world, with the exception of the Arctic Ocean.{{Cite news|url=http://news.bbc.co.uk/earth/hi/earth_news/newsid_8638000/8638527.stm|title=Giant deep sea jellyfish filmed|date=23 April 2010|access-date=17 March 2019|language=en-GB}}{{cite journal |last1=Benfield |first1=Mark C. |last2=Graham |first2=William M. |title=In situ observations of Stygiomedusa gigantea in the Gulf of Mexico with a review of its global distribution and habitat |journal=Journal of the Marine Biological Association of the United Kingdom |date=September 2010 |volume=90 |issue=6 |pages=1079–1093 |doi=10.1017/S0025315410000536|bibcode=2010JMBUK..90.1079B |s2cid=85342580 }}{{cite web |title=Giant phantom jelly |work=MBARI |date=29 November 2021 |url=https://www.mbari.org/products/creature-feature/giant-phantom-jelly}}

;Box jellyfishes (Chirodropida)

:The largest box jellyfish Chironex fleckeri is the largest of the cubozoans (collectively called box jellyfish), many of which may carry toxic venom. Its bell usually reaches about {{cvt|16|cm}} in diameter but can grow up to {{cvt|35|cm}}.{{cite journal |last1=Hamner |first1=W. M. |last2=Jones |first2 = M. S. | last3 = Hamner | first3 = P. P. | title = Swimming, feeding, circulation and vision in the Australian box jellyfish, Chironex fleckeri (Cnidaria: Cubozoa) | journal = Marine and Freshwater Research |date=1995 | volume = 46 | issue = 7 | page = 985 | issn = 1323-1650 | doi = 10.1071/MF9950985 | pmid = | url = }} Each of the four corners of the bell trails a cluster of 15 tentacles. The pale blue bell has faint markings; viewed from certain angles, it bears a somewhat eerie resemblance to a human head or skull. Since it is virtually transparent, the creature is nearly impossible to see in its habitat, posing significant danger to swimmers.

File:Xestospongia muta 1.jpg is indeed an animal]]

The largest known species of sea sponge is the giant barrel sponge, Xestospongia muta. These massively built sponges can reach {{convert|8|ft|m|abbr=on|order=flip}} in height and can be about the same thickness at the thickest part of the "body".[http://www.care2.com/c2c/groups/disc.html?gpp=11767&pst=1376156 Biggest, Smallest, Fastest, Deepest: Marine Animal Records – Marine Biology: Life in the Ocean]. Care2.com (4 March 2009) Some of these creatures have been estimated to be over 2,400 years of age.[http://www.eol.org/pages/338183/overview Xestospongia muta]. Encyclopedia of Life.

;Calcareous sponges (Calcarea)

:The largest known of these small, inconspicuous sponges is probably the species Pericharax heteroraphis, attaining a height of {{convert|30|cm|ft|abbr=on}}. Most calcareous sponges do not exceed {{convert|10|cm|in|abbr=on}} tall.{{Citation needed|date=January 2021}}

;Hexactinellid sponges (Hexactinellida)

:A relatively common species, Rhabdocalyptus dawsoni, can reach a height of {{convert|1|m|ft|abbr=on}} once they are of a very old age.{{Cite Q|Q56915355 | last1 = Yahel | first1 = G. | last2 = Eerkes-Medrano | first2 = D. I. | last3 = Leys | first3 = S. P.|authorlink3=Sally Leys}} This is the maximum size recorded for a hexactinellid sponge.{{Citation needed|date=January 2021}}

• Largest prehistoric animals
• Megafauna
• Largest organisms

{{notelist}}

{{reflist}}

Animals

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Category:Heaviest or most massive organisms