Hemiauchenia#Hemiaucheia vera .28 .22True hemiauchenia.22.29

{{Automatic taxobox

| name = Hemiauchenia

| fossil_range = Mid Miocene – Late Pleistocene
c. {{fossil range|10.3 | 0.012}}

| image = Hemiauchenia macrocephala FLMNH.jpg

| image_upright =

| image_caption = Reconstructed H. macrocephala skeleton, Florida Museum of Natural History

| taxon = Hemiauchenia

| authority = Gervais & Ameghino, 1880

| subdivision_ranks = Species

| subdivision = *H. macrocephala (Cope, 1893)

H. minima (Leidy, 1886)
H. blancoensis (Meade,1945)
H. vera (Matthew, 1909)
H. paradoxa (Gervais & Ameghino, 1880)
H. seymourensis
H. edensis
H. guanajuatensis
H. mirim Greco et al., 2022

| synonyms = Tanupolama Stock 1928

Holomeniscus Cope 1884

}}

Hemiauchenia{{Cite web |url=https://paleobiodb.org/classic/checkTaxonInfo?taxon_no=42528 |title=Paleobiology Database - Hemiauchenia basic info |access-date=2009-11-15 |archive-date=2012-10-16 |archive-url=https://web.archive.org/web/20121016051513/http://paleodb.org/cgi-bin/bridge.pl?action=checkTaxonInfo&taxon_no=42528&is_real_user=1 |url-status=live }} is a genus of lamine camelids that evolved in North America in the Miocene period about 10 million years ago. This genus diversified and entered South America in the Late Pliocene about three to two million years ago, as part of the Great American Biotic Interchange. The genus became extinct at the end of the Pleistocene. The monophyly of the genus has been considered questionable, with phylogenetic analyses finding the genus to paraphyletic or polyphyletic, with some species suggested to be more closely related to living lamines (llamas and relatives) than to other Hemiauchenia species.{{Cite journal |last=Scherer |first=Carolina Saldanha |date=March 2013 |title=The Camelidae (Mammalia, Artiodactyla) from the Quaternary of South America: Cladistic and Biogeographic Hypotheses |url=http://link.springer.com/10.1007/s10914-012-9203-4 |journal=Journal of Mammalian Evolution |language=en |volume=20 |issue=1 |pages=45–56 |doi=10.1007/s10914-012-9203-4 |issn=1064-7554|url-access=subscription }}{{Cite journal |last1=Lynch |first1=Sinéad |last2=Sánchez-Villagra |first2=Marcelo R. |last3=Balcarcel |first3=Ana |date=December 2020 |title=Description of a fossil camelid from the Pleistocene of Argentina, and a cladistic analysis of the Camelinae |journal=Swiss Journal of Palaeontology |language=en |volume=139 |issue=1 |page=5 |doi=10.1186/s13358-020-00208-6 |issn=1664-2376 |pmc=7590954 |pmid=33133011 |doi-access=free |bibcode=2020SwJP..139....8L }}

This genus gave rise to the genus Lama, of which modern lamines belong to.

Broad features of genus ''Hemiauchenia''

The genus name is derived from the {{langx|grc|ἡμι-}} ({{transliteration|grc|hēmi-}}, "half"-){{LSJ|h(mi^|ἡμι-|ref}} and αὐχήν ({{transliteration|grc|auchēn}}, "neck").{{LSJ|au)xh/n|αὐχήν|ref}}{{refn|These are used to form a feminine noun to mean "half-neckedness" or "half-carrying the neck"; cf. {{lang|grc|ὑψηλαυχενία}}, ({{transliteration|grc|hypsēlauchenía}}, "carrying the neck high").{{LSJ|u(yhlauxeni/a|ὑψηλαυχενία|ref}}|group="nb"}} Species are specified using Latin adjectives or Latinised names from other languages.

= North American fossils =

File:Rattlesnake Formation Mural.jpg fleeing a volcanic eruption]]

Remains of these species have been found in assorted locations around North America, including Florida, Texas, Kansas, Nebraska, Arizona, Mexico, California, Oklahoma, New Mexico, Oregon, Colorado, and Washington.{{cite web |last1=Hulbert Jr. |first1=Richard C. |last2=Valdes |first2=Natali |title=Hemiauchenia macrocephala |url=https://www.floridamuseum.ufl.edu/florida-vertebrate-fossils/species/hemiauchenia-macrocephala/ |website=Florida Museum |publisher=Florida Museum of Natural History |access-date=16 May 2021 |date=June 6, 2015}}{{Cite web|last=Heckert|first=Andrew B. Ph D.|title=Pliocene (latest Hemphillian and Blancan) vertebrate fossils from the Mangas Basin, southwestern New Mexico|url=https://libres.uncg.edu/ir/asu/listing.aspx?id=4718|access-date=2022-01-17|website=libres.uncg.edu}}

The "large-headed llama", H. macrocephala, was widely distributed in North and Central America, with H. vera being known from the western United States and northern Mexico. H. minima has been found in Florida, and H. guanajuatensis in Mexico.{{Cite journal

| last = Ruez

| first = D. R.

| authorlink =

| title = Earliest Record of Palaeolama (Mammalia, Camelidae) with Comments on "Palaeolama" guanajuatensis

| journal = Journal of Vertebrate Paleontology

| volume = 25

| issue = 3

| pages = 741–744

| publisher = Society of Vertebrate Paleontology

| date = 2005-09-30

| jstor = 4524496

| issn =

| doi = 10.1671/0272-4634(2005)025[0741:eropmc]2.0.co;2

| s2cid = 86522528

}}

H. macrocephala gave rise to modern lamines (guanacos, vicuñas, and their domesticated forms) when a population migrated southward towards South America.{{Cite journal |last=Meachen |first=Julie A. |date=2005-12-31 |title=A New Species of Hemiauchenia (Artiodactyla, Camelidae) from the Late Blancan of Florida |journal=Bulletin of the Florida Museum of Natural History |publisher=University Press of Florida |volume=45 |issue=4 |pages=435–448 |doi=10.58782/flmnh.stwk6834}}{{Cite book |last=Cowie |first=Helen |url=https://books.google.com/books?id=CGkwDwAAQBAJ&pg=PA10 |title=Llama |date=2017-05-15 |publisher=Reaktion Books |isbn=978-1-78023-786-2 |pages=10 |language=en}}{{Cite book |last=Defler |first=Thomas |url=https://books.google.com/books?id=-HWADwAAQBAJ&pg=PA266HL=EN |title=History of Terrestrial Mammals in South America: How South American Mammalian Fauna Changed from the Mesozoic to Recent Times |date=2018-12-19 |publisher=Springer |isbn=978-3-319-98449-0 |pages=266–267 |language=en}}

= South American fossils =

File:Hemiauchenia paradoxa.png, H. paradoxa]]

Fossils of Hemiauchenia in South America are restricted to the Pleistocene and have been found in the Luján and Agua Blanca Formations of Buenos Aires Province and Córdoba Province, Argentina, the Tarija Formation of Bolivia, Pilauco of Osorno, Los Lagos, Chile and Paraíba, Ceará, and the Touro Passo Formation of Rio Grande do Sul, Brazil.[https://paleobiodb.org/classic/checkTaxonInfo?taxon_no=42528 Hemiauchenia] at Fossilworks.org Hemiauchenia paradoxa is suggested to have been a browser.{{Cite journal |last1=Lopes |first1=Renato Pereira |last2=Scherer |first2=Carolina Saldanha |last3=Pereira |first3=Jamil Corrêa |last4=Dillenburg |first4=Sérgio Rebello |date=July 2023 |title=Paleoenvironmental changes in the Brazilian Pampa based on carbon and oxygen stable isotope analysis of Pleistocene camelid tooth enamel |url=https://onlinelibrary.wiley.com/doi/10.1002/jqs.3502 |journal=Journal of Quaternary Science |language=en |volume=38 |issue=5 |pages=702–718 |doi=10.1002/jqs.3502 |bibcode=2023JQS....38..702L |issn=0267-8179|url-access=subscription }}

Distinguishing characteristics of members of ''Hemiauchenia''

= ''H. vera'' =

Relatively low-crowned teeth (part of visible teeth ends close to gums)
Large caniniform (canine-like) upper first premolar
Retention of lower third premolar

= ''H. blancoensis'' =

Named for Blancan Age stratum where typically found
Shorter mandibular diastema (teeth-spacing between incisors and molars) than H. macrocephala and H. vera
Caniniform upper first premolar
Absent second premolar
Upper third premolar present or absent
Lower crowned molars

= ''H. macrocephala'' =

File:Hemiauchenia macrocephala skull.png

Possesses a larger skull relative to other species
Long, robust limbs
Large skeletal size
Presence of a deciduous upper second premolar
Fully molariform deciduous second premolar (its infant bicuspids were like molars)
High-crowned molars
Thick layer of cementum on the teeth
Broad mandibular symphysis (line where the bones of the jaw join together) with incisors in a vertical fashion

Thought to have been browsers{{Cite journal |last1=Marín-Leyva |first1=Alejandro Hiram |last2=Delgado-García |first2=Sabrina |last3=García-Zepeda |first3=María Luisa |last4=Arroyo-Cabrales |first4=Joaquín |last5=López-García |first5=J. Ramón |last6=Plata-Ramírez |first6=Ramón Adrián |last7=Meléndez-Herrera |first7=Esperanza |date=2023-06-03 |title=Environmental inferences based on the dietary ecology of camelids from west-central Mexico during the Late Pleistocene |url=https://www.tandfonline.com/doi/full/10.1080/08912963.2022.2073822 |journal=Historical Biology |language=en |volume=35 |issue=6 |pages=1011–1027 |doi=10.1080/08912963.2022.2073822 |bibcode=2023HBio...35.1011M |issn=0891-2963|url-access=subscription }} and mixed feeders.{{Cite journal |last1=Semprebon |first1=Gina M. |last2=Rivals |first2=Florent |date=September 2010 |title=Trends in the paleodietary habits of fossil camels from the Tertiary and Quaternary of North America |url=https://linkinghub.elsevier.com/retrieve/pii/S0031018210003202 |journal=Palaeogeography, Palaeoclimatology, Palaeoecology |language=en |volume=295 |issue=1–2 |pages=131–145 |doi=10.1016/j.palaeo.2010.05.033|bibcode=2010PPP...295..131S |url-access=subscription }} Suggested to be less closely related to modern Lama and Vicugna than H. paradoxa is.

Native to the southern United States, spanning from California to Florida,Grayson, D. K. 1994. The extinct Late Pleistocene mammals of the Great Basin. Pages 55–85 in Natural history of the Colorado Plateau and Great Basin ( K. T. Harper, J. L. ST. Clair, K. H. Thorne, and W. M. Hess, editors). University Press of Colorado, Niwot. and as far north as Nebraska. Also present in Mexico.

= ''H. minima'' =

File:Hemiauchenia minima limb FLMNH.jpg

Despite being the earliest recognized species, general distinguishing characteristics for H. minima are little known.

= Other species =

File:Hemiauchenia edensis toe bone FLMNH.jpg

Also, a few lesser known species, such as H. paradoxa, H. seymourensis, H. edensis and H. guanajuatensis, have been found. Depending on which source is consulted, these may or may not be considered legitimate taxa.{{citation needed|date=August 2017}}

Classification history

Prior to 1974, fossil specimens now thought to be Hemiauchenia were classified as Holomeniscus, Lama, and Tanupolama, until S. David Webb proposed that these North and South American fossil species were part of a single genus.{{cite web|title=Hemiauchenia macrocephala|publisher=University of Florida, Florida Museum of Natural History|url=https://www.floridamuseum.ufl.edu/florida-vertebrate-fossils/species/hemiauchenia-macrocephala/|access-date=23 May 2016}} This has been accepted by all subsequent researchers, although in 2013, Carolina Saldanha Scherer questioned the inclusion of a certain North American species and suggested that Hemiauchenia is paraphyletic.

Diet

Over the Pliocene and Pleistocene, Hemiauchenia was an intermediate feeder that preferred browsing with a hypsodont dentition.{{Cite journal |last=Feranec |first=Robert S. |date=Spring 2003 |title=Stable isotopes, hypsodonty, and the paleodiet of Hemiauchenia (Mammalia: Camelidae): a morphological specialization creating ecological generalization |url=https://www.cambridge.org/core/journals/paleobiology/article/abs/stable-isotopes-hypsodonty-and-the-paleodiet-of-hemiauchenia-mammalia-camelidae-a-morphological-specialization-creating-ecological-generalization/5D9461E1DDB39CF43D43F03F470A439F |journal=Paleobiology |language=en |volume=29 |issue=2 |pages=230–242 |doi=10.1666/0094-8373(2003)029<0230:SIHATP>2.0.CO;2 |issn=0094-8373 |access-date=6 May 2024 |via=Cambridge Core|url-access=subscription }} According to δ¹³C analyses of H. paradoxa teeth from the Touro Passo and Santa Vitória Formations of Brazil, H. paradoxa was primarily a grazer of C₃ grasses.{{Cite journal |last1=Carrasco |first1=Thayara S. |last2=Scherer |first2=Carolina S. |last3=Ribeiro |first3=Ana Maria |last4=Buchmann |first4=Francisco S. |date=12 April 2022 |title=Paleodiet of Lamini camelids (Mammalia: Artiodactyla) from the Pleistocene of southern Brazil: insights from stable isotope analysis (δ 13 C, δ 18 O) |url=https://www.cambridge.org/core/journals/paleobiology/article/abs/paleodiet-of-lamini-camelids-mammalia-artiodactyla-from-the-pleistocene-of-southern-brazil-insights-from-stable-isotope-analysis-13c-18o/30203E033D9182B1824BCD676BA313DC |journal=Paleobiology |language=en |volume=48 |issue=3 |pages=513–526 |doi=10.1017/pab.2022.10 |bibcode=2022Pbio...48..513C |issn=0094-8373 |access-date=5 May 2024 |via=Cambridge Core|url-access=subscription }}