Rahiolisaurus
{{Short description|Genus of abelisaurid dinosaur from the Late Cretaceous period}}
{{Italic title}}
{{Use dmy dates|date=November 2024}}
{{speciesbox
| image= Rahiolisaurus restoration.png
| image_caption= Life restoration of Rahiolisaurus gujaratensis
| name = Rahiolisaurus
| fossil_range =
Late Cretaceous, {{fossil range|70|66}}
| genus = Rahiolisaurus
| display_parents=3
| parent_authority = Novas et al., 2010
| species = gujaratensis
| authority = Novas & Chatterjee et al., 2010
}}
Rahiolisaurus is a genus of abelisaurid theropod dinosaur which existed in India during the Late Cretaceous period. It was described in 2010, based on fossils recovered from the Lameta Formation in the Indian state of Gujarat. These fossils include elements from at least seven different individuals and are believed to have been from the Maastrichtian stage, sometime between 70 and 66 million years ago, making it one of the last non-avian dinosaurs known in the fossil record. Despite representing a variety of different growth stages, all recovered fossils from the locality indicate a single species, the type species Rahiolisaurus gujaratensis.
Discovery and naming
{{Location map|India
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|coordinates={{coord|23.1|N|73.3|E|display=inline}}
|caption= Rahiolisaurus type locality in Kakda Kho, Rahioli village, Gujarat, India
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}}
During two expeditions, one in 1995 and the other in 1997, numerous remains of abelisaurids were recovered from a single quarry 50 square metres in area. The collected remains included cervical, dorsal, sacral, and caudal vertebrae, portions of pectoral and pelvic girdles, and several hind limb bones. Because of the unearthing of seven differently sized right tibiae, it was suggested that the assemblage was formed by at least seven individuals of different ontogenetic stages. Within the collection were several duplicate bones, such as the ilia, pubes, femora and tibiae, that exhibited similar morphological features of typical abelisauroid traits. However, despite these remains being of different size gradation and representing growth series, hardly any taxonomic variation was discovered. It was interpreted by Novas et al. that the entire theropod collection from this quarry may be referred to the single species Rahiolisaurus.
File:Kakda Kho 02.jpg, in which the remains of Rahiolisaurus were found]]
Individual bones of the newly discovered abelisaurid was given separate catalogue numbers. The holotype of Rahiolisaurus is represented by a partial association of pelvic elements and a femur that were found in the field. It consists of a right ilium (ISIR 550), a right pubis (ISIR 554), and a right femur (ISIR 557). In addition, an axis (ISIR 658) was found in articulation with cervicals 3 (ISIR 659) and 4 (ISIR 660) and are attributed to the species. These bones are currently housed at the collection of the Geology Museum, Indian Statistical Institute, Kolkata.
Rahiolisaurus was named after the village of Rahioli, located near the fossil site where the dinosaurs remains were discovered. The specific name, gujaratensis, means "from Gujarat" in Latin.
Description
Rahiolisaurus was initially described as a large-sized abelisaurid and around {{convert|8|m|ft}} long and weighing {{convert|2|MT|ST}},{{cite book|last=Paul|first=G. S.|author-link=Gregory S. Paul|year=2010|title=The Princeton Field Guide to Dinosaurs|publisher=Princeton University Press|pages=[https://archive.org/details/princetonfieldgu0000paul/page/84 84–86]|isbn=978-0-691-13720-9|title-link=The Princeton Field Guide to Dinosaurs}} but the allometry-based estimate for different specimens suggest a shorter body length of {{convert|6.22|-|6.75|m|ft}}.{{cite journal |last1 = Grillo | first1 = O. N. | last2 = Delcourt | first2 = R. |date = 2016 | title = Allometry and body length of abelisauroid theropods: Pycnonemosaurus nevesi is the new king | journal = Cretaceous Research | volume = 69 | pages = 71–89 | doi = 10.1016/j.cretres.2016.09.001| bibcode = 2017CrRes..69...71G }} It shares many similarities with another Indian abelisaurid, Rajasaurus, but includes differences such as an overall more gracile and slender-limbed form.Novas, Fernando E., Chatterjee, Sankar, Rudra, Dhiraj K., Datta, P.M. (2010). "[https://doi.org/10.1007%2F978-3-642-10311-7_3 Rahiolisaurus gujaratensis, n. gen. n. sp., A New Abelisaurid Theropod from the Late Cretaceous of India]" in: Saswati Bandyopadhyay (ed.): New Aspects of Mesozoic Biodiversity. Springer Berlin / Heidelberg. pp. 45–62. {{doi|10.1007/978-3-642-10311-7}}. {{ISBN|978-3-642-10310-0}}. Abelisaurids typically had four fingers, short arms, and, to compensate, a heavily constructed head which was the primary tool for hunting; however, the skull was short, they probably had modest jaw musculature, and the teeth were short. Abelisaurids likely had a bite force similar to Allosaurus at around {{convert|3500|N|lbf}}.{{cite journal|first=R.|last=Delcourt|year=2018|title=Ceratosaur Palaeobiology: New Insights on Evolution and Ecology of the Southern Rulers|journal=Scientific Reports|volume=8|issue=9730|page=9730 |doi=10.1038/s41598-018-28154-x|pmc=6021374|pmid=29950661|bibcode=2018NatSR...8.9730D }}
Classification
In 2014, the subfamily Majungasaurinae was erected by palaeontologist Thierry Tortosa to separate the newly discovered European Arcovenator, Majungasaurus, Indosaurus, Rahiolisaurus, and Rajasaurus from South American abelisaurids based on physical characteristics such as elongated antorbital fenestrae in front of the eye sockets, and a sagittal crest that widens into a triangular surface towards the front of the head. In more recent analyses Rahiolisaurus as appeared as being more closely related to the South American abelisaurids, further strengthening the faunal similarities between India and South America in the mesozoic.
The following cladogram was recovered by Tortosa (2014):{{cite journal| doi=10.1016/j.annpal.2013.10.003 | volume=100 | title=A new abelisaurid dinosaur from the Late Cretaceous of southern France: Palaeobiogeographical implications | journal=Annales de Paléontologie | pages=63–86| year=2014 | last1=Tortosa | first1=T. | last2=Buffetaut | first2=E. | last3=Vialle | first3=N. | last4=Dutour | first4=Y. | last5=Turini | first5=E. | last6=Cheylan | first6=G. | issue=1 | bibcode=2014AnPal.100...63T }}
{{clade| style=font-size:100%; line-height:100%
|label1=Ceratosauria
|1={{clade
|1=Ceratosaurus File:Ceratosaurus_nasicornis_DB.jpg
|2=Noasauridae
|3={{clade
|label1=Abelisauridae
|1={{clade
|1={{clade
|label1=Carnotaurinae
|1={{clade
|1=Carnotaurus File:Carnotaurus_DB_2_white_background.jpg
|2=Abelisaurus
}}
}}
|2={{clade
|label1=Majungasaurinae
|1={{clade
|1=Rajasaurus File:Rajasaurus_restoration.jpg
|2=Majungasaurus File:Majungasaurus_BW_(flipped).jpg
|3=Indosaurus
|4=Rahiolisaurus
|5=Arcovenator File:Arcovenator.jpg
}} }} }} }} }} }}
A phylogeny from 2018 recovered Rahiolisaurus as forming a clade with the Madagascan abelisaurid Dahalokely within majungasaurinae.{{Cite journal |last=Delcourt |first=Rafael |date=June 2018 |title=Ceratosaur palaeobiology: New insights on evolution and ecology of the southern rulers |url=https://www.researchgate.net/publication/326017886 |url-status=live |journal=Scientific Reports |volume=8 |issue=1 |page=9730 |doi=10.1038/s41598-018-28154-x |pmid=29950661 |pmc=6021374 |bibcode=2018NatSR...8.9730D |archive-url=https://web.archive.org/web/20221109055615/https://www.researchgate.net/publication/326017886_Ceratosaur_palaeobiology_New_insights_on_evolution_and_ecology_of_the_southern_rulers |archive-date=9 November 2022 |via=ResearchGate}} Only the phylogenies for Abelisauridae is depicted here.
{{clade| style=font-size:100%; line-height:100%
|label1=Abelisauridae
|1={{clade
|2={{clade
|1=Abelisaurus 15px
|2={{clade
|1=Ilokelesia 15px
|label2=Carnotaurinae
|2={{clade
|label1=Majungasaurinae
|1={{clade
|1=Arcovenator 15px
|2={{clade
|1=Indosaurus 15px
|3=Rajasaurus
}}
|3={{clade
|1=Dahalokely 15px
|2=Rahiolisaurus 15px
}} }}
|label2=Brachyrostra
|2={{clade
|1={{clade
}}
|label2=Furileusauria
|2={{clade
|1=Viavenator 15px
|3=Quilmesaurus 15px
|4={{clade
|1=Carnotaurus 15px
|2=Aucasaurus 15px
}} }} }} }} }} }} }} }}
In 2021, Rahiolisaurus and Dahalokely were again recovered as sister taxa, however they were placed outside of majungasaurinae as basal brachyrostrans.{{Cite journal |last1=Gianechini |first1=Federico A. |last2=Méndez |first2=Ariel H. |last3=Filippi |first3=Leonardo S. |last4=Paulina-Carabajal |first4=Ariana |last5=Juárez-Valieri |first5=Rubén D. |last6=Garrido |first6=Alberto C. |date=10 December 2020 |title=A new furileusaurian abelisaurid from La Invernada (Upper Cretaceous, Santonian, Bajo de la Carpa Formation), northern Patagonia, Argentina |url=https://www.tandfonline.com/doi/full/10.1080/02724634.2020.1877151 |journal=Journal of Vertebrate Paleontology |language=en |volume=40 |issue=6 |pages=e1877151 |doi=10.1080/02724634.2020.1877151 |bibcode=2020JVPal..40E7151G |issn=0272-4634 |access-date=13 June 2024 |archive-date=13 June 2024 |archive-url=https://web.archive.org/web/20240613061213/https://www.tandfonline.com/doi/full/10.1080/02724634.2020.1877151 |url-status=live |url-access=subscription }}
{{Clade|{{clade
|2={{clade
|2={{clade
|label1=Majungasaurinae
|1={{clade
|1={{clade
|1=Genusaurus 15px
|2=Arcovenator 15px }}
|2={{clade
|1=Rajasaurus 15px 70px
|2=Indosaurus 15px
|3=Majungasaurus 15px 70px}} }}
|label2= Brachyrostra
|2={{clade
|2={{clade
|1={{clade
|1=Dahalokely 15px
|2=Rahiolisaurus 15px }}
|2={{clade
|1={{clade
|1=Ilokelesia 15px
|2={{clade
|2=Skorpiovenator 15px 70px}} }}
|label2=Furileusauria
|2={{clade
|3=Quilmesaurus 15px 70px
|4=Viavenator 15px 70px
|label5=Carnotaurini
|5={{clade
|1=Carnotaurus 15px 70px
|2={{clade
|1=Aucasaurus 15px 70px
|2=Abelisaurus 15px }} }} }} }} }} }} }} }} }}|label1=Abelisauridae}}
Palaeoecology
Rahiolisaurus has been found in the Lameta Formation, a rock unit radiometrically dated to the Maastrichtian age of the latest Cretaceous representing an arid or semi-arid landscape with a river flowing through it–probably providing shrub cover near the water–which formed between episodes of volcanism in the Deccan Traps.{{cite journal|first1=M. E.|last1=Brookfield|first2=A.|last2=Sanhi|year=1987|title=Palaeoenvironments of the Lameta beds (late Cretaceous) at Jabalpur, Madhya Pradesh, India: Soils and biotas of a semi-arid alluvial plain|journal=Cretaceous Research|volume=8|issue=1|pages=1–14|doi=10.1016/0195-6671(87)90008-5|bibcode=1987CrRes...8....1B }}{{cite journal|first=D. M.|last=Mohabey|year=1996|title=Depositional environment of Lameta Formation (late Cretaceous) of Nand-Dongargaon inland basin, Maharashtra: the fossil and lithological evidences|journal=Memoirs of the Geological Survey of India|volume=37|pages=1–36}} Rahiolisaurus likely inhabited what is now the Narmada River Valley. The formation is known for being a sauropod nesting site, yielding several dinosaur eggs, and sauropod herds likely chose sandy soil for nesting;{{cite journal|first1=S. K.|last1=Tandon|first2=A.|last2=Sood|first3=J. E.|last3=Andrews|first4=P. F.|last4=Dennis|year=1995|title=Palaeoenvironments of the dinosaur-bearing Lameta Beds (Maastrichtian), Narmada Valley, Central India|journal=Palaeogeography, Palaeoclimatology, Palaeoecology|volume=117|issue=3–4|pages=153–184|doi=10.1016/0031-0182(94)00128-U|bibcode=1995PPP...117..153T |url=http://doc.rero.ch/record/15457/files/PAL_E1623.pdf }} though eggs belonging to large theropods have been found, it is unknown if they belong to Rahiolisaurus.{{Cite news|author=Lovgren, S.|date=13 August 2003|title= New Dinosaur Species Found in India|url=https://news.nationalgeographic.com/news/2003/08/0812_030812_indiadinosaur.html|archive-url=https://web.archive.org/web/20031211084950/http://news.nationalgeographic.com/news/2003/08/0812_030812_indiadinosaur.html|url-status=dead|archive-date=11 December 2003|work=National Geographic News|access-date=8 April 2009}} Sauropod coprolite remains indicate they lived in a forested landscape, consuming plants such as Podocarpus, Araucaria, and Cheirolepidiaceae conifers; cycads; palm trees; early grass; and Caryophyllaceae, Sapindaceae, and Acanthaceae flowering plants.{{cite journal|first1=H.|last1=Sonkusare|first2=B.|last2=Samant|first3=D. M.|last3=Mohabey|year=2017|title=Microflora from Sauropod Coprolites and Associated Sedimentsof Late Cretaceous (Maastrichtian) Lameta Formation of Nand-Dongargaon Basin, Maharashtra|journal=Geological Society of India|volume=89|issue=4|pages=391–397|url=https://www.researchgate.net/publication/315814360|doi=10.1007/s12594-017-0620-0|bibcode=2017JGSI...89..391S |s2cid=135418472 }}
Several dinosaurs have been described from the Lameta Formation, such as the noasaurid Laevisuchus; abelisaurids Indosaurus, Indosuchus, Lametasaurus, and Rajasaurus; and the titanosaurian sauropods Jainosaurus, Titanosaurus, and Isisaurus. The diversity of abelisauroid and titanosaurian dinosaurs in Cretaceous India indicates they shared close affinities to the dinosaur life of the other Gondwanan continents, which had similar inhabitants.{{cite book |last1=Weishampel |first1=D. B. |first2=P. M.|last2=Barrett |first3=R.|last3=Coria |first4=J.|last4=Le Loeuff |first5=Z.|last5=Xijin |first6=X.|last6=Xing |first7=A.|last7=Sahni |first8=E. M. P.|last8=Gomani|first9=C. R.|last9=Noto|chapter=Dinosaur Distribution |editor1-first=D. B.|editor1-last=Weishampel |editor2-first=P.|editor2-last=Dodson |editor3-first=H.|editor3-last=Osmólska |title=The Dinosauria |url=https://archive.org/details/dinosauriandedit00weis |url-access=limited |edition=2nd |year=2004|publisher=University of California Press |location=Berkeley |isbn=978-0-520-24209-8 |page=[https://archive.org/details/dinosauriandedit00weis/page/n613 595]}} Dinosaurs in India probably went extinct due to volcanic activity around 350,000 years before the Cretaceous–Paleogene boundary. They likely avoided areas with volcanic fissure vents and lava flows.{{cite journal|first1=D. M.|last1=Mohabey|first2=B.|last2=Samant|year=2013|title=Deccan continental flood basalt eruption terminated Indian dinosaurs before the Cretaceous–Paleogene boundary|journal=Geological Society of India Special Publication|number=1|pages=260–267|url=https://www.researchgate.net/publication/263733418}}
See also
References
{{Reflist|30em}}
{{Theropoda|B.}}
{{Taxonbar|from=Q134070}}
Category:Maastrichtian dinosaurs
Category:Taxa named by Fernando Novas
Category:Taxa named by Sankar Chatterjee