Najash
{{Short description|Extinct genus of snakes}}
{{Automatic taxobox
| fossil_range = Late Cretaceous, {{fossilrange|90}}
| image = Boli-ischi 100.jpg
| image_caption = Sacral region of the holotype of the “legged snake” Najash rionegrina
| taxon = Najash
| authority = Apesteguía & Zaher, 2006
| type_species = Najash rionegrina
| type_species_authority = Apesteguía & Zaher, 2006
}}
Najash is an extinct genus of basal snake from the Late Cretaceous Candeleros Formation of Patagonia.{{cite journal |last1=Apesteguía |first1=S. |first2=H. |last2=Zaher |year=2006 |title=A Cretaceous terrestrial snake with robust hindlimbs and a sacrum |journal=Nature |volume=440 |issue=7087 |pages=1037–1040 |doi=10.1038/nature04413 |pmid=16625194 |bibcode=2006Natur.440.1037A |s2cid=4417196 }} Like a number of other Cretaceous and living snakes it retained hindlimbs, but Najash is unusual in having well-developed legs that extend outside the rib cage, and a pelvis connected to the spine.
Discovery and description
Fossils of Najash were found in the terrestrial Candeleros Formation, in Rio Negro Province, Argentina, and date to roughly 90 million years ago. The skull and spine of Najash show primitive features that resemble other Cretaceous snakes, such as Dinilysia patagonica and Madtsoiidae.{{Cite journal|last1=Garberoglio|first1=Fernando F.|last2=Gómez|first2=Raúl O.|last3=Apesteguía|first3=Sebastián|last4=Caldwell|first4=Michael W.|last5=Sánchez|first5=María L.|last6=Veiga|first6=Gonzalo|date=2019-02-04|title=A new specimen with skull and vertebrae of Najash rionegrina (Lepidosauria: Ophidia) from the early Late Cretaceous of Patagonia|journal=Journal of Systematic Palaeontology|volume=17|issue=18|language=en|pages=1313–1330|doi=10.1080/14772019.2018.1534288|s2cid=91780191|issn=1477-2019}} Also, several characteristics of the neck and tail of Najash and Dinilysia patagonica show how the body plan of snakes evolved from a lizard-like ancestor.{{Cite journal|last1=Garberoglio|first1=Fernando F.|last2=Gómez|first2=Raúl O.|last3=Simões|first3=Tiago R.|last4=Caldwell|first4=Michael W.|last5=Apesteguía|first5=Sebastián|date=2019|title=The evolution of the axial skeleton intercentrum system in snakes revealed by new data from the Cretaceous snakes Dinilysia and Najash|journal=Scientific Reports|language=en|volume=9|issue=1|page=1276|doi=10.1038/s41598-018-36979-9|pmid=30718525|issn=2045-2322|pmc=6362196|bibcode=2019NatSR...9.1276G}}
Najash had not lost its sacrum, the pelvic bone composed of several fused vertebrae, nor its pelvic girdle, which are absent in modern snakes, and in all other known fossil snakes as well.Other known fossil snakes with developed hindlimbs, Haasiophis, Pachyrhachis and Eupodophis—all found in marine environments—all lack a sacral region. Nearly all phylogenetic analyses place Najash as an early offshoot of the snake tree, outside of all living snakes.{{cite journal |last1=Longrich |first1=N. R. |first2=B.-A. S. |last2=Bhullar |first3=Jacques A. |last3=Gauthier |display-authors=2 |year=2012 |title=A transitional snake from the Late Cretaceous period of North America |journal=Nature |volume=488 |issue=7410 |pages=205–208 |doi=10.1038/nature11227 |pmid=22832579 |bibcode=2012Natur.488..205L |s2cid=4411744 |url=http://opus.bath.ac.uk/37338/3/00_Tetrapodophis_Science.pdf }}
See also
{{Portal|Paleontology}}
References
{{Reflist}}
External links
- [http://photos1.blogger.com/hello/297/8739/1024/060419_snake_hips_02.jpg Pelvic region of a Najash fossil]
{{Fossil snakes}}
{{Taxonbar|from=Q2720361}}
Category:Late Cretaceous reptiles of South America
Category:Fossil taxa described in 2006
{{Paleo-snake-stub}}