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.<ref name=AZ>{{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 }}</ref> 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.<ref name=":0">{{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|bibcode=2019JSPal..17.1533G |s2cid=91780191|issn=1477-2019}}</ref> 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.<ref name=":1">{{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}}</ref>

''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.<ref>Other known fossil snakes with developed hindlimbs, ''Haasiophis'', ''Pachyrhachis'' and ''Eupodophis''—all found in marine environments—all lack a sacral region.</ref> Nearly all phylogenetic analyses place ''Najash'' as an early offshoot of the snake tree, outside of all living snakes.<ref name="AZ" /><ref name=":0" /><ref name=":1" /><ref>{{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 }}</ref>

== Ecology == The cranial morphology of ''Najash'' suggests that it had only limited unilateral movements of the mandibles, and lacked the attributes of macrostomatan snakes to ingest large prey, Apesteguía suggests, presumably based on the associated fauna, that this snake preyed on a variety of small vertebrates, such as ‘lizards’, micro-mammals and dinosaur hatchlings. This assumption is well supported by the snake body size.<ref>{{Cite journal|author=Adriana M. Albino|name-list-style=amp|year=2011|title=Evolution of Squmata Reptiles in Patagonia based on the fossil record|journal=Biological Journal of the Linnean Society|volume=103|issue=2|pages=441–457|doi=10.1111/j.1095-8312.2011.01691.x }}</ref>

== References == {{Reflist}}

==External links== *[http://photos1.blogger.com/hello/297/8739/1024/060419_snake_hips_02.jpg Pelvic region of a ''Najash'' fossil]

Category:Ophidia Category:Late Cretaceous reptiles of South America Category:Candeleros Formation Category:Fossil taxa described in 2006 Category:Cretaceous Argentina Category:Taxa named by Hussam Zaher