''Nagini'' (from

Sanskrit Sanskrit (; attributively , ; nominally , , ) is a classical language belonging to the Indo-Aryan branch of the Indo-European languages. It arose in South Asia after its predecessor languages had diffused there from the northwest in the late ...

'' Nāgá'', "snake") is an extinct genus of

recumbirostra Recumbirostra is a clade of tetrapods which lived during the Carboniferous and Permian periods. They are thought to have had a fossorial (burrowing) lifestyle and the group includes both short-bodied and long-bodied snake-like forms. At least one ...

tetrapod Tetrapods (; ) are four-limbed vertebrate animals constituting the superclass Tetrapoda (). It includes extant and extinct amphibians, sauropsids ( reptiles, including dinosaurs and therefore birds) and synapsids (pelycosaurs, extinct theraps ...

s from the middle

Carboniferous The Carboniferous ( ) is a geologic period and system of the Paleozoic that spans 60 million years from the end of the Devonian Period million years ago ( Mya), to the beginning of the Permian Period, million years ago. The name ''Carbonifero ...

of the Mazon Creek fossil beds,

Illinois Illinois ( ) is a U.S. state, state in the Midwestern United States, Midwestern United States. Its largest metropolitan areas include the Chicago metropolitan area, and the Metro East section, of Greater St. Louis. Other smaller metropolita ...

, United States. The type and only species, ''Nagini mazonense'', was named by Arjan Mann and colleagues in 2022 from two specimens, both of which preserve soft tissue like other fossils from Mazon Creek: MPM VP359229.2 and FMNH PR 1031. It is a member of the Molgophidae, a lineage of amniote-like tetrapods which exhibited a pattern of body elongation and digit reduction on the limbs. ''Nagini'' is the first member of the group that shows the complete loss of the forelimbs and pectoral girdle, but it still has intact hindlimbs; this mirrors the pattern seen in the evolution of snakes, and suggests that molgophids underwent a similar mechanism of limb reduction beginning with the failure to form distinct forelimbs.

References

Lysorophians Moscovian life Pennsylvanian tetrapods of North America Paleontology in Illinois Fossil taxa described in 2022 {{Carboniferous-animal-stub