From Newsgroup: sci.bio.paleontology
https://www.nature.com/articles/s41586-025-09566-y (open access)
Mosaic anatomy in an early fossil squamate
Abstract
Squamates (lizards and snakes) comprise almost 12,000 living species,
with wide
ecological diversity and a crown group that originated around 190
million years ago1,2
.
Conflict between morphology and molecular phylogenies indicates a complex pattern of anatomical transformations during early squamate evolution, which remains poorly understood owing to the scarcity of early fossil taxa1,3.
Here we present
Breugnathair elgolensis gen. et sp. nov., based on a new skeleton from
the Middle
Jurassic epoch (167 million years ago) of Scotland, which is among the
oldest relatively
complete fossil squamates. Breugnathair is placed in a new family, Parviraptoridae,
an enigmatic group with potential importance for snake origins, that was previously
known from very incomplete remains. It displays a mosaic of anatomical
traits that
is not present in living groups, with head and body proportions similar
to varanids
(monitor lizards) and snake-like features of the teeth and jaws,
alongside primitive
traits shared with early-diverging groups such as gekkotans.
Phylogenetic analyses
of multiple datasets return conflicting results, with parviraptorids
either as early
toxicoferans (and potentially stem snakes) or as stem squamates that convergently
evolved snake-like dental and mandibular traits related to feeding.
These findings
indicate high levels of homoplasy and experimentation during the initial radiation
of squamates and highlight the potential importance of convergent morphological
transformations during deep evolutionary divergences.
Squamates evidentky diverged in the Triassic, but fossils are rare.
This new find (from the Jurrasic) gives a glimpse of stem squamates.
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