Simões et al. 2020 brings us their study
on the rates of evolutionary change in reptiles with a diapsid skull architecture.
From the abstract:
“The origin of phenotypic diversity among higher clades is one of the most fundamental topics in evolutionary biology. However, due to methodological challenges, few studies have assessed rates of evolution and phenotypic disparity across broad scales of time to understand the evolutionary dynamics behind the origin and early evolution of new clades. Here, we provide a total-evidence dating approach to this problem in diapsid reptiles. We find major chronological gaps between periods of high evolutionary rates (phenotypic and molecular) and expansion in phenotypic disparity in reptile evolution. Importantly, many instances of accelerated phenotypic evolution are detected at the origin of major clades and body plans, but not concurrent with previously proposed periods of adaptive radiation. Furthermore, strongly heterogenic rates of evolution mark the acquisition of similarly adapted functional types, and the origin of snakes is marked by the highest rates of phenotypic evolution in diapsid history.”
This study suffers from taxon exclusion
By adding taxa the first dichotomy of the Reptilia (Amniota is a junior synonym) splits taxa closer to lepidosaurs (Lepidosauromorpha) from those closer to archosaurs (Archosauromorpha, including Synapsida). Thus members of the traditional clade ‘Diapsida’ are convergent. Other than through the last common ancestor of all Reptiles, Silvanerpeton in the Viséan, archosaurs are not related to lepidosaurs. The present paper by Simões et al. 2020 fails to recover this topology due to taxon exclusion. Without a valid phylogenetic context, the results are likewise hobbled.
References
Simões TR, Vernygora O, Caldwell MW and Pierce SE 2020. Megaevolutionary dynamics and the timing of evolutionary innovation in reptiles. Nature Communications 11: 3322.
