Kammerer et al. 2020 bring us news of a
Lagerpeton-like (Fig. 2) ‘tiny ornithodiran archosaur’ from Mid-Late Triassic of Madagascar. What little is known of Kongonaphon (Fig. 1) might have stood 10 cm tall, according to the authors.
From the PNAS significance paragraph:
“Reptiles of the Mesozoic Era are known for their remarkable size: dinosaurs include the largest known land animals, and their relatives, the pterosaurs, include the largest creatures to ever fly. The origins of these groups are poorly understood, however.”
No. This is a traditional myth.
The origins of both groups are well known. In the large reptile tree (LRT, 1707 taxa) the origins of dinosaurs and the completely separate origins of pterosaurs are well documented back to Cambrian chordates.
From the abstract
“Early members of the dinosaur–pterosaur clade Ornithodira are very rare in the fossil record, obscuring our understanding of the origins of this important group. Small ancestral body size suggests that the extreme rarity of early ornithodirans in the fossil record owes more to taphonomic artifact than true reflection of the group’s evolutionary history.”
Fossils should be rare
because a dinosaur-pterosaur clade ‘Ornithodira” is invalid. When taxa are added dinosaurs arise from archosaurs. Pterosaurs arise from lepidosaurs. Their last common ancestor is the last common ancestor of all reptiles, Silvanerpeton, from the Early Carboniferous. That makes ‘Ornithodira’ a junior synonym of ‘Reptilia’.
From the abstract
“Kongonaphon is recovered as a member of the Triassic ornithodiran clade Lagerpetidae, expanding the range of this group into Africa and providing data on the craniodental morphology of lagerpetids.”
Funny thing is
Lagerpeton and kin are not related to dinosaurs OR pterosaurs. They are related to Tropidosuchus (Fig. 2) and the Proterochampsidae (Fig. 2). These authors, despite their PhDs, are painfully unaware of reptile systematics. All they need to do is add taxa to come to an understanding.
That miniaturization preceded the origin
of pterosaurs, dinosaurs, turtles, snakes, reptiles, mammals, birds and almost every other major clade has been well known for years.
Kammerer CF, Nesbitt SJ, Flynn JJ, Ranivoharimanana L and Wyss AR 2020. A tiny ornithodiran archosaur from the Triassic of Madagascar and the role of miniaturization in dinosaur and pterosaur ancestry. PNAS https://doi.org/10.1073/pnas.1916631117