SVP 2021 abstracts – 09: Dinosaur diversity missing? Still, no.

Napoli 2021 reports:
“A large suite of research is predicated upon the assumption that the incomplete fossil record is
representative of the actual diversity that existed in the past. Based on several lines of evidence, I argue that this assumption is unjustifiable.”

The LRT disagrees. Completely new taxa that don’t fit in the present tree are no longer being discovered and described.

“Approximately 1,300 species of non-avian dinosaurs are known from the entire Mesozoic Era. This diversity pales in comparison to that of modern diverse amniote clades. The mean species
richness of diverse, disparate amniote clades in the present is ~104, while an average of only 7 non-avian dinosaurs are known from any 1 Ma interval in the Mesozoic.”

That doesn’t matter. No weird taxa are showing up anymore. Only more species.

“The vast quantity of missing species in the fossil record is problematic for macroevolutionary and paleoecological research, as the influence of unknown taxa is unquantifiable and consistent with an infinite number of scenarios.”

We will always find new species. No two Pteranodon or Triceratops are alike.

“Field exploration and the discovery of new fossils remain critical components of paleontological research.”

Agree.

“As methods for morphological species delimitation improve, it is likely that collections of individuals currently referred to a single species will prove to represent assemblages of
multiple taxa, especially when the specimens come from a wide spatial or temporal distribution. As species are continually discovered, phylogenetic topologies will likely change considerably, particularly within clades that comprise mostly small taxa such as Paraves.”

Disagree. A good phylogenetic topology will not shift as species are added, except at the species level, not at the larger branches.

References
Napoli JG 2021. The missing diversity of the dinosaur fossil record. Journal of Vertebrate Paleontology abstracts.