Untangling basal dinosaur interrelationships

Lovegrove, Upchurch and Barrett 2024 stated,
“Our goal is to evaluate the key barriers preventing a consensus on early dinosaur phylogeny, and to identify the lines of research that are likely to overcome these barriers.”

Hopefully the authors created their own cladogram and added more taxa than prior workers (listed in their Introduction). The paper is unread, behind a paywall/.

“… many aspects of the clade’s early evolutionary history remain shrouded in mystery, due to a paucity of Middle and Late Triassic fossil sites, the rarity of early dinosaur fossils, and disagreements over the relationships of many early-occurring taxa.”

By contrast, there’s no shroud of mystery here in
the large reptile tree (LRT, 2319 taxa) which found relatively little problem (compared to other more difficult clades) with the origin and radiation of dinosaurs.

The twin problems for all prior dinosaur papers are simple:
1. too few relevant outgroup taxa,  and
2. too many irrelevant outgroup taxa.

Figure 2. Tested taxa in the LRT nesting in the Phytodinosauria. ” data-image-caption=”

Figure 2. Tested taxa in the LRT nesting in the Phytodinosauria.

” data-medium-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2022/01/phytodinosauria2022-588.jpg?w=88″ data-large-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2022/01/phytodinosauria2022-588.jpg?w=299″ class=”size-full wp-image-64386″ src=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2022/01/phytodinosauria2022-588.jpg” alt=”Figure 2. Tested taxa in the LRT nesting in the Phytodinosauria.” width=”584″ height=”1997″ />

Figure 1. Tested taxa in the LRT nesting in the Phytodinosauria about a decade ago.

Cherry-picking #1: Relevant taxon omission
All prior workers omitted long lists of Poposauria and Crocodylomorpha, which are the two proximal outgroups to the Dinosauria in the LRT. Both include basal bipeds and derived quadreupeds, as in the Dinosauria. Workers also seem adverse to admitting the presence of the Phytodinosauria (= Ornithisichia + Sauropoda and their sometimes carnivorous ancestors that are not members of Theropoda).

Figure 3. Subset of the LRT focusing on Crocodylomorpha. The new nestings represent just the latest of a changing hypothesis of interrelationships. ” data-image-caption=”

Figure 3. Subset of the LRT focusing on Crocodylomorpha. The new nestings represent just the latest of a changing hypothesis of interrelationships.

” data-medium-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2023/08/crocodylomorpha2023.jpg?w=249″ data-large-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2023/08/crocodylomorpha2023.jpg?w=584″ class=”size-full wp-image-80902″ src=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2023/08/crocodylomorpha2023.jpg” alt=”Figure 3. Subset of the LRT focusing on Crocodylomorpha. The new nestings represent just the latest of a changing hypothesis of interrelationships.” width=”584″ height=”704″ />

Figure 2. Subset of the LRT focusing on Crocodylomorpha. The new nestings represent just the latest of a changing hypothesis of interrelationships.

Cherry-picking #2: Irrelevant taxon inclusion
The addition of Lagerpeton relatives and pterosaurs to dinosaur studies has been falsified by the LRT. Neither are closely related, yet workers seem bent on their inclusion.

Don’t trust the consensus
Consensus = trust ≠ science. Find out for yourself. Build your own LRT.

Make a discovery or two.

References
Lovegrove J, Upchurch P and Barrett PM 2024. Untangling the tree or unraveling the consensus? Recent developments in the quest to resolve the broad-scale relationships within Dinosauria. Journal of Systematic Palaeontology 22(1): online abstract.

wiki/Dinosauria