Tim Williams wrote- "If _Changmiania_ is a fossorial/burrowing ornithopod, then it suggests this behavior is primitive for Ornithopoda; this is because the next outgroup (Orodrominae) also comprises fossorial burrowers (as the paper makes clear)."
Not necessarily. It takes the same number of steps if Changmiania and orodromids (shouldn't that family have been called Orodromeidae?) evolve burrowing convergently (2 steps) than if their common ancestor evolves it then other ornithopods reverse it
(2 steps).
"Parksosaurinae should be Hypsilophodontidae, because it includes _Hypsilophodon_. There is already a family Hypsilophodontidae available, and has been for donkey's years (it goes back to Dollo, 1882)."
And Iguanodontia needs to be defined with Iguanodon bernissartensis as an internal specifier instead of as "all ornithopods more closely related to Parasaurolophus walkeri than to Hypsilophodon foxii or Thescelosaurus neglectus" (Phylocode Article 11.10).
Mickey Mortimer
On Wed, Sep 9, 2020 at 12:59 AM Ben Creisler <bcreisler@gmail.com> wrote:
Ben Creisler
A new paper with free pdf:
Changmiania liaoningensis gen. et sp. nov.
Yuqing Yang, Wenhao Wu, Paul-Emile Dieudonné & Pascal Godefroit (2020)
A new basal ornithopod dinosaur from the Lower Cretaceous of China.
PeerJ 8:e9832
doi: https://doi.org/10.7717/peerj.9832
https://peerj.com/articles/9832/
A new basal ornithopod dinosaur, based on two nearly complete articulated skeletons, is reported from the Lujiatun Beds (Yixian Fm, Lower Cretaceous) of western Liaoning Province (China). Some of the diagnostic features of Changmiania liaoningensis nov. gen., nov. sp. are tentatively interpreted as adaptations to a fossorial behavior, including: fused premaxillae; nasal laterally expanded, overhanging the maxilla; shortened neck formed by only six cervical vertebrae; neural spines of the sacral vertebrae completely fused together, forming a craniocaudally-elongated continuous bar; fused scapulocoracoid with prominent scapular spine; and paired ilia symmetrically inclined dorsomedially, partially covering the sacrum in dorsal view. A phylogenetic analysis places Changmiania liaoningensis as the most basal ornithopod dinosaur described so far. It is tentatively hypothesized that both Changmiania liaoningensis specimens were suddenly entrapped in a collapsed underground burrow while they were resting, which would explain their perfect lifelike postures and the complete absence of weathering and scavenging traces. However, further behavioural inference remains problematic, because those specimens lack extensive sedimentological and taphonomic data, as it is also the case for most specimens collected in the Lujiatun Beds so far.