Aaron Dyer

A troodontid with a pathologic metatarsal Iifts its foot towards its face to investigate. The pathologic bone is highlighted and features a red line to indicate where a thin section was taken. The thin section appears as aarge imags behind the troodontid, the troodontid's tail passing through the central medullary cavity.

Published yesterday in @journalofanatomy.bsky.social with open access, we demonstrate how tiny slices of isolated bones (in this case, troodontid metatarsals) can provide a wealth of information on the growth, lifestyle, and injuries of these animals. (🧵) (Troodontid art by Henry Sharpe )

Skeletal reconstruction of UALVP 2, the most complete specimen of Stegoceras validum, after Gilmore (1924).

Anatomical description and digital reconstruction of the skull of Jeholosaurus shangyuanensis (Dinosauria, Ornithopoda) from China Ornithopod dinosaurs appeared during the Middle Jurassic, but it was in the Lower Cretaceous they started their successful evolutionary history. Different phylogenies describing the evolutionary relat...

Bertozzo F, Kecheng N, Gillette NV, Godefroit P (2025) Anatomical description and digital reconstruction of the skull of Jeholosaurus shangyuanensis (Dinosauria, Ornithopoda) from China. PLoS ONE 20(1): e0312519. doi.org/10.1371/jour...

A. Danison et al. (2024)
Chimerism in specimens referred to Saurophaganax maximus reveals a new species of Allosaurus (Dinosauria, Theropoda)
Vertebrate Anatomy Morphology Palaeontology 12(1): 81-114
doi: doi.org/10.18435/vam...
journals.library.ualberta.ca/vamp/index.p...

I typed too quickly, even I need a correction!. Lambe 1918 named S. brevis (CMN 1423). S. browni (AMNH 5450) was named by Wall and Galton (1979).

Lambe (1902) named S. validum from two figured specimens (and one unfigured). No type specimen was selected.

Lambe (1918) then split those two figured specimens into separate species, designating CMN 1423 as the holotype of S. browni, and leaving CMN 515 to be the lectotype of S. validum.

Top left and middle left: CMN 515, the lectotype of Stegoceras validum (Lambe 1902)

A common misconception, UALVP 2 is not the holotype of Stegoceras validum. While it remains the most complete specimen, it was described 22 years after Lambe named S. validum. In fact, there is no holotype!

Individual, ontogenetic, and phylogenetic variation in the dentition of hadrosaurids (Iguanodontia: Ornithischia) Phylogenetic analyses of Hadrosauroidea are generally well-resolved, but finer resolution within Hadrosauromorpha remains contentious. This lack of resolution is due in part to the inability of dis...

Glad to see our latest work on hadrosaur teeth is out today!

Gill Gallimore, David Evans, and I did a deep dive into whether hadrosaur teeth are as useful as they seem in phylogenetics. A thread [1/14]
dx.doi.org/10.1080/1477...

Finally set up a Blue Sky account in time for #FossilFriday! Hey all, I'm wrapping up my MSc on centrosaurines while searching for a PhD or museum position (visa life). In the meantime, enjoy this pretty Centrosaurus skull from our collections, the articulated neck is stuck right under the frill.