Fabanychus, new drepanosauromorph from Late Triassic of Arizona
137 views
Skip to first unread message
Ben Creisler
Oct 23, 2025, 12:22:26 PMOct 23
to DinosaurMa...@googlegroups.com
Ben Creisler
A new paper:
Fabanychus monos gen. et sp. nov.
Megan P. Sodano, Ben T. Kligman, Adam D. Marsh, Adam C. Pritchard, Michelle R. Stocker, William G. Parker, Gabriel S. Gonçalves & Sterling J. Nesbitt (2025)
Gross anatomy and histological analysis of manual unguals of Drepanosauromorpha (Sauropsida: Diapsida) and description of a new taxon from the Sonsela Member of the Chinle Formation (Late Triassic) of the southwestern United States
The Anatomical Record (advance online publication)
doi: https://doi.org/10.1002/ar.70057
https://anatomypubs.onlinelibrary.wiley.com/doi/10.1002/ar.70057
Unguals (“claws”) are important tools that allow terrestrial vertebrates to navigate their environments, from subduing prey to climbing, running, and digging, with the shape of the element being broadly correlated with their ecological niche. Middle Triassic-Late Triassic drepanosauromorphs (Sauropsida: Diapsida) have been hypothesized to occupy various niches and functional modes from arboreality to fossoriality based on a range of evidence including claw anatomy. Hypertrophied manual unguals are present in many members of Drepanosauromorpha and vary in shape from the strongly curved, mediolaterally compressed, and dorsoventrally tall Drepanosaurus-like forms to the shallowly curved and mediolaterally wide unguals of Skybalonyx. Here, we detail and compare the external and internal features of western North American drepanosauromorph unguals. Using osteohistology and micro-computed X-ray tomography, we find that drepanosauromorph manual unguals possess a combination of characteristics that differentiate drepanosauromorph taxa. Using external and internal characteristics, we identify a new taxon of drepanosauromorph, Fabanychus monos gen. et sp. nov., from the upper Sonsela Member of the Upper Triassic Chinle Formation (~214 Ma) at Petrified Forest National Park in northeastern Arizona. More broadly, we find that drepanosauromorph manual unguals share a set of unique character states compared to other extant and extinct reptilian and mammalian unguals. Each drepanosauromorph ungual morphotype is diagnostic to a distinct taxon, revealing biostratigraphic patterns of the clade. The spatiotemporal and lithostratigraphic occurrence of drepanosauromorphs in equatorial Pangaea reveal a long record of the group, co-occurring taxa, and possible genus-level turnover in the middle Norian (~215 Ma).
====
Fabanychus monos gen. et sp. nov.
Megan P. Sodano, Ben T. Kligman, Adam D. Marsh, Adam C. Pritchard, Michelle R. Stocker, William G. Parker, Gabriel S. Gonçalves & Sterling J. Nesbitt (2025)
Gross anatomy and histological analysis of manual unguals of Drepanosauromorpha (Sauropsida: Diapsida) and description of a new taxon from the Sonsela Member of the Chinle Formation (Late Triassic) of the southwestern United States
The Anatomical Record (advance online publication)
doi: https://doi.org/10.1002/ar.70057
https://anatomypubs.onlinelibrary.wiley.com/doi/10.1002/ar.70057
Unguals (“claws”) are important tools that allow terrestrial vertebrates to navigate their environments, from subduing prey to climbing, running, and digging, with the shape of the element being broadly correlated with their ecological niche. Middle Triassic-Late Triassic drepanosauromorphs (Sauropsida: Diapsida) have been hypothesized to occupy various niches and functional modes from arboreality to fossoriality based on a range of evidence including claw anatomy. Hypertrophied manual unguals are present in many members of Drepanosauromorpha and vary in shape from the strongly curved, mediolaterally compressed, and dorsoventrally tall Drepanosaurus-like forms to the shallowly curved and mediolaterally wide unguals of Skybalonyx. Here, we detail and compare the external and internal features of western North American drepanosauromorph unguals. Using osteohistology and micro-computed X-ray tomography, we find that drepanosauromorph manual unguals possess a combination of characteristics that differentiate drepanosauromorph taxa. Using external and internal characteristics, we identify a new taxon of drepanosauromorph, Fabanychus monos gen. et sp. nov., from the upper Sonsela Member of the Upper Triassic Chinle Formation (~214 Ma) at Petrified Forest National Park in northeastern Arizona. More broadly, we find that drepanosauromorph manual unguals share a set of unique character states compared to other extant and extinct reptilian and mammalian unguals. Each drepanosauromorph ungual morphotype is diagnostic to a distinct taxon, revealing biostratigraphic patterns of the clade. The spatiotemporal and lithostratigraphic occurrence of drepanosauromorphs in equatorial Pangaea reveal a long record of the group, co-occurring taxa, and possible genus-level turnover in the middle Norian (~215 Ma).
====
Mickey Mortimer
Dec 1, 2025, 4:07:07 PM (6 days ago) Dec 1
to Dinosaur Mailing Group
This paper also provides support to Cau's idea the supposed Bissekty theropod phalanges ZIN PH 2644/16 and 2645/16 belong to turtles instead. If you compare their Figure 10k of Chelydra's manual ungual cross section with Averianov's (2025) Figure 3a, the shape and internal structure are basically identical. The theropod ungual in Sodano et al.'s Figure 10o is quite different. It's enough for me to say Cau is probably correct.
Mickey Mortimer
Reply all
Reply to author
Forward
0 new messages