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Abstract A vast array of pseudosuchian body plans evolved during the diversification of the group in the Triassic Period, but few can compare to the toothless, long‐necked, and bipedal shuvosaurids. Members of this clade possess theropod‐like character states mapped on top of more plesiomorphic pseudosuchian character states, complicating our understanding of the evolutionary history of the skeleton. One taxon in this clade,Shuvosaurus inexpectatushas been assigned to various theropod dinosaur groups based on a partial skull and referred material and its postcranium was assigned to a different taxon in Pseudosuchia. After the discovery of a skeleton of a shuvosaurid with aShuvosaurus‐like skull and a pseudosuchian postcranial skeleton, it became clearShuvosaurus inexpectatuswas a pseudosuchian. Nevertheless, a number of questions have arisen about what skeletal elements belonged toShuvosaurus inexpectatus, the identification of skull bones, and the resulting implication for pseudosuchian evolution. Here, we detail the anatomy of the skeletonShuvosaurus inexpectatusthrough a critical lens, parse out the bones that belong to the taxon or those that clearly do not or may not belong to the taxon, rediagnose the taxon based on these revisions, and compare the taxon to other archosaurs. We find thatShuvosaurus inexpectatuspossesses similar anatomy to other shuvosaurids but parts of the skeleton of the taxon clarifies the anatomy of the group given that they are preserved inShuvosaurus inexpectatusbut not in others.Shuvosaurus inexpectatusis represented by at least 14 individuals from the West Texas Post Quarry (Adamanian holochronozone) and allShuvosaurus inexpectatusskeletal material from the locality pertains to skeletally immature individuals. All of the skeletons are missing most of the neural arches, ribs, and most of the forelimb. We only recognizeShuvosaurus inexpectatusfrom the Post Quarry and all other material assigned to the taxon previously is better assigned to the broader group Shuvosauridae.
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This content will become publicly available on January 31, 2026
Anatomy and revised diagnosis of the embolomere Calligenethlon watsoni from Joggins, Nova Scotia, based on micro-computed tomography
Abstract Although Calligenethlon watsoni, an enigmatic embolomere from Joggins, Nova Scotia, has been known since 1934, an in-depth description of its anatomy (including CT data) and updated taxonomic diagnosis has yet to be completed. Additionally, subsequently discovered embolomere specimens have been referred to the taxon simply if they display embolomere traits. As a result, Calligenethlon is represented by a collection of specimens united on the basis of largely non-diagnostic traits. Here, the exquisitely preserved specimen identified as Calligenethlon, NSM 994GF1.1, is described in detail using micro-computed tomography. Comparison of this specimen to the holotype supports its referral to Calligenethlon and the anatomical knowledge gained here allows for the generation of a more robust morphological diagnosis of the genus Calligenethlon. We then re-evaluate all other referred specimens to determine which are consistent with their referral to the taxon, and which are inconclusively referred to the taxon. These data are discussed as they provide new insights into the anatomy of Calligenethlon and the diversity of embolomeres at the Joggins’ locality.
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- Award ID(s):
- 2209043
- PAR ID:
- 10579943
- Publisher / Repository:
- Oxford University Press on behalf of the Linnean Society
- Date Published:
- Journal Name:
- Zoological Journal of the Linnean Society
- Volume:
- 203
- Issue:
- 2
- ISSN:
- 0024-4082
- Subject(s) / Keyword(s):
- Carboniferous computed-tomography Embolomeri Joggins Nova Scotia tetrapod
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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