SVP 2018: Junggarsuchus µCT scans

Ruebenstahl and Clark 2018
pull new data from the basalmost crocodylomorph, Junggarsuchus (Fig. 1) using µCT scans. They consider it a sphenosuchian nesting uneasily deep within Crocodylomorpha. I hope they test it with basal bipedal crocs listed in the large reptile tree (LRT, 1315 taxa, subset Fig. 3). PVL 4597 is a LRT sister that will provide clues to the hind quarters of Junggarsuchus, currently missing.

Figure 8. The CAPPA specimen of Buriolestes compared to the more primitive Junggarsuchus, basal to the other branch of archosaurs, the crocs.

Figure 1 The CAPPA specimen of Buriolestes (a dinosaur) compared to the more primitive Junggarsuchus, basal to the other branch of archosaurs, the crocs.

The authors report, “In addition to braincase characters, we also identify a unique morphology in the palate and pterygoid of Junggarsuchus, which, although similar to the condition in other sphenosuchians, has several aspects that are unlike anything reported in any ‘sphenosuchians’, including a far reaching anterior process of the pterygoid.” A similar pterygoid is found in the basal dinosaur, Herrerasaurus (Fig. 2) and the poposaur, Silesaurus.

Figure 1. The basalmost dinosaur, Herrerasaurus. Note the palate and the long pterygoid.

Figure 2. The basalmost dinosaur, Herrerasaurus. Note the palate and the long pterygoid.

Ruebenstahl and Clark 2018
provide no indication that they understand the close relationship of Junggarsuchus to basal dinosaurs, basal poposaurs and Decuriasuchus. If the authors only see croc interrelationships it’s time to add taxa.

Figure 2. Subset of the LRT focusing on Crocodylomorpha (basal Archosauria) including Armadillosuchus.

Figure 3. Subset of the LRT focusing on Crocodylomorpha (basal Archosauria) including Armadillosuchus.

References
Ruebenstahl AA and Clark JM 2018. Junggarsuchus sloani: a transitional ‘sphenosuchian’ and the evolution of the crocodilian skull.” SVP abstracts.

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