Phylogenetic data for: Upside down: ‘Cryobatrachus’ and the lydekkerinid record from Antarctica ...

• Main Author: Gee, Bryan M.
• Format: Dataset
• Language: English
• Published: Dryad 2021
• Subjects: Temnospondyli; Lydekkerinidae; Antarctica; Capitosauroidea; Triassic; Fremouw Formation; FOS: Biological sciences; Antarctic; Colbert; The Antarctic; Antarc*
• Online Access: https://dx.doi.org/10.5061/dryad.j3tx95xfm; https://datadryad.org/stash/dataset/doi:10.5061/dryad.j3tx95xfm

Temnospondyl amphibians are a common component of non-marine Triassic assemblages, including in the Fremouw Formation (Lower to Middle Triassic) of Antarctica. Temnospondyls were among the first tetrapods to be collected from Antarctica, but their record from the lower Fremouw Formation has long been tenuous. One taxon, ‘Austrobrachyops jenseni,’ is represented by a type specimen comprising only a partial pterygoid, which is now thought to belong to a dicynodont. A second taxon, ‘Cryobatrachus kitchingi,’ is represented by a type specimen comprising a nearly complete skull, but the specimen is only exposed ventrally, and uncertainty over its ontogenetic maturity and some aspects of its anatomy has led it to be designated as a nomen dubium by previous workers. Here we redescribe the holotype of ‘C. kitchingi,’ an undertaking that is augmented by tomographic analysis. Most of the original interpretations and reconstructions cannot be substantiated, and some are clearly erroneous. Although originally classified ... : We analyzed both specimens separately in the most recent version of Schoch's (2013) temnospondyl-wide matrix (Schoch et al., 2020). This matrix was selected because of its wide taxonomic coverage, which mitigates any preconceived notions of taxonomic affinities (e.g., to Stereospondyli). We omitted the lissamphibians and lepospondyls included in the original matrix since the question of lissamphibian origins is irrelevant to the position of the Antarctic temnospondyls discussed here. Two OTUs were scored for AMNH FARB 9503: one based on the interpretations of Colbert and Cosgriff (1974) and one based on our revised interpretations. We also added several small-bodied Triassic stereospondyls that share some features with these specimens: the rhinesuchid Broomistega putterilli Shishkin and Rubidge, 2000 (Broom, 1930; Shishkin and Rubidge, 2000); the rhytidosteid Nanolania anatopretia (Yates, 2000); the putative rhytidosteid Laidleria gracilis Kitching, 1958 (Warren,1998b; Dias-da-Silva and Marsicano, 2011); the ...