Diminutive temnospondyls from the lower and middle Fremouw Formation (Lower Triassic) of Antarctica

Temnospondyls were one of the most geographically widespread and abundant tetrapod clades in non-marine settings for much of the late Paleozoic and early Mesozoic. Because of their ubiquity, they frequently occur in relatively depauperate or undersampled regions and thus often serve as important datapoints for biostratigraphy and paleoenvironmental inference. Temnospondyls were among the first tetrapods to be recovered from the Lower-Middle Triassic Fremouw Formation of Antarctica and remain one of the most commonly identified clades, but the overall characterization of the assemblages still lags behind the more extensive coeval records from the Karoo Basin of South Africa and coeval basins of Australia. The informal middle unit of the Fremouw Formation, in turn, has been historically undersampled relative to the lower and upper units. Recent collecting efforts in the 2017/18 austral summer recovered appreciable tetrapod material, including the remains of numerous small-bodied temnospondyls. We describe this material in full, documenting the occurrence of the relict dissorophoid Micropholis stowi, previously recorded from the lower Fremouw Formation and which supports a correlation of the middle Fremouw with part of the Lystrosaurus declivis Assemblage Zone, as well as numerous immature capitosaurs, which represent some of the smallest known specimens of the clade and thus contribute valuable data on the earliest ontogenetic stages in this primarily large-bodied clade.