Cryobatrachus

Cryobatrachus (from Greek, (krýos, "cold") and (batrakhos, "frog")) is an extinct genus of temnospondyl amphibian from the Early Triassic of Antarctica. The type species is Cryobatrachus kitchingi. It is known from a partial skull and an imprint of the skull roof, both found in the Fremouw Formation of the Transantarctic Mountains at about 85° south latitude and described in 1974. Many small bone fragments have also been identified, although they cannot be attributed with certainty to C. kitchingi. Cryobatrachus has been classified in the family Lydekkerinidae, as it is similar in appearance to the genus Lydekkerina from South Africa. Because only a small number of features distinguish it from other lydekkerinids, Cryobatrachus kitchingi has more recently been considered a nomen dubium, meaning that its distinction from other better-known species may be unwarranted.

==Discovery and specimens== left|thumb|James Kitching, the discoverer of Cryobatrachus and the namesake of its type species, C. kitchingi Fossils of Cryobatrachus were first found by South African paleontologist James Kitching in the austral summer of 1971–72 as part of an expedition headed by the Institute for Polar Studies at Ohio State University, now known as the Byrd Polar Research Center. Paleontologists Edwin Harris Colbert of the American Museum of Natural History and John Cosgriff of Wayne State University described these fossils in 1974, positing the new genus and species Cryobatrachus kitchingi with the specific name honoring Kitching. All specimens were uncovered from the lower part of the Fremouw Formation, which dates back to the Early Triassic. The holotype specimen, cataloged as AMNH 9503, is a partial skull with the ventral surface of the dermal bones present. The palate and braincase are not preserved. An additional paratype specimen called AMNH 9556 includes an impression of the skull roof, but no preserved bones. AMNH 9503 was found on Kitching Ridge (which is also named after James Kitching) near Shackleton Glacier, and AMNH 9556 was found on Mount Kenyon near McGregor Glacier. Two crushed skulls from Kitching Ridge were also considered possible specimens of Cryobatrachus, as was part of an upper jaw from Halfmoon Bluff (which is on the opposite side of Shackleton Glacier as Kitching Ridge). Colbert and Cosgriff tentatively attributed six smaller fragments from Coalsack Bluff to Cryobatrachus, including parts of lower jaw, the clavicle, and the interclavicle. Fifteen other Coalsack Bluff fragments, attributed as possible remains of Cryobatrachus based on their small size alone, were described. These bones included parts of the legs, hips, vertebrae, and skull. A 1977-78 expedition found a bone fragment on Collinson Ridge and an interclavicle on Shenk Peak southeast of the paratype locality on Mount Kenyon, both of which were referred to Cryobatrachus in 1984.