Cranial anatomy of the stem salamander Kokartus honorarius (Amphibia: Caudata) from the Middle Jurassic of Kyrgyzstan

The cranial anatomy of the stem salamander Kokartus honorarius, from the Middle Jurassic of Kyrgyzstan, is redescribed in detail on the basis of all available material using conventional methods and high‐resolution computed microtomography. In contrast to previous interpretations, the skull is characterized by posteriorly positioned external nostrils, the presence of an internarial fenestra between the premaxillae, the maxillae are not shortened, the overlapping of the frontal by the nasal and the parietal by the frontal, a dentate vomer, a dentate pterygoid with a long, strongly arcuate and anteromedially orientated anterior process, the absence of a fontanelle between frontals and pineal pit on the ventral surface of the frontals, and an inferred unique attachment of the adductor mandibulae internus to the lateral border and ventral ridge of the frontals and parietals. Kokartus is closely related to Karaurus and both these taxa constitute the monophyletic taxon Karauridae, which forms the sister group of crown‐group salamanders (Urodela). Karaurids were neotenic forms and neoteny was probably the ancestral life history strategy of salamanders. The morphological analysis of Kokartus supports the current phylogenetic hypothesis that Permian amphibamids (including branchiosaurids) are the closest relatives of salamanders amongst known non‐lissamphibian temnospondyls. © 2011 The Linnean Society of London, Zoological Journal of the Linnean Society, 2011, 161 , 816–838.     

AMPHIBIANS FROM THE MIDDLE JURASSIC BALABANSAI SVITA IN THE FERGANA DEPRESSION, KYRGYZSTAN (CENTRAL ASIA)

Abstract: Larval and metamorphosed Ferganobatrachus riabinini (Temnospondyli, Brachyopoidea), metamorphosed Kokartus honorarius (Caudata, Karauridae), an indeterminated karaurid (Karauridae indet.) and, presumably, anurans (?Anura indet.) are represented by isolated cranial and postcranial skeletal elements in the Middle Jurassic (Bathonian–Callovian) Balabansai Svita of the Fergana Depression, Kyrgyzstan. The Balabansai vertebrate assemblage is one of the few faunas in which non‐lissamphibian temnospondyls, stem caudates and anurans occur together. The presence of a supraglenoid foramen and a complex strap‐like glenoid on the scapulocoracoid in Kokartus supports its basal phylogenetic position within the Caudata.