Osteology and myology of the cephalic region and pectoral girdle of Glyptothorax fukiensis (Rendahl, 1925), comparison with other sisorids, and comments on the synapomorphies of the Sisoridae (Teleostei : Siluriformes)

The cephalic and pectoral girdle structures of the sisorid Glyptothorax fukiensis (tribe Glyptothoracini) are described and compared with those of representatives of the other three sisorid tribes, namely Glyptosternon reticulatum (tribe Glyptosternini), Bagarius yarreli (tribe Bagariini) and Gagata cenia (tribe Sisorini), as well as with those of several other catfishes, as the foundation for a discussion on the synapomorphies and phylogenetic relationships of the Sisoridae. Our observations and comparisons support de Pinna's (1996) phylogenetic hypothesis, according to which the Asiatic Sisoridae is the sister-group of a clade formed by the Neotropical Aspredinidae and the Asiatic Erethistidae. In addition, our observations and comparisons pointed out a new, additional character to diagnose the family Sisoridae, namely: presence of a well-developed, wide, deep fossa on the neurocranial floor between the ventro-medial surface of the pterotic and the ventro-lateral surface of the exoccipital.