Osteology of some catfishes of the genus Glyptothorax (Teleostei: Siluriformes) of northeastern India

The morphology of the premaxilla, dentary, Weberian lamina, infraorbital series, vomer and frontal bones were observed in eight species of Glyptothorax of northeastern India. In G. botius, G. granulus, G. manipurensis, G. ngapang, G. striatus and G. ventrolineatus, the premaxilla consists only of proximal and distal tooth plates, the anterior portion of the dentary is slender and its dorsal surface bears villiform teeth, the lateral extension of posterior portion of Weberian lamina terminates at the level of the lateral margin of its anterior portion, and the frontal has a shallow orbital notch. In G. cavia and G. chindwinica, the premaxilla consists of proximal, distal and posterior elements on the roof of the oral cavity; the anterior portion of the dentary bears posterior extension of dentary tooth-plate; the lateral extension of the posterior portion of Weberian lamina extends almost to the distal tip of the fifth parapophysis; there are nine or ten infraorbital bones with a longer and broader body of the lacrimal; greatly enlarged vomerine head; and frontal bears a deep orbital notch. The jaw structure of G. burmanicus is discussed.