Species authentication of Tor spp. (family Cyprinidae) in Indonesia based on osteocranium structure and biometric data

Currently, the existence of Tor species is threatened with extinction and is listed on the IUCN red list due to overfishing, forest destruction, water pollution, fluctuations in water volume, and land conversion. This study aims to fully describe the differences in the osteocranium structure of four Tor species (T. tambroides, T. douronensis, T. tambra, and T. soro) in Indonesia. Visually, the genus Tor is identified by the presence of a lobe on the ventral side of the lower lip. T. tambroides has long and thick lobes, T. tambra has short lobes, T. douronensis has long and thin lobes, while T. soro has very short lobes. The results of the osteocranium structure analysis of four Tor species showed differences, including the occipital, lateral ethmoid, frontal, infraorbital, nasal, preethmoid, prootic, pterotic, vomer, lateral ethmoid processus, pterotic processus, and lateral processus bones, where the differences in the osteocranium structure include the size, number, and development of the bone. The results of the univariate analysis (analysis of variance) of 33 characters of bio- metric data showed that 20 characters were significantly different (P < 0.05) and the other 13 characters were not significantly different (P > 0.05). Furthermore, the results of multivariate analysis (principal component analysis) of 33 biometric data characters succeeded in discriminating four Tor species into four separate groups; however, T. tambroides and T. douronensis tended to be more closely related than the other two species. In conclusion, this study shows that osteocranium structure and biometric analysis have successfully authenticated four Tor species into four separate groups validly.