Comparative osteology of Tor tambroides (Bleeker, 1854) and Tor tambra (Valenciennes 1842) vertebral column (ossa vertebrae)

Abstract
Information related to osteology plays a vital role in support ecomorphology and phylogenetic relationship analysis in fish. This study aimed to describe the comparative morphology of the vertebral column between Tor tambroides (Bleeker, 1854) and Tor tambra (Valenciennes 1842). Samples of Tor tambroides and Tor tambra were obtained from fish traders in the Tangse River area of Pidie Regency and Sampoinet River area, Aceh Jaya Regency, Aceh Province. Vertebral column preparation consists of five steps: muscles and scales separation, immersion in a formaldehyde solution, drying, morphometric measurements, photographing and image editing, and identification of terminology. The results showed that there are morphological differences between Tor tambroides and Tor tambra vertebral column, particularly in the axial vertebrae, posterior vertebrae caudales, and urostylus regions. The pleural costae of Tor tambroides have a posterior curve with the left and right sides interlocking. The lateral Tor tambroides process tends to curve posteriorly, while the Tor tambra tends to round up parallel to the dorsal costae. Tor tambroides tend to have stronger ligaments marked by the absence of a foramen between the hypural. Morphometrically, Tor tambroides tend to have higher centrum ratios (length, width, and height), neural spine, haemalis spine, and costae compared to Tor tambra. The significant difference in morphometric results in observed the axial vertebrae and the posterior vertebrae caudales region. Further research related to the correlation of vertebral column morphology with the environmental condition of these fish is still necessary.