Morphological profile of the forelimb long bones and ribs in the Ganges River dolphin, Platanista gangetica (Lebeck, ۱۸۰۱) (Mammalia: Cetacea: Platanistidae)

We conducted a study on the morphology of the forelimb long bones and ribs in the Ganges River dolphin, Platanista gangetica (Lebeck, ۱۸۰۱) using traditional morphometric methods. A total of ۱۷ morphometric measurements of six specimens of P. gangetica were taken. The humerus was the longest bone in the forelimb morphology, with its length ranging from ۴۱.۷۵ to ۵۲.۷۸ mm (mean: ۴۵.۵۷, SD: ± ۵.۰۷) in juveniles/subadults and ۶۰.۵۶ to ۹۰.۹۲ mm (mean: ۷۶.۷۵, SD: ± ۲۲.۹۰) in adults. The length of the scapula was ۸۵.۸۴ to ۱۳۵.۴۶ mm (mean: ۱۰۲.۱۸, SD: ± ۲۳.۰۰) in juveniles/subadults and ۱۷۱.۷۹ to ۲۵۱.۹۵ mm (mean: ۲۱۱.۸۷, SD: ± ۵۶.۶۸) in adults. Of ۱۰ ribs, the sixth rib was the longest (mean: ۱۳۳.۵۵, SD: ± ۲۴.۱۲) in juveniles/subadults and the seventh (mean: ۲۴۰.۶۲, SD: ± ۵۴.۲۴) in adults. All measurements (except the two variables of the scapula) were significantly correlated (P < ۰.۰۵) with specific bone length. The allometric coefficients of all correlated variables of the humerus, radius, ulna, scapula, and the depths of ribs exhibited isometry against the length of the particular bone, respectively. We discussed the morphological patterns of the forelimb long bones and ribs in P. gangetica along with the structural and functional aspects of the aquatic lifestyles.

کلیدواژه ها:

Allometry ، forelimb ، Platanista gangetica ، ribs ، morphological pattern