بومشناسی آبزیان (Mar 2020)
Cephalic osteology of Caspian nase Chondrostoma cyri (Kessler, 1877)
Abstract
The study of the osteological features of fishes head can help to better understand their biological characteristics such as feeding and respiration. Hence, this study aimed to provide the characterization of the cephalic osteology of Caspian nase, Chondrostoma cyri. Six specimens of Caspian nase were caught from Aras River by electroschoker and seine net, preserved in 10% buffered formalin, established with the aim of osteology, and cleared and stained. Bony structure was reviewed under a stereomicroscope and described. The skeletal structure of the head showed differences compared to other cyprinids. In the neurocranium, the posterior pharyngeal process of basioccipital is broad from the beginning to the end and slowly narrows down at the end. The masticatory plate is large and its width is greater than the basioccipital width. The upper part of the kinethmoid is round and unbranched and is similar to bowling rods. In the opercular series of the upper edge at the point of attachment to the hyomandibular is rounded and the front of the opercular series is jagged. Quadrate bone is long and developed and symplectic bone is roughly long and elongated. In the jawbone, maxillary mid-lateral ascending process is round or crested, in the mandibular, the dorsal part of the articular is convex and the coronoid process is flat and small. Regarding the weakness of the morphometric, meristic and color pattern traits for taxonomic study, the results of this research can be used for future studies of species of this genus.
