THE IDENTIFICATION OF NEW TYPES OF INTERMUSCULAR BONES IN COILIA NASUS

Intermuscular bones (IBs) are common in the lower teleost and its morphology types and numbers are varied among different fish species. In this study, we documented the number, morphology, and distribution of IBs in Coilia nasus. The morphology of IBs in C. nasus was not different with Cyprinidae species; however, the distribution of IBs was quite different. Besides epineurals, epicentrals, and epipleurals, we found two others categories of IBs in C. nasus, which are located in the dorsal and ventral parts on both sides of the vertebrae. According to the reference, we called them dorsal and ventral myorhabdoi, respectively. These types of IBs were also identified in C. brachygnathus. The morphology of these IBs showed non-forked type (“1” or “(”). The number of IBs in C. nasus ranged from 492 to 543, and the number of epineurals, epicentrals, epipleurals, dorsal myorhabdoiand ventral myorhabdoi ranged from 114 to 142 (\bar x=133), 28 to 51 (\bar x=42), 138 to 153 (\bar x=142), 92 to 135 \bar x=114), 66 to 98 (\bar x=89), respectively. IBs can be stained by alizarin red, but not alcian blue. For epineurals and epipleurals, the IBs were connected with one by one through connective tissues. The study identified new categories of IBs that supplement the type of IBs in teleost.