牙鲆、大黄鱼和小黄鱼不同部位鳞片类型的比较

真骨鱼类的骨鳞有圆鳞和栉鳞两种类型,观察了大黄鱼(Larimichthys crocea)和小黄鱼(Pseudosciaena polyactis)成体的鳞片类型,发现同一个体同时存在圆鳞和栉鳞,有典型的圆鳞和栉鳞结构,也有两者的过渡型形态。而对100日龄和成体牙鲆(Paralichthys olivaceus)不同部位鳞片类型的观察发现,100日龄牙鲆眼侧存在圆鳞向栉鳞过渡的Ⅲ型鳞片、Ⅳ型初始栉鳞和Ⅴ型典型栉鳞,而成体牙鲆有眼侧仅覆盖Ⅴ型典型栉鳞,推测栉鳞和圆鳞可能存在发育上的联系。通过统计大黄鱼和小黄鱼不同部位的圆鳞和栉鳞数量,发现二者体表栉鳞数量均为从头部到尾部依次减少,而背部与腹部之间没有明显差异。

Comparative Analysis on Scale Types from Different Body Part in Flounder, Large Yellow Croaker and Small Yellow Croaker

In teleosts there are two types of scales, cycloid scale and ctenoid scale. In Paralichthys olivaceus, Larimichthys crocea and Pseudosciaena polyactis, these two typical types of scales can be found in different body areas. In addition, some scales with transitional morphological features between typical cycloid scale and ctenoid scale also existed in same individual, indicating that ctenoid scale might be developed from the cycloid scale. The numbers of cycloid scales and ctenoid scales in different body areas were further statistics analysis. In P. olivaceus, ctenoid scales were only found on the ocular side and cycloid scales on the blind side. Moreover, the cycloid scales were also found in the area without pigment cells on the ocular side of albinic flounder, indicating there are linkage between the developments of ctenoid scale and melanotrope. In Larimichthys crocea and Pseudosciaena polyactis, the numbers of ctenoid scales and cycloid scales are only found different in the body along anterior to posterior axis, indicating that in this two species fishes the development of ctenoid scale might be related to swimming dynamics. On the whole, we first provide statistic data in this study to show the number difference of ctenoid scale and cycloid scale in different body area in teleosts, and the clue about the possible roles of swimming dynamics and light in the development of ctenoid scale.