タイ型魚類の眼骨
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概要
- 論文の詳細を見る
1. The orbital bones and suborbital shelves of 16 species of Japanese sparoid fishes referred to 10 genera have been carefully examined in order to make an accurate elucidation of their intergeneric relationships. The results obtained in this study will afford abundant evidence for explaining the criterion of the so-called "Sparoid fishes" and their relationships. 2. The sparoid fish has got its first suborbital bone well developed, which is very similar to the preorbital bone both in size and shape. This fact alone may be an important diagnosis in separating the sparoid fish from any other closely-related perch-like fish, which has its first subobital bone smaller than its preorbital one. 3. The fish has its orbital bones including suborbital shelf consisting of one preorbital bone and five suborbital ones, and so far as they are concerned the sparoid fish can be classified into the following five types. Type 1 represented by Nemipterus is the most primitive at least in having the following characters (Fig. 1, A): 1) the preorbital bone and the first suborbital bone are almost equal both in length and width or less wide than long;^* 2) the anterior part of the second suborbital bone is firmly attached to a shallow but rather large concave of the dorsoposterior part of the first suborbital bone; 3) the upper surface of the second suborbital bone is bordered along the entire length by the suborbital shelf, which is larger than that of any other type of the fish and roughly elliptical in shape. Type 2 including Taius, Chrysophrys, Argyrops and Evynnis has several generalized characters as sparoid fishes, as shown in (Fig. 1, B-E): 1) the preorbital bone and the first suborbital one are slightly wider than long; 2) the suborbital shelf is of a wedge-shaped lamina tapering forward, but it is not so with Evynnis, for its suborbital shelf is of an elongated rhomb in shape tapering both forward and backward. Type 3 comprises Mylio and Rhabdosargus (Fig. 1, F・G). This type closely resembles type 2, but differs from it in the following two points: 1) the suborbital shelf does not taper in any direction; 2) the shelf is of an obtuse-angled parallelogram or triangular in general shape. Type 4 including Gymnocranius and Monotaxis may be regarded as specialized among sparoid fishes in having the following characters (Fig. 1, H・I): 1) the preorbital bone and the first suborbital one are twice as wide as their length or more; 2) the lower parts of these bones are not completely ossified; 3) the suborbital shalf is small in size and boot-like in shape; 4) the second suborbital bone is triangular in shape. Type 5 represented by Lethrinus relatively resembles type 4, but is distinguished from it by having the following features (Fig. 1, J): 1) the suborbital shelf is entirely absent; 2) the second suborbital bone is rectanguler in shape and the anterior margin is connected with the dorso-posterior part of the first suborbital bone.
- 社団法人日本動物学会の論文
- 1958-10-15