メイチダイ科魚類の形態比較
スポンサーリンク
概要
- 論文の詳細を見る
1. In order to clarify the taxonomic status of the family Pentapodidae erected by Smith, the author has carefuly examined the morphological features of 6 species of the fish which were caught in the sea around the Amami Islands and which have hitherto been referred to the four genera, Pentapodus, Gnathodentex, Gymnocranius and Monotaxis. The results obtained in this study will, it is hoped, offer some sufficient ground for explaining the differences between Pentapodus and the rest of the four genera. 2. Careful examination of the internal features of the genera has led the author to the following conclusions. 1) Pentapodus has a preorbital bone narrower than long, as shown in Fig. 1. A., while the other 3 genera have those wider than long. The former has a suborbital shelf elliptical in shape, projected inward from the entire length of the inner margin of the second suborbital bone. But the latter have shelves smaller and boot-like in shape, developed only from the anterior inner margin of the second suborbital bone. 2) The opisthotic bone is present in Pentapodus, whereas absnet in the other genera. Moreover, Pentapodus has a single process of parasphenoid projected downward from the bone, but the other genera have a double process of parasphenoid bone (Fig. 1. D). 3) Pentapodus has 2 imperfect interneural spines placed before the 1st interneural spine, but the other genera have 3 of them (Fig. 1. C). 4) Pentapodus have 5 anterior branchiostegal rays attached to the ventral side of the ceratohyal with the hindmost one placed in the interspace between ceratohyal and epihyal. But the other genera have 4 anterior ones attached to the ceratohyal with the fifth one associated with the interspace between ceratohyal and epihyal, the last one joining the epihyal (Fig. 1. B). 5) Pentapodus has a premaxillary pedicely moderatel developed, which is shorter than the lower base of the premaxillary. On the other hand, the other genera have the same pedicel well elongated upwards, which is as long as the base of the premaxillary, or often longer. 6) There area but 8 pyloric caeca in Pentapodus, while there are only 3 in the other genera. 3. As to the external features, the genus Pentapodus can be clearly distinguished from others in the following points: 1) Pentapodus has 7 anal soft rays, while the other genera have 9 or 10. 2) Pentapodus generally has the tip of the caudal fin made either filamentous or pointed and the posterior of this fin is well emarginated, while the other genera have the tip of the same fin made rather bluntly rounded, the posterior margin of the fin being moderately forked. 4. As mentioned above, there are remarkable differences in morphological features between Pentapodus and the other 3 genera, which may suggest that Pentapodidae should be divided in 2 different families.
- 社団法人日本動物学会の論文
- 1959-10-15