Morphological and Taxonomical Studies on Natural Hybrids of the Pufferfih Genus Takifugu.

本研究的材料是从本州的日本海沿岸和九州的西海岸收集的。对这些材料的形态学观察表明，东方鲀属有3个自然杂交种，它们是（I）黄鳍东方鲀（Takifugu xanthopterus x T. rubripes，（II）赤眼蜂T. xanthopterus x T. vermicularis和（III）T. porpbyreus x T. rubripes（或T. chinensis）。杂种（Ⅰ）的特征是体背腹侧有小刺，背黑色，有白色线和斑点的斜纹。这是从九州附近的沃茨采集的杂交种。（II）的杂种表现出介于T. xanthopterus和T.虫体的形状和颜色。它的特征是：所有的鳍都是黄色的，身体的背侧深褐色，有许多不规则的白色斑点，身体的背侧和腹侧有微弱的微小刺。这是在有明湾采集的杂交种。（III）的杂种的特征是在身体的背侧和腹侧上具有非常弱的刺，身体的黑色背部在胸鳍后面的侧面上具有大的圆形黑色斑点，以及白色的臀鳍。这种杂交种在中国东海和日本海西部都有发现。对有关Takifugu属名的命名混乱进行了仔细澄清。文献调查表明，被许多作者频繁使用的河豚（Fugu）实际上是东方鲀（Takifugu）的一个较低级的主观同义词。并给出了该物种的检索表。

Materials for this research were collected from the Japan Sea coasts of Honshu and from the west coast of Kyushu. Morphological examinations on these materials revealed that there are three natural hybrids in the genus Takifugu; they are (I) Takifugu xanthopterus x T. rubripes, (II) T. xanthopterus x T. vermicularis, and (III) T. porpbyreus x T. rubripes (or T. chinensis). The hybrid (I) is characterized by having small spines on the dorsal and ventral sides of the body, black back with oblique patterns of white lines and spots. This hybrid has been collected from the waters around Kyushu. The hybrid of (II) shows intermediate conditions between T. xanthopterus and T. vermicularis in the body shape and color. It is distinct in the combination of the following characters: all fins yellow, dorsal side of body dark brown with many irregular white spots, and weak minute spines on the dorsal and ventral sides of the body. This hybrid has been collected in Ariake Bay. The hybrid of (III) is characterized by having very weak spines on the dorsal and ventral sides of the body, black back of the body with a large round black blotch on the side behind the pectoral fin, and the white anal fin. This hybrid has been known from the East China Sea and the western part of the Japan Sea.The nomenclatural confusion about the generic name of Takifugu was carefully clarified. Literature surveys revealed that Fugu, which has been frequently used by many authors, is actually a junior subjective synonym of Takifugu.Japanese species of Takifugu were also examined to clarify their systematic features. A key to these species was given.