著者

明仁 藍澤 正宏 池田 祐二 岸田 宗範 林 公義 中山 耕至 中坊 徹次

出版者

日本魚類学会

雑誌

魚類学雑誌 (ISSN:00215090)

巻号頁・発行日

2019

---

<p>Hybrids of <i>Rhinogobius biwaensis</i> and <i>Rhinogobius</i> sp. BF were identified in the ponds of Sento Imperial Palace, Kyoto City, Japan, from microsatellite and mitochondrial DNA markers. Mitochondrial DNA analysis indicated that five of seven <i>Rhinogobius</i> specimens had <i>R. biwaensis</i> haplotypes, the remaining specimens having those of <i>Rhinogobius</i> sp. BF. In DAPC and STRUCTURE analyses based on microsatellite data, all specimens examined showed intermediate status between <i>R. biwaensis</i> and <i>Rhinogobius</i> sp. BF, the two species being considered to have formed a hybrid swarm in the ponds because genetically pure individuals of either were not found. This is the first report of recent hybridization under field conditions in <i>Rhinogobius</i> fishes from Japan, confirmed by nuclear and mitochondrial DNA data. Hybrid <i>Rhinogobius</i> specimens from the ponds had 5–17 predorsal scales, an intermediate range between those of non-hybrid <i>R. biwaensis</i> (0–6) and <i>Rhinogobius</i> sp. BF (11–20). However, in appearance they were more similar to <i>R. biwaensis</i> than <i>Rhinogobius</i> sp. BF, having bluish-white distal coloring anteriorly on the first and second dorsal fins, a reduced reddish longitudinal band on the anal fin, and lacking yellowish dorsal and posterior margins on the caudal fin. However, they differed from <i>R. biwaensis</i> in having a narrower white posterior caudal fin margin. Further morphological differentiation of the hybrid specimens was not apparent.</p>