Misawa Ryo, Orlov Alexei M, Orlova Svetlana Y, Gordeev Ilya I, Ishihara Hajime, Hamatsu Tomonori, Ueda Yuji, Fujiwara Kunihiro, Endo Hiromitsu, Kai Yoshiaki
Tohoku National Fisheries Research Institute, Japan Fisheries Research and Education Agency, National Research and Development Agency, 25-259 Shimomekurakubo, Same, Hachinohe, Aomori 031-0841, Japan.
Zootaxa. 2020 Oct 20;4861(4):zootaxa.4861.4.3. doi: 10.11646/zootaxa.4861.4.3.
A new species of softnose skate (Arhynchobatidae), Bathyraja sexoculata Misawa, Orlov, Orlova, Gordeev and Ishihara is described on the basis of five specimens collected from off the east coast of Simushir Island, Kuril Islands, located in the western North Pacific. The specimens conformed to the genus Bathyraja by having the anteriormost pectoral-fin skeleton almost reaching the snout tip, and a slender unsegmented rostral cartilage. Within Bathyraja, the new species belongs to the subgenus Arctoraja (currently with four valid species) due to the relatively short tail (79-86% of disc width), high count of predorsal caudal vertebrae (more than 86), and large strong nuchal and scapular thorns. It is most similar to Bathyraja (Arctoraja) smirnovi, distributed in the Seas of Japan and Okhotsk, in having tail thorns not extending to the nuchal area, median thorns discontinuous from the nape to the tail, and no mid-dorsal thorns. However, B. sexoculata can be distinguished from B. smirnovi by the following characters: three pairs of white blotches on the dorsal disc surface (vs. blotches absent, or a pair of white or dark blotches in B. smirnovi), dark blotch around cloaca, dark bands along mid ventral line of tail (vs. dark blotch and band usually absent ventral disc surface in B. smirnovi), 86-93 predorsal caudal vertebrae (vs. 80-87 in B. smirnovi), and a unique mitochondrial DNA cytochrome c oxidase subunit I sequence. Proportional measurements, including disc width, disc length, head length, preoral length, prenarial length, internarial distance, eye diameter, and tail length, also differ between the two species. For the referential purpose, geographical variations of B. smirnovi distributed in the Seas of Japan and Okhotsk are analyzed and clarified based on morphological and genetic data. Significant morphological and genetic differences were found between local populations in the Seas of Japan and Okhotsk.
基于从位于北太平洋西部的千岛群岛择捉岛东海岸外采集的5个标本，描述了软鼻鳐科（Arhynchobatidae）的一个新物种——六眼深海鳐（Bathyraja sexoculata），三泽、奥尔洛夫、奥尔洛娃、戈尔杰夫和石原。这些标本符合深海鳐属的特征，即最前端的胸鳍骨骼几乎到达吻尖，且有一根细长的不分节的吻软骨。在深海鳐属中，该新物种属于Arctoraja亚属（目前有4个有效物种），这是因为其尾巴相对较短（为盘宽的79 - 86%），背前尾椎数量较多（超过86个），以及有大而强壮的颈部和肩胛棘。它与分布在日本海和鄂霍次克海的斯氏深海鳐（Bathyraja (Arctoraja) smirnovi）最为相似，其尾棘不延伸至颈部区域，中间棘从颈部到尾巴不连续，且没有背中棘。然而，六眼深海鳐可通过以下特征与斯氏深海鳐区分开来：背盘表面有三对白色斑点（相比之下，斯氏深海鳐没有斑点，或有一对白色或深色斑点），泄殖腔周围有深色斑点，尾巴腹中线有深色带（相比之下，斯氏深海鳐的腹盘表面通常没有深色斑点和带），86 - 93个背前尾椎（相比之下，斯氏深海鳐为80 - 87个），以及独特的线粒体DNA细胞色素c氧化酶亚基I序列。两个物种之间的比例测量值，包括盘宽、盘长、头长、口前长、鼻前长、鼻间距、眼径和尾长，也有所不同。为作参考，基于形态学和遗传学数据，对分布在日本海和鄂霍次克海的斯氏深海鳐的地理变异进行了分析和阐明。在日本海和鄂霍次克海的当地种群之间发现了显著的形态学和遗传学差异。
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