Bathyraja (Arctoraja) sexoculata sp. nov., a new softnose skate (Rajiformes: Arhynchobatidae) from Simushir Island, Kuril Islands (western North Pacific), with special reference to geographic variations in Bathyraja (Arctoraja) smirnovi.
Bathyraja (Arctoraja) sexoculata sp. nov., a new softnose skate (Rajiformes: Arhynchobatidae) from Simushir Island, Kuril Islands (western North Pacific), with special reference to geographic variations in Bathyraja (Arctoraja) smirnovi.
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Bathyraja (Arctoraja) sexoculata sp.
DOI：
10.11646/zootaxa.4861.4.3
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发表时间：
2020
期刊：
影响因子：
0.9
通讯作者：
Y. Kai
中科院分区：
文献类型：
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作者：
Ryo Misawa;A. Orlov;S. Orlova;I. Gordeev;H. Ishihara;T. Hamatsu;Y. Ueda;Kunihiro Fujiwara;Hiromitsu Endo;Y. Kai
记述了采自北太平洋西部千岛群岛锡穆希尔岛东海岸的软鼻鳐科一新种，即六眼深鳐（Bathyraja sexoculata Misawa，奥尔洛夫，奥尔洛娃，Gordeev，Ishihara）。这些标本符合深海鳐属的特征，因为它们的胸鳍骨骼最前端几乎达到吻尖，喙软骨细长不分节。在深海鳐属中，该新种属于熊鳐亚属（目前有四个有效种），因为它的尾巴相对较短（约为盘宽的79-86%），背前尾椎数量较多（超过86个），颈刺和肩胛刺大而结实。它与分布于日本海和鄂霍次克海的深海鳐（Bathyraja（Arctoraja）smirnovi）最为相似，尾刺不延伸至颈部区域，中刺从颈背到尾不连续，没有中背刺。然而，B。sexoculata与B有明显区别。smirnovi的主要特征为：在椎间盘背面有三对白色斑点（而在B中没有斑点，或有一对白色或深色斑点）。smirnovi），泄殖腔周围有深色斑点，尾腹中线有沿着深色条纹（而B的腹面通常无深色斑点和条纹。smirnovi）、86-93个背前尾椎（而B. smirnovi）和独特的线粒体DNA细胞色素c氧化酶亚基I序列。比例测量，包括盘宽，盘长，头长，口前长度，围前长度，围内距离，眼睛直径和尾长，也不同的两个物种之间。为供参考，本文对B.根据形态学和遗传学资料，对分布于日本海和鄂霍次克海的smirnovi进行了分析和澄清。显着的形态和遗传差异，发现在日本海和鄂霍次克当地人群之间。
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.