Yamashita Ryunosuke, Komai Tomoyuki, Kon Koetsu
1School of Marine Resources and Environment, Tokyo University of Marine Science and Technology, 4-5-7 Konan, Tokyo, Minato 108-8477 Japan..
2Natural History Museum and Institute, Chiba, 955-2 Aoba, Chiba, Chuo 260-8682, Japan.
Zootaxa. 2023 Mar 29;5258(3):317-330. doi: 10.11646/zootaxa.5258.3.5.
The alpheid shrimp genus Metabetaeus Borradaile, 1899 was previously known from two species associated with anchialine pools and caves, M. minutus (Whitelegge, 1897) and M. lohena Banner & Banner, 1960, and one species inhabiting in coral reef, M. mcphersonae Anker, 2010. In this study, a new species of the genus is described based on fourteen specimens collected from Shizuoka and Mie Prefectures, Honshu, central Japan. Metabetaeus lapillicola n. sp. inhabits interstitial spaces among small pebbles deposited in lower intertidal to upper subtidal zone, representing rather unusual habitat not only for Metabetaeus, but even for carideans. It is distinguished from three congeneric species by the presence of a pterygostomial spine on the carapace, greatly unequal chelipeds with the major one being substantially elongate, and the lack of a distinct distolateral spine on the uropodal endopod. Phylogenetic analyses using the mitochondrial 16S rRNA and COI genes support the recognition of the new species. The generic diagnosis of Metabetaeus is emended to accommodate the new species.
1899年博勒代尔（Borradaile）所描述的阿氏虾属（Metabetaeus）之前已知有两个与沿岸洞穴池塘相关的物种，即微小阿氏虾（Metabetaeus minutus，怀特莱格，1897年）和洛氏阿氏虾（Metabetaeus lohena，班纳和班纳，1960年），以及一个栖息在珊瑚礁中的物种，即麦克弗森阿氏虾（Metabetaeus mcphersonae，安克，2010年）。在本研究中，基于从日本中部本州静冈县和三重县采集的14个标本描述了该属的一个新物种。石砾阿氏虾（Metabetaeus lapillicola）新种栖息于低潮线下部至潮下带上部沉积的小卵石间的间隙空间，这不仅对阿氏虾属，甚至对虾类来说都是相当不寻常的栖息地。它与三个同属物种的区别在于，头胸甲上有一个翼状口刺，螯足极不对称，大螯足显著延长，并且尾足内肢上没有明显的远端外侧刺。使用线粒体16S rRNA和COI基因进行的系统发育分析支持了对新物种的识别。对阿氏虾属的属征进行了修订以容纳这个新物种。
