Crabs (Crustacea, Decapoda) from the Sea off East and Southeast Asia collected by the RV Hakuhō Maru (KH- 72 - 1 Cruise) 1. Sulu Sea and Sibutu Passage Author Takeda, Masatsune Department of Zoology, National Museum of Nature and Science, 4 - 1 - 1 Amakubo, Tsukuba, Ibaraki 305 - 0005, Japan E-mail: takeda @ kahaku. go. jp (MT) / h-komatu @ kahaku. go. jp (HK) takeda@kahaku.go.jp Author Ohtsuchi, Naoya International Coastal Research Center, Atmosphere and Ocean Research Institute, The University of Tokyo, 1 - 19 - 8 Akahama, Otsuchi, Iwate 028 - 1102, Japan E-mail: ohtsuchi @ g. ecc. u-tokyo. ac. jp ohtsuchi@g.ecc.u-tokyo.ac.jp Author Komatsu, Hironori Department of Zoology, National Museum of Nature and Science, 4 - 1 - 1 Amakubo, Tsukuba, Ibaraki 305 - 0005, Japan E-mail: takeda @ kahaku. go. jp (MT) / h-komatu @ kahaku. go. jp (HK) takeda@kahaku.go.jp text Bulletin of the National Museum of Nature and Science. Series A, Zoology 2021 2021-05-21 47 2 65 97 journal article 10.50826/bnmnszool.47.2-65 2434-091X 12759907 09E0EFF3-ABE7-43D7-AA85-DA3BF08E47B9 Pycnoplax surugensis ( Rathbun, 1932 ) Material examined . RV Hakuhō Maru KH-72-1 cruise, sta. 20 (Sibutu Passage; 05°40.9′N , 119°46.3′E – 05°43.1′N , 119°47.0′E ; 460–514 m deep); otter trawl; 10 June, 1972; 1˂ ( CB 19.2 mm including second anterolateral teeth; CL 17.3 mm ) , NSMT-Cr 28986. Remarks . This species has been placed in Carcinoplax since the original description in 1932, and wholly figured in some monographic works such as Guinot (1989) , Sakai (1976) , Chen (1984a , b), and Dai and Yang (1991) together with several taxonomic records. In the monographic work of the family Goneplacidae , however, Castro (2007) designated this species as the type species of the new genus Pycnoplax , and referred C. bispinosa Rathbun, 1914 , C. meridionalis Rathbun, 1923 , C. vioctoriensis Rathbun, 1923 and P. latifolia Castro, 2007 to the new genus. Some characters important to distinguish P. surugensis from the congeners are that the external orbital angle is triangular with an obtuse tip, the carapace first anterolateral tooth is narrow, sharp and directed forward, and the second (last) anterolateral tooth is markedly strong, sharply tuberculate and directed obliquely forward. Distribution . West to South Pacific ( Japan , East China Sea, Taiwan , Philippines , Indonesia , and New Caledonia ); 65–496 m deep.