Diogenidae Ortmann, 1892

Osawa, Masayuki & Ota, Yuzo, 2020, New Records of Species of Gebiidea and Anomura (Crustacea: Decapoda) from the Sea of Japan, Species Diversity 25, pp. 295-307 : 298

Family Diogenidae Ortmann, 1892 Paguristes gonagrus (H. Milne Edwards, 1836) ( Figs 2E , 3A )

Restricted synonymy.

Pagurus gonagrus H. Milne Edwards, 1836: 281 (type locality: China Sea ).

Paguristes gonagrus: Alcock 1905: 155 (list); Rahayu and Forest 2009: 1312, figs 1, 2; Komai 2010: 10, figs 1–5 (compilation).

Paguristes balanophilus non Alcock, 1905: Miyake 1978: 40, text-fig. 14, pl. 2, fig. 7; Miyake 1982: 97, pl. 33, fig. 1; Minemizu 2000: 131, unnumbered fig.

Material examined. Tottori Prefecture. Off Nagaobana (35°55′N, 134°00′E), Tottori: 50 m, beam trawl, 13 July 2018, coll . Y . Ota , 1 male (sl 5.6 mm), TRPM-781; 50 m, beam trawl, 20 August 2018, coll . Y . Ota, 1 male (sl 6.4 mm), TRPM-782.

Distribution. Japan, Taiwan, China Sea, Bohol in the Philippines; depths of 13–200 m ( Komai 2010). Japanese records include the Pacific coast from Sagami Bay to the Ryukyu Islands, and Tottori Prefecture on the coast of the Sea of Japan ( Komai 2010; present study). The present specimens reveal the first record of this species from the Sea of Japan.

Habitat. Muddy sand; found in various species of gastropod shells, which are always encrusted with Epizoanthus Gray, 1867 (Cnidaria: Anthozoa: Zoantharia : Epizoanthidae ) ( Minemizu 2000; Komai 2010). The present specimens were collected from the bottom containing dead shells and gravels.

Remarks. Paguristes gonagrus has been confounded with P. balanophilus Alcock, 1905 in Japanese literature (cf. Miyake 1978, 1982). The true identities of the two species were clarified by the re-examinations of respective type specimens by Rahayu and McLaughlin (2006) and Rahayu and Forest (2009) and a subsequent detailed description of P. gonagrus by Komai (2010). Paguristes gonagrus is distinctive among Japanese congeners and practically distinguished by the dense covering of long soft setae on the dorsal surface of each chela, which obscure or conceal the armature, and the lateral surfaces of the meri of the chelipeds and ambulatory legs each with a small red spot distally, which is circumscribed by a broad violet ring (cf. Komai 2010).

Figures

Fig. 2. Preserved specimens. A, Austinogebia narutensis (Sakai, 1986), female (cl 18.9mm), TRPM-780, left lateral view; B, same, carapace, dorsal view; C, same, left lateral view, anterior part of body, showing pereopod 1; D, Austinogebia narutensis (Sakai, 1986), male (cl 17.9mm), TRPM-780, left lateral view; E, Paguristes gonagrus (H. Milne Edwards, 1836), male (sl 6.4mm), TRPM-782, dorsal view; F, Paguristes versus Komai, 2001, male (sl 5.8mm), TRPM-783, dorsal view; G, Nematopagurus australis (Henderson, 1888), female (sl 4.3mm), TRPM-784, dorsal view; H, Galathea guttata Osawa, 2004, male (pcl 3.1mm), TRPM-785, dorsal view; I, Munida agave Macpherson and Baba, 1993, ovigerous female (pcl 7.4mm), TRPM-788, dorsal view.

Fig. 3. Fresh specimens. A, Paguristes gonagrus (H. Milne Edwards, 1836), male (sl 6.4mm), TRPM-782, dorsal view; B, Paguristes versus Komai, 2001, male (sl 5.8mm), TRPM-783, right lateral view; C, Nematopagurus australis (Henderson, 1888), female (sl 4.3mm), TRPM- 784, dorsal view; D, Munida agave Macpherson and Baba, 1993, ovigerous female (pcl 7.5mm), TRPM-787, dorsal view; E, Munida pherusa Macpherson and Baba, 1993, ovigerous female (pcl 7.7mm), TRPM-802, dorsal view; F, Munida pherusa Macpherson and Baba, 1993, male (pcl 6.6mm), TRPM-802, dorsal view; G, Paramunida tricarinata (Alcock, 1894), ovigerous female (pcl 7.9mm), TRPM-790; H, Pagurus nipponensis (Yokoya, 1933), ovigerous female (sl 5.9mm), TRPM-798; I, Bathymunida brevirostris (Yokoya, 1933), female (pcl 5.4mm), TRPM-801.