Lophoplax sextuberculata Takeda and Kurata, 1984

Shaga, I Bevin, Priya, K, Ramar, Selvakumar, Srinidhi, S, Mohan, G Chandra, Ranganathan, Sukanya, Moulvi, S M M & Mani, Bhuvaneswari, 2023, A Small Collection of Subtidal Crabs (Crustacea: Decapoda: Brachyura) from the Palau Islands Collected by Dredging, Bulletin of the National Museum of Nature and Science. Series A, Zoology 49 (1), pp. 7-42 : 28-30

Lophoplax sextuberculata Takeda and Kurata, 1984

( Fig. 9C )

Lophoplax sextuberculata Takeda and Kurata, 1984, p. 200 , figs. 14–16.─Takeda and Marumura, 1995b, p. 87, fig. 1. ─ Marumura and Kosaka, 2003, p. 47, pl. 7 fig. 41.─Takeda and Komasu, 2018, 176, fig. 6H.

Lophoplax aff. sextuberulata Takeda and Kurata : Takeda and Marumura, 1995a, p. 4, pl. 1 figs. 7–8.

Material examined. Entrance to Toagel Mid in Arangel Channel, Babelthuap I., Palau Is., dredged, 30–40 m in depth, with coralline algae; 1 ovig.♀ (cb 5.2×cl 4.0 mm), NSMT-Cr 30992; June 19, 1980; K. Baba leg.

Remarks. This small ovigerous female agrees well with the female holotype and two male paratypes found in stomach contents of roundspot goatfish/sidespot goatfish, Parupeneus pleurostigma (Bennett) from the Ogasawara Islands. In the original description, otherwise, a male from Tanega-shima Island in the south of Kyushu was also recorded as the paratype. In the specimens from the Ogasawara Islands as well as the present ovigerous female, the carapace dorsal surface is ornamented only with a transverse row of six, weakly raised, bare areolets behind the front-orbital margin. Takeda and Marumura (1995b), however, mentioned on the variations of the areolets on the carapace dorsal surface in three Japanese localities. In the specimens from the Kii Peninsula and Tanega-shima Island, the carapace dorsal surface is ornamented, in addition to six areolets behind the front-orbital margin, with two transverse rows of four and three areolets at level of the gastric and cardiac regions, respectively; in a female from Ie-jima Island in the Ryukyu Islands, it is almost impossible to locate the posterior seven areolets.

The carapace anterolateral margin is armed with three tubercular teeth tipped each with a short stiff seta; the third tooth is similar to, but much smaller than the first and second teeth.

The genus Lophoplax is composed of L. bicristata Tesch, 1918 , L. sculpta ( Stimpson, 1858) , L. takakurai Sakai, 1935 , and L. sextuberculata Takeda and Kurata, 1984 , because L. teschi Serène, 1971 was transferred to Serratocoxa Ng, 1987 and then to Cryptolutea Ward, 1936 (Ng et al., 2008). Takeda and Kurata (1984) and Takeda and Marumura (1995b) considered that Pseudocryptocoeloma symmetrinudus Edmondson, 1951 , is to be transferred to Lophoplax , but at present, Pseudocryptocoeloma is considered to be generically distinct from Lophoplax , with two species, P. parvus Ward, 1936 (type species) from Queensland, Australia, and P. symmetrinudus from Samoa and the Ryukyu Islands ( Edmondson, 1951; Marumura and Takeda, 2012; Maenosono, 2019).

Distribution. Previously known only from Japanese waters (Kii Peninsula, Wakayama Prefecture, 80–100 m in depth; Tanega-shima Island, ca. 70 m in depth; Ie-jima Island in the Ryukyu Islands, 70 m in depth; Ogasawara Islands), and now the Palau Islands, 30–40 m in depth.

Figures

Fig. 9. A: Gaillardiellus rueppellii (Krauss), ♂ (NSMT-Cr 30985; cb 8.8×cl 6.6mm). B: Metaxanthops acutus Serène, ♂ (NSMT-Cr 30987; cb 6.8×cl 5.5mm). C: Lophoplax sextuberculata Takeda and Kurata, ovig.♀ (NSMT-Cr 30992; cb 5.2×cl 4.0mm). D: Vellumnus pygmaeus (Takeda), ♂ (NSMT-Cr 30994; cb 5.7×cl 4.5mm). E: Chlorodiella corallicola Miyake and Takeda, ovig.♀ (NSMT-Cr 30980; cb 4.8×cl 3.2mm). F: Chlorodiella xishaensis Chen and Lan, ♂ (NSMT-Cr 30983; cb 8.0×cl 5.7mm).