Actumnus squamosus (De Haan, 1835)

Arzivian, Arteen, Alrubaie, Ahmad, Yang, Jessica, Lin, Huiyu, Zhang, Eva & Leong, Rupert, 2022, Crabs (Crustacea, Decapoda) from the Seas of East and Southeast Asia Collected by the RV Hakuhō Maru (KH- 72 - 1 Cruise) 4. South China Sea, Bulletin of the National Museum of Nature and Science. Series A, Zoology 48 (4), pp. 147-191 : 170

Actumnus squamosus (De Haan, 1835)

( Fig. 10E–F )

Material examined. RV Hakuhō Maru KH-72-1 cruise, sta. 45, 1Ə (CB 5.1×CL 4.6 mm), NSMT-Cr 30931; 1 8 (7.7× 5.5 mm), NSMT-Cr 30932.

Remarks. The most remarkable feature of Actumnus squamosus is the pavement of tubercles covering the whole outer surface of the palm, as shown by A. Milne-Edwards (1865) and Sakai (1939). Takeda and Komatsu (2017) clearly figured this feature with a photograph of both chelae in comparing the new species, A. tsu- rukaii, with the related species. The present female ( Fig. 10E–F ) agrees with the ovigerous female from the Sahul Shelf in having the carapace covered with a thick felt of short setae and in not being strongly convex dorsally, and also in having the characteristic chelipeds reported by Takeda et al. (2022b). In the specimen examined, however, the tubercles covering the cheliped palm seem to be somewhat loosely spread all over the surface, showing the obtuse polygonal form of various sizes.

Distribution. Indo-West Pacific from Japan to India, 10–324 m depth.

Figures

Fig. 10. A–B: Pilumnus minutus (De Haan), Ə (NSMT-Cr 30937; CB 8.0×CL 6.1mm) from sta. 45. C–D: Actumnus forficigerus (Stimpson), Ə (NSMT-Cr 30929; CB 10.0mm×CL 7.0 mm) from sta. 45. E–F: Actum- nus squamosus (De Haan), 8 (NSMT-Cr 30932; CB 7.7×CL 5.5 mm) from sta. 45.