Pleistacantha griffini Ahyong and Lee, 2006

Islam, Atikul, Banerjee, Abhishek, Wati, Sisca Meida, Banerjee, Sumita, Shrivastava, Deepti & Srivastava, Kumar Chandan, 2022, Crabs (Crustacea, Decapoda) from the Sea off East and Southeast Asia Collected by the RV Hakuhō Maru (KH- 72 - 1 Cruise) 2. Timor Sea, Bulletin of the National Museum of Nature and Science. Series A, Zoology 48 (1), pp. 5-24 : 13

Pleistacantha griffini Ahyong and Lee, 2006

( Fig. 5A )

Material examined. RV Hakuhō Maru KH-72-1 cruise, sta. 28 (Timor Sea; 09°34.4′S, 128°06.0′E – 09°33.5′S, 128°03.4′E, 295–296 m depth); 3 m beam trawl; June 24, 1972; 1 ♂ (NSMT-Cr 29258: CL 10.2 mm excluding pseudorostral spines, CB 6.7 mm).

Remarks. The general appearance of species of Pleistacantha changes somewhat owing to sizerelated inflation of the branchial regions and to sexual dimorphism (e.g. Prema et al., 2020). In addition, as briefly discussed by Ahyong and Lee (2006), the distinctness of sexual dimorphism probably varies among species. The taxonomy is, therefore, usually discussed mainly on the basis of adult specimens. The present specimen, a juvenile male with poorly developed gonopods, nevertheless possesses diagnostic features of P. griffini , described from the North West Shelf, Western Australia ( Ahyong and Lee, 2006).

Pleistacantha griffini closely resembles P. moseleyi ( Miers, 1886) from the Philippines ( Ahyong and Lee, 2006), and of five features discussed by Ahyong and Lee (2006), the followings are available to distinguish the two species (see also Ng et al., 2017, figs. 3A, 4A, 5A, 6A–B, 7A–C, 8A–B, 9A–B, 10A–D). The mesial margins of the branchial regions are more widely separated such that several rows of small spines are present along the midline between the two regions in P. griffini (a single row of spines in P. moseleyi ); and the merus of the fifth ambulatory leg is relatively shorter in P. griffini than in P. moseleyi (merus length/pcl: 0.7 in P. griffini ; 0.8–1.0 in P. moseleyi ; 0.6 in the present male).

Distribution. North West Shelf of Australia; Timor Sea; Sumatra and off the Tanimbar Islands, Indonesia; 295–400 m depth.

Figures

Fig. 5. A: Pleistacantha griffini Ahyong and Lee, male (NSMT-Cr 29258: CB 6.7mm×CL 10.2mm excluding pseudorostral spines) from sta. 28 (Timor Sea, 295–296m depth). B: Cyrtomaia suhmi Miers, male infected by epicaridean parasites in both branchial chambers (NSMT-Cr 29259: CB 31.6mm excluding branchial spines×CL 26.2mm excluding pseudorostral spines) from sta. 26 (Timor Sea, 610–690m depth). C–D: Dorhynchus rostratus (Sakai), female (NSMT-Cr 29261: CB 15.2mm×CL 15.0mm excluding pseudorostral spines) from sta. 26 (Timor Sea, 610–690m depth). E: Platymaia fimbriata Rathbun, male (NSMT-Cr 29263: CB 14.0mm×CL 12.6mm excluding pseudorostral spines) from sta. 26 (Timor Sea, 610–690m depth). F: Platymaia wyvillethomsoni Miers, ovigerous female (NSMT-Cr 29264: CB 39.5mm excluding branchial spines×CL 36.7mm excluding pseudorostral spines) from sta. 28 (Timor Sea, 295–296m depth).