Mabui calculus Naruse, Maenosono and Ng, 2021

Alrasheedi, Sami M, Alrashdi, Mousa N, Alhumaidan, Lama S, Alkhdairi, Ahmad, Alzweihary, Ali M, Alhussaini, Omar M, Alharbi, Lama S, Albalawi, Amirah N, Almutairi, Turki F, Alharbi, Osama A G & Bashal, Afaf A M, 2024, Crabs of the Families Tetraliidae, Trapeziidae and Xanthidae (Crustacea: Decapoda: Brachyura) new to the Ogasawara Islands, Japan, Bulletin of the National Museum of Nature and Science. Series A, Zoology 50 (1), pp. 1-17 : 9

Mabui calculus Naruse, Maenosono and Ng, 2021

[Jn: Mabuigani]

( Fig.3F)

Material examined. A photograph only. The specimen was collected at the diving site Shihon-iwa North, Haha-jima Island, on 2 July, 2015, by H. Komatsu, and photographed, but unfortunately the specimen was missing.

Remarks. The photograph at hand agrees well with the detailed description, photographs and line drawings in the original description ( Naruse et al., 2021). The carapace is elliptical in outline, smooth and ill-defined, with the weakly fourlobed anterolateral margins. Although the carapace formation is rather simple and not much different from the related xanthid species, but the original description made clear that the external genital structures are bilaterally asymmetric in both sexes, being exceptional as the crabs.

Distribution. This species is known from some local places of Okinawa-jima Island, the Ryukyu Islands, and said that the type specimens were collected from the exposed surf zones of rocky coast or the narrow crevasses in shallow-water coral reefs.