Macrophthalmus (Paramareotis) Komai, Goshima & Murai, 1995

Barnes, R. S. K., 2010, A Review Of The Sentinel And Allied Crabs (Crustacea: Brachyura: Macrophthalmidae), With Particular Reference To The Genus Macrophthalmus, Raffles Bulletin of Zoology 58 (1), pp. 31-49 : 42

Macrophthalmus (Paramareotis) Komai, Goshima & Murai, 1995

( Fig. 4B )

Small, carapace breadth <15 mm; ocular peduncles short and stout, not projecting beyond lateral carapace margins, subequal in length to breadth of front or shorter; front broad, not constricted between bases of ocular peduncles, where its breadth is 20–30% distance between external orbital angles; ischium of external maxilliped ca. 1.25 times length of merus; carapace with breadth 1.3–1.6 times length, with lateral margins subparallel, with broad-based subrectangular or pointed anterolateral teeth, without conspicuous aggregations of granules into rows or clumps on branchial regions (indistinct rows present in some); central region of posterior border of epistome usually straight (with convexity in one species); males with stridulatory apparatus in all species (i.e. with short horny ridge on ventoroflexor margin, or on inner surface near ventoroflexor margin, of cheliped merus, and lower orbital border with 1–2 large triangular protuberances occupying at least one fifth of that margin); fingers of male chela short with index straight or slightly downflexed and with differentiated teeth on both fingers. Intertidal, with one species often occurring in holes in limestone rocks and the others often associated with mangrove pneumatophores.

Four species are included: M. boteltobagoe ( Sakai, 1969) , M. erato de Man, 1888 , M. holthuisi Serène, 1973 , and M. quadratus A. Milne Edwards, 1873 (the type), Kosuge & Davie (2001) having demonstrated that M. boteltobagoe and M. holthuisi are distinct species contra the opinion of Barnes (1976). Molecular sequence data ( Kitaura et al., 2006) suggest that M. erato + M. quadratus are only distantly related to M. holthuisi + M. boteltobagoe , but instead are related to the M. brevis group of the subgenus Macrophthalmus .

Figures

Fig. 4. Form of the carapace and adult male chela of subgroups of the genus Macrophthalmus IV: (a) the M. japonicus group of the subgenus Mareotis (both the relatively parallel-sided and relatively rounded carapace types), and (b) subgenus Paramareotis. Scale bars = 5mm.