Macrophthalmus (Macrophthalmus) Desmarest, 1823

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 : 37-39

Macrophthalmus (Macrophthalmus) Desmarest, 1823

( Figs. 2A, 2B, 2C ; 3A, 3B )

Large, up to 40 mm carapace breadth; ocular peduncles elongate to extremely elongate, projecting or not projecting beyond lateral carapace margins, much longer than breadth of front; front narrow, constricted between bases of ocular peduncles, where its breadth is 7–17% the distance between external orbital angles; ischium of external maxilliped> 1.7 times length of merus; carapace with breadth> 1.5 and usually> 2 times length, with large, well-developed, outwardly directed, pointed anterolateral teeth of which external orbital angle often narrowly-based, with lateral margins diverging anteriorly, branchial regions without longitudinal or transverse granular rows of granules but with three distinct clumps of granules longitudinally aligned; central region of posterior border of epistome with a central protuberance; fingers of male chelae short to elongate with index straight or downflexed, differentiated teeth on both dactylus and index, inner surface of palm often with large spine near joint with carpus. Intertidal to subtidal, the intertidal species usually in firmer, sandier substrata than those inhabited by Mareotis .

The type subgenus contains 21 species, divisible into two speciose groups and three small ones, two of them monotypic:

Figures

Fig. 2. Form of the carapace and adult male chela of subgroups of the genus Macrophthalmus II, the subgenus Macrophthalmus part 1: (a) M. telescopicus group, (b) M. brevis group, and (c) M. convexus group. Scale bars = 5mm.

Fig. 3. Form of the carapace and adult male chela of subgroups of the genus Macrophthalmus III: (a, b) the subgenus Macrophthalmus part 2, M. transversus (a) and Macrophthalmus dentatus (b); (c) the M. crinitus group of the subgenus Mareotis. Scale bars = 5mm.