Migmarma modestum ( De Man, 1902 )

Schubart, Christoph D. & Ng, Peter K. L., 2020, Revision of the intertidal and semiterrestrial crab genera Chiromantes Gistel, 1848, and Pseudosesarma Serène & Soh, 1970 (Crustacea: Brachyura: Sesarmidae), using morphology and molecular phylogenetics, with the establishment of nine new genera and two new species, Raffles Bulletin of Zoology 68, pp. 891-994 : 968

Migmarma modestum ( De Man, 1902)

( Figs. 45 , 46 )

Sesarma (Sesarma) modesta De Man, 1902: 511 , pl. 19 fig. 8; Tesch, 1917: 175; Roux, 1917: 619.

Sesarma (Sesarma) modestum – Serène, 1968: 105.

Pseudosesarma modestum – Serène & Soh, 1970: 400; Ng et al., 2008a: 222.

Material examined. Holotype: male (25.0 × 20.9 mm) ( SMF 1989 ), Ternate , Moluccas, Indonesia, coll. W. Kükenthal, 26 December 1893 – 11 June 1894.

Diagnosis. Carapace trapezoidal, wider than long; dorsal carapace surface uneven but not setose; epibranchial tooth distinct, separated by deep notch; posterolateral margins slightly divergent; outer surface of chela covered with rounded granules, those on margins relatively larger, outer surface almost flat, ventral margin of palm almost straight; suture between male thoracic sternites 3 and 4 distinct; ambulatory merus short, broad; male pleon triangular, telson relatively elongate, not sunken into distal margin of somite 6; male pleonal somite 6 relatively broader; G1 relatively stout, almost straight, chitinous distal part relatively short, stout, tip subtruncate.

Remarks. The identity of this species has long been uncertain. Serène & Soh (1970) referred it to Pseudosesarma where it has remained since, and the type has never been redescribed or refigured. Roux (1917) identified a female specimen from New Guinea to this species, but this cannot be confirmed until it can be re-examined. It is also possible that his specimen belongs to M. lustrum , new species, which is close to M. modestum but differs markedly in the form of the G1 (see next species).

Figures

Fig. 45. Migmarma modestum, holotype male (25.0 × 20.9 mm) (SMF 1989), Indonesia. A, overall habitus; B, dorsal view of carapace; C, frontal view of cephalothorax; D, anterior thoracic sternum and pleon; E, sternopleonal cavity; F, outer view of right chela; G, H, left G1; I–K, distal part of left G1.

Fig. 46. Migmarma modestum, holotype male (25.0 × 20.9 mm) (SMF 1989), Indonesia. A, left third maxilliped (denuded); B, pleon; C, left G1 (ventral view); D, left G1 (dorsal view); E, distal part of left G1 (ventral view); F, distal part of left G1 (mesial view); G, distal part of left G1 (dorsal view); H, distal part of left G1 (mesial view); I, left G2. Scales: A, C, D, I = 1.0 mm; B = 5.0 mm; E–H = 0.5 mm.