Mesotheres strombi ( Rathbun, 1905 ) Ng & Ahyong & Campos, 2019

Ng, Peter K. L., Ahyong, Shane T. & Campos, Ernesto, 2019, Two new genera of pinnotherid crabs (Crustacea: Brachyura: Pinnotheroidea) from the Americas and the Western Pacific, Raffles Bulletin of Zoology 67, pp. 337-351 : 339

Mesotheres strombi ( Rathbun, 1905) new combination

( Figs. 1–6 )

Pinnotheres strombi Rathbun, 1905: 371 , figs. 1, 2; Rathbun, 1918: 90, pl. 20 figs. 1, 2; Wass, 1955: 158; Menzel, 1956: 46; Reed, 1992: 229.

Orthotheres strombi — Sakai, 1969: 275; Schmitt et al., 1973: 27; Abele & Kim, 1986: 64, fig. 705; Ng et al., 2008: 250; Felder et al., 2009: 1086; Hernández et al., 2017: 17, figs, 1, 2. Material examined. USNM 172221, 1 male (4.5 × 4.0 mm), 1 female (7.3 × 5.3 mm), Cedar Keys, coll. R. Merz & A. B. Williams, 1979; USNM 122770, 1 male (12.5 × 10.2 mm), 1 female (16.5 × 13.2 mm), from mantle of Florida Horse Conch Pleuroploca gigantea (at present Triplofusus giganteus [Kiener, 1840]) ( Fasciolariidae ), Cape Florida flats, Florida, U.S. A, coll. J. Roth, 26 May 1965; ULLZ 2595, 1 female, from within spire of large Pleuroploca, St. Joseph’s Bay, Florida, U.S.A., coll. S. & G. Graves, 25 July 1982.

Diagnosis. Carapace glabrous, convex in all directions. Short pubescence on carapace frontal margin, lower surface of carapace, pleon, MXP3, and margins of P2–P4 except dactyli. Eyes partially visible in dorsal view; front distinctly deflexed, defined by convex median projection in frontal view. P2–P4 similar, slender; P5 remarkably short, narrower than other legs.

Remarks. The female specimens of A. strombi studied by Rathbun (1905, 1918) had carapace width to length ratios of 1.45, but the two females examined are only 1.28 and 1.38, respectively, possibly due to individual variation and the state of preservation. Hernández et al. (2017) recently noted that his Venezuelan material had a mean carapace width to length ratio of 1.5.

Figures

Fig. 1. Mesotheres strombi (Rathbun, 1905) new combination, male (4.5 × 4.0 mm) (USNM 172221), Florida. A, overall dorsal habitus; B, ventral view of cephalothorax.

Fig. 2. Mesotheres strombi (Rathbun, 1905) new combination, female (7.3 × 5.3 mm) (USNM 172221), Florida. A, overall dorsal habitus; B, ventral view of cephalothorax.

Fig. 3. Mesotheres strombi (Rathbun, 1905) new combination, male (12.5 × 10.2 mm) (USNM 122770), Florida. A, overall dorsal habitus; B, frontal view of cephalothorax; C, ventral view of cephalothorax.

Fig. 4. Mesotheres strombi (Rathbun, 1905) new combination, female (16.5 × 13.2 mm) (USNM 122770), Florida. A, overall dorsal habitus; B, frontal view of cephalothorax; C, ventral view of cephalothorax.

Fig. 5. Mesotheres strombi (Rathbun, 1905) new combination, male (4.5 × 4.0 mm) (USNM 172221), Florida. A, outer view of right MXP3; B, inner view of right MXP3; C, pleon; D, anterior thoracic sternum, buccal cavity and right third MXP3; E, outer view of right chela; F, right P2; G, right P3; H, right P4; I, right P5; J, K, left G1; L, left G2. Scales: A, B, J–L = 0.5 mm; C–I = 1.0 mm.

Fig. 6. Mesotheres strombi (Rathbun, 1905) new combination, A–H, female (7.3 × 5.3 mm) (USNM 172221), Florida; I–P, male (12.5 × 10.2 mm) (USNM 122770), Florida. A, I, outer view of right MXP3; C, K, outer view of carpus, propodus and dactylus of right MXP3; B, J, inner view of right MXP3; D, outer view of right chela; E, right P2; F, right P3; G, right P4; H, right P5; L, pleon; M–O, left G1; P, left G2. Scales: A, B, D–H, I, J, M–P = 1.0 mm; C, K = 0.5 mm; L = 2.0 mm.