Mecataleptodius, Tavares & de Mendonça, 2022

In, First Published, 2022, Brachyuran crabs (Crustacea, Decapoda) from the remote oceanic Archipelago Trindade and Martin Vaz, South Atlantic Ocean, Zootaxa 5146, pp. 1-129 : 65

Mecataleptodius gen. nov.

Type species. Cancer parvulus Fabricius, 1793: 451 , by original designation [Type locality: “Americae meridionalis insulis”]. Gender: masculine.

Species included. Mecataleptodius parvulus (Fabricius, 1793), gen. nov., comb. nov., and Mecataleptodius olsoni ( Manning & Chace, 1990) , gen. nov., comb. nov. (type locality: Ascension Island).

Etymology. The name Mecataleptodius is formed from the Greek prefix “me” (not) and the masculine generic name Cataleptodius .

Diagnosis. Carapace suboval ( Fig. 34A, C ), about 1.5 times broader than long, moderately convex anteriorly, flat posteriorly. Areas of carapace generally well recognizable, anterior two-thirds lobulated, but not posteriorly. Anterolateral margin cut into 5 broad teeth or lobes; posterolateral margins nearly straight, strongly convergent. Frontorbital margin (exorbital tooth included) about half of maximum carapace width, incised in middle line. Orbits suboval; eyestalks short, massive. Antennal flagellum not excluded from orbit, lodged in infraorbital notch. Chelipeds ( Fig. 34A–C, E ) slightly to moderately unequal in both sexes; tips of fingers spooned. Pleon of male with somites 3–5 fused. Gonopod as illustrated ( Fig. 35D, E ).

Remarks. The two species here transferred to Mecataleptodius gen. nov. strongly differ from the species in Cataleptodius Guinot, 1968 , in the morphology of the first gonopod, as revealed by its type species, C. floridanus ( Gibbes, 1850) (type locality: Key West, Florida), and the east Pacific C. occidentalis ( Stimpson, 1871b) (type locality: Panama and Manzanillo, Mexico) ( Figs. 35A–C , 36C ). In Mecataleptodius gen. nov. the first gonopod ends in a rounded apical projection extending beyond the subterminal field of spines and long setae ( Fig. 35D, E ).

Ng et al. (2008) suspected that Mecataleptodius parvulus gen. nov., comb. nov., was not a member of Cataleptodius by referring to it with a question mark,? Cataleptodius parvulus . Barros-Alves et al. (2013) compared the first zoea stage of M. parvulus gen. nov., comb. nov. (as Cataleptodius parvulus ) with the first zoea of a number of other Xanthidae (including Cataleptodius floridanus ) and opined that the differences found suggested that it was not a member of Leptodius A. Milne-Edwards, 1869 , Xantho Leach, 1814 , Xanthodius Stimpson, 1859 , or Cataleptodius , as also shown herein by the morphology of the first male gonopod ( Figs. 35A–E , 36A–D ).

More research is necessary to confirm as to whether or not other species currently included in Cataleptodius actually belong to Mecatalecptodius gen. nov.

Figures

FIGURE 34. A, B, Mecataleptodius parvulus (Fabricius, 1793), gen. nov., comb. nov., male, cl 6.5 mm, cw 10 mm (MZUSP

FIGURE 35. A–E, First male gonopods. A–C, Cataleptodius floridanus (Gibbes, 1850). A, B, Male, cl 17 mm, cw 27 mm (MZUSP 9937). C, Male from Tortugas, Florida, cl 7 mm, cw 11 mm (after Monod 1956: 293, fig. 356, as Xantho floridana, reproduced by Guinot 1968: 707, fig. 23, as Cataleptodius floridanus). D, Mecataleptodius parvulus (Fabricius, 1793), gen.

FIGURE 36. A–D, First male gonopods. A, Leptodius exaratus (H. Milne Edwards, 1834), type species of Leptodius A. Milne- Edwards, 1869, neotype, cl 16.1 mm, cw 23.7 mm, after Lee et al. (2013:195, fig. 4B). B, Xantho hydrophilus (Herbst, 1790), senior synonym of Cancer incisus Leach, 1814, type species of Xantho Leach, 1814, after Drach & Forest (1953:18, fig. 21, as Xantho floridus Montagu, 1808). C, Cataleptodius occidentalis (Stimpson, 1871), after Holthuis (1954: 30, fig. 11b). D, Xanthodius sternberghii Stimpson, 1859, type species of Xanthodius Stimpson, 1859 (after López 1990).