Cronius ruber ( Lamarck, 1818 )

TAVARES, MARCOS & MENDONÇA, JOEL BRAGA DE JR., 2022, Brachyuran crabs (Crustacea, Decapoda) from the remote oceanic Archipelago Trindade and Martin Vaz, South Atlantic Ocean, Zootaxa 5146 (1), pp. 1-129 : 53-54

Cronius ruber ( Lamarck, 1818)

( Fig. 27C, F )

Portunus ruber Lamarck, 1818: 260 .

Trindade specimens. 1 juvenile male ( MZUSP 40173 ), Brazil, off Espírito Santo, Trindade Island , Enseada dos Portugueses, 20°30’17.7”S, 29°18’56.7”W, J.B. Mendonça coll., 18.iv.2014, 10.2 m .

Size of largest male: cl 7 mm, cw 10 mm.

Comparative material examined. Cronius ruber : Brazil: 1 female ( MZUSP 4243 ), São Sebastião, São Paulo, E. Garbe coll. , 1915.

Distribution. Amphi-Atlantic. Western Atlantic: New Jersey, Virginia throughout the Gulf of Mexico and Antilles, Colombia, Venezuela, and Brazil (Amapá to Rio Grande do Sul) ( Rodriguez 1980; Lemaitre 1981; Williams 1984; Melo 1996; Felder et al. 2009). Williams (1984) cautioned that the record from New Jersey was based on a single male taken in 1974. This is the first record of Cronius ruber from Trindade. Eastern Atlantic: Madeira, Canary Islands ( González et al. 2017; Schäfer et al. 2019; Maggio et al. 2021), Cape Verde Islands, Dakar, Senegal ( Monod 1956; Manning & Holthuis 1981; Fransen 1991).

Ecological notes. Inhabits hard- (rocks, coralline reefs, rubbles, sublittoral caves) and soft bottoms (organogenic and, occasionally sandy bottoms, sand-seagrass meadow including Thalassia testudinum ) between the tide mark to 105 m ( Coelho & Ramos 1972; Heck 1977; González et al. 2017). Cronius ruber has been reported to use colonies of the bryozoan Schizoporella unicornis as a feeding site (Ales et al. 2013); juveniles were found in association with the sponge Amphimedon viridis (see Alves et al. 2012c). In Trindade, C. ruber was found in sandy bottom, close to rocks. A West African female was found to carry 474,400 eggs ( González et al. 2017). Ovigerous females are parasitized by Sacculina ( Rodríguez 1982) . Freitas et al. (2017) reported that the grouper Epinephelus morio (Valenciennes) feeds more heavily on crustaceans, particularly on C. ruber in the Abrolhos Bank (Bahia, Brazil); the grouper E. striatus , the mutton snapper Lutjanus analis (Cuvier) and Octopus vulgaris are also known to prey upon C. ruber ( Randall 1967; Anderson et al. 2008; Begossi et al. 2012).

Remarks. Ng & Nyberg (2013) showed that Portunus ruber Lamarck, 1818, is a junior synonym of Cancer thunborgii Euphrasén, 1795 , and clarified that P. ruber should be conserved by reversal of precedence under Art. 23.9.1 of the ICZN (1999: 27).

Manning & Holthuis (1981) discussed the morphological differences between the west- and east Atlantic populations of C. ruber ( Fig. 27C, F ) and mentioned that the name C. millerii (A. Milne-Edwards, 1867) is available for the west African population if, ultimately, it proves to be taxonomically distinct.

Figures

FIGURE 27. A, D, Achelous ordwayi Stimpson, 1860, male, cl 16.1 mm, cw 28.1 mm (MZUSP 21204). B, E, Achelous tumidulus Stimpson, 1871, ovigerous female, cl 10.5 mm, cw 16.5 mm (MZUSP 41419). C, F, Cronius ruber (Lamarck, 1818), juvenile male, cl 7 mm, cw 10 mm (MZUSP 40173). Note in (B, C) carapace anterolateral teeth unequal, alternating large and small (arrows). Scales: D–F, 0.5 mm.