Chaceon gordonae

Chaceon gordonae (Ingle, 1985)

(Figure 2)

Geryon gordonae Ingle, 1985: 90, fig.: 1, 2, 5a.

Chaceon gordonae — Manning and Holthuis, 1989: 8.— Afonso-Dias et al., 2008: 1, fig. 2a.

Material examined. 2♀, MOUFPE 15256, São Pedro e São Paulo Archipelago (0°54'787''N e 29°21' 451''W), 200 m, June 2012. 2♂, MOUFPE 15257, São Pedro e São Paulo Archipelago (0°54'787''N e 29°21' 451''W), 700 m, December 2013 (Table 2).

Diagnosis. Lateral part of orbital dorsal margin slightly concave, first anterolateral tooth produced, inner infraorbital tooth/antennal third peduncular segment noticeably depressed, dactylus of pereopods 2–5 laterally compressed, submedian frontal teeth on a frontal projection, inner orbital teeth spinosed, breadth of orbit (measured from inner to outer orbital tooth) noticeably less than width of frontal margin. Upper margin of cheliped palm with distal tooth, outer anterior margin of carpus with a tooth in small males. Dorsal margin of merus with distal and subdistal teeth. Merus of pereopods 4–5 with antero-dorsal tooth, third maxilliped merus with length/ breadth as broad as long, third maxilliped merus with outer margin disto-externally angular and, finally, carapace broader than long (Ingle, 1985; Afonso-Dias et al., 2008).

Distribution. Geryonid crabs are widely distributed in the world´s ocean, commonly occurring on continental slopes at depths of 100- 2.000 m (Manning & Houlthuis, 1989). Ingle (1985), based on two males and two females caught at 1.153 m, from southern Iceland to Sierra Leone Ridge, off western Africa, reported the occurrence of Chaceon gordonae, in the Atlantic Ocean.

Afonso-Dias et al. (2008), analyzing collections of São Tomé e Príncipe Archipelago, also off western Africa, was the second to report the specie in the North Atlantic Ocean. They found C. gordonae in reasonable quantities, enough to sustain a small artisanal fishery since 1980. The species was reported for the first time from SPSPA, by Ferreira et al. (2016).

Parameters

Specimens CW CL LQL LQW RQL RQW AW 1 79.1 56.7 41.1 13.3 42.6 13.9 25.2 2 75.1 48.5 38.7 12.7 36.9 11.4 21.1 3 122.1 88.3 72.1 22 76.6 24.6 - 4 1 3 0 1 0 6 9 2 3 2 9 4 3 5 - Remarks. The Geryonidae family currently has three genera: Geryon with five species, Chaceon with 28 species and Zariquieyon with a single species (Manning & Holthuis, 1989; Ng et al., 2008). In Brazil, there were three species of the genus Chaceon already reported: C. notialis Manning and Holthuis, 1989; C. ramosae Manning, Tavares and Albuquerque, 1989; and C. linsi Tavares & Pinheiro, 2011. Chaceon gordonae, collected at SPSPA, represents the fourth species occurring in Brazilian waters (Pezzuto et al., 2006; Tavares & Pinheiro, 2011; Ferreira et al., 2016).