Argyropelecus hemigymnus Cocco 1829

Argyropelecus hemigymnus Cocco, 1829

(Fig. 5E)

Diagnosis. Argyropelecus hemigymnus differs from congeners by the PAN, AN and SC in separated groups; AN series length shorter than the gap between AC and SC; a single post-abdominal spine with serrated margins; an elongated, slender posterior body trunk; 8 dorsal-fin rays (Baird, 1971; Borodulina, 1978; Lima et al., 2011; Harold et al., 2015).

Geographical distribution. Circumglobal in tropical and temperate waters, between 66ºN and 60ºS, including the Mediterranean Sea (Baird, 1971; Borodulina, 1978; Pequeño, 1989; Quéro et al., 1990b; Harold, 2003; Møller et al., 2010; Harold et al., 2015; Elbaraasi et al., 2019; Sutton et al., 2020; Love et al., 2021). In the western Atlantic, the species was reported from off Greenland to Argentina, including the Gulf of Mexico and the Caribbean Sea (Parin et al., 1974; Borodulina, 1978; Baird, 1971; McAllister, 1990; McEachran, Fechhelm, 1998; Harold, 2003; Møller et al., 2010; Judkins, Haedrich, 2018). Argyropelecus hemigymnus was also reported along almost the entire Brazilian coast, and off Saint Peter and Saint Paul Archipelago (Borodulina, 1978; Figueiredo et al., 2002; Menezes et al., 2003; Bernardes et al., 2005; Haimovici et al., 2008; Costa, Mincarone, 2010; Lima et al., 2011; Olivar et al., 2017; Judkins, Haedrich, 2018; Eduardo et al., 2020a). Larvae were recorded off Rio de Janeiro State (Bonecker et al., 2014). Specimens of A. hemigymnus examined here were collected off Pernambuco, Alagoas, and Rio Grande do Norte States (including the seamounts), and off the Rocas Atoll and Fernando de Noronha Archipelago, between depths of 260 and 1,113 m (Fig. 3E).

Specimens examined. 53 (8–31 mm SL): NPM 3201, 7 (8–20 mm), AB1#15; NPM 3202, 3 (27–30 mm), AB1#14; NPM 3203, 5 (21–26 mm), AB1#22; NPM 3204, 11 (16–22 mm), AB1#26; NPM 3999, 2 (11–13 mm), AB1#52; NPM 4136, 4 (14–28 mm), AB2#59A; NPM 4137, 3 (23–26 mm), AB2#16; NPM 4138, 2 (26–31 mm), AB2#42A; NPM 4139, 1 (25 mm), AB2#52A; NPM 4140, 5 (22–28 mm), AB2#41A; NPM 4188, 2 (17–21 mm), AB2#56C; NPM 4429, 1 (22 mm), AB2#44A; NPM 4432, 5 (19–22 mm), AB2#46A; NPM 4456, 1 (21 mm), AB2#46B; NPM 5734, 1 (15 mm), AB2#52B.