Loligo vitreus Rang, 1837: 71

Loligo vitreus Rang, 1837: 71 , pl. 96.

Type material: MNHN type; specimen not extant [fide Lu et al. (1995: 327)] .

Type locality: Equatorial coast of Africa (Equatorial Atlantic).

Diagnosis

Ommastrephes with a maximal mantle length of 900 mm and weight of 25 kg; maximal spermatophore length 21–41 mm (9.5 ± 1.45% DML), cement body of spermatophore 11%, sperm reservoir 44.7% and posterior empty end 22% of spermatophore length. Cytochrome c oxidase I diagnostic characters: 30, G; 103, G; 306, A; 493, T; 16S rRNA diagnostic character: 435, G.

Name of the species in the phylogenetic analyses: Ommastrephes group 2.

Distribution: Tropical and South Atlantic (from 14 to ~ 50°S) and tropical and south Indian (~10– 35°S) waters. A significant part of the distributional range for this species was confirmed with COI ( Fig. 3), but specimens were not available for genetic analysis from the eastern part of the Indian Ocean or from the southernmost part of the Atlantic Ocean. The absence of differences in substrate- and inhibitor-specific cholinesterase activities of optical ganglia between specimens sampled in the South Atlantic and south-eastern Indian waters reported by Shevtsova et al. (1979) and Rozengart & Basova (2005) supports the conspecificity of all Ommastrephes specimens within the distributional range depicted for O. cylindraceus ( Fig. 3). It is also noteworthy that Dunning (1998) described a discontinuous distributional range of Ommastrephes spp. at the tip of South America and the south-eastern tip of Australia and considered both populations reproductively isolated. The results provided here ( Figs 1–3; Tables 2 –5) support this point of view and ensure the recognition of O. cylindraceus and O. brevimanus as different species.

The single specimen of this species analysed from Cape Verdean waters (18°N) merits further discussion. Zuev et al. (1976) sampled Equatorial Atlantic waters extensively without finding any Ommastrephes individuals. Therefore, it is commonly accepted that the genus Ommastrephes is not present in Equatorial Atlantic owing to the temperature (see Roper et al., 2010). However, sequences obtained herein reveal that the Cape Verde individual belongs to O. cylindraceus ( Figs 1–3; Tables 2 –5). This isolated spot from the remaining distributional range of the species can be explained by drift of specimens from the Southern Hemisphere, along with the subsurface and intermediate waters of southern origin with the South Atlantic central water (100–500 m, 5–18 °C) and the Antarctic intermediate water (500–1200 m, 2–6 °C), which penetrate from the southern subtropical zone to the north-western coast of Africa up to 20–24 and 28– 34°N, respectively ( Arístegui et al., 2009; Machini & Pelegri, 2009). Similar cases of distant migrations far outside the main distributional range of the species to the other hemisphere with deep waters are also known ( Mǿller et al., 2003; Arkhipkin et al., 2010).