INTRODUCTION
The deep-sea fauna from the Cape Verde region is poorly known so far. The earliest surveys were made in 1957–1959, and the information was compiled by Franca & Vasconcelos (Reference Franca and Vasconcelos1962). Reiner (Reference Reiner1996, Reference Reiner2005) reviewed the data on fish biodiversity of Cape Verde, and more recently Menezes et al. (Reference Menezes, Tariche, Pinho, Duarte, Fernandes and Aboim2004) and Monteiro et al. (Reference Monteiro, Ribeiro, Silva, Bispo and Gonçalves2008) provided new information on the ichthyofauna for the archipelago.
The genus Kali belongs to the deep-sea fish family Chiasmodontidae, which includes the species: K. indica Lloyd 1909; K. kerberti (Weber, 1913); K. macrodon (Norman, 1929); K. macrurus (Parr, 1933); and K. parri Johnson and Cohen, Reference Johnson and Cohen1974. The first taxonomic revision of Kali was conducted by Johnson (Reference Johnson1969), after examining a large collection from the Pacific. The same author considered K. keberti as a junior synonym of K. indica and subsequently recorded K. parri for the Atlantic waters (Johnson & Cohen, Reference Johnson and Cohen1974). Due to their similarities, the juvenile pelagic stage of the chiasmodontid Kali sp. are currently referred to as the gargaropteron stage (Melo, Reference Melo2008), characterized by greatly elongated paired fin rays and covered with spinoid scales (Mooi & Paxton, Reference Mooi, Paxton, Carpenter and Niem2001). Melo (Reference Melo2008) recently assessed the taxonomic state of the genus and described two new species: K. colubrina and K. falx. The global distribution of the genus Kali is recognizable, except for K. falx, which has been found only in the northern hemisphere (Melo, Reference Melo2008).
The genus is clearly taxonomically complex, with the existence of synonymous species (reviewed by Melo Reference Melo2008, Reference Melo2010). The most distinctive characters of Kali spp. are recurved teeth, weak bones and, in some species, enlarged fangs.
New findings of chiasmodontid species were recently published by Prokofiev (Reference Prokofiev2009, Reference Prokofiev2011a, Reference Prokofievb). However, Kali macrodon has never been recorded from Cape Verdean waters until now.
MATERIALS AND METHODS
During the research cruise RV ‘Meteor M79/3’, one specimen of snaketooth Kali macrodon (Figure 1) was collected from a deep-sea trawl catch made north of Senghor Seamount, off Cape Verde, on 30 September 2009. The sampling gear was a 45 ft semiballoon otter trawl towed on a single warp at 2–3 knots along the transect from 18°1.701′N 22°4.277′W to 18°7.780′N 21°57.745′W to a maximum depth of 3310 m. The estimated horizontal net opening of the trawl was 8.6 m (Merrett & Marshall, Reference Merrett and Marshall1981); the mesh size was 44 mm in the front part and 37 mm in the intermediate and rear parts, with a 13 mm inner liner in the cod-end.
(A) Kali macrodon (165 mm total length) collected off Cape Verde (ZMH 25902); (B) close-up of dentition of the specimen.
Total length (TL) of the fish was measured immediately after recovery of the catch. All fish taken in the haul were frozen at −20°C. The fish was thawed for examination in the laboratory and refrozen before being fixed in formalin and later transferred to be preserved in 70% ethanol. The specimen was identified after Melo (Reference Melo2008) following morphological, morphometric and meristic characters.
Material examined
One specimen, Zoological Museum of Hamburg (ZMH) 25902, 165 mm TL, Cape Verde, off Senghor Seamount, 18°1.701′N 22°4.277′W to 18°7.780′N 21°57.745′W, 3310-0 m, 30 September 2009, RV ‘Meteor.
Comparative material
Kali macrodon: one specimen, ZHM 7123, 280 mm TL, station 196, 34°2′N–15°18′W, 3900-0 m, 8 March 1970, RV ‘Meteor'; 1 specimen, ZHM 120838, 160 mm TL, Mid-Atlantic Ridge, station 401/82, 49°51.7′N–16°51.7′W, 3200 m, 19 June 1982, RV ‘Walther Herwig'; two specimens, ZHM 120873, 200 mm TL, Mid-Atlantic Ridge, station 336/82, 45°02.6′N–16°06.7′W, 3200 m, 6 June 1982, RV ‘Walther Herwig'; one specimen, ZHM 121779, 260 mm TL, station 3/3, 46°04.5′N–16°48.6′W, 2300 m, 12 June 1983, RV ‘Walther Herwig'.
RESULTS AND DISCUSSION
The specimen identified as Kali macrodon was photographed and preserved before inclusion at the reference collection of the ZMH (Catalogue number ZMH 25902). Meristics and morphometry agree with a combination of characteristics given by Melo (Reference Melo2008). Although some meristic data and characters were difficult to discriminate in the partially damaged specimen, the dentition allowed for a definite identification of the collected individual (Figure 1). Teeth are present on premaxilla, dentary, palatine, upper and lower pharyngobranchials. Premaxilla elongate, strongly arched laterally, with two series of teeth, lateral and mesial. Lateral series in single row, needle-like, small numerous, without flange, closely spaced, increasing in size from anterior to posterior on first half, gradually decreasing in size to posterior end. Teeth at anterior portion smaller, increasing in size until middle of premaxilla then decreasing in size posteriorly. Mesial series in single row, irregularly arranged. First tooth type 4, conical, slightly curved, without flange, not developed as fang; following teeth with ventral attachment, recurved fang-like, largest tooth ~20% in premaxillary length, with flange. Base of first tooth at anterior-ventral tip of premaxilla; second to last teeth (fangs) equally spaced between level of ascending process of premaxilla and posterior margin of orbit, decreasing in size from anterior to posterior.
Kali macrodon differs from other Kali species, except K. kerberti, by the ascending process of the premaxilla with a strong concavity limited anteriorly by a bony crest (versus ascending process of premaxilla flat or with gentle concavity, anterior bony crest absent); teeth in lateral series of premaxilla and dentary 16 or more, type 4, needle-like (versus teeth in lateral series of premaxilla with ventral attachment, recurved, teeth in K. parri; premaxilla six to 11, dentary five to eight, caniniform, slightly curved in K. indica and K. falx; premaxilla 13–22, dentary 6–10, recurved in K. colubrina). Kali macrodon can also be distinguished from K. macrura by teeth in lateral series of premaxilla and dentary type 4, needle-like, extending to the end of dentigerous area, teeth with ventral attachment absent in lateral series (versus teeth in lateral series of premaxilla and dentary type 4, needle-like in anterior third and fourth, respectively, followed by teeth with ventral attachment, recurved in posterior areas). Kali macrodon differs from K. kerberti by the teeth in the mesial series of premaxilla six to nine, modally seven, and of dentary seven to nine, modally eight (versus teeth in mesial series of premaxilla and dentary four to five, modally five) (Melo, Reference Melo2008).
Kali macrodon is a bathypelagic species, living generally between 1000 and 2500 m deep. Diel vertical migrations are unknown for the genus Kali (Melo, Reference Melo2008). The exact sampling depth of the specimen described above cannot be determined, since no closing net was used.
The presence of K. macrodon is reported for tropical and subtropical regions of the Indian and Pacific Oceans (Melo, Reference Melo2008; Froese & Pauly, Reference Froese and Pauly2012). In the Atlantic, this deep-sea species is known from 53°N to 40°S, including some localities from the Gulf of Mexico (biodiversity occurrence data accessed through the Global Biodiversity Information Facility (GBIF) data portal (http://data.gbif.org/)), Atlantic Sub-Antarctic (Melo, Reference Melo2008), and the Mid-Atlantic Ridge, where five specimens were found from the Charlie-Gibbs Fracture Zone to the Azores (Sutton et al., Reference Sutton, Porteiro, Heino, Byrkjedal, Langhelle, Anderson, Horne, Søiland, Falkenhaug, Godø and Bergstad2008). In the eastern Atlantic the species was reported at four stations between 24°N and 19°S, but its occurrence is unknown from the Benguela Current and Gulf of Guinea (Melo, Reference Melo2008; Froese & Pauly, Reference Froese and Pauly2012). The new record of K. macrodon is the first in Cape Verdean waters, the fifth report for the north-eastern Atlantic and the third specimen ever caught in tropical waters. In this respect, it can be predicted that K. macrodon may occur in the vicinity of other Macaronesian islands, particularly the Canary archipelago, or associated with seamounts along the north-eastern part of the Atlantic.
ACKNOWLEDGEMENTS
The authors are grateful to Jim Ellis and two anonymous referees for comments that improved the manuscript, to Marcelo Melo for the useful information and literature provided, and to the crew of RV ‘Meteor' for their professional support on the cruise. Rui Pedro Vieira would like to thank DAAD—Deutscher Akademischer Austauschdienst (German Academic Exchange Service) for providing a short-term scholarship for research in the Institut für Hydrobiologie und Fischereiwissenschaft—Universität Hamburg (Germany), and CCMAR for their financial support. The Deutsche Forschungsgemeinschaft (DFG) provided the ship time and financial support for the ‘Meteor M79/3' cruise.
