Barathronus multidens Nielsen, 1984

Nielsen, Jørgen G., 2019, Revision of the circumglobal genus Barathronus (Ophidiiformes, Bythitidae) with a new species from the eastern North Atlantic Ocean, Zootaxa 4679 (2), pp. 231-256 : 246-248

Barathronus multidens Nielsen, 1984

Table 2. Figs. 1 , 18–20

Barathronus multidens Nielsen, 1984a: 583 (type locality: 32°54.6’N, 11°40.0’W).

Barathronus multidens: Nielsen et al. 1999: 139 ; Evseenko et al. 2018.

Material examined (3 specimens, SL 45–83 mm): Holotype: BMNH 1983.2 .28.1 (SL 72 mm, male), off southern Morocco, 32°54.6’N, 11°40’W, RV Discovery , cr. 77, st. 8976, bottom trawl, 3610–3646 m, 5 Aug. 1976 . Paratype: ZMUC P77712 (SL 83 mm ,, male), north of Bahamas, 29°19.7’N, 73°18.6’W, RV Columbus Iselin , cr. 8007, st. CO57, 45’ otter trawl, 4269–4279 m, 19. Sep. 1980 . Non-type ; IORAS 03293 (SL 45 mm, juv.), Mid-Atlantic ridge, 16°50.052’N, 46°33.045’W, RV Professor Logachev, cr. 37, st. 158, Sigsbee trawl, 3227 m, 4 Mar. 2015 .

Diagnosis. Barathronus multidens differs from the other four Barathronus species with a transparent peritoneum by the following combination of characters: vomer with 11 and dentaries with 8–11 fangs, dorsal-fin rays 72–ca. 75, anal-fin rays 62– ca. 65, pectoral-fin rays 23–24, precaudal vertebrae 32–34, total vertebrae 77–79, long gill rakers on anterior arch 23–25, paired bulbs at basis of penis absent ( Fig. 19 ), penis protected ventrally by large urogenital hood and no ventral flexure of anterior vertebrae. The very small otolith ( Fig. 20 ) is almost circular with the undivided sulcus placed centrally. Head and body yellowish without pigmentation.

Description. For a detailed description of the holo- and paratype see Nielsen (1984a: 583) and for the juvenile see Evseenko et al. (2018: 138). The principal meristic and morphometric characters are shown in Table 2.

Comparisons. Barathronus multidens seems most similar to B. parfaiti sharing a transparent peritoneum and lack of ventral flexure of anteriormost vertebrae. They differ by B. multidens having more fangs on vomer (7–11 vs. 1+) and less long rakers on anterior gill arch (23–25 vs. 29).

Distribution ( Fig. 1 ). The three specimens known are from the East (3610-3646 m) and West (4269-4279 m) Atlantic Ocean and from the Mid-Atlantic Ridge (3227 m), all caught in bottom fishing gear. The specimen from the Mid-Atlantic Ridge is a juvenile with weekly ossified vertebrae which indicates that it might have been caught pelagically during hauling of the trawl. The other two specimens are adult males with well-ossified vertebrae indicating a benthopelagic occurrence.

Remarks. Evseenko et al. (2018: 139) presented two phylogenies each based on two different genes.

Figures

FIGURE 1. Records of Atlantic Barathronus species. Numbers indicate several stations.

FIGURE 18. Barathronus multidens, BMNH 1983.2.28.1, holotype, male, SL 72 mm (M. Krag photo).

FIGURE 19. Intromittent organ of Barathronus multidens, BMNH 1983.2.28.1, holotype, male, SL 72 mm (from Nielsen 1984a).

FIGURE 20. Right otolith from paratype of Barathronus multidens, ZMUC P77712, male, SL 83 mm.