Seleniolycus robertsi

biology_ecology

Reproduction. The ovary of the only ripening female (BMNH 2006.6.21.1, 348 mm SL) measures 52.3 mm in length. Light orange eggs up to 5.9 mm in diameter.

Two new species of eelpouts (Teleostei, Zoarcidae) of the genus Seleniolycus from the Ross Dependency, Antarctica.

description

Description. Principal counts and measurements are presented in Table 1. Vertebral centra symmetrical, with prezygapophyses and postzygapophyses of equal horizontal length. Anal fin pterygiophores 2 (1 - 2) inserted anterior to haemal spine of first caudal vertebra. Caudal fin with 1 (1 - 2) epurals, 4 upper and 4 (4 - 5) lower hypural rays. Epipleural ribs on 4 (3 - 4) to penultimate precaudal vertebra. Gill rakers on outer surface of first gill arch simple (not furcate) and with spinules. Branchiostegal rays 6. Pectoral fin relatively short; its origin below body midline; lower rays not thickened. Pelvic fin absent. Body elongate; trunk relatively slender, tail laterally compressed. Head ovoid, robust; snout broadly rounded. Eyes small, slightly ellipsoid, not reaching dorsal profile of head. Mouth terminal; lower lips without lateral lobe; upper lip continuous across snout. Snout blunt, upper jaw not protruding, reaching posteriorly to about mid-eye or before. Nasal tube well developed, but not reaching upper lip. Gill slit moderate, extending ventrally to base (or just below base) of pectoral fin. Opercular lobe at dorsal margin of gill slit, short, rounded. Jaw, vomer, and pal

Two new species of eelpouts (Teleostei, Zoarcidae) of the genus Seleniolycus from the Ross Dependency, Antarctica.

diagnosis

Diagnosis. Differs from congeners by the presence of scales on posterior half of body, a short pectoral fin 7.9 - 9.4 % SL, dorsal fin rays 84 - 89, and anal fin rays 69 - 73. It is further diagnosed by the following combination of characters: suborbital head pores 6, preoperculomandibular pores 8; predorsal length 27.1 - 36.4 % SL; snout length 29.8 - 51.6 % HL, eye diameter 11.0 - 13.0 % HL; pectoral fin rounded, 15 - 16 rays, none exserted; anterior dorsal fin pterygiophore associated with vertebra 6 - 8; vertebrae 24 - 26 + 63 - 71 = 88 - 97.

Two new species of eelpouts (Teleostei, Zoarcidae) of the genus Seleniolycus from the Ross Dependency, Antarctica.

discussion

Comparison with congeners. Seleniolychys robertsi resembles S. laevifasciatus in having a rounded pectoral fin without ventrally exserted rays, and in most morphometric characters (Table 1). It differs, however, by the longer predorsal distance (27.1 - 36.4 vs. 20.0 - 23.8 % SL), a scaled posterior part of the body (vs. naked), and by having more suborbital head pores (6 vs. 5). It resembles S. pectoralis sp. nov. (see below) in having a scaled posterior body, (although the distance from the snout to the anterior scales is shorter (48.9 - 55.4 vs. 58.7 - 61.8 % SL )) and in the number of head pores and most other characters (Table 1). But S. robertsi is more slender, has a shorter head (16.1 - 18.8 vs. 19.8 - 24.6 % SL) and a different pectoral fin shape from S. pectoralis (Fig. 3).

Two new species of eelpouts (Teleostei, Zoarcidae) of the genus Seleniolycus from the Ross Dependency, Antarctica.