Bagbelly Cusk

biology_ecology

Biology and distribution (Fig. 25). The 18 examined specimens were caught in bottom fishing gear at depths of 440 – 850 m from off East Africa to Hawaii.

Revision of Hastatobythites and Saccogaster (Teleostei, Bythitidae) with three new species and a new genus

description

Description. The principal meristic and morphometric characters are shown in Table 6. Body compressed and elongate with tapering caudal part and blunt snout. Scales absent. Skin relatively thick, loose and semitransparent. Lateral line indistinct, originating above gill opening, descends gradually above anus and continues in midline becoming obscure posteriorly. In some specimens the 25 – 30 lateral line papillae are black clearly showing the course of the line. Dorsal fin origin above vertebrae 6 – 8 and anal fin origin below vertebrae 21 – 23. Pectoral fin reaching more than halfway to anus. Anterior gill arch (Fig. 18 F) with 3 – 4 spiny knobs on upper branch, a developed raker in angle and lower branch with two developed rakers with a knob between followed by 7 – 11 knobs. Number of knobs varies between 14 and 19. Two pseudobranchial filaments. Intromittent organ of holotype on a thick, fleshy, posteriorly directed stalk with the vent immediately anterior to its base; distal rim of stalk swollen and divided into two lobes, with a small penis in the middle; sections of the testes show spermatozoans arranged in spermatophores. In USNM 207354 (SL 130 mm) ovaries contain several hu

Revision of Hastatobythites and Saccogaster (Teleostei, Bythitidae) with three new species and a new genus

diagnosis

Diagnosis. Saccogaster tuberculata differs from the other Saccogaster species by the following combination of characters: No body scales; a pair of small, sub-dermal spines on frontal plate just behind eyes, median subdermal ethmoidal spine in front of eyes; skin rather thick; large posterior mandibular pore behind end of maxilla; cartilaginous ethmoidal spine on snout; opercular spine hidden, no preopercular spine; three developed rakers on anterior gill arch almost equal in length to developed rakers; pectoral peduncle prolonged; no fangs on dentigerous bones, palatines with 3 to several tooth rows; precaudal vertebrae 14 – 15 and total vertebrae 55 – 58; fin rays in dorsal 82 – 93, anal 54 – 60 and pectoral 19 – 22; otolith length to height 2 – 2.1, otolith length to colliculum length variable, 2.5 – 3.3. Similarity. Saccogaster tuberculata seems most close to S. horrida, both having developed gill rakers on anterior arch equal to or longer than long filaments, three developed gill rakers and no scales. They differ from each other by S. tuberculata having an indistinct frontal plate and small subdermal spines (vs. a distinct frontal plate with a pair of well developed, visible s

Revision of Hastatobythites and Saccogaster (Teleostei, Bythitidae) with three new species and a new genus

discussion

Remarks on variability. Saccogaster tuberculata is the most widely distributed species of the genus. It also shows a remarkably high variation of certain characters, which however is not consistent enough to warrant distinction of separate species. Particularly it appears that it is always single characters that make the distinction of any given variation, which is not supported by any independent second character. Two specimens from Hawaii, the northeastern-most occurrence of the species, show otoliths with a regularly curved dorsal rim (Fig. 18 G), whereas all others exhibit an undulating dorsal rim. The southwestern-most specimen, from off Madagascar, has a tight head skin (vs. mostly loose) and a distinctly narrower interorbital width (3.4 % SL vs. 3.9 – 5.6 % SL). A specimen from off New South Wales, Australia, has a single, feeble neuromast (Fig. 18 E) and two specimens from off the Solomon Islands show 2 and 3 neuromasts, respectively, all on the upper lip behind the eye. A few specimens from off the Solomon Islands show dusky pigmentation on the posterior part of the body.

Revision of Hastatobythites and Saccogaster (Teleostei, Bythitidae) with three new species and a new genus