Saccogaster hawaii

biology_ecology

Biology and distribution (Fig. 25). Saccogaster hawaii is only known from the holotype caught at the upper continental shelf at a depth of 234 m off Maui, Hawaiian Islands.

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 4. Head and body elongate and compressed with tapering caudal part and blunt snout. Scales absent from predorsal part and from band along bases of dorsal and anal fins. Anteriormost scales widely scattered, those more posteriorly positioned closely spaced and on rear of body regularly imbricate. Lateral line indistinct. Dorsal fin origin above distal part of pectoral peduncle, anal fin origin well behind midpoint of fish and pelvic fins inserted below hind margin of opercle, ending below middle of pectoral fin. Anterior gill arch (Fig. 6 D) with three barely developed rakers scarcely longer than the three spiny knobs on upper branch and the knobs on lower branch. Very short gill filaments on anterior arch. No pseudobranchial filaments observed. No intromittent organ developed so it is probably an immature female. A pair of elongate gonads visible through transparent skin. Axial skeleton (from radiographs): Number of precaudal vertebrae 18. Anterior neural spine very short. Neural spines 2 – 4 long, depressed and with pointed tips. Neural spines 5 – 18 with short, blunt spines. Parapophyses developed

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

diagnosis

Diagnosis. Saccogaster hawaii differs from all other Saccogaster species by the opercular spine ending in three prongs. Also the following combination of characters is diagnostic: A pair of sub-dermal spines on frontal behind and above eyes, median sub-dermal ethmoidal spine in front of eyes with forward pointed tip; three developed rakers on anterior gill arch hardly longer than the knobs, extremely small filaments on anterior gill arch; scales absent on predorsal and present on median part of body; thin, transparent skin; palatines with single row of teeth; elongate pectoral peduncle longer than high; precaudal vertebrae 18 and total vertebrae 54; fin rays in dorsal 92, anal 55 and pectoral 22. Similarity. Saccogaster hawaii seems most similar to S. brayae (see comparison above).

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

materials_examined

Material examined (1 specimen, 69 mm SL). Holotype: USNM 207355, female, 69 mm SL, off Maui, Hawaii, 21 ° 00 ’ N, 156 ° 47 ’ W, R / V Townsend Cromwell, st. 40 – 62, bottom trawl, bottom temp. 15.9 ° C, 234 m, 19 Nov. 1968.

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