Saccogaster maculata

biology_ecology

Biology and distribution (Fig. 25). A viviparous species caught in bottom fishing gear on the upper continental slope at depths between 265 and 600 m. Six specimens were caught in the Gulf of Bengal and one in the Gulf of Aden. * Dorsal fin, anal fin and vertebral counts from only two specimens

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

description

Description (from Cohen & Nielsen 1972: 449) The principal meristic and morphometric characters are shown in Table 5. Head and body elongate and compressed with tapering tail and blunt snout. Skin thin and transparent. Scales absent on predorsal and in a band along bases of dorsal and anal fins except posteriorly, where entire body is scaled. Anteriorly scales widely scattered, posteriorly scales imbricate. The scale pattern in Alcock and McArdle (1900, pl. 29, fig. 2) is inaccurate. Lateral line (Fig. 9) in two non-overlapping sections; anterior, dorsal part with about 12 small papillae extending from upper angle of opercle to about anus; posterior, median part with 8 – 10 small papillae ending somewhat anterior to base of caudal fin. Dorsal fin origin above pectoral peduncle and anal fin origin well behind midpoint of fish. Pectoral fin extending to more than half the distance from upper angle of peduncle to anal fin; peduncle longer than broad and free of body. Snout depressed and rounded. Small, darkly pigmented papillae and dermal fringes sparsely distributed on snout and a few on posterior part of head. Posterior tip of opercle ends in blunt spine. In some specimens ventral a

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

diagnosis

Diagnosis. Saccogaster maculata differs from all other Saccogaster species by the following combination of characters: Distinct pair of (probably) free spines on frontal plate above and behind eyes, strong ethmoidal spine in front of eyes; scales present on sides of body but not on predorsal; some specimens with ventral arm of opercle terminating in a short spine; opercular spine free and with one prong; presence of 2 posterior infraorbital pores, 1 supraorbital pore at upper angle of gill opening and 1 posterior mandibular behind maxillary; anterior gill arch with three long rakers about half length of longest filaments; elongate pectoral peduncle; palatines with several tooth rows; precaudal vertebrae 12 – 13 and total vertebrae 53 – 55; fin rays in dorsal 83 – 85, anal 53 – 56 and pectoral 17 – 18. Similarity. Saccogaster maculata is most similar to S. staigeri as both are scaled, have gill filaments 1 – 2 times length of developed rakers and fangs on dentigerous bones. They differ by S. maculata having palatines with several tooth rows (vs. single tooth row) and opercular spine free (vs. hidden). Also S. maculata has posterior infraorbital, supraorbital and posterior mandibular

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

materials_examined

Material examined (5 specimens and radiograph of syntype (ZSI 11673), 75 – 87 mm SL). ZSI 13527, female, 81 mm SL and ZSI 13528, female, 75 mm SL, Bay of Bengal, R / V Investigator, bottom trawl, 265 – 458 m. ZSI 13045, male, 77 mm SL, Bay of Bengal, R / V Investigator, bottom trawl, 439 m. IOM no cat. no., male, 87 mm SL, Bay of Bengal, 16 ° 56 ’ 08 ’’ N, 83 ° 13 ’ 04 ’’ E, R / V Vityaz, cr. 33, st. 4929, bottom trawl, 600 m, 1 Jan. 1961. IOM, no cat. no., 72 mm SL, Gulf of Aden, 10 ° 32 ’ 12 ’’ N, 49 ° 22 ’ 12 ’’ E, R / V Dmitry Stefanov, cr. 5, st. 98, bottom trawl, 450 – 445 m, 6 Dec. 1989. Remarks on material: It was not possible to borrow any of the five specimens from ZSI for this revision and the IOM specimens seem lost so information about S. maculata is based on Cohen & Nielsen (1972: 448 – 451). Consequently, our information on ethmoid and frontal spines is not based on direct observation, but from available radiographs.

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