Saccogaster staigeri Cohen & Nielsen, 1972

Nielsen, Jørgen G., Schwarzhans, Werner & Cohen, Daniel M., 2012, Revision of Hastatobythites and Saccogaster (Teleostei, Bythitidae) with three new species and a new genus, Zootaxa 3579, pp. 1-36 : 20-22

Saccogaster staigeri Cohen & Nielsen, 1972

Figs. 15 , 16 , 26 , Table 1 , 2, 6

Saccogaster staigeri Cohen & Nielsen 1972: 2 , fig. 1 (type locality: east coast of Florida). Saccogaster staigeri: Cohen 1987: 2 ; Nielsen et al. 1999: 109.

? Saccogaster staigeri: Séret & Andreatta 1992: 92 (off Brazil).

Material examined (5 specimens, 49–93 mm SL)*. Holotype: USNM 207357, male, 93 mm SL, east coast of Florida, 27°11’N, 79°49’W, R/V Gerda, st. 657, 10’ otter trawl, 201–216 m, 16 July 1965. Paratype: USNM 164144, female, 61 mm SL, off Tortugas, Gulf of Mexico, 24°20’ N, 82°55’W, R/V Oregon, st. 1005, 40’ shrimp trawl, 347 m, bottom temp. 10.0°C, 13 Apr. 1954. Non-types: USNM 158640, female, 72 mm SL, off Dry Tortugas, Florida, 24°20’N, 83°20’W, R/V Oregon, st. 1005, 347 m, 13 Apr. 1954. TCWC 6146.1, female, 65 mm SL, northwestern Gulf of Mexico, 27°44.9’N, 95°20.1’W, R/V Alaminos, st. 68A13–19, 2 m dredge, 338–384 m, 19 Nov.1968. TCWC 7027.20, male, 49 mm SL, northern Gulf of Mexico, 28°28’47’’N, 86°2’32’’W, R/V Gyre, st. E1, 9 m otter trawl, 351–357 m, 14 May 1985.

* The following specimen of S. staigeri was reported upon by Séret and Andreatta (1992) but it has not been available to us for checking the identification. It is tentatively referred to S. staigeri : USU 0 1501, 80 mm SL, off Rio de Janeiro, 23°41.64’S, 42°06.53’W, R/V Marion Dufresne, st. 63 CB 104, Blake trawl, 430–450 m, 1 June, 1987.

Diagnosis. Saccogaster staigeri differs from all other Saccogaster species by the following combination of characters: Frontal plate with a pair of small, hidden, sub-dermal spines above and behind eyes and a small, median, sub-dermal, ethmoidal spine in front of eyes; opercular spine hidden by skin, preopercular spine absent; pectoral peduncle prolonged; three developed rakers on anterior gill arch 1.5–2 times length of gill filaments; palatines with one tooth row and fang-like teeth on all dentigerous bones; precaudal vertebrae 13–14 and total vertebrae 53–54; fin rays dorsal 86–88, in anal 53–57 and pectoral 18–19; otolith length to height = 2.1, otolith length to colliculum length = 2.8.

Similarity. Saccogaster staigeri is most similar to S. maculata as both are scaled, have gill filaments 1.5–2 times length of developed rakers and fangs on dentigerous bones. They differ by S. staigeri having palatines with a single tooth row (vs. several tooth rows) and opercular spine and pair of spines on frontals hidden (vs. free). Also S. staigeri has no posterior infraorbital, supraorbital and posterior mandibular pores, which all are present in S. maculata .

Description. The principal meristic and morphometric characters are shown in Table 6 . Body moderately compressed and elongate with tapering caudal part and blunt snout. Scales on body concentrated around midline, hardly overlapping; no scales on head and abdomen. Lower part of lateral line in holotype with about 20 papillae. Dorsal fin origin above proximal part of pectorals and anal fin origin well behind midpoint of fish. Pectoral fin ending almost halfway to anus with prolonged peduncle not attached to body. Pelvic fins ending below anterior part of pectoral fins. Anterior gill arch ( Fig. 16 D) with four flat, spiny knobs on upper branch, a developed raker in the angle and lower branch with two longer rakes with a knob in between followed by 11 low knobs. Developed rakers on anterior arch 1.5–2 times length of filaments. Two pseudobranchial filaments. Holotype with 9 mm long penis and rear part of body cavity with swollen testes. Eggs are visible through the body wall of paratype.

Axial skeleton (from radiographs): Number of precaudal vertebrae 13–14. Anterior neural spine very short. Neural spines 2–4 long and with pointed tips and neural spines 5–12 distinctly shorter, with blunt tips and enlarged basis. All remaining neural and haemal spines with pointed tips. Parapophyses developed on vertebrae 7 to 13–14. Pleural ribs on vertebrae 3–4 to 9. Epipleural ribs on vertebrae 3–9.

Dentition: Vomer boomerang-shaped with 7–8 fangs in 1–2 rows. Palatines with 10–12 fangs in a single row. Dentaries with 15–20 fangs in one row. Premaxillaries with granular teeth in many rows and 2–3 fangs near symphysis.

Head morphology ( Fig. 16 A–C): Head profile straight above eyes. Head with pair of tiny sub-dermal spines on frontal plate above and behind eyes, distinct on radiographs, small, median, sub-dermal, ethomoidal spine in front of eyes and blunt sub-dermal spine above eyes. Frontal plate behind frontal spines with coarsely textured subdermal surface. Anterior nostril placed close to upper lip; posterior nostril a mere hole placed close to eye. Head pores: 1 supraorbital pore at tip of snout, 2 anterior infraorbital pores below and in front of eye, 1 anterior mandibular pore at tip of jaw. Head skin thin, loose. No neuromasts visible. No head pigmentation visible. Upper jaw ends well behind eye; posterior end of maxilla vertically expanded. Opercular spine pointed, subdermal, not reaching hind margin of opercle. No spine at lower angle of preoperculum.

Otolith ( Fig. 16 E–F): Otolith elongate, moderately thick; otolith length to height = 2.1, otolith height to thickness = 2.3. Dorsal and ventral rims regularly curved, smooth. Anterior and posterior tips pointed resulting in a symmetrical outline of the otolith. Inner face slightly convex with centrally positioned, undivided, oval, shallow sulcus without anterior projection; otolith length to colliculum length = 2.8. Outer face convex.

Coloration: After about 50 years of preservation the specimens are uniformly brownish except for the darkblue eyes.

Biology and distribution ( Fig. 25 ). Caught in bottom fishing gear at the upper continental slope at a depth of 201– 450 m. The holotype is from off the east coast of Florida and the paratype and three more specimens from the Gulf of Mexico. According to Séret and Andreatta (1992) a fifth specimen was trawled off Rio de Janeiro, which is here recorded as tentatively assigned.

Figures

FIGURE 15. Saccogaster staigeri, holotype, USNM 207357, SL 93 mm, (photo Sandra Raredon).

FIGURE 16. Saccogaster staigeri: A—Lateral view of head (paratype, USNM 164144). B—Lateral radiograph of head (holotype, 207357, photo S. Raredon). C—Dorsal view of head (paratype, 164144). D—Anterior right gill arch (holotype, from Cohen & Nielsen 1972). E—Median view of right otolith (USNM 158620). F—Dorsal view of right otolith (USNM 158640).

FIGURE 25. Geographic distribution of Hastatobythites and Saccogaster in the Indo-West Pacific. Each marking may represent more than one locality.

FIGURE 26. Geographic distribution of Parasaccogaster and Saccogaster in East Pacific and West Atlantic waters. Each marking may represent more than one locality.