Parasaccogaster normae ( 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 : 29-31

Parasaccogaster normae ( Cohen & Nielsen, 1972)

Figs. 21 , 22 , 26 , Tables 1 , 2, 7

Saccogaster normae Cohen & Nielsen 1972: 463 , figs. 1 and 6 (type locality: off northern Peru). Saccogaster normae: Cohen 1987: 1 ; Nielsen et al. 1999: 110.

Material examined (6 specimens, 118–142 mm SL). Holotype: USNM 207356, female, 140 mm SL, off northern Peru, 4°57’S, 81°23’W, R/V Anton Bruun, cr. 16, st. 625A, otter trawl, 118–133 m, 2 June 1966. Paratype: IM 421, male, 138 mm SL, off northern Peru, 5°04’S, 80°24’W, R/V Lance, st. 76, 150 m, 7 May 1969. Non-types: UCR 1555-5 (male, 102 mm SL), UCR 1555-8 (female, 128 mm SL) and UCR 2072-21 (female, 118 mm SL), Peninsula de Nicoya, Costa Rica, 9°44’N, 85°22’W, R/V Nautilus III, bottom trawl, 30 Oct. 1983. UCR 760-1, female, 142 mm SL, off Quepos, Puntarenos Prov., Costa Rica, 9°24’50’’N, 85°22’W, bottom trawl, 25 Mar. 1973.

Diagnosis. Parasaccogaster normae differs from the other two species of the genus by the gill filaments on anterior arch being 4–5 times the length of the developed rakers and by the following combination of characters: A pair of very small, subdermal, closely set spines on frontal plate above and behind eyes, no spine on ethmoid; 2–3 developed rakers on anterior arch not much longer than spiny knobs; gill filaments on anterior arch 4–5 times length of developed rakers; palatines with 2–4 tooth rows; pectoral peduncle prolonged and adnate to body; precaudal vertebrae 14–16 and total vertebrae 54–56; fin rays in dorsal 83–87, caudal 12–13, anal 51–54 and pectoral 17–19.

Similarity. Parasaccogaster normae is most similar to P. rhamphidognatha with hidden opercular spine, nasal chamber not black and distinctly more anal fin rays and vertebrae than found in S. melanomycter . Parasaccogaster normae differs from P. rhamphidognatha by the longer gill filaments on anterior arch (4–5 times length of long rakers vs. 1–3 times), more pectoral fin rays (17–19 vs. 12) and lack of an ethmoidal spine vs. spine present.

Description. The principal meristic and morphometric characters are shown in Table 7 . Head and body elongate with tapering caudal part and blunt snout. Scales absent. Origin of lateral line dorsally above pectoral peduncle and from above anus running in midline ending at base of caudal fin with 27 to ca. 40 small, dark papillae. Dorsal fin origin above anterior part of pectoral fin and anal fin well behind midpoint of fish. Pectoral fin ending far from halfway to anal fin and with prolonged peduncle. Anterior gill arch ( Fig. 22 E) with 3–4 small, spiny knobs on upper branch, one a little longer raker in the angle and lower branch with two short rakers with a knob in between followed by ca. ten spiny knobs. Long gill filaments 4–5 times length of developed rakers. Two pseudobranchial filaments. Ovaries large, but no embryos observed.

Axial skeleton (from radiographs): Number of precaudal vertebrae 15–16. Anterior neural spine one fourth length of second spine. Neural spines 2–4 long and depressed and with pointed tips, spines 5–10 with blunt tips and nos. 5–8 depressed and with enlarged basal parts. Parapophyses developed on vertebrae 8–15, pleural ribs on vertebrae 3–10 and epipleural ribs not observed.

Dentition: Palatines with 2–3 rows of pointed teeth, largest in inner row. Vomer boomerang-shaped and with 2–3 irregular rows of pointed teeth, largest in inner row. Premaxillaries with several irregular rows of pointed teeth and a few fangs at symphysis. Dentaries with pointed teeth in irregular rows, largest in inner row.

Head morphology ( Fig. 22 A–B): Head profile slightly or not concave above eyes. Head with pair of very small, sub-dermal, closely set spines on frontal plate above and behind eyes, no spine on ethmoid, broad, blunt, sub-dermal spine above eyes, frontal plate with a median, bony ridge. Anterior nostril placed close to upper lip and larger posterior nostril placed close to small 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 thick, loose. Head with blunt snout, sunk-in eye covered by window of translucent skin. Upper jaw ends well behind eye with posterior margin vertically expanded. Opercular spine hidden below thick skin. No subdermal preopercular spine. Gill opening ending slightly below level of dorsal margin of pectoral peduncle.

Otolith ( Fig. 22 C–D): Otolith elongate, thin; otolith length to height = 2.3, otolith height to thickness = 2.5. Dorsal and ventral rims gently and 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 = 2.5. Outer face nearly flat.

Coloration: Head and body chocolate brown with darker fins.

Biology and distribution ( Fig. 26 ). A viviparous species living on the lower part of the continental shelf (80–150 m). Four of the examined specimens are females with well developed eggs but apparently no embryos. Sections of ripe testes show that the spermatozoans are arranged in spermatophores ( Cohen and Nielsen 1972: 465). Known from off northern Peru and from the Pacific coasts of Costa Rica.

Figures

FIGURE 21. Parasaccogaster normae, holotype, USNM 207356, SL 140 mm, (from Cohen & Nielsen 1972).

FIGURE 22. Parasaccogaster normae: A—Lateral view of head (UCR 2072 - 21). B—Lateral radiograph of head (holotype, USNM 207356, photo S. Raredon). C—Median view of right otolith (UCR 2072 - 21). D—Dorsal view of right otolith (UCR 2072 - 21). E—Anterior right gill arch (paratype, IM 421, from Cohen & Nielsen 1972).

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