Forsterygion flavonigrum Fricke and Roberts, 1994

Jawad, Laith A., 2008, Second revision of the New Zealand triplefin genus Forsterygion Whitley and Phillips, 1939 (Pisces: Tripterygiidae), Journal of Natural History 42 (47 - 48), pp. 2943-2989 : 2965-2967

Forsterygion flavonigrum Fricke and Roberts, 1994

Yellow-Black triplefin

Tripterygion sp. B Doak 1972, p. 103; Doak 1978, p. 103; Housley 1980, p. 87. Forsterygion n. sp. 5 Anderson 1973, p. 99.

Tripterygion n. sp. 2 Willan et al. 1979, p. 452.

Forsterygion sp. B Thompson 1981, p. 235–236.

Tripterygion sp. 3 Ayling 1982, p. 281.

Tripterygiidae g. and sp. Indet Hardy 1986b, p. 31.

Tripterygion sp. Roberts et al. 1986, p. 358.

Gen. and sp. Indet (Ayling sp3) Hardy et al. 1987, p. 246.

Forsterygion sp. Francis 1979, p. 50

Tripterygion: Paulin et al. 1989, p. 220

Tripterygion sp. Y-B: Roberts et al. 1991, p. 33

Diagnosis

A species of Forsterygion with the following set of characters: Short denticles present on inter-radial circuli. Pterygiophore supporting first segmented ray of third dorsal fin anterior to neural spine of twenty fifth vertebra. Dorsal fin formula V-0N-0-1-0- 1. Nine procurrent rays in upper caudal lobe, eight in lower lobe; in upper lobe one ray between upper lobe and posterior epural, five rays opposite epurals, three rays anterior to anterior epural; in lower lobe, one ray between lower lobe and haemal spine of second preural vertebra, six rays opposite haemal spine of third preural vertebra, one ray anterior to haemal spine of third preural vertebra. Front of body white with black eyes, black stripe extending to below base of second dorsal fin, rear part of body white or yellow; body yellow with black head in breeding males, females and non-breeding males white anteriorly, white or yellow posteriorly, with black stripe along lateral line, only reaching to mid-body.

(35)

Description

The following counts and proportions (given as times in standard length unless otherwise stated) are based on 64 non-type specimens of 26–50mm SL. F. flavonigrum differs from F. varium in the following combination of characters: supraorbital tentacles bifid. Long nasal tentacles. Head and body slender.

Head length 4.1–4.3; predorsal length 6.6–7.2; preanal length 2.5–2.9; peduncle length 8.6–11.0; peduncle depth 13.8–13.9; pectoral fin length 3.5–3.6; eye diameter 2.3–2.6 in HL; upper jaw length 2.0– 2.4 in HL; snout length 3.8–4.0 in HL.

First dorsal fin spines V–VI; second dorsal fin spines XVIII–XXI; third dorsal fin rays 12–15; pectoral fin rays 16–19; anal fin with 2 spines and 25–30 soft rays. Discontinuous lateral line with 14–23 tubular scales, lower lateral line absent. Total vertebral number 39–46.

Head sensory canals. Postocular canal extending beyond supratemporal canal. Supratemporal canal with few small sensory pores. No sensory papillae on frontal, temporal and upper part of otic areas. Ventral part of preoperculo-mandibular canal with seven pores, arranged linearly, four at base of pre-operculum, two below posterior edge of lower jaw and one at lower jaw symphysis.

Squamation. Head, nape, pectoral fin base, and belly naked. Scales with undulate anterior margin. Secondary radii present in scales from all body regions. One group of ctenii on posterior side of lateral line scales. In young individuals (, 28mm) ctenii in a straight line. Variable-sized posterior projection on lateral line scales.

Osteology

Post-temporal smooth, embedded. Partially ossified, incomplete inter-orbital septum. Large lacrimal. Second, third and fourth infraorbital with wavy ventral margin, but series not increasing in length posteriorly. Club-shaped basihyal. Basibranchials closelyspaced. Shallow, wide gap between legs of third hypobranchial. Unstalked, oppositely arranged gill rakers. Phalanges on lateral end of first epibranchial directed anteriorly and posteriorly. Notch at anterior edge of urohyal. One free pterygiophore between second and third dorsal fins. Dorsal fin formula V-0N-0-1-0-1 (35). Upper hypural with straight dorsal edge, lower hypural with wavy ventral edge. Nine procurrent rays in upper caudal lobe, eight in lower lobe; in upper lobe one ray between upper lobe and posterior epural, five rays opposite epurals, three rays anterior to anterior epural; in lower lobe, one ray between lower lobe and haemal spine of second preural vertebra, six rays opposite haemal spine of third preural vertebra, one ray anterior haemal spine of third preural vertebra. Fourteen soft rays in caudal fin, two unbranched and five branched (multiple branched) rays in upper and lower caudal lobes.

Otolith. Fine lobate ventral margin. Rounded posterior end. Crista inferior absent. Long, blunt rostrum. Rounded antirostrum.

Colour. Anterior body white, eyes black. Black stripe extends halfway along body above lateral line; posterior half of body yellow or white. Breeding males bright yellow, with head and (often) caudal fin black.

Size. 50mm SL.

Distribution

Forsterygion flavonigrum is widely distributed around the North and the South Islands including Stewart Island , the Chatham Rise to Chatham Islands, Snares Islands, and Auckland Islands. It usually inhabits rocky reefs in depths of 7–110 m ( Fricke 1994) .

Material examined

Museum specimens (n 564): NMNZ P. 24029, 5, 42–46mm SL, Paradise Beach, Port Pegasus, Stewart Island , 6 Feb 1989 . University of Auckland specimens: 18, 38– 49mm SL, North Cape, 28 Feb 1999 ; 5, 36– 42mm SL, Ti Point , 14 May 1998 ; 5, 33– 40mm SL, Great Barrier Island , 5 Sept 1997 ; 1, 38mm SL, Nelson Island, Great Barrier Island , 5 Sep 1998 ; 2, 32– 38mm SL, Hen and Chickens Islands , 6 Feb 1997 ; 13, 32– 42mm SL, Mokohinau Islands , 9 Dec 1997 ; 1, 47mm SL, Breaker Bay , Wellington, 9 Feb 1998 ; 7, 37– 42mm SL, Milford Sound, Fiordland , 3 Apr 1998 ; 2, 26– 28mm SL, R / V Munida , Otago, 2 May 1998 ; 5, 45– 50mm SL, Ulva Island, Stewart Island , 30 Jan 1998 .