Forsterygion lapillum Hardy, 1989

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 : 2970-2972

Forsterygion lapillum Hardy, 1989

Common triplefin

Forsterygion capito (non Jenyns) Thompson 1981, p.231, Fig. on 232; Roberts et al. 1986, p. 358; Hardy et al. 1987, p. 248.

Tripterygion capito (non Jenyns) Grace R. V. 1971, p. 132, 133; Doak 1972, p. 105, 106; Ruck 1973, p. 1–7; Gordon and Ballantine 1976, p. 34, 133; Nicholson 1979, p. 136; Willan et al. 1979, p. 452; Nicholson and Roberts 1980, p. 141; Ayling 1982, p. 280.

Diagnosis

A species of Forsterygion with the following set of characters: first dorsal fin spines V– VII ( Hardy (1989) lists specimen having VIII spines); second dorsal fin spines XIX– XXIII; third dorsal fin rays 11–14 ( Hardy (1989) gives range of 11–13 rays). Discontinuous lateral line with 19–24 tubular scales, 14–24 notched scales. Total vertebral number 40–44 ( Hardy (1989) gives range of 43–45 vertebrae). Snout profile steep (70–75 °). Preoperculo-mandibular canal with seven pores, three at lower corner of preopercular, three at tip of upper jaw and one at lower jaw symphysis. Five to six scale rows between anterior end of second dorsal fin and lateral line. Four scales between second and third dorsal fins. Twelve to thirteen scales around caudal peduncle. Eight to eleven radii in scales from area below lateral line and under pectoral fin. Long ctenii in scales from above and below lateral line in caudal peduncle area. Lateral line canal constricted with W-shaped anterior and posterior openings. Short denticles on interradial circuli. Post-temporal partially exposed. Pterygiophore supporting first segmented ray of third dorsal fin anterior to twenty-fourth vertebra. Dorsal fin formula V-0N-0-1-0-1 (32). Ventral edge of lower caudal plate straight. Short neural spine of second preural vertebra. Epurals of different length. Fourteen soft rays in caudal fin, two unbranched and five branched (non multibranched) rays in upper and lower caudal lobes. Ten procurrent rays in upper caudal lobe, eight in lower lobe; in upper lobe, two procurrent rays between upper lobe and posterior epural, four rays opposite epurals, one between neural spine of second preural vertebra and neural spine of third vertebra, one opposite neural spine of third preural vertebra and two anterior to neural spine of third vertebra; in lower lobe, one procurrent ray between lower lobe and haemal spine of second preural vertebra, five rays opposite haemal spine of second preural vertebra, one between haemal spines of second and third preural vertebrae, one ray opposite neural spine of third preural vertebra. Rounded posterior end. Short, pointed rostrum. Broad antristrum. Excisura shallow.

Description

The following counts and proportions (given as times in standard length unless otherwise stated) are based on 166 non-type specimens, 21–59mm SL. The description of F. lapillum differs from F. varium in the following characters: medium sized species. Snout steep, angle 70–75 °.

Head length 3.8–4.0; predorsal length 4.3–5.2; preanal length 1.9–2.2; peduncle length 10.1–11.5; peduncle depth 12.0–14.1; pectoral fin length 3.2–4.0 in eye diameter 2.6–3.0 in; upper jaw length 2.3–2.5 in HL; snout length 2.9–3.5 in HL.

First dorsal spines V–VII; second dorsal spines XIX–XXIII; third dorsal fin rays 11–14; pectoral fin rays 16–19; anal with 2 spines and 23–27 soft rays. Discontinuous lateral line with 19–24 tubular scales, lower lateral line present; total vertebral number 40–44.

Head sensory canals. Supratemporal canal with few small sensory papillae. Few sensory papillae present on frontal, temporal and upper part of otic areas. Ventral part of the preoperculo-mandibular canal with seven pores, three at lower corner of preoperculum, three at tip of upper jaw and one at lower jaw symphysis.

Squamation. Head, nape, pectoral fin-base and anterior part of belly naked. Five to six scales between anterior end of second dorsal fin and lateral line. Five to six scales between the last pored scale and the second dorsal fin. Four scales between second and third dorsal fins. Twelve to thirteen scales around caudal peduncle. Scales with undulate anterior margin. Secondary radii present in all body regions. Eight to eleven radii in scales from area below lateral line and under pectoral fin. Short ctenii in scales from above and below lateral line in caudal peduncle area. Lateral line canal constricted with W-shaped anterior and posterior openings. Short denticles on interradial circuli. Tongue present, variable in shape.

Osteology. Post-temporal partially serrated and exposed. Club-shaped basihyal. Shallow gap between legs of third hypobranchial. Gill rakers oppositely arranged. Epibranchials straight, first epibranchial with phalanges at lateral end directed anteriorly and posteriorly. Notch at anterior edge of urohyal. Pterygiophore supporting first segmented ray of third dorsal fin anterior to twenty fourth vertebra. Dorsal fin formula V-0N-0-1-0-1 (32). One free pterygiophore between second and third dorsal fins. Short neural spine of second preural vertebra. Lower hypural with straight ventral edge. Epurals having different length. Fourteen soft rays in caudal fin, two unbranched and five branched (non multibranched) rays in upper and lower caudal lobes. Ten procurrent rays in upper caudal lobe, eight in lower lobe; in upper lobe, two procurrent rays between upper lobe and posterior epural, four rays opposite epurals, one between neural spine of second preural vertebra and neural spine of third vertebra, one opposite neural spine of third preural vertebra and two anterior to neural spine of third vertebra; in lower lobe, one procurrent ray between lower lobe and haemal spine of second preural vertebra, five rays opposite haemal spine of second preural vertebra, one between haemal spines of second and third preural vertebrae, one ray opposite neural spine of third preural vertebra.

Otolith. Rounded posterior end. Short, cauda. Pointed rostrum. Broad antirostrum. Excisura shallow.

Colour. Head covered with olive-brown spots, with three yellow patches of varying intensity anterior to nape and above orbits. A pale, reddish line through orbit continues anteroventrally through the mouth corner. Preoperculum with olive with greyish blotches becoming pinkish ventrally. Iris black with thin orange rim. Body greyish to white in colour with dark grey to black stripe running dorsolaterally across it from post-temporal, above lateral line, to caudal fin base. Small brownish blotches adjacent to both sides of the stripes. Belly white. First dorsal fin membrane greyish-olive, with irregular, deep reddish blotches. Second dorsal fin membrane and spine bases reddish, becoming slightly greyish with a line of red spots on spines, distal membrane darker greyish, spines red. Third dorsal fin rays reddish proximally, becoming reddish grey distally, membrane pale greyish. Caudal fin with pinkish rays, membrane transparent, slightly greyish distally. Anal fin rays reddish, with fleshly, white tips, membrane pale greyish. Pectoral fins pale, greyish-green. Pelvic fins mostly pale greenish becoming white distally. Breeding males (and some juveniles) all black except for white pelvic fins and white anal fin margin.

Size. 65mm SL.

Distribution

Forsterygion lapillum is common in tidal pools and on subtidal rocky reefs around New Zealand. It is most common in shallow water (0–5m), although Hardy (1989) recorded it from depths of 30 m. Not recorded from the Three Kings, Snares or Chatham Islands ( Hardy 1989), and uncommon at many offshore islands ( Syms 1995; Francis 2001).

Material examined

Museum specimens (n 5166): NMNZ P. 24086, 60, 24–56mm SL, Islet Cove, Stewart Island , 29 Jan 1989 ; NMNZ P. 30488, 5, 46–58mm SL, Bowen Channel, Dusky Sound, Fiordland , 22 Mar 1993 . University of Auckland specimens: 18, 29– 47mm SL, North Cape, 5 Mar 1999 ; 27, 38– 56mm SL, Ti Point, 27 Feb 1997, 21 Oct 1997; 27, 35– 52mm SL, Nelson Island, Great Barrier Island , 12 Jan 1997 ; 4, 23– 24mm SL, Hen and Chickens Islands , 6 Feb 1997 ; 4, 35– 42mm SL, Great Barrier Island , 5 Sep 1997 ; 1, 54mm SL, Manukau Harbour , 21 Jun 1998 ; 1, 48mm SL, Stirling Point , 26 Jan 1998 ; 9, 46– 59mm SL, Ulva Island, Stewart Island , 1 Feb 1998 ; 2, 21– 23mm SL, Whakatu Point, Kaikoura , 3 Feb 1998 ; 8, 48– 56mm SL, Island Bay , Wellington, 7 Feb 1998 .