Alabes elongata, Hutchins & Morrison, 2004

Hutchin, Barry & Morrison, Sue, 2004, Five New Fish Species of the Genus Alabes (Gobiesocidae: Cheilobranchinae), Records of the Australian Museum 56 (2), pp. 147-158 : 150-151

Alabes elongata n.sp.

Fig. 2 ; Tables 1–2

Alabes dorsalis (non Richardson). Hutchins, 1994: 313 (in part).

Type material. HOLOTYPE: WAM P.28296-003, 86 mm SL, male, Western Australia, Recherche Archipelago, Mondrain Island , eastern side of island (34°08'S 122°15'E), rock and weed, rotenone at 5–6 m, J.B. Hutchins et al., 13 April 1984 . PARATYPES (5 specimens, 42–92 mm SL, from Western Australia) : AMS I.42136-001, 80 mm SL, male, collected with holotype ; WAM P.26004-012, 56 mm SL, Recherche Archipelago, Lucky Bay , unnamed island on eastern side of bay (34°00'S 122°14'E), rock and weed, rotenone at 14 m, J.B. Hutchins, 17 March 1978 ; WAM P.28280-002, 58 mm SL (cleared and stained), female, Israelite Bay, Dempster Point (33°37'S 123°53'E), seagrass bed, box trawl at 0.5–2.0 m, J.B. Hutchins, 1 April 1984 ; WAM P.28296- 050, 92 mm SL, male, collected with holotype ; WAM P.32205-001, 42 mm SL, Cervantes , NW of Outer Rocks (30°26'S 114°59'E), rocky reef, in sponge at 15 m, L.M. Marsh et al., 4 May 1987 .

Diagnosis. Diagnostic characters of Alabes elongata are listed in Table 1. It differs from all other species of Alabes by a combination of its elongate but robust body (depth 12.5–14.9 in SL), large gill slit (2.9–4.4 in HL), prominent rudimentary pelvic fin with obvious fin rays, single postocular pore on each side of head, and unique colour pattern. Alabes elongata is most similar to A. dorsalis , differing in its more elongate body (depth usually greater than 12 times in SL versus 11 or less) and different coloration (lacks the dark circular blotches on midside of body that characterize the adult male of A. dorsalis ).

Description. Measurements of the holotype and paratypes are presented in Table 2. Maximum body depth 13.5 (12.5– 14.9) and width at level of gill slit (= maximum body width) 13.9 (13.1–18.6), both in SL; head bluntly rounded anteriorly, somewhat compressed, slightly wider than body, head width 1.5 (1.4–1.8) in HL; HL 8.2 (7.9–9.1) in SL; snout short, rounded to truncate in dorsal view, length 4.4 (3.9–4.8) in HL; diameter of orbit 4.2 (4.3–5.6) in HL, slightly greater than bony interorbital width (5.1 [4.1–6.9] in HL); total of two lateral-line pores on each side of head, consisting of one postocular pore and one anterior nasal pore (indication of dorsal lacrymal pore visible in smallest paratype); gill opening a moderately wide slit, length 3.0 (2.9–4.4) in HL; mouth slightly inferior, upper lip projecting slightly forward of lower lip; rear corner of mouth below or slightly behind anterior margin of eye; teeth small, conical, caninelike, 1–2 rows in upper and lower jaws; caudal fin with 7 (6–9) fin rays; bases of dorsal and anal fins long, insertion of dorsal fin slightly to well posterior to vertical through urogenital opening (snout to insertion 2.3 [1.5–2.4] in SL); insertion of anal fin about half way between urogenital opening and caudal fin (snout to insertion 1.7 [1.3–1.5] in SL); total vertebrae 75 (74–78), precaudal 22, last epineural on 28th vertebra.

Preserved coloration. Head and body overall pale creamy brown, fins more translucent.

Live coloration (based on colour transparencies of freshly collected holotype, see Fig. 2 ): ground colour pale creamy brown, with fine mottling of darker brown tending to form narrow, somewhat irregular cross bars on anterior portion of body, breaking up into a fine irregular reticulate pattern enclosing pale spots on posterior two-thirds (pattern extending onto fins); head with faint darker cross bars, red colour of gills visible through skin; paratypes range from similar to holotype to an overall pale brown or apple green without markings (smaller specimens).

Distribution. Alabes elongata is known only from southern Western Australia, from the Recherche Archipelago (including Israelite Bay) in the southeast to Cervantes on the mid-west coast.

Remarks. This species inhabits reef and weed areas from the intertidal to depths of 15 m. It has been found in both seagrass beds as well as on rocky reefs. It is apparently the sister species of Alabes dorsalis (both possess large gill openings and prominent pelvic-fin rudiments), the latter occurring in shallow intertidal areas of New South Wales, Victoria, Tasmania and South Australia. The two differ mainly in body depth and coloration of the adult male (see Diagnosis above). It is named elongata with reference to its elongate body.

Figures

Fig. 2. Alabes elongata. Holotype, male, WAM P.28296-003, 86 mm SL, Recherche Archipelago, Western Australia.