Brachionichthys australis, Peter R. Last, Daniel C. Gledhill & Bronwyn H. Holmes, 2007

Peter R. Last, Daniel C. Gledhill & Bronwyn H. Holmes, 2007, A new handfish, Brachionichthys australis sp. nov. (Lophiiformes: Brachionichthyidae), with a redescription of the critically endangered spotted handfish, B. hirsutus (Lacepede)., Zootaxa 1666, pp. 53-68 : 55-59

Brachionichthys australis sp. nov.

Figs 1-2, Table 1

Brachionichthys sp. 2 : Last, Scott & Talbot, 1983, p 252-253, fig. 22.4.

Brachionichthys sp.: Hutchins & Swainston, 1986, p 34, fig. 111.

Brachionichthys sp.: Gomon, Glover & Kuiter, 1994, p 283-284, fig. 252.

Holotype. CSIRO H 4451-02 , 45.9 mm SL, E of Disaster Bay , New South Wales, 37° 18′S, 150° 17′E, 125 m, 7 Dec. 1996 .

Paratypes. 39 specimens. CSIRO A 4316 , 45.1 mm SL, S of Lakes Entrance, Bass Strait , Victoria, 38° 39′S, 148° 19′E, 90-100 m, 4 Nov. 1978 ; CSIRO H 3505-03 , 45.6 mm SL, S of Lakes Entrance, Bass Strait , Victoria, 38° 38′S, 148° 21′E, 112-118 m, 27 Jul. 1993 ; CSIRO H 3530-02 , 34.5 mm SL, Disaster Bay , New South Wales, 37° 17′S, 150° 01′E, 24-33 m, 11 Aug. 1993 ; CSIRO H 3794-01 , 44.1 mm SL, E of Bermagui , New South Wales, 36° 23′S, 150° 15′E, 123-277 m, 8 Sep. 1994 ; CSIRO H 3795-02 , 41.9 mm SL, SE of Gabo Island , Victoria, 37° 43′S, 150° 05′E, 136 m, 16 Sep. 1994 ; CSIRO H 4114-06 , 48.4 mm SL, no data ; CSIRO H 4114-07 , 55.8 mm SL, no data ; CSIRO H 4259-02 , 38.1 mm SL, Disaster Bay , New South Wales, 37° 18′S, 150° 02′E, 56 m, 25 Apr. 1996 ; CSIRO H 4259-03 , 44.7 mm SL, Disaster Bay , New South Wales, 37° 18′S, 150° 02′E, 56 m, 25 Apr. 1996 ; CSIRO H 4448-03 , 2 specimens, 27.2 and 28.9 mm SL, S of Montague Island (E of Bermagui), Tasman Sea , New South Wales, 36° 28′S, 150° 13′E, 118-121 m, 1 Dec. 1996 ; CSIRO H 4460-02 , 45.4 mm SL, E of Mallacoota , Victoria, 37° 60′S, 149° 54′E, 79 m, 27 Nov. 2006 ; CSIRO H 4465-01 , 40.7 mm SL, CSIRO H 4465-02 , 42.6 mm SL, Disaster Bay , New South Wales, 37° 18′S, 150° 00′E, 38 m, 27 Nov. 2006 ; CSIRO H 4466-01 , 49.1 mm SL, CSIRO H 4466-02 , 53.5 mm SL, east of Disaster Bay , New South Wales, 37° 18′S, 150° 04′E, 79 m, 2 Dec. 1996 ; CSIRO H 5699-01 , 16.7 mm SL, off Deep Glen Bay, Forestier Peninsula , Tasmania, 42° 58'S, 147° 59'E, 18 m, 2 Jan. 2002 ; CSIRO T 1991-01 , 23.5 mm SL, Maria Island, eastern Tasmania , 7 May 1979 ; CSIRO T 1992-01 , 2 specimens, 39.0 and 39.7 mm SL, 210 m, 15 Dec. 1982 ; NMV A 226 , 47.1 mm SL, off Lakes Entrance, Bass Strait , Victoria, Aug. 1960 ; NMV A 1619 , 44.1 mm SL, 96 km E of Cape Farewell, King Island, Bass Strait , Victoria, 39° 38'S, 145° 05'E, 66 m, 3 Feb. 1981 ; NMV A 2617 , 51.6 mm SL, NNE of Eddystone Point, E Bass Strait , Tasmania, 40° 43'S, 148° 37'E, 67 m, 14 Nov. 1981 ; NMV A 2668 , 24.1 mm SL, S of South East Point, Wilsons Promontory, Bass Strait , Victoria, 39° 13'S, 146° 27'E, 65 m, 18 Nov. 1981 ; NMV A 2670 , 28.3 mm SL, SW of Cape Paterson, central Bass Strait , Victoria, 38° 56'S, 145° 17'E, 70 m, 12 Nov. 1981 ; NMV A 2675 , 49.8 mm SL, S of Cape Otway, W Bass Strait , Victoria, 39° 06'S, 143° 37'E, 92 m, 23 Nov. 1981 ; NMV A 4314 , 2 specimens, 44.5 and 46.8 mm SL, N of North Point, Flinders Island, E Bass Strait , Victoria, 39° 00'S, 148° 24'E, 90 m, 13 Oct. 1984 ; NMV A 8765 , 2 specimens, 45.2 and 47.4 mm SL, SE of Loch Sport, Bass Strait , Victoria, 39° 06'S, 148° 32'E, 95 m, 10 Sep. 1983 ; NMV A 9043 , 27.7 mm SL, S of Middini Beach, Great Australian Bight , Western Australia, 33° 17'S, 127° 31'E, 167-180 m, 14 Feb. 1990 ; NMV A 11462 , 13.4 mm SL, ENE of North Point, off Flinders Island, E Bass Strait , Tasmania, 39° 28'S, 148° 41'E, 110 m, 28 Mar. 1979 ; NMV A 29406-001 , 2 specimens, 48.3 and 63.5 mm SL, central Bass Strait , Victoria ; NMV A 29410-001 , 2 specimens, 34.6 and 40.0 mm SL, S of Waratah Bay, Bass Strait , Victoria, 39° 10'S, 146° 00'E, 69 m, 26 Nov. 1973 ; NMV A 29411-001 , 37.0 mm SL, eastern Bass Strait , Victoria, 38° 00'S, 148° 05'E, 44 m, 14 Feb. 1971 ; NMV A 29412-001 , 34.8 mm SL, eastern Bass Strait , Victoria, 37° 55'S, 148° 18'E, 48 m, 15 Feb. 1971 ; TMH D 246 , 28.2 mm SL, D'Entrecasteaux Channel , Tasmania, GP 43° 03'S, 147° 20'E, 24 Aug. 1964 .

Diagnosis. Esca small, 8-24 (mean 14)% of illicium length (including esca); illicium elongate, without dermal spinules, length 23-28% SL, 1.8-2.1 times in head length; eye large, mainly less than 5.4 times in head; body entirely covered with close-set, non-imbricate scales; scale bases subcircular with long unicuspid spinules (except for those closely associated with pores of the acoustico-lateralis system); spinules originating from middle of scale base, variable in length over body; second dorsal-fin rays 16-18 (mean 17), fin base 55- 61 (mean 58)% SL; length of first ray of first dorsal fin 1.1-1.4 times length of longest ray of second dorsal fin; usually 9-10 anal-fin rays; 7 pectoral-fin rays; upper body lightly covered with longitudinal streak-like markings rather than spots; caudal fin with sparse coverage of large dark spots, not forming a broad submarginal bar.

Description. D1 2 (2, n = 31 paratypes, damaged in one specimen); D2 16 (16-18, usually 17, n = 31); A 9 (8-11, rarely 8 or 11, n = 31); Pc 7 (7, n = 31); Pv i, 4 (i, 4, n = 31); C 1 (1-2) + 5 (5-7) + 3 (1-2) = 9 (9, n = 31); Vt 9 (9-10) + 14 (13-14) = 23 (22-23, n=13); Br 5, n=l.

Body moderately elongate, weakly compressed; upper anterior profile convex, elevated slightly, upper eye close to dorsal margin; somewhat subtriangular when viewed anteriorly; nape rarely humped; anterior ventral profile weakly convex to flattened; abdomen expanded slightly (globose in some paratypes); caudal peduncle elongate, length 10 (8-10)% SL. Head relatively short, 48 (46-49)% SL; snout short, 5.3 (4.0-5.2) times in head; eye relatively large, 5.4 (4.9-5.4) times in head length; gill opening small, aperture smaller than pupil, located slightly above and behind insertion of pectoral fin; nostril aperture size and protrusibility variable, usually moderate; anterior opening tubular, fringed distally, posterior opening tubular; posterior opening well elevated above anterior opening, well removed from orbit. Mouth relatively small, terminal, moderately protractile; upper jaw weakly oblique, 4.3 (4.0-4.3) in head; upper lip fleshy; lower lip fleshy medially, connected laterally to lower jaw by fleshy dorsoventrally flattened fold; angle of jaw partly retracting into groove; tongue well developed, rounded apically. Teeth minute, villiform, in narrow bands in both jaws; band in lower jaw slightly longer than in upper jaw; vomer edentate.

Skin rather thick, covered with pungent, unicuspid scales; no separate wart-like patches of skin; prominent dermal flap present on mid-arm of pectoral fin; flap thallate, strongly compressed, irregular in shape, sub-equal in size to gill opening; flattened, dermal filaments distributed variably along ventrolateral surface of body. Body scales close-set, not arranged in defined rows; distributed over entire body (absent from midbelly in some paratypes), those on ventral surface much smaller than those on dorsal surface; spiny scales present on orbital membrane; spinules slender, upright to recurved slightly posteriorly, well exposed apically; scale base embedded in raised mound of thickened skin; scale bases subcircular with irregular margins, their width mostly exceeding spinule length; spinules arising from near middle of scale base. Anterior margin of first dorsal fin ray, and usually lateral margins of second ray, covered with minute spinulose scales; anterior basal third to a half of first ray of second dorsal fin densely spinulose, 0-4 spiny scales on basal third of each subsequent ray; upper surface of pectoral-fin rays and ray bases of caudal fin spinulose; remaining fin rays and all fin membranes naked. Illicium naked, covered with thin skin. Scales of acoustico-lateralis system bispinulate, with small central pore on oval base flanked by slender apical spinules; spinules shorter than spinules of body scales; widely separated and arranged in ill-defined rows; pronounced at chin apex and jaw angle, otherwise indistinct on head.

Illicium terminal on snout, elongate and very slender, 1.8 (1.8-2.1) times in head, 1.0 (1.0-1.2) times in length of first ray of first dorsal fin; apex of esca reaching well behind base of second ray of first dorsal fin when fin depressed; illicium not or partly retractable into shallow fleshy groove beside first dorsal fin (when present, on one side only); esca small, finely filamentous, 12.3 (4.2-11.5) times in length of illicium; filaments multiple, dense, obscure to somewhat globate; illicial base weakly bulbous. First dorsal fin well elevated; rays unsegmented; first ray distinctly recurved, originating about half an eye diameter behind base of illicium, distinctly longer than second ray; membrane of fin terminating above level of insertion of pelvic fin; first dorsal-fin base 2.2 (2.0-2.4) times in second dorsal-fin base. Second dorsal-fin rays tall, fin margin not indented, anterior and penultimate posterior rays similar in length; rays simple; fin base moderately elongate, 55 (57-61)% SL; longest second dorsal-fin ray 1.4 (1.1-1.3) times in longest first dorsal-fin ray; fin membrane relatively thin, only partly concealing bases of fin rays. Anal fin moderately elongate, penultimate posterior rays longer than those anteriorly; anal-fin base 1.9 (1.8-1.9) times in second dorsal-fin base. Pectoral fin strongly arm-like, radiais elongate, relatively slender, extending posteriorly for almost an eye diameter behind gill opening; fin rays filamentous, slender, membranes deeply incised, increasingly so posteriorly, tips highly flexible. Pelvic fin elongate; rays slender, filamentous, rather deeply incised; anterior spine short, embedded and indistinct; fin located on ventral surface, usually directed ventrolaterally, base aligned horizontally; interpelvic space broad, flat to slightly concave. Caudal fin moderately elongate, narrowly rounded to subtruncate; length 4.2 (3.9-4.8) times caudal peduncle.

Coloration. In life (based on figured specimen in Gomon, et al, 1994): upper body pale, whitish to light greyish brown; variably covered with thin, widely spaced pale brown or yellowish streaks; body not densely spotted; faint brownish saddles, often on nape and below origin, middle and insertion of second dorsal fin; sides with silvery white blotches, somewhat yellowish anteriorly; head below eye, belly, and ventral surface of tail white. Streaks on head and dorsal surface darkest; a few short yellowish brown streaks radiating diagonally from eye, and vertically from below nape toward pectoral-fin base; those on trunk aligned longitudinally. Lips uniformly white or dusky; gill opening and dermal filaments white. Illicium uniformly dusky. Fins mostly with dark spots or streaks; markings relatively large, brownish black, located mainly on fin membranes; membranes mostly translucent. Dorsal fins with widely spaced, spots and streaks, their densities and colour similar on both fins; no dark large patches or blotches on second dorsal fin. Caudal fin relatively sparsely spotted; most spots slightly larger than on other fins, arranged in vague vertical rows; basal spots occasionally black with yellowish borders. Anal fin translucent or white, rarely more than 1-2 spots on membranes of posterior rays. Pectoral fins with about 3-5 small, dark spots on dorsal surface; ventral surface usually uniformly pale or translucent. Pelvic fin uniformly pale or translucent, with single dark spot. Juvenile (CSIRO H 5699-01, 18.5 mm SL) with yellowish or golden streaks, most prominent over lower head behind eye and on ventral half of abdomen; upper surface with darker, closely spaced, parallel streaks forming a lozenge pattern (hood-like); streaks appearing dusky, more sharply defined than paler golden streaks below; two slightly darker bars located through anterior and posterior bases of second dorsal fin; prominent circular spot on junction between dorsal and ventral markings above origin of pectoral radials; snout and head anterior to mid-eye white, ventral surface white, dark spots evident on first dorsal fin, and anterior and posterior portions of second dorsal fin; middle of second dorsal fin with some golden spots, pectoral fin with a few median blotches anteriorly, penultimate rays with an equivalent blotch located closer to fin base; caudal fin with some large black irregular spots on posterior half of fin; anal fin pale or translucent with a single, dark, oblique blotch on posterior rays

In preservative (holotype): Body pale greyish dorsally, white ventrally; dark markings persistent on upper surface, usually indistinct ventrally; on caudal fin, spots largest distally, forming a subvertical row near fin base; about 5 spots on left pectoral fin; single indistinct posterior spot on anal fin; pelvic fins plain.

Size. Attains at least 63.5 mm SL, commonly 35-50 mm SL; smallest specimen examined 13.4 mm SL. Newly hatched young and egg capsule diameter unknown; egg diameter 1.7-1.9 mm.

Distribution. Demersal, off southern and eastern coastlines of Australia; mainly continental shelf from Bermagui, New South Wales (36° 23′S, 150° 15′E), to Middini Beach in the Great Australian Bight, Western Australia (33° 17′S, 127° 31′E). Southward along the east coast of Tasmania to the D’Entrecasteaux Channel (near 43° 03′S, 147° 20′E); not yet recorded from Tasmania’s west coast. Recorded from depths of 18 m to at least 210 m, commonly ca. 40-150 m depth, but may occur deeper; one specimen was taken by a trawler fishing in 123-277 m but the depth of capture cannot be determined.

Etymology. Epithet based on the Latin australis (southern) in reference to its wide southern Australian distribution. Proposed vernacular name is the Australian Spotted Handfish.

Comparisons. Brachionichthys australis closely resembles its slightly larger congener, B. hirsutus , but the two can be distinguished based on a combination of colour, meristics and morphometrics. Brachionichthys australis has a longer illicium (length 23-28% vs. 19-20% SL; 1.8-2.1 vs. 2.3-2.4 in head length) that usually has a relatively smaller esca (length 8-24%, mean 14% vs. 15-26%, mean 20% of illicium length), longer first ray of the first dorsal fin (length 1.1-1.4 vs. 0.7-1.0 times length of longest ray of second dorsal fin), larger eye (diameter mainly less than 5.4 rather than exceeding 5.4 in head), fewer second dorsal-fin rays (16- 18, mainly 17 vs. 17-19, mainly 18) with a shorter fin base (55-61% vs. 61-64% SL), and the upper body lightly covered with thin streak-like markings (rather than spots), and the caudal fin sparsely spotted (densely covered with fine spots). Juveniles of B. australis are similar to the adults in form and colour. A juvenile of B. australis (CSIRO H 4448-03, 27.2 mm SL) differed from a similar size juvenile of B. hirsutus (29.3 mm SL) in having much larger caudal (length 44.1% vs. 32.9% SL) and pelvic fins (length 20.9% vs. 15.4% SL), and a larger eye (length 9.2% vs. 7.1% SL). Juveniles of B. australis have large dark spots over the caudal fin (fin with a dark submarginal caudal bar in B. hirsutus juveniles), spots are evenly distributed over the soft dorsal (largely absent on central fin, markings concentrated anteriorly and posteriorly and coalescing with dark saddles on body), slightly longer, thinner scale spination, and the anterior first dorsal-fin ray (when depressed) reaches to (or just behind) the second dorsal-fin origin (first dorsal fin well short of soft second-fin origin).

Intraspecific COI DNA sequence divergences within both Brachionichthys australis and B. hirsutus were low, 0.5% and 0.08% respectively (Fig. 3). The sequence divergence between these two species was an order of magnitude higher at 4%, supporting their non-conspecificity. Specimens within each species formed discrete clusters with 100% bootstrap values. Unsurprisingly, the Sladenia and the Lophiodes specimens were deeply divergent from the Brachionichthys specimens (25% sequence divergence).

Remarks. Brachionichthys australis has been frequently misidentified in museum collections as its micro-endemic relative B. hirsutus . As discussed above, these species are strikingly similar and are probably sister taxa. Brachionichthys australis , which has possibly the widest distributional range of any handfish, is still nonetheless confined to southern and southeastern Australia. It appears to be reasonably abundant across its range and was once sympatric with the now rare B. hirsutus in D’Entrecasteaux Channel, off southeastern Tasmania. Brachionichthys australis is caught frequently as bycatch by scallop dredges, and occasionally by trawlers and Danish seiners. It is rarely seen by divers but an excellent image of a live specimen was captured by Rudie Kuiter (see Gomon et al, 1994).