Galaxias gunaikurnai, Raadik, 2014

Raadik, Tarmo A., 2014, Fifteen from one: a revision of the Galaxias olidus Günther, 1866 complex (Teleostei, Galaxiidae) in south-eastern Australia recognises three previously described taxa and describes 12 new species, Zootaxa 3898 (1), pp. 1-198 : 63-68

Galaxias gunaikurnai , new species

Shaw Galaxias

Tables 4 to 9, 12, 19 to 20; Figures 7 & 15

Galaxias olidus olidus (non G.olidus Günther, 1866 )— Frankenberg, 1969: 170 (partim).

Galaxias olidus (non G. olidus Günther, 1866 )— Dixon, 1976: 108; McDowall & Frankenberg, 1981: 469 (partim); Cadwallader & Backhouse, 1983: 69 (partim); McDowall, 2003a: 364 (partim).

Galaxias findlayi (non G. findlayi Macleay, 1882 )— Dixon, 1976: 108.

Galaxias sp. 7 — DSE, 2013: 17.

Galaxias sp. 14— Kuiter, 2013: 72.

Conforms to the allozymically defined and morphologically diagnosed taxon ‘SH’ of Adams et al. (2014), and ‘shaw’ of Raadik (2011).

Material Examined.

Holotype. NMV A.30573-2, 94.6 mm LCF, (83.5 mm SL), female, Shaw Creek, at walking track off Howitt Road at the Gorge , Bennison High Plains , Alpine National Park , Victoria, 37° 23' 39”S 146° 44' 51”E, T.A. Raadik, 28 February 2002.

Paratypes. AMS I.44915-1 (1), 91.7 mm LCF (82.0 mm SL) and NMV A.30573-1 (3), 88.6–98.9 mm LCF (78.9–88.4 mm SL), collected with holotype.

Non-type material. all VIC: NMV A.30640-1 (12), 51.6–82.3 mm LCF (45.4–72.4 mm SL), Shaw Creek , at type locality, JPO, 23 March 1998 ; NMV A.26403-1 (5), 95.3–98.9 mm LCF (84.1–88.0 mm SL), Shaw Creek , at type locality, P.S. Fairbrother and M. Nicol, 17 April 2008 ; NMV A.9922 (11), 31.6–79.5 mm LCF (26.9–69.8 mm SL), and NMV A.10381 (4), 55.7–75.0 mm LCF (63.3–66.7 mm SL), Shaw Creek , Bennison High Plains, P.A. Rhodes, 1 April 1960 .

Additional material examined (not measured): see Appendix 5.

Diagnosis. Galaxias gunaikurnai sp. nov. differs from all other species within the Galaxias olidus complex by a combination of the following characters: dorsal fin set far back (PreD about 70.4–74.1 % SL); distance between pectoral and pelvic fin bases long (30.8–33.8 % SL); caudal fin shorter than caudal peduncle length and vertical width of expanded caudal fin rays about the same as the body depth through the pectoral fin base; caudal peduncle flanges just reaching adpressed anal fin rays; head short (20.0–20.7 % SL), distinctly shorter than PelAn distance, but wide (66.2–71.2 % HL) and deep (44.2–49.9 % SL); snout long (29.2–32.0 % HL); nostrils short, not visible from ventral view; eye relatively small (16.6–17.8 % HL); inter-orbital gap broad (39.2–41.2 % HL); most posterior extent of mouth usually 0.8 ED below ventral margin of eye; dorsal and anal fin bases short (8.3–10.1 and 8.8–10.7 % SL), with AL/LAB ratio high (147–163 %); anal fin origin usually under 0.74 distance posteriorly along dorsal fin base; anal fin segmented ray count usually 10; gill rakers moderately long and usually pointed; usually 1, sometimes 2 stout and wide pyloric caecae of moderate length (2.0 % SL); and, lack of black midlateral bars.

Description. As for the genus and members of the Galaxias olidus complex, except as indicated below, based on five specimens, 78.9–88.4 mm SL, and 30 additional, non-type specimens for meristics. See Table 4 to 9 for frequencies of meristic values and Table 19 for a summary of meristic variation. Segmented dorsal fin rays 9 (8–10*), of these 8 (7–8) branched and 2 (1–2) unbranched; segmented anal fin rays 10 (10–11), of these 8 (8–9) branched and 2 (1–2) unbranched; caudal fin rays 16 (14–16); segmented pectoral fin rays 14 (14–16; [15*]), of these 12 (12–14; [13*]) branched and 2 unbranched; pelvic fin rays 7 [8*], of these 6 [7*] branched and one unbranched; gill raker total count (lower limb and upper limb) 12 (11*–13), lower arch with 9 (8–9) and 3 (2*–4) on upper, variation on first gill arch 8+3 (2), 9+2 (5*), 9+3 (9), 9+4 (1), 10+3 (1); vertebrae 53 (52*–55); usually one, sometimes two*, pyloric caecae on stomach.

See Table 20 for comparative value ranges of morphometric characters. Body stout and moderately elongate, dorsal midline usually broadly flattened anteriorly from above pelvic fin bases, depth through pectoral base 1.1–1.2 that through vent, trunk with dorsal and ventral profiles evenly arched from snout to dorsal fin origin; body tapering back to a caudal peduncle of moderate depth, 11.9 (11.4–12.8) in SL, and length, 7.1 (6.9–7.3 in SL), the peduncle depth 1.6–1.7 in its length; accessory lateral line present. Head short 4.9 (4.8–5.0 in SL), shorter (0.8–0.9) than PelAn distance, but wide, 1.45 (1.40–1.50) in HL, and deep, 2.1 (2.0–2.3) in HL, distinctly wider than deep (depth 1.46 (1.43–1.50) in HW), lateral profile slightly wedge-shaped, dorsal profile distinctly flat anterior to nape; eyes moderately small, 5.8 (5.6–6.0) in HL and 2.7–2.8 in HD, situated high on head, distinctly below dorsal head profile, interorbital flat to convex, moderately broad, 2.5 (2.3–2.5) in HL and 2.3–2.4 times ED; cheeks expanded below eyes, eye profiles not visible laterally from ventral view; snout long, 3.3 (3.1–3.4) in HL and 1.7–1.8 times ED, lateral profile rounded; post-orbital head length moderately short, 1.9 in HL; nostrils relatively short, just extending to posterior edge of upper lip or less, not visible from ventral view; mouth generally terminal, moderately long, 2.6–2.7 in HL, posterior extent reaching back to under anterior 0.25–0.50 of eyes, and about 0.8 (0.7–1.0) ED below ventral margin of eye, most anterior tip of upper lip level with middle of eye, gape moderately wide, 2.4 (2.2–2.6) in HL, width 1.1 (1.0–1.1) that of length of upper jaw and 1.7 (1.6–1.7) in HW. Jaws subequal, lower 0.9 times length of upper. Pyloric caecae of moderate length, longest averaging 2.0 % SL (0.8–3.6 %), stout, wide at base and blunt; gill rakers moderately long, stout and usually pointed.

Fins fleshy at bases, median fins more so, with thickening extending distally over 0.5 of fin area, extending to about 0.9 distance distally between fin rays; dorsal and anal fin bases short, usually 11.0 (10.3–12.0) and 10.5 (9.5–11.4) in SL respectively, dorsal fin base usually 0.9 of length of anal fin base, fins of moderate length, rounded, usually equal though anal sometimes slightly longer (1.0–1.1 times DL), middle rays longest; anal fin origin usually under 0.74 (0.64–0.87) distance posteriorly along dorsal fin base. Pelvic fins of moderate length, 9.2 (8.5–9.7) in SL, usually 0.9 of pectoral fin length, inserted at about mid-point of standard length and usually extending to 0.45 (0.43–0.49) distance to anal fin base; pectoral fin of moderate length and paddle-shaped, 8.1 (7.8–8.5) in SL, extending less than 0.4 distance to pelvic fin base, low on body with dorsal end of fin base level with posterior extent of mouth, lamina of paired fins oriented anterio-ventrally to ventrally, raised lamellae on ventral surface of rays usually present and strongly developed. Caudal fin moderately short, 8.1 (7.6–8.5) in SL, emarginate, shorter than caudal peduncle, vertical width of expanded rays about same as body depth through pectoral fin base, flanges moderately developed along caudal peduncle, just reaching adpressed anal fin rays.

Size. Recorded to 104 mm LCF and 11 g; commonly to 65–70 mm LCF.

Colour in life. Body predominantly grey-brown to grey-tan on back and upper sides above lateral line, extending onto top and sides of head and snout, becoming light tan to creamy brown on lower lateral sides of trunk to cream or white ventrally. Dorsal surface of trunk and head, and upper surface of sides, also overlain by dusky grey shading, with grey-brown to dark grey, almost black, irregularly shaped blotches and stripes (very occasionally tending to a diffuse black bar), some extending ventrally across lateral line; gill cover translucent with golden patch; iris coppery gold; fins translucent, slightly pale yellow to dusky. See below for more detailed comments on body pattern.

Colour of preserved material. Base colour of head and body pale creamy yellow to tan, with overlying very light stippling of grey on dorsal and dorso-lateral surface. Dorsal surface of trunk with small to medium sized, irregular shaped dark brown to grey brown spots or blotches, more dense dorsally, extending down sides and coalescing on some individuals to form larger blotches and elongate, narrow and irregular shaped, vertical, midlateral bars, roughly centred on the lateral line. Trunk pattern extends down sides to near ventro-lateral region well below lateral line; lateral trunk pattern widely spread over caudal peduncle, except on ventral and ventro-lateral surfaces. Dorsal trunk pattern extends across the nape and inter-orbital region to the snout, behind and below eyes and onto upper opercular region, with rest of lateral surfaces of head slightly dusky grey; upper jaw and anterior portion of lower lip slightly dusky. Ventral surface of head pale cream to tan, with fine stippling along posterior lateral and ventral edges of gill covers; fine to medium black and brown spotting inside opercula, with fine, grey spotting at base of, and along, gill filaments.

Eye grey, pupil translucent pale orange to brown. Teeth translucent yellow to pale orange–yellow, tips orange to orange–red; gill rakers pale cream. Fins pale creamy yellow, becoming slightly more translucent on posterior margins, fleshy bases of dorsal fin with fine brown. Fin rays slightly opaque, external edges of rays highlighted with fine pale brown spots forming thin lines.

Etymology. The specific name gunaikurnai, named after the Gunai/Kurnai indigenous nation, the traditional inhabitants of the Gippsland region of Victoria. Galaxias gunaikurnai is found within the country of the Brayakuloong people, one of the five major clans. A noun in apposition. Suggested vernacular name ‘Shaw Galaxias’.

Genetics. Allozyme and mtDNA analysis of this species can be found in Adams et al. (2014; taxon code SH). Diagnostic allozyme loci (4–16) between this taxon and the other species in the Galaxias olidus complex are provided in Table 12.

Distribution. See Fig. 7 . Currently only known from the type locality in the headwaters of Shaw Creek, a tributary of the Caledonia River (Macalister River catchment) in the coastal Gippsland region of Victoria, at an elevation of 1470 m asl. The location is approximately 4 km (river distance) from the source, which is at 1580 m asl, in a catchment of approximately 8 km 2. Historical data indicates a more extensive distribution in this system, previously extending farther downstream (at least 12 km in the mid 1960s). The alien predatory species Brown Trout was recorded as abundant, and galaxiids absent, 400 m farther downstream from this site in 2002, below a small instream barrier. By 2012 Brown Trout had colonised upstream past this barrier to the source of the stream, eliminating Galaxias gunaikurnai from the majority of its small distribution and essentially restricting it to a single side tributary (see below).

Habitat. In 2002 recorded from a small (0.6–1.4 m average width and 0.15–0.20 m in average depth), cool, clear, alpine creek, flowing through a grassy plain, consisting of pools, glides and riffles, with smaller amounts of small cascades, and with very little shading except that provided by grasses ( Fig. 15d ). During winter the catchment is usually covered by snow for varying periods of time. Substrate consisted of bedrock, boulder and cobble, with smaller amounts of pebble, gravel and coarse sand. Instream cover was provided predominantly by rock and from bank and vegetation (alpine grasses) overhang, and pools averaged 0.5 m in depth.

General Biology. Confined to freshwater and considered not to undertake diadromous migrations. Recorded at densities of 0.05–0.18 fish/m 2 and is the only native fish species so far recorded from within its range. Spawning period unknown, though possibly winter to early spring: fish collected in late February were at an early stage of gonad development, with the majority of the body cavity full of fat deposits (though one female was significantly advanced in development), those collected in mid-April (NMV A.26403-1) and had gonads filling 50–60 % of the body cavity and males collected in early May 2013 were running ripe and females were at a ripe stage. The smallest presumed 0+ age fish recorded in April 1960 and May 2012 was 32 mm LCF with the smallest fish collected in mid-April 2008 measuring 40 mm LCF and 70 % of 95 individuals ranging in length from 40–60 mm LCF. Able to survive in very cold water (<5 o C) during winter.

Conservation status. Critically endangered ( DSE 2013). Brown Trout had invaded the upper Shaw Creek between 2010 and 2011 when high flows appear to have eroded the instream barrier which previously excluded them. In May 2012 Galaxias gunaikurnai had disappeared from the entire 4 km of main stream length in their habitat, declining from a fish density of 0.18 fish/m 2 recorded in April 2008 (Raadik unpubl. data). Approximately 150 fish remained in three small pools in a sphagnum bog in a 300 m long section of the headwaters of a 0.3 m wide side tributary, and a single adult was recorded from the headwaters of a separate, small, side tributary.

Remarks. The morphometric description of Galaxias gunaikurnai is based on only five, large, specimens. Consequently, examination of additional, moderately sized individuals is required to further define the morphometric variation within this species. This can only be undertaken once population size increases so that collection of additional individuals does not affect population viability. Of great concern is the incursion of Brown Trout into this small population. An instream barrier has been constructed and trout removal from the upstream ‘galaxiid-zone’ has commenced (2012) and is planned to occur until all trout are removed.

This species is considered to have been historically more widespread, at least extending throughout the Shaw Creek system and probably downstream into the mid-reaches of the larger Caledonia River system. Systematic survey effort, focussing on headwater sections of smaller streams in the upper reaches of the Macalister River catchment, and the headwater reaches of the adjacent Wonnangatta River catchment, is required to determine if additional, remnant populations remain, to accurately delineate the small distribution of this species and to search for suitable potential translocations sites within its presumed former range. A population of galaxiids, referrable to the Galaxias olidus complex, could not be relocated from the headwaters of Pieman Creek, Bryces Plain (Mitchell River system) (NMV A.490), approximately 14 km farther north from the type locality of Galaxias gunaikurnai , and hence its identity could not be determined.

Figures

FIGURE 7. Distribution of Galaxias aequipinnis (open circles), Galaxias brevissimus (grey square), Galaxias gunaikurnai (black square), Galaxias lanceolatus (grey circle), Galaxias longifundus (black diamond), Galaxias mcdowalli (inverted black triangle), Galaxias mungadhan (open squares), Galaxias supremus (open triangle), Galaxias tantangara (grey triangle), and Galaxias terenasus (black circles) (river basins shown—refer to Fig. 1).

FIGURE 15. A–B: Galaxias gunaikurnai sp. nov. holotype, NMV A.30573-2, 94.6 mm LCF, Shaw Creek, off Howitt Road, Bennison High Plains, Alpine National Park, Victoria, A) line drawing (R. Plant), B) image of preserved specimen (T.A. Raadik); C) G. gunaikurnai sp. nov., collected at the type locality with the holotype, 28 February 2002; ~ 80 mm LCF. (R. Kuiter); D) Shaw Creek, at the type locality of G. gunaikurnai sp. nov., 16 April 2013 (T.A. Raadik). Scale bar = 5 mm.