Galaxias supremus, 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 : 135-142

Galaxias supremus , new species

Kosciuszko Galaxias

Tables 4 to 9, 35 & 36; Figures 7 , 33 & 34

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

Galaxias olidus (non G. olidus Günther, 1866 )— Helms, 1890 (partim): 12; McDowall & Frankenberg, 1981: 469 (partim); Campbell et al., 1986: 95 (partim); Terzis, 1986 (partim); Green & Osbourne, 1994: 124 (partim); Green, 2002: 37; McDowall, 2003a: 364 (partim); Green, 2008: (partim).

Galaxias findlayi (non G. findlayi Macleay, 1882 )— Ogilby, 1896: 66 (partim) [see Appendix 11 for text of revision]; Frankenberg, 1969: 329; Timms, 1980: 123; Hebert, 1977: 391; Raadik & Kuiter, 2002: 831 (partim).

Galaxias sp. 1 – Raadik & Kuiter, 2002: 831.

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

Material Examined.

Holotype. NMV A.30571-3, 86.6 mm LCF, (77.0 mm SL), female, Carruthers Creek, on Main Range Track, south-east of Blue Lake , Mount Kosciuszko National Park , New South Wales, 36° 24' 37”S 148° 18' 20”E, T.A. Raadik, 15 March 2002.

Paratypes. NSW: AMS I.44919-001 (3), 72.8–84.3 mm LCF (64.2–74.8 mm SL), NMNZ P.045750 (1), 75.2 mm LCF (66.0 mm SL) and NMV A.30571-1, (10), 77.0– 96.1 mm LCF (68.63–85.4 mm SL), collected with holotype; AMS I.44920-001 (3), 71.3–87.5 mm LCF (62.9–76.6 mm SL), NMNZ P.045751 (2), 82.2–83.0 mm LCF (72.3–73.5 mm SL) and NMV A.30570-1 (10), 60.9–94.0 mm LCF, (53.8–83.3 mm SL), Blue Lake , west shore and inflowing tributary, off Blue Lake walking track, Mount Kosciuszko National Park, 36° 24' 20”S 148° 18' 48”E, T.A. Raadik, 15 March 2002 .

Non-type material. NSW: NMV A.30571-2 (1), Carruthers Creek , collected with holotype; NMV A.30570-2 (16), Blue L., collected with NMV A.30570-1 .

Diagnosis. Galaxias supremus sp. nov. differs from all other species within the Galaxias olidus complex by a combination of the following characters: 8 segmented pelvic fin rays; very high mean vertebral count of 57, though range broad (52–59); mouth distinctly subterminal; dorsal, anal and pelvic fin origins set far back along trunk (70.4–75.1, 74.8–80.2 and 49.7–55.6 % SL respectively); distance between pectoral and pelvic fin bases long (27.8–35.7 % SL); body depth shallow (8.4–12.4 % SL) and much greater through pectoral fin base (11.8–16.4 % SL) than that through vent; caudal peduncle very short and shallow (10.0–12.7 and 6.3–8.9 SL respectively) and caudal fin much longer (120 %) than caudal peduncle; snout long (26.7–34.9 % HL) and eye small (13.1–20.7 % HL); nostrils short, not visible from ventral view; anal fin base short (8.7–10.9 % SL); dorsal and anal fins short (12.6–15.9 and 13.1–15.9 % SL respectively); dorsal midline usually flattened anteriorly from above or slightly posterior to pectoral fin bases; posterior extent of mouth about 0.8 ED below ventral margin of eye; usually 2, occasionally 1, pyloric caecae of moderate length (4.6 % SL); gill rakers short to moderately long; anal fin origin usually under 0.85 distance posteriorly along dorsal fin base, the greatest setback in all members of the species complex; lack of distinct black bars along lateral line though, very occasionally, dark patches on dorsal midline may have a very small, black bar in the centre; and, distinctive, mottled colour pattern.

Description. As for the genus and members of the Galaxias olidus complex, except as indicated below, based on 29 specimens, 53.8–85.4 mm SL, and 15 additional, non-type specimens for meristics. See Tables 4 to 9 for frequencies of meristic values and Table 35 for a summary of meristic variation. Segmented dorsal fin rays 10 (9–11), of these 8 (7–9) branched and 2 (1–3) unbranched; segmented anal fin rays 11 (10–12), of these 9 (8–10) branched and 2 (1–2) unbranched; caudal fin rays 16 (15–16); segmented pectoral fin rays 15 (14–16), of these 13 (12*–15) branched and 2 (2–3) unbranched; pelvic fin rays 8 (7–9), of these 7 (6–8) branched and one unbranched; gill raker total count (lower limb and upper limb) 13 (10–13; [11*]), lower arch with 9 (8–10) and 3 (2*–4) on upper, variation on first gill arch 8+2 (2), 9+2 (5*), 9+3 (10), 9+4 (3), 10+2 (1), 10+3 (11), 10+4 (1); vertebrae 57 (53–58); usually two*, occasionally one, pyloric caecae on stomach.

See Table 36 for comparative value ranges of morphometric characters. Body moderately long but shallow, relatively shallow at vent and of moderate depth through pectoral base, dorsal midline usually flattened anteriorly from above or slightly posterior to pectoral fin bases, depth through pectoral base much greater than that through vent, 1.3 (1.2–1.6) times BDV, trunk with dorsal profile evenly arched from snout to dorsal fin, ventral less arched from snout to anal fin, body tapering back to a relatively short, 8.8 (7.0–10.0) in SL, and shallow, 13.5 (11.2–15.9) in SL, caudal peduncle, the peduncle depth 1.5 (1.3–1.9) in its length; accessory lateral line present. Head of moderate length and shorter, 0.9 (0.8–1.1) than PelAn distance, of moderate depth and width, 2.5 (2.0–2.7) and 1.6 (1.5–1.7) in HL respectively, distinctly wider than deep (depth 1.6 (1.4–1.7) in HW), dorsally compressed and lateral profile wedge-shaped; eyes small, 6.0 (4.8–7.6) in HL, 2.4 (2.0–3.0) in HD, situated at or just below dorsal head profile, interorbital flat to very slightly convex, relatively broad, 2.6 (25–2.9) in HL and 2.3 (1.8–2.8) times ED; cheeks expanded below eyes, eye profiles usually not visible laterally from ventral view; snout relatively long, 3.3 (2.9–3.7) in HL and 1.9 (1.4–2.5) times ED, lateral profile usually pointed; post-orbital head length of moderate length, 1.9 (1.7–1.9) in HL; nostrils short and not visible anterio-laterally from ventral view; mouth subterminal, of moderate length, 2.7 (2.4–3.2) in HL, posterior extent reaching to below middle of eyes or slightly farther and usually 0.8 (0.6–1.1) of ED below ventral margin of eye, most anterior tip of upper lip level with about middle of eye, occasionally just lower, gape of moderate width, 2.6 (2.3–3.0) in HL, wider than length of upper jaw and about 1.6 in HW. Jaws subequal, 1.1–1.2 times length of lower. Pyloric caecae moderately long, longest averaging 4.6 % (2.7–7.9 %) of SL; gill rakers stout, short to moderately long and rounded to bluntly pointed.

Median fins moderately fleshy at bases, paired fins less so, with thickening extending distally over about 0.5 of fin area, extending farther between fin rays, dorsal fin base usually slightly shorter than anal fin base, dorsal and anal fins rounded and relatively short, anal longer than dorsal, middle rays longest; anal fin origin usually under 0.85 (0.66–1.21) distance posteriorly along dorsal fin base. Pelvic fins relatively long, 8.7 in SL, 0.9 of pectoral fin length, inserted just posterior to mid-point of standard length and extending just under 0.5 distance to anal fin base; pectoral fin of moderate length and paddle-shaped, 7.6 in SL, extending abut 0.4 distance to pelvic fin base, low on body with dorsal extent of fin base level with posterior extent of mouth, lamina of paired fins oriented distinctly ventrally, raised lamellae on ventral surface of rays usually present and strongly developed. Caudal fin of moderate length, 7.5 (6.4–8.3)in SL, emarginate, 1.2 times length of caudal peduncle, vertical width of expanded rays greater than maximum body depth, flanges low and moderately well-developed along caudal peduncle, reaching to distal end of rays of adpressed anal fin as a low ridge, or slightly farther.

Size. Recorded to 96 mm LCF and 8 g; commonly to 80–85 mm LCF.

Colour in life. Body and head light brown to tan overall, body usually slightly lighter below lateral line, belly lighter. Overlain by moderate to large sized brown to dark brown, sometimes dark grey to almost black, irregularly shaped blotches usually coalescing to form irregular shaped bands, more densely spaced above lateral line, extending down sides and reaching about mid-laterally, sometimes overlain with shading formed by minute, closely spaced, dark grey spots. Blotches centred along lateral line darkest and blotches/bands more widespread laterally on caudal peduncle: very occasionally tiny black bars present, located around the centre of the trunk and interspersed amongst the blotches and bands. Gill cover light brown, with a moderately large gold blotch; iris gold. Mid-dorsal surface of trunk sometimes with a thin band composed of gold spots extending from nape to dorsal fin base; head broadly scattered with diffuse small gold flecks, and broad, diffuse band of golden to coppery spots usually extending from near base of pectoral fin onto caudal peduncle, usually mostly below lateral line and quite distinct posteriorly, though can extend dorsally to above lateral line along flanks of trunk. Fins translucent lemon to light brown. See below for more detailed comments on body pattern.

Colour of preserved material. Base colour of head and body pale cream to creamy yellow, with overlying light dusky shading of fine brown-black stippling, particularly on dorsal and latero-ventral surface. Dorsal and lateral surfaces of trunk with distinctive bold pattern of closely spaced, irregular shaped, dark brown to grey spots and blotches, smaller on dorsal surface and coalescing to form distinct broad patches, sometimes crisply outlined, centred on the lateral line, ranging from pectoral fin base posteriorly to caudal fin; with dark brown to black regions on lateral line. Mid-lateral bars rarely present, if so, tiny and black, located around centre of trunk and usually within other diffuse dark brown bars and larger blotches. Lateral trunk pattern extends below lateral line to ventro-lateral region, fading rapidly and merging with overlying ventro-lateral stippling. Dorsal trunk pattern extends onto nape, behind eyes and upper opercular region, with rest of dorsal surface of head and snout, including lateral surfaces of head, dusky grey. Fine, sparse black stippling extends onto ventral surface of head, and fine to medium black and brown spotting inside operculum, with black spotting at base of, and along, gill filaments.

Eye grey to black, pupil translucent pale orange yellow. Teeth translucent yellow to pale orange–yellow, tips orange to orange–red; gill rakers cream to pale yellow. Fins pale creamy yellow, becoming more translucent on posterior margins, fleshy bases of dorsal, anal and pectoral fins with fine brown stippling, also just extending onto base of caudal fin. Fin rays opaque, external edges of rays highlighted with fine brown spots forming thin lines, first few rays generally darker.

Etymology. From Latin supremus , meaning highest, uppermost, in reference to this species being the galaxiid found at the highest elevation of all the Galaxiidae , occurring at over 2000 m asl on Mount Kosciuszko, Australia’s highest mountain. Suggested vernacular name as the ‘Kosciuszko Galaxias’.

Genetics. Allozyme and mtDNA analysis of this species can be found in Adams et al. (2014; taxon code KO). Diagnostic allozyme loci (2–9) between this taxon and the other species in the Galaxias olidus complex are provided in Table 12.

Distribution. See Fig. 7 . Poorly known. Confirmed records only from Blue Lake and type locality in the upper reaches of Carruthers Creek, headwaters of the Blue Lake Creek system in the upper Snowy River on Mount Kosciuszko, Mount Kosciuszko National Park in NSW, at an elevation of 1900 to 1950 m asl. The Carruthers Creek location is approximately 1.3 km (river distance) from the source, which is at 2100 m asl, in a catchment of approximately 3.5 km 2, and that of Blue Lake approximately 1.6 km (river distance) from the source (at 2150 m asl), in a catchment of approximately 5.5 km 2. Alien trout are abundant in the Snowy River approximately 2 km downstream from the Carruthers Creek and Blue Lake locations, and therefore the populations of Galaxias supremus are considered to be currently restricted to the upper reaches of each system; within the Blue Lake Creek possibly to upstream of Hedley Tarn which is just over 1 km upstream from the Snowy River. The identity of galaxiids in many nearby waters in the upper reaches of the Snowy River system on Mount Kosciuszko (e.g. Snowy River, Thredbo River, Club Lake, Merritts, Spencers, Betts, Perisher, Pipers and Diggers creeks, etc.) are unconfirmed (see Remarks). Consequently, changes to historical distributions are currently unknown.

Sympatry. Considered to have been sympatric with Galaxias olidus , though alien trout have substantially altered distributional patterns in the last 150 years and fragmented and reduced galaxiid populations.

Habitat. Collected from cold and clear water in small flowing creeks (0.6–1.1 m average width, 0.1–0.2 m average depth, 0.5–0.6 m maximum depth) and from an on-stream lake (Blue Lake). During winter all sites are covered by snow and ice for an extended period of time. Substrate consisted of bedrock, boulder, cobble, gravel and sand in the creeks, and cobble, pebble, gravel and silt in the lake, with fish collected from amongst rock, undercut banks and overhanging grasses in the creeks, mainly from pools. In Blue Lake, fish were collected from amongst small cobbles and from within 2 m of the shoreline; fish location and habitat in deeper water is unknown. All sites lacked emergent or submerged aquatic vegetation or overhead shading.

General Biology. Confined to freshwater and considered not to undertake diadromous migrations. Collected at a density of 4.5 fish/m 2 in Carruthers Creek, 2.5 fish/m 2 along the edges of Blue Lake, and 1.5 fish/m 2 in an inflowing tributary to Blue Lake, and is the only native fish species so far recorded from within its range, though Galaxias olidus is presumed to be present nearby. Collected in Carruthers Creek with an unidentified native spiny crayfish Euastacus sp. (possibly E. rieki ). Spawning period unknown, though possibly very late spring to early summer: adult fish collected in mid-March were from early to mid-stage of gonad development, and the smallest presumed 0+ age fish recorded was 34.1 mm LCF; and, an additional 13 fish between 35.0– 49.4 mm LCF were also collected in mid-March (NMV A.30570-2). Able to withstand very cold water (<2 o C) for extended periods, as Blue Lake, and possibly the creeks, ice over during winter; Green (2000) reported an active fish lying on the ice of Blue Lake in October 1977.

Variation. Individuals from Carruthers Creek differ slightly in overall morphology to those from Blue Lake, being shallower in body and head depth, the posterior end of the mouth is positioned slightly lower below the eyes, and the body pattern is more intense and extends farther down the sides to cross the lateral line. Juvenile fish (<55 mm LCF) from Blue Lake had a larger eye than similar sized individuals from Carruthers Creek. In addition, one individual from Blue Lake lacked the typical large dark brown blotches along the mid-lateral region of the trunk, which were replaced by a lateral series of closely spaced, small (1.1–1.2 mm wide x 1.6–1.8 mm long), relatively diffuse black bars, extending from the pectoral fin base to above the pelvic fin base. Putative hybridisation with G. olidus is not considered to cause difficulties in identification (see below).

Conservation status. Considered critically endangered based on IUCN criteria ( ISPS 2013): A2e; B1+2abc; C2a(i)—two locations/populations, estimated EOO of 6 km 2 and AOO of 1.4 km 2.

Remarks. Potentially hybridise with Galaxias olidus , with putative hybrid fish genetically identified from Sawpit Creek. These individuals were morphologically similar to G. olidus , with only very subtle differences in characteristics. The degree of putative hybridisation, and hybrid morphology, requires detailed study.

Galaxias supremus is recorded from a similar location to the poorly defined type locality for Galaxias findlayi Macleay, 1882 from near Mount Kosciuszko (see Appendix 1). The type specimens for G. findlayi have been lost and could not be examined, but, based on comparison with the published description, significant differences exist in the morphology of both taxa, particularly the pelvic fin ray count. Consequently it is considered that G. findlayi is not referrable to Galaxias supremus . The taxonomic status of G. findlayi could therefore not be resolved and its placement as a junior synonym of Galaxias olidus Günther is upheld.

Galaxias supremus is probably more widespread than currently known and is highly likely to be the galaxiid found in the upper Snowy River near the summit of Mount Kosciuszko, at an elevation of ~ 2100 m ( Green 2002). It is also probably the species present in nearby Club Lake. Many additional populations of galaxiids in the Galaxias olidus complex, are known throughout the upper headwaters of the Snowy River system (e.g. Munyang, Snowy, and Thredbo rivers, and Betts, Diggers, Four Mile, Merritts, Perisher, Pipers, Racecourse, Rawsons, Spencers, creeks), and have been fragmented by alien trout ( Green 2008). Given the possibility for unrecognised species in the catchment (e.g. Galaxias findlayi or new taxa), that putative hybrids have been identified between Galaxias supremus and Galaxias olidus , and that many populations of galaxiids remain to be identified, detailed assessment of the genetic and morphological variation of galaxiids in the upper Snowy River system, upstream of Dalgety, is urgently required, based on systematic collection of fresh material, to resolve the systematics of the species complex and to define distributions.

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 33. Galaxias supremus sp. nov., A–B: holotype, NMV A.30571-3, 86.6 mm LCF, female, Carruthers Creek, Main Range Track, south-east of Blue Lake, Mount Kosciuszko National Park, New South Wales, A) line drawing (R. Plant), B) image of preserved specimen (T.A. Raadik); C), collected at the type locality with the holotype, 15 March 2002; ~ 80 mm LCF. (R. Kuiter); D), collected from Blue Lake, 15 March 2002; ~ 70 mm LCF. (R. Kuiter). Scale bar = 5 mm.

FIGURE 34. A) Carruthers Creek, at type locality of G. supremus sp. nov., 15 March 2002 (T.A. Raadik); B) habitat of G. supremus sp. nov., Blue Lake and inflowing tributary, Mount Kosciuszko National Park, 15 March 2002 (T.A. Raadik).