Galaxias mcdowalli, 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 : 79-85

Galaxias mcdowalli , new species

McDowall’s Galaxias

Tables 4 to 9, 12, 25 & 26; Figures 7 , 18 & 19

Galaxias olidus (non G. olidus Günther, 1866 )— Cadwallader & Backhouse, 1983: 69 (partim); Koehn et al., 1991: 19; Raadik, 1992a: 51; Raadik, 1992b: fig. 16 (partim); Raadik, 1995b: 51, fig A4.7 (partim).

Galaxias sp. 5 — DSE, 2013: 17.

Galaxias sp. 12— Kuiter, 2013: 69.

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

Material Examined.

Holotype. NMV A.30572-2, 74.2 mm LCF, (65.6 mm SL), male, Rodger River, at bridge on Waratah Flat Road, Waratah Flat , Snowy River National Park , Victoria, 37° 17' 01”S 148° 34' 12”E, T.A. Raadik, 27 February 2002.

Paratypes. AMS I.44918-001 (2), 70.2–84.0 mm LCF (62.1–74.1 mm SL), NMNZ P.045749 (2), 73.6–75.1 mm LCF (65.7-66.1 mm SL) and NMV A.30572-1 (10), 69.0– 78.2 mm LCF (61.2–69.4 mm SL), collected with holotype; NMV A.30574-1 (8), 60.0– 82.5 mm LCF (53.1–73.3 mm SL) Rodger River , type locality, TAR, 4 March 1993 .

Non-type material. VIC: NMV A. 30572-3 (2), collected with holotype; NMV A.30574-2 (3), Rodger R, collected with NMV A.30574-1 .

Diagnosis. Galaxias mcdowalli sp. nov. differs from all other species within the Galaxias olidus complex by a combination of the following characters: 8 segmented pelvic fin rays; high vertebral count of 55; head length about as long as PelAn distance; dorsal and anal fin bases relatively long (9.9–13.0 and 11.0–12.5 % SL); snout long (27.0–33.7 % HL) and post-orbital head length short (48.9–55.2 % HL); inter-orbital relatively wide (38.6–44.8 % HL); nostrils of moderate length, not visible from ventral view; pelvic fins moderately short (8.9–10.8 % SL); caudal peduncle relatively shallow (7.2–8.1 % SL), longer than length of caudal fin and flanges moderately developed and longish, reaching to or anteriorly past distal end of adpressed anal fin rays; dorsal midline usually quite broadly flat anteriorly from above pelvic fin bases; raised laminae on ventral surface of paired fins sometimes evident though not strongly developed; gill rakers short and stout; pyloric caecae absent; anal fin origin usually under 0.53 distance posteriorly along dorsal fin base; and, lack of distinct black bars along lateral line.

Description. As for the genus and members of the Galaxias olidus complex, except as indicated below, based on 23 specimens, 61.2–74.1 mm SL, and 5 additional, non-type, specimens for meristics. See Tables 4 to 9 for frequencies of meristic values and Table 25 for a summary of meristic variation. Segmented dorsal fin rays 10 (9–12), of these 8 or 9* (6–10) branched and 2 (1*–3) unbranched; segmented anal fin rays 11* or 12, of these 9* or 10 branched and 2 (1–2) unbranched; caudal fin rays 16; segmented pectoral fin rays 14 (14–16), of these 12 (11–14) branched and 2 (2–3) unbranched; pelvic fin rays 8, of these 7 (6–7) branched and one unbranched; gill raker total count (lower limb and upper limb) 12 (11–13*), lower arch with 9 (9–10*) and 3 (2–4) on upper, variation on first gill arch 8+2 (1), 9+2 (2), 9+3 (13), 10+3 (10*), 10+4 (1); vertebrae 55 (54–56); no pyloric caecae on stomach.

See Table 26 for comparative value ranges of morphometric characters. Body moderately deep and long, dorsal midline usually quite broadly flat anteriorly from above pelvic fin bases, body depth through pectoral base 1.25 (1.0–1.3) that through vent, trunk with dorsal and ventral profiles evenly arched from snout to dorsal fin, dorsal arched slightly more than ventral, laterally compressed posteriorly from about above pelvic fin bases; body tapering back to a caudal peduncle of moderate length, 7.5 (6.8–9.0) in SL and depth, 13.1 (12.3–13.9) in SL, the peduncle depth 1.7 (1.5–1.8) in its length; accessory lateral line present. Head of moderate length, 4.5 (4.1–4.7) in SL and similar to PelAn distance (0.9–1.1), moderately deep, 2.4 (2.2–2.8) in HL, and wide, 1.6 (1.5–1.7) in HL, distinctly wider than deep (depth 1.5–1.7 in HW), lateral profile weakly wedge-shaped and slightly depressed and flattened dorsally; eyes moderate, 5.3 (4.8–5.8) in HL, situated high on head, just below dorsal head profile, interorbital usually flat but occasionally convex, broad, 2.4 (2.2–2.6) in HL and 2.2 (1.9–2.6) times ED; cheeks expanded slightly below eyes, eye profiles just visible laterally from ventral view; snout long, 3.2 (3.0–3.7) in HL and 1.6 (1.4–1.9) times ED, lateral profile rounded to slightly pointed; post-orbital head length short, 1.9 (1.8–2.0) in HL; nostrils of moderate length, just extending to posterior edge of upper lip, not visible from ventral view; mouth subterminal, of moderate length, 2.7 (2.4–3.1) in HL, posterior extent reaching back to under anterior 0.3 of eyes, and 0.7 (0.56–0.74) ED below ventral margin of eye, most anterior tip of upper lip usually level with about middle of eye, gape moderately wide, 2.5 (2.3–2.7) in HL, width 1.1 times length of upper jaw and 1.6 (1.4–1.8) in HW. Jaws subequal, lower usually 1.1 in upper, upper jaw relatively thick and fleshy. Gill rakers short, stout and bluntly pointed.

Fins moderately fleshy at bases, median fins more so, with thickening extending distally over 0.3–0.5 of fin area, extending farther distally between fin rays; dorsal and anal fin bases long and about equal in length, though dorsal base sometimes very slightly shorter, fins moderately long and rounded, usually of equal length (0.9–1.1), middle rays longest; anal fin origin usually under 0.52 (0.35–0.65) distance posteriorly along dorsal fin base. Pelvic fins relatively short, 10.2 (9.2–11.2) in SL, 1.2 in pectoral fin length, inserted at about mid-point of standard length and extending to just under 0.5 distance to anal fin base; pectoral fin moderately short and paddle-shaped, 8.5 (7.9–9.2) in SL, extending about 0.4 distance to pelvic fin base, low on body with dorsal end of fin base at, or just above, level of posterior extent of mouth, lamina of paired fins oriented anterio-ventrally to ventrally, raised lamellae on ventral surface of rays sometimes present though not strongly developed. Caudal fin of moderate length, 7.7 (7.3–8.5) in SL, emarginate, about as long as caudal peduncle, vertical width of expanded rays greater than maximum body depth, flanges moderately well-developed along caudal peduncle, reaching anteriorly past distal end of adpressed anal fin rays.

Size. Recorded to 84 mm LCF and 6 g; commonly to 65–75 mm LCF.

Colour in life. Body predominantly olive-brown on back and upper sides above lateral line, extending onto top and sides of head and snout, and lateral sides of trunk posterior to anal fin, becoming light brown to cream ventrally, belly almost white. Overlain by small to moderate sized dark brown to black, irregular shaped blotches or flecks, some coalescing to form irregularly shaped vertical bands; wide mid-lateral band of gold flecks present, becoming iridescent posteriorly, and dorsal midline with thin row of gold flecks extending from nape to dorsal fin origin. Gill cover translucent with large golden patch; iris golden, fins translucent grey to light brown or olive-grey. See below for more detailed comments on body pattern.

Colour of preserved material. Base colour of head and body pale creamy tan, darker brownish dorsally, generally above lateral line. Dorsal surface of trunk with irregular shaped medium-size, diffuse, dark brown spots or flecks and small to medium sized diffuse to distinct blotches, particularly abundant on sides, extending well below lateral line and onto ventro-lateral surface, some almost reaching pelvic fin base; very fine, sparse, brown stippling extending onto ventral surface. A few blotches coalesce to form diffuse vertical bars near, or centred on, the lateral line, and some spots or blotches become much darker brown to almost black in the area of the lateral line. Dorsal and lateral surfaces of head brown, darker dorsally, behind eye and on upper opercle, extending onto ventral surface as fine, sparse, brown stippling. Fine black spotting inside operculum and at base of, and along, gill filaments. Trunk with very fine, light coloured lines following myomeres, etched across body pattern.

Eye grey-black, pupil translucent pale brownish yellow. Teeth translucent yellow to pale orange–yellow, tips orange to orange–red; gill rakers pale cream. Fins creamy white, becoming more translucent on posterior margins, finer body stippling extending onto fleshy bases of dorsal, anal and pectoral fins. Fin rays translucent, external edges of rays highlighted with very fine black lines or row of fine spots.

Etymology. Named for the late Dr Robert (Bob) Montgomery McDowall (1939–2011), for his long and valuable contribution to galaxioid systematics. Suggested vernacular name as ‘McDowall’s Galaxias’.

Genetics. Allozyme and mtDNA analysis of this species can be found in Adams et al. (2014; taxon code RO). Diagnostic allozyme loci (7–17) between this taxon and the other species in the Galaxias . olidus complex are provided in Table 12.

Distribution. See Fig. 7 . Currently known from the type locality in the headwaters of the Rodger River, a tributary of the Snowy River in the coastal East Gippsland region of Victoria, at an elevation of 680 m asl. The location is approximately 10 km (river distance) from the source, which is at 1140 m asl, in a catchment of approximately 30 km 2. Not recorded from elsewhere in the catchment and alien Brown Trout are present throughout the lower and mid reaches of the Rodger River, extending upstream at least to the Deddick Track which is approximately 15 km (river distance) downstream of the type locality. Presumably an instream barrier is present between the type locality and the Deddick Track, which has prevented the colonisation of trout farther upstream.

Sympatry. Only species of Galaxias found within its restricted range. Galaxias brevipinnis , Galaxias maculatus and Galaxias truttaceus are found farther downstream and their ranges may have historically overlapped with that of Galaxias mcdowalli before trout disrupted and reduced distributional ranges. An unidentified species of Galaxias has been recorded from the lower to mid Rodger River system, in the Yalmy River and Serpentine Creeks, though its identity has not been established (see Remarks).

Habitat. Recorded from a cool, clear flowing, heavily shaded and shallow (0.5 m) freshwater river, 3–5 m wide, with a substrate of sand, silt and clay, and areas of cobble and pebble. Instream cover was provided by logs, branches and bank and vegetation overhang, and pools ranged from 1–2 m in depth.

General Biology. Confined to freshwater and considered not to undertake diadromous migrations. Recorded at densities of 0.15–0.18 fish/m 2 and collected with the native species Shortfinned Eel and East Gippsland Spiny Crayfish. Spawning period unknown, though possibly late spring to summer: fish collected in late February/early March were at an early stage of gonad development, though a male (74.2 mm LCF) appeared to be almost ripe (NMV A.30572-2), and the smallest presumed 0+ age fish recorded (33.9 mm LCF) was collected in early March (NMV A.30574-1). One individual recorded with a short, thin, white worm, coiled and pointed at both ends, from amongst fat deposits around the stomach in the body cavity.

Conservation status. Critically endangered ( DSE 2013).

Remarks. Considered to have been historically more widespread before trout reduced their range, possibly extending into the Snowy and lower Buchan River systems, and into adjacent catchments (e.g. Mountain and New Country creeks). A few Galaxias individuals, belonging to the Galaxias olidus complex, and superficially similar to Galaxias mcdowalli , have been recorded at lower elevation farther downstream in the Yalmy River and Serpentine Creek (NMV A.30569-2) in the Rodger River system, and at higher elevations to the north-west in the Suggan Buggan River (NMV A.12415 and A.30615-1) and headwaters of the Buchan River (AMS I.17994-001 and I.19262-001; NMV A.9920) which includes Native Dog Creek (NMV A.10419). The identities of these populations have not been determined due to a lack of suitably preserved fresh material, the rarity of individuals (Serpentine Creek, Suggan Buggan and Yalmy rivers), and the apparently recent possible extinction of the population in the Buchan River headwaters following upstream invasion and colonisation of Brown Trout (Raadik unpubl. Data). Extensive sampling in these areas for this study failed to locate any individuals and therefore additional, targeted sampling is strongly recommended to locate fresh material for taxonomic study.

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 18. A–B: Galaxias mcdowalli sp. nov. holotype, NMV A.30572-2, 74.2 mm LCF, Rodger River, Waratah Flat Road, Waratah Flat, Snowy River National Park, Victoria, A) line drawing (R. Plant), B) image of preserved specimen (T.A. Raadik); C–D G. mcdowalli sp. nov. collected at the type locality with the holotype, 27 February 2002, C) ~ 80 mm LCF. (R. Kuiter), D) showing different pattern, collected at the type locality with the holotype, 27 February 2002; ~ 85 mm LCF (R. Kuiter). Scale bar = 5 mm.

FIGURE 19. Rodger River, at the type locality of G. mcdowalli sp. nov., 27 February 2002 (T.A. Raadik).