Galaxias terenasus, 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 : 147-156

Galaxias terenasus , new species

Roundsnout Galaxias

Tables 4 to 9, 39 & 40; Figures 7 , 36 to 38

Galaxias bongbong (non Macleay, 1881)— Whitley, 1939: 268 (partim).

Galaxias olidus olidus Günther, 1866 — Frankenberg, 1969: 170 (partim). Galaxias olidus (non G. olidus Günther, 1866 )— McDowall & Frankenberg, 1981: 469 (partim); Koehn et al., 1991: 17; Raadik, 1992a: 19, 21; Schiller et al., 1997: 75 (partim); Lintermans, 1998: site 73 and 83; McDowall, 2003a: 364 (partim).

Galaxias sp. 2 — Kuiter, 2013: 42.

Galaxias sp. 3 — DSE, 2013: 17; Lieschke et al. 2013a,b.

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

Material Examined.

Holotype. NMV A.30592-3, 65.4 mm LCF (58.6 mm SL), female, Maclaughlin River, at Allen Caldwell Bridge on Ando (Dalgety/Bombala) Road , north-north-west of Bombala , New South Wales, 36° 38' 50”S 149° 06' 40”E, T.A. Raadik, 14 March 2002.

Paratypes. NSW: AMS I.44931-001 (3), 56.2–65.0 mm LCF (49.9–58.2 mm SL), NMNZ P.045754 (2), 56.1–59.5 mm LCF (50.0– 53.4 mm SL) and NMV A.30592-2 (9), 52.0– 69.4 mm LCF (46.8–62.2 mm SL), collected with holotype; NMV A.9897-1 (12), 45.3–53.4 mm LCF (39.8–46.4 mm SL), Church Creek , at bridge on Bombala / Delegate Road, east of Delegate, 37° 02' 18”S 148° 59' 17”E, R.S. Frankenberg, 8 March 1966 ; NMV A.30557-1 (4), 57.9–64.0 mm LCF (51.3–57.0 mm SL), Church Creek , at bridge on Bombala / Delegate Road, east of Delegate, 37° 02' 18”S 148° 59' 17”E, T.A. Raadik, 17 December 2003 ; NMV A.30591-2 (10), 51.7–62.7 mm LCF (45.6–55.2 mm SL), Genoa River , at bridge on Monaro Highway, Rockton, 37° 08' 03”S 149° 18' 50”E, T.A. Raadik, 16 December 2003 ; NMV A.30584-2 (2), 53.3–64.9 mm LCF (47.1–57.4 mm SL), Genoa River , as for NMV A.30591-2, T.A. Raadik, 26 February 2002 ; NMV A.30554-1 (6), 54.2–66.1 mm LCF (47.4–58.3 mm SL), White Rock River , downstream of culvert on Southern Access Road , upstream of Nalbaugh Falls , north-east of Rockton, Nalbaugh State Forest, 37° 03' 21”S 149° 20' 10”E, T.A. Raadik, 26 February 2002 ; AMS I.44932-001 (3), 52.4–58.2 mm LCF (46.3–51.5 mm SL) and NMV A.30542-2 (6), 57.6–62.0 mm LCF (51.2–54.7 mm SL), White Rock River , location as for NMV A.30554-1, T.A. Raadik, 16 February 2003 ; NMV A.30560-1 (5), 48.9–56.9 mm LCF (47.1–50.4 mm SL), White Rock River , at bridge on track to Nalbaugh Falls, Nalbaugh State Forest, 37° 03' 33”S 149° 20' 50”E, T.A. Raadik, 16 December 2003 ; VIC: NMV A.30548-1 (2), 45.1–47.2 mm LCF (39.2–41.1 mm SL), Back Creek , at bridge on Back Creek Track, Noorinbee North, 37° 25' 41”S 149° 12' 32.”E, TAR, 5 May 1993 .

Non-type material. NSW: NMV A.30592-1 (9), 43.1–60.0 mm LCF (38.6–54.7 mm SL), Maclaughlin River , collected with holotype; NMV A.9897-2 (60), 20.7–43.9 mm LCF (18.0– 37.8 mm SL), Church Creek, collected with NMV A.9897-1; AMS I.40037-001 (2), Delegate River, Delegate, (37.1–37.5 mm LCF), 13 April 1999 ; NMV A.30591-1 (10), 19.1–34.6 mm LCF (16.5–30.8 mm SL), Genoa River , collected with NMV A.30591-2; NMV A.30584-1 (4), 43.7–47.8 LCF (38.7–42.0 SL), Genoa River, collected with NMV A.30584-2; NMV A.11622 (6), 49.6–57.3 mm LCF (43.5–50.6 mm SL), Genoa River, location as for NMV A.30591-2, PJU and C. Brumley, 19 January 1993 ; NMV A.11621 (4), 23.7–35.1 mm LCF (20.8–30.9 mm SL), White Rock River , at Imlay Road, east of Rockton, 37° 08' 05”S 149° 21' 22”E, PJU and C. Brumley, 19 January 1993 ; NMV A.30542-1 (9), 36.9–46.5 mm LCF (31.9–40.1 mm SL), White Rock River , collected with NMV A.30542-2; NMV A.30560-2 (1), 43.6 mm LCF (38.6 mm SL), White Rock River , collected with NMV A.30560-1. VIC: NMV A.30548-2 (5), 32.3–37.4 mm LCF (28.6–32.1 mm SL), Back Creek, collected with NMV A.30548-1; NMV A.30549-1 (8), 18.4.0– 48.5 mm LCF (16.7–41.8 mm SL), Back Creek, location as for NMV A.30548-1, TAR, 15 December 2003 .

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

Diagnosis. Galaxias terenasus sp. nov. is the most distinctive species in the Galaxias olidus complex and differs from the other species by a combination of the following characters: diminutive size; long anterior nostrils, usually visible anterio-laterally from ventral view; distinctive body colour pattern and thin fins; low mean total pectoral fin segmented ray count of 13; low mean vertebral count of 51; dorsal and ventral trunk profiles straight or nearly so; lateral snout profile usually rounded; body depth shallow through pectoral fin base (11.2–14.3 % SL); dorsal midline usually distinctly flattened anteriorly from dorsal fin base; mouth small, usually reaching back to anterior margin of eye with posterior extent of mouth about 0.4 ED below ventral margin of eye; head and interorbital narrow (49.8–64.0 and 31.4–40.5 % HL respectively) but head length greater than PelAn distance; eye large (17.5–27.7 % HL and 45.7–73.3 % HD); gape narrow (26.4–34.4 % HL and 48.7–64.2 % HW); snout, upper and lower jaws short (17.6–29.8, 24.4–29.9 and 21.2–29.2 % HL respectively); lower jaw about 95 (82.9–100.0) % length of upper; caudal peduncle moderately long and longer than length of caudal fin; caudal peduncle flanges moderately developed but short, usually not reaching to adpressed anal fin; dorsal fin base short (7.1–11.6 % SL); distance between pelvic and anal fins short (17.8–24.6 % SL); pelvic fin very short (6.3–11.2 % SL), only about 74.4 % of length of pectoral fin; raised lamellae absent from ventral surface of rays of paired fins; accessory lateral line absent; anal fin origin usually under 0.42 distance posteriorly along dorsal fin base; 2 thin to moderately thick and long (5.1 % SL) pyloric caecae; gill rakers short and stout; 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 64 specimens, 39.9–62.2 mm SL, and 51 additional, non-type specimens for meristics. See Tables 4 to 9 for frequencies of meristic values and Table 39 for a summary of meristic variation. Segmented dorsal fin rays 9 (8–10), of these 7 (6–8) branched and 2 (1–3) unbranched; segmented anal fin rays 11 (10–12), of these 9 (8*–10) branched and 2 (2–3*) unbranched; caudal fin rays 16; segmented pectoral fin rays 13 (12–14), of these 11 (10–12) branched and 2 (1–3) unbranched; pelvic fin rays 7 (7–8), of these 6 (6–7) branched and one unbranched; gill raker total count (lower limb and upper limb) 12 (11–13), lower arch with 9 (7–10) and 3 (3–4) on upper, variation on first gill arch 7+3 (4), 7+4 (1), 8+3 (28), 8+4 (14), 9+3 (33*), 9+4 (14), 10+3 (4), 10+4 (2); vertebrae 51 (49–53); two* pyloric caecae on stomach.

See Table 40 for comparative value ranges of morphometric characters. Body elongate and relatively shallow, dorsal midline usually distinctly flattened anteriorly from dorsal fin base, depth through pectoral base 1.1 (1.0–1.4) that through vent, trunk with dorsal and ventral profiles near parallel from head to tail, dorsal profile very slightly arched; PelAn distance short, 4.7 (4.1–5.6) in SL; body tapering back to a moderately long, 6.9 (5.8–8.9) in SL, and shallow, 13.1 (11.1–14.7) in SL, caudal peduncle, the peduncle depth 1.9 in its length; accessory lateral line appears to be absent. Head of moderate length, 4.6 (4.2–5.1) in SL, and similar to PelAn distance (0.9–1.3), quite narrow, 1.8 (1.6–2.0) in HL, and relatively shallow, 2.6 (2.2–3.0) in HL, distinctly wider than deep (depth 1.4–1.5 in HW), lateral profile weakly wedge-shaped and rounded to obtuse, dorsal profile anterior to nape flattish; eyes large, 4.7 (3.6–5.7) in HL and 1.8 (1.4–2.2) in HD, situated high on head slightly below dorsal head profile, interorbital flat to slightly convex, narrow, 2.8 (2.5–3.2) in HL and 1.7 (1.5–1.8) times ED; cheeks not expanded below eyes, eye profiles visible laterally from ventral view; snout short, 4.0 (3.3–5.7) in HL and 1.2 (0.7–1.5) times ED, lateral profile usually rounded to blunt; post-orbital head length of moderate length, 1.9 (1.7–2.1) in HL; nostrils long and just visible anterio-laterally from ventral view; mouth terminal, short, 3.7 (3.3–4.1) in HL, posterior extent reaching anterior border of eyes and 0.4 (0.3–0.5) of ED below ventral margin of eye, most anterior tip of upper lip usually level with 0.6 ED above ventral margin of eyes, gape narrow, 3.2 (2.9–3.8) in HL, 1.1 times wider than length of upper jaw and 1.8–1.9 in HW. Jaws usually subequal, lower a little shorter (1.0– 1.1 in UJL). Pyloric caecae thin to moderate thickness and long, longest averaging 5.1 % SL (3.6–7.8 %), usually rounded on end; gill rakers short, stout and bluntly rounded.

Median fins moderately fleshy at bases, paired fins less so, with thickening extending distally over 0.3–0.5 of fin area, extending farther between fin rays, dorsal and anal fin bases of moderate length, dorsal fin base usually 1.2 in length of anal fin base and sometimes noticeably extended anteriorly as a low ridge supported by short procurrent rays, fins rounded and relatively low, anal usually a little longer than dorsal, middle rays longest; anal fin origin usually under 0.4 (0.2–0.7) distance posteriorly along dorsal fin base. Pelvic fins small, 10.7 (8.9–15.9) in SL, 0.7 of pectoral fin length, usually inserted just posterior to mid-point of standard length and extending just over 0.45 distance to anal fin base; pectoral fin of moderate length and paddle-shaped, 7.9 (6.7–10.3) in SL, extending just over 0.43 distance to pelvic fin base, low on body with dorsal extent of fin base usually level with posterior extent of mouth, lamina of paired fins oriented anterio-ventrally to ventrally, raised lamellae absent from ventral surface of rays. Caudal fin of moderate length, 7.5 (6.1–9.6) in SL, emarginate, shorter than caudal peduncle (1.1 in LCP), vertical width of expanded rays greater than body depth through pectoral fin base, flanges moderately developed along caudal peduncle, not reaching distal end of rays in adpressed anal fin.

Size. Recorded to 70 mm LCF and 3 g; commonly to 45–55 mm LCF. Males do not grow as large as females.

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 lighter ventrally, belly silvery white, lips usually slightly dusky. Overlain by small brown, dark brown to grey-brown, irregularly shaped blotches relatively densely space on dorsal and lateral surfaces of trunk and extending onto the head and snout, less so in juveniles, many coalescing to form irregular shaped vertical bands. Blotches and bands sometimes obscured by fine dark stippling. Gill cover translucent with a small golden patch; iris coppery gold. Fins clear to translucent light brown. Gravid females usually with profuse, fine, black to dark grey stippling along ventro-lateral surface of trunk between the pectoral fin base and vent, sometimes extending almost to mid-lateral region. See below for more detailed comments on body pattern.

Colour of preserved material. Base colour of head and body pale cream to creamy yellow, overlain with a very faint shading of fine, sparse, brown stippling, fading ventrally. Surface of trunk typically with dense and diffuse pattern of irregular shaped, medium-size, relatively faint brown blotches, more densely spaced and darker on dorsal surface, extending laterally down sides, just reaching ventral surface, and extending onto caudal peduncle flanges; pattern fades gradually down sides of trunk. Dorsal trunk pattern extends onto nape and upper opercular region of head, with rest of dorsal head region densely stippled dark brown; stippling extending onto upper and lower lips, down sides of head and onto ventral surface; relatively dense stippling along posterior and ventral margin of gill cover. Dense dark brown to black spotting inside operculum and black spotting at base of, and along, gill filaments. Trunk and head pattern appears to be absent from most fish in the Genoa River system, and overlying shading is stronger, consisting of closely spaced brown to dark brown stippling, darkest on the dorsal surface and fading laterally.

Eye grey to black, pupil translucent pale orange yellow or brownish yellow. Teeth translucent yellow to pale orange–yellow, tips orange to orange–red; gill rakers cream. Fins pale creamy yellow to dusky grey, becoming more translucent on posterior margins, fleshy bases of dorsal and anal fins with fine brown stippling extending to about half distance of fin length, generally restricted to pectoral fin base; body pattern and fine shading extending onto caudal fin base to about one third to one half of fin length. Fin rays translucent, external edges of rays highlighted with very fine brown to black lines.

Etymology. From the Latin teres, meaning rounded or smooth, and nasus, meaning nose, in reference to the rounded snout of this species. Suggested vernacular name as the ‘Roundsnout Galaxias’.

Genetics. Allozyme and mtDNA analysis of this species can be found in Adams et al. (2014; taxon code GE). Diagnostic allozyme loci (9–16) between this taxon and the other species in the Galaxias olidus complex are provided in Table 12. Two genetically distinct subpopulations were identified, with individuals in the Genoa River (and presumably Cann River) differing by two diagnostic allozyme loci from those in the Snowy River system ( Raadik 2011). Morphological variation between these subpopulations was not quantitatively investigated.

Distribution. See Figure 7 . Found in the very south-east corner of southern NSW and East Gippsland, Victoria, in the mid Snowy River, Cann River and Genoa River systems. In the Snowy River, recorded from Burnt Hut Crossing (approximately 500 m asl), Maclaughlin River system (to 780 m asl) and widespread in the Delegate/ Bombala River systems (760 and 785 m asl respectively). Known from the mid to upper reaches of the Genoa River system (250–680 m asl), predominantly in NSW, and also recorded from at least one confirmed location in the mid Cann River system in Victoria; possibly more widespread in this catchment. Apparently absent from the very upper, headwater reaches of all these systems. Historical data generally lacking, except for a record from Curry Flat, Nimmitabel (possibly Bobundara Creek system) c. 1914 (BMNH 1914.8.20.67–68), near Bombala in 1938 (AMS IA.7904 to IA.7906) and from Church Creek near Delegate in 1965–6 (NMV A.9897 and NMV A.30581-1); the species was reconfirmed from the Bombala and Church Creek systems in 2002–3.

Sympatry. Currently the only species in the Galaxias olidus complex, found throughout its restricted range, though probably historically found with Galaxias olidus in the mid reaches of the Snowy River in NSW. Recorded with Galaxias brevipinnis (Genoa and Cann river systems), and possibly also occurs with Galaxias maculatus in the mid-reaches of the Genoa River in Victoria.

Habitat. Typically recorded from clear water in slow to moderately flowing creeks to large rivers (1.0–12.0 m average width and 0.1–0.6 m average depth), flowing through light to heavily forested (and shaded) catchments, consisting predominantly of pools, glides and riffles with smaller areas of still backwaters. Also recorded from modified streams in areas almost completely cleared for grazing. Substrate usually consists of bedrock, boulder, cobble and coarse sand with smaller amounts of pebble, gravel and silt and instream cover is typically provided predominantly by rock, timber debris, and smaller amounts of aquatic vegetation, leaf litter and bank and vegetation overhang. Average pool depth ranged from 0.2–1.8 m.

General Biology. Confined to freshwater and considered not to undertake diadromous migrations. Collected at densities ranging from <0.1–1.5 fish/m 2 and found with the native fish species Shortfinned Eel, Longfinned Eel ( Anguilla reinhardtii), Eastern Smelt ( Retropinna sp. ), and River Blackfish (also see ‘Sympatry’ above), the native decapod crustaceans Common Freshwater Shrimp, East Gippsland Spiny Crayfish and Variable Spiny Crayfish ( Euastacus yanga ), and a native bivalve mollusc ( Hyridella sp. ). Also recorded with the alien species Brown Trout, though probably occupies a discrete micro-habitat.

Spawning period unknown, though possibly spring to early summer, or earlier in the Snowy River catchment: an adult female collected in mid-September from Back Creek was gravid and close to spawning (swollen vent) and fish from White Rock River were spawning in the middle of December, though both sexes from the Delegate River system were well developed to ripe in June; fish were at an early stage of gonad development during January–February; the smallest presumed 0+ age fish recorded (16.7 mm LCF) was collected from Back Creek in mid-December; and, juvenile fish 20.2–24.7 mm LCF were recorded from Church Creek in November; 23.7 mm LCF from White Rock River in mid-January, and 26.4 mm LCF from Maclaughlin River in February. Fish in the length range 16.7–24.8 had a keel present on the ventral midline, extending from the pectoral fin based posteriorly to anus. The smallest fish which could be reliably sexed were a female at 35.1 mm LCF (White Rock River, Genoa catchment) and a male at 42.4 mm LCF (Little River, Goulburn River system), though males, as in other species of Galaxias , are considered to mature at a smaller size than females. Galaxias terenasus is therefore considered to become sexually mature at about 30–35 mm LCF. Fecundity is low; gravid females (52–63 mm LCF) recorded with 220–240, relatively small (1.2 mm average diameter), unshed eggs.

Larger adults usually solitary, but younger fish typically found in loose shoals amongst habitat near the substrate; occasionally in midwater close to habitat. Fish from the Genoa River system are heavily infected with large, white to cream cysts, possibly trematode metacercariae, embedded in the skin, fins, and eyes. Galaxias terenasus also found to be infected by the parasitic copepod Anchor Worm Lernaea cyprinacea (?), and 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.

Variation. Populations in the Genoa and Cann River catchments differ slightly in morphology to those in the Snowy River catchment (see Fig. 36 ), with the dorsal fin extending anteriorly as a low ridge, underlain by a number (~4–5+) short, procurrent rays (lacking, or much shorter, with 1–2 procurrent rays, in the Snowy catchment), the snout is more rounded, and colour pattern is often less pronounced. The population level (within species) differences are also supported by molecular data.

Conservation status. Critically endangered in Victoria ( DSE 2013).

Remarks. The only diminutive species in the G. olidus complex, and outside of the diminutive genus Galaxiella in Australia, being much smaller than all other members in the genera Galaxias and Neochanna on the mainland and in Tasmania. Galaxias terenasus is also the most morphologically distinctive taxon in the complex, differing from all other members by the lack of an accessory lateral line, lack of paired fin ray lamellae (except for Galaxias brevissimus sp. nov. and Galaxias tantangara sp. nov.), elongate anterior nostrils, dorsal and ventral trunk profiles straight or nearly so, low pectoral fin ray count, and long pyloric caecae. It also shares a number of morphological characters with Galaxias parvus from Tasmania: relatively elongate tubular, anterior nostrils; a tubular trunk; small mouth with jaws of relatively equal length; a low ridge in front of the dorsal fin; the relatively small setback of the anal fin origin from that of the dorsal fin origin; small pectoral fins with a low ray count; and, short gill rakers. Investigation of the evolutionary relationship between the taxa within the Galaxias olidus complex, and with non-diadromous galaxiids from Tasmania, would be of value in understanding Australian galaxiid phylogeny.

Galaxias terenasus are able to survive amongst populations of alien trout in the Genoa, Cann and Snowy river systems, though the mechanisms of predator-avoidance are unknown but may include occupying habitat marginal to trout; the majority of G. terenasus collected from the Maclaughlin River were located in shallow riffle areas about 0.1 or less in depth (and not in pools). Additionally, instream habitat complexity in Back Creek is high as the stream is not sand impacted, and areas of the Genoa River may be marginal for trout due to degradation and higher water temperatures. Additional sampling in the mid Snowy River system, the upper Cann River catchment, and the Wallagaraugh and upper Genoa River systems, is required to more accurately define the specific distribution of this species.

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 36. Galaxias terenasus sp. nov., A–C: holotype, NMV A.30592-3, 65.4 mm LCF, female, Maclaughlin River, Allen Caldwell Bridge on Ando Road, north-north-west of Bombala, New South Wales, A) line drawing (R. Plant), B) image of preserved specimen (T.A. Raadik), C) dorsal view of head showing anterior, elongate, tubular nostril (T.A. Raadik); D–E: paratype, NMV A.30542-2, 62.0 mm LCF, White Rock River, Southern Access Road, NE of Rockton, D) line drawing (R. Plant), E) image of preserved specimen (T.A. Raadik). Scale bar = 5 mm.