Short-tail Galaxias, Galaxias brevissimus Raadik 2014


Short-tail Galaxias, Galaxias brevissimus. Source: Tarmo A. Raadik. License: All rights reserved

Summary:
A galaxias with a very short caudal peduncle and caudal fin, and a pattern of small to moderately large brown to blackish profuse blotches and spots, some coalescing to form larger patches.

The Short-tail Galaxias is restricted to upper reaches of the Tuross River system in southern, coastal New South Wales.

Cite this page as:
Bray, D.J. 2020, Galaxias brevissimus in Fishes of Australia, accessed 09 Apr 2020, http://136.154.202.208/home/species/5123

Short-tail Galaxias, Galaxias brevissimus Raadik 2014

More Info


Distribution

Known only from the upper reaches of the Tuross River system in southern, coastal New South Wales: Guinea Creek, and its tributary Jibolaro Creek, along with Bumberry Creek. The species is considered to have been historically more widespread, extending a considerable distance farther downstream before predatory trout reduced and fragmented its range.
Inhabits very small, shallow,  clear, gently flowing creeks with pools connected by very short sections of shallow riffles - with clay substrates overlain with fine and coarse sand, with areas of silt. Instream cover was provided by rock, aquatic vegetation and overhanging grasses, and maximum pool depth was less than 1 metre. The area was used as pasture and all riparian vegetation had been cleared.

Features

Segmented dorsal-fin rays 9-10, of these 7-8 branched, 1-2 unbranched; segmented anal-fin rays 10-12, of these 8-10 branched, 2 unbranched; caudal-fin rays 16-17; segmented pectoral-fin rays 13-16, of these 11-14 branched, 2 unbranched; pelvic-fin rays 7, of these 6 branched, one unbranched; Gill rakers total count (lower limb and upper limb ) 10-13, lower arch with 8-10, 2-3 on upper; vertebrae 51-52; one pyloric caeca on stomach. 

Conservation

IUCN: Critically Endangered.
Australian Society for Fish Biology: Critically Endangered.
Major threats include predation by invasive Brown Trout, increase in fire frequency and/or intensity, increase in sedimentation from stock, and the impacts of climate change including drought and severe storms.

Similar Species

Differs from other species within the Galaxias olidus complex in having the following combination of characters: caudal peduncle and caudal fin short (10.3–12.0 % SL) and (10.1–12.2 % SL) respectively; anal and pelvic fins set far back at about 76 and 53 % SL respectively; anal and dorsal fin lengths short, dorsal-fin base short (8.0–9.6 % SL); pectoral fin small (9.6–12.0 % SL); dorsal midline of trunk  usually flattened anteriorly from above midpoint between pectoral- and pelvic-fin bases; head quite narrow (55.9–59.6 % HL), eye relatively large (18.3–21.0 % HL); nostrils moderately long, not visible from ventral view; gape about as wide as length of lower jaw; often a single, sometimes two, unbranched, segmented rays in the dorsal fin (versus usually 2); low mean number of vertebrae (52); raised lamellae on the ventral surface of paired fins appear to be absent; caudal peduncle flanges relatively short, occasionally just reaching adpressed anal fin; single, moderately short (1.7 % SL), thin pyloric caecum; anal-fin origin usually under 0.8 distance posteriorly along dorsal-fin base; gill rakers sharply pointed; black bars absent along lateral line.

Etymology

The specific name brevissimus is Latin meaning 'shortest' or 'small', in reference to this species having the shortest caudal peduncle and caudal fin compared with other members of the Galaxias olidus complex.

Species Citation

Galaxias brevissimus Raadik 2014, Zootaxa 3898(1): 48, Fig. 12. Type locality: Jibolaro Creek, at bridge on Tuross Road, northwest of Kybeyan, New South Wales, 36°14'01"S, 149°27'10"E.

Author

Bray, D.J. 2020

Resources

Atlas of Living Australia

Short-tail Galaxias, Galaxias brevissimus Raadik 2014

References


Adams, M., Raadik, T.A., Burridge, C.P. & Georges, A. 2014. Global biodiversity assessment and hyper-cryptic species complexes: more than one species of elephant in the room. Systematic Biology 63(4): 518–533. (taxon code JI) http://dx.doi.org/10.1093/sysbio/syu017

Lintermans, M. 2016. Conservation Status of Australian Fishes – 2016. . Australian Society for Fish Biology Newsletter 46(2): 142-144.

Lintermans, M. & Raadik, T. 2019. Galaxias brevissimus . The IUCN Red List of Threatened Species 2019: e.T122902298A123382111. https://dx.doi.org/10.2305/IUCN.UK.2019-3.RLTS.T122902298A123382111.en. Downloaded on 14 February 2020.

Raadik, T.A. 2011. Systematic revision of the Mountain Galaxias, Galaxias olidus Gunther, 1866 species complex (Teleostei: Galaxiidae) in eastern Australia. Ph.D thesis, University of Canberra. (as Galaxias 'jibolaro') PDF

Raadik, T.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): 1–198. PDF

Quick Facts


CAAB Code:37102026

Conservation:IUCN Critically Endangered

Habitat:Freshwater streams

Max Size:9.5 cm TL

Native:Endemic

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