Galaxias oliros

Last updated

Galaxias oliros
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Galaxiiformes
Family: Galaxiidae
Genus: Galaxias
Species complex: Mountain galaxias
Species:
G. oliros
Binomial name
Galaxias oliros
Raadik, 2014

Galaxias oliros, the obscure galaxias, is a galaxiid of the genus Galaxias , a member of the Mountain Galaxias species complex group of freshwater fish, found in Australia. [2]

Contents

Description

Similar to other members of the species complex with a long tubular body, commonly 75–90 millimetres (3.0–3.5 in) to a maximum recorded of 133 millimetres (5.2 in), moderately deep and laterally compressed behind the pelvic fins. Upper surface evenly arched from the nape to the beginning of the tail fin, the belly follows a similar profile but less pronounced. Caudal peduncle is relatively shallow and strongly laterally compressed. Head medium sized, noticeably wider than deep and slightly to moderately wedge-shaped when viewed from the side. Eyes relatively large and set high on the head. Mouth positioned at the end of the snout, medium sized with a shorter lower jaw. [2]

Fins fleshy at the base, less so in paired fins. Anal fin has a long base whereas the dorsal fin base is short. Fins rounded, dorsal fin medium length, anal fin about 10-20 percent longer than the dorsal fin. Leading edge of the anal fin usually at a position about halfway along the dorsal fin base. Pelvic fins medium sized and positioned low at about the midpoint of the body with the anal fin positioned halfway between the pelvic fins and the tail. Pectoral fins medium sized, rounded to paddle shaped, positioned low on the body with the upper edge even with or slightly higher than the rear end of the mouth. Tail fin is moderately long, weakly forked and usually longer than the caudal peduncle. Flanges medium height and length and quite well developed on the caudal peduncle, often extending as far forward as the rear of the anal fin. [2]

Galaxias oliruos is mainly olive to grey brown over the back and sides extending over the head and snout, fading to cream or white to silvery below the lateral line and silvery on the belly. The base colour is overlaid with a pattern of small to medium sized dark irregularly shaped blotches with many joining up to form uneven vertical bands. These markings are more closely spaced over the upper surface including the nape but are not present on the head and snout and sometimes are very faint. Sometimes a medium thick row of copper to gold spots extends over the upper surface from the nape to the dorsal fin and occasionally there may be a slight scattering of small gold flecks over the head and snout. The gill covers are translucent with a large gold to silver or turquoise patch. Fins light grey to olive and translucent. [2]

Distribution

Distribution map of Galaxias oliros, the obscure galaxias Galaxias oliros distribution.jpg
Distribution map of Galaxias oliros, the obscure galaxias

The obscure galaxias is found at a wide range of elevations from 0–600 metres (0–1,969 ft) in the Murray River system in Victoria and southern New South Wales as well as south of the Great Dividing Range in western Victoria including all tributaries to the Wimmera River and several tributaries to the Murray River within the Mount Lofty Ranges in South Australia. The fish is also recorded from coastal drainages in western Victoria including the Corangamite Basin, the Hopkins River and extending through to Mosquito Creek within the Bool Lagoon catchment in South Australia. Additionally, the fish is found very close to the sea in the Merri River and the Darlot/Fitzroy River systems in western Victoria. [2]

Habitat

Mainly inhabits lowland to foothill reaches of a diverse number of stream types including clear to turbid, medium to large 4–20 metres (13–66 ft) wide rivers, smaller (0.5–4 metres (1.6–13.1 ft)) gently to faster flowing creeks as well as anabranches, billabongs and occasionally wetlands. Juveniles are often found in shallow riffle zones around the edges of pools with adults in deeper pools 10–120 centimetres (0.33–3.94 ft) and more open areas. Usually found taking cover in heavy macrophytes or woody debris, but sometimes found in open water or near the surface. Can be very abundant in swamps. [2]

Lifecycle/Reproduction

The obscure galaxias lives its entire lifecycle in freshwater. It has high tolerance for water conditions being found in very turbid or highly saline pools or stagnant water with high amounts of organic material. Spawning generally occurs from late May to early July but sometimes as late as August. Eggs are quite small 0.9–1.0 millimetre (0.035–0.039 in) and the females are relatively fecund for members of the species complex, for example one 105.6 millimetres (4.16 in) female was recorded with 2057 eggs. [2]

Conservation

Least Concern. [1]

Utility to humans

Not an angling target due to small size.

Related Research Articles

<i>Galaxias olidus</i> Species of fish

Galaxias olidus, the mountain galaxias, is a species of freshwater galaxiid fish widely found in southeastern Australia.

<span class="mw-page-title-main">Tasmanian mudfish</span> Species of fish

The Tasmanian mudfish, Neochanna cleaveri, is a small Australian amphidromous fish in the galaxiid family, of the order Osmeriformes.

<span class="mw-page-title-main">Whitefin dogfish</span> Species of shark

The whitefin dogfish is a species of deep-sea dogfish shark in the family Etmopteridae. It has only been found in the northwest Pacific Ocean off the southeastern coast of Japan, between the latitudes of 35 and 32°N. It inhabits continental slopes and seamounts at a depth of 320 to 1,100 m. Reproduction is ovoviviparous. It is of no interest to fisheries and almost nothing is known of its biology. The specific epithet ritteri is in honor of Dr. William Emerson Ritter of the University of California.

<span class="mw-page-title-main">Longnose sawtail catshark</span> Species of shark

The longnose sawtail catshark is a little-known species of catshark, part of the family Scyliorhinidae, found off the northwestern Pacific islands of Amami Ōshima, Ogasawara, and Izu at depths of 350–550 m (1,150–1,800 ft). Reaching a length of 80 cm (31 in), it is characterized by a long flattened snout, a long space between the pelvic and anal fins, and a crest of enlarged dermal denticles along the dorsal caudal fin edge. Adults are plain dark gray above, while juveniles have a few faint dark saddles on the back and tail.

Denticetopsis is a genus of catfishes of the family Cetopsidae.

<span class="mw-page-title-main">Longnose shiner</span> Species of fish

The longnose shiner is a species of ray-finned fish in the genus Notropis.

<i>Clinus agilis</i> Species of marine fish

Clinus agilis, the agile klipfish, is a species of clinid found in subtropical waters of the Atlantic Ocean from Namibia to South Africa where it is commonly found in estuaries and tide pools. This species can reach a maximum length of 10 centimetres (3.9 in).

Astyanax microschemos is a species of characid fish from Brazil. It belongs to the A. scabripinnis species complex and differs from other species outside it by having a lower number of branched anal fin rays and its shallow body depth being about 26.9-29.7 vs more than 35% of its standard length (SL). Compared to species of its own complex, it can be distinguished by the combination of its shallow body depth, and smaller interorbital width. The species name comes from the Greek mikroschemos, meaning "low stature", which refers to the shallow body depth of the animal.

<i>Deuterodon pelecus</i> Species of fish

Deuterodon pelecus is a species of characid fish from Brazil. It can be distinguished from other species by: its body depth ; its short and pointed snout smaller than the orbital diameter; and a reduced number of branched anal fin rays. D. pelecus also differs from members of its genus by its characteristic color pattern. It possesses a single humeral spot that is constricted to the region above the lateral line; at the same time it shows a conspicuous midlateral body stripe from opercle to the caudal fin base, an autapomorphy of this precise species. Other Deuterodon species have a humeral spot that is vertically or horizontally elongate and have the midlateral stripe becoming faint near that humeral spot. The species name is derived from the Greek pelekus, meaning "axe", referring to the pigmentation shape resulting from the adjoinment of the humeral spot with the midlateral stripe.

Galaxias arcanus, the riffle galaxias, is a galaxiid of the genus Galaxias, a member of the Mountain Galaxias species complex group of freshwater fish, found in Australia.

Galaxias brevissimus, the short-tail galaxias, is a galaxiid of the genus Galaxias, a member of the Mountain Galaxias species complex group of freshwater fish, found in Australia.

Galaxias gunaikurnai, the Shaw galaxias, is a galaxiid of the genus Galaxias, a member of the Mountain galaxias species complex group of freshwater fish, found in Australia.

Galaxias lanceolatus, the tapered galaxias, is a galaxiid of the genus Galaxias, a member of the Mountain Galaxias species complex group of freshwater fish, found in Australia.

Galaxias longifundus, the West Gippsland galaxias, is a galaxiid of the genus Galaxias, a member of the Mountain Galaxias species complex group of freshwater fish, found in Australia.

Galaxias mcdowalli, McDowall's galaxias, is a galaxiid of the genus Galaxias, a member of the Mountain Galaxias species complex group of freshwater fish, found in Australia.

Galaxias mungadhan, the Dargo galaxias, is a galaxiid of the genus Galaxias, a member of the Mountain Galaxias species complex group of freshwater fish, found in Victoria, Australia.

Galaxias ornatus, the ornate galaxias, is a galaxiid of the genus Galaxias, a member of the Mountain Galaxias species complex group of freshwater fish, found in Australia.

<i>Galaxias supremus</i> Species of fish

Galaxias supremus, commonly known as the Kosciuszko galaxias, is a galaxiid of the genus Galaxias, a member of the Mountain galaxias species complex group of freshwater fish, found in Australia.

Galaxias tantangara, commonly known as the stocky galaxias, is a galaxiid of the genus Galaxias, a member of the Mountain galaxias species complex group of freshwater fish, found in Australia. Only discovered in 2014, the fish is classed as critically endangered, mainly because of being preyed upon by introduced species of trout.

Galaxias terenasus, the roundsnout galaxias, is a galaxiid of the genus Galaxias, a member of the Mountain Galaxias species complex group of freshwater fish, found in Australia.

References

  1. 1 2 Raadick, T. (2019). "Galaxias oliros". The IUCN Red List of Threatened Species . 2019. IUCN: e.T122902581A123382146. doi: 10.2305/IUCN.UK.2019-3.RLTS.T122902581A123382146.en .
  2. 1 2 3 4 5 6 7 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" (PDF). Zootaxa. 3898 (1): 1–198. doi:10.11646/zootaxa.3898.1.1. PMID   25543673.