| Variable spiny cray | |
|---|---|
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Subphylum: | Crustacea |
| Class: | Malacostraca |
| Order: | Decapoda |
| Suborder: | Pleocyemata |
| Family: | Parastacidae |
| Genus: | Euastacus |
| Species: | E. yanga |
| Binomial name | |
| Euastacus yanga Morgan, 1997 | |
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| Distribution map of Euastacus yanga [3] | |
Euastacus yanga, also known as the variable spiny cray, is a freshwater crayfish endemic to south eastern Australia.
The maximum recorded size was 61.2 mm (2.41 in) OCL (Occipital Carapace Length) which is used to measure the species' size. [4]
The rostrum is short and in individuals over 50 mm (2.0 in) OCL usually does not reach the base of the third antenna segment. In those measuring 20–140 mm (0.79–5.51 in) OCL the rostrum is to the base or midpoint of that segment and, in some under 20 mm (0.79 in), goes to the end of the third segment. [4]
The cephalon is spiny on most organisms but less so on specimens under 20 mm (0.79 in) OCL. In southern populations the spines are larger and more numerous. [4]
Their thorax has up to 20 spines on each side in one or two irregular rows although this is usually absent on smaller individuals (under 20 mm (0.79 in) OCL). The spines are generally longer and sharper in southern populations. The tubercles are moderately to densely distributed on specimens over 30 mm (1.2 in) OCL, very sparse to moderately on smaller examples, occasionally absent. [4]
Their abdomen has one, or very occasionally, two, dorsal-lateral spines on somite 1 of individuals over 20 mm (0.79 in) OCL. Dorsal spine often present on somite 1, especially on larger specimens. Somite 2 has three to seven (very occasionally two) in lateral line 1, often absent on smaller specimens. Somites 3-5 of larger specimens, over 30 mm (1.2 in) OCL and most over 20 mm (0.79 in), have a single spine in line 1. One to three line 2 spines are usually found on somites 3–6. A single dorsal-lateral spine is usually found on somites 3-5 and occasionally somite 6. [4]
There are typically 17 telsonic spines present in each specimen's tailfan. The inner branch of their uropod has zero to four median spines of variable size whereas the outer branch has zero to five marginal spines. The uropod and often the telsonic spines are absent in northern animals, becoming more numerous in the south. [4]
Their chelae or moveable claws are variable in form, occasionally stout but often longer. Most specimens over 30 mm (1.2 in) OCL have well developed teeth. The propodus (fixed part of claw) has a well developed row of ventrolateral spines often extending to the tip of the finger, except in small specimens under 20 mm (0.79 in) OCL. [4]
The body is a deep brown-green or red-brown to brown on the back and fades to paler on the belly. The back spines on the thorax are dark and may be black or vary in colour. Their tubercules are pale brown to orange or yellow. Their abdominal spines are yellow to pale orange though some larger specimens have a blue tinge. Their leg joints may be red or orange while the body of legs are generally dark brown, brown-green or blue-green. The fingers are deep blue-green, brown or orange and finger tips may be red in southern populations. [4]
The variable spiny cray is found in New South Wales from the Robertson to Bundanoon area in the Southern Highlands south to just inside the Victorian border near Genoa. E. Yanga is the third most widely distributed Euastacus species behind E. armatus and E. spinifer. [4]
The species has been collected in streams from 60–720 m (200–2,360 ft) AMSL. The surrounding streamside vegetation consisted mainly of temperate rainforest with dry sclerophyll along the ridge-lines but with dry sclerophyll extending to the stream bank in areas lacking rainforest. This species prefers smaller streams and has not been collected at any site together with other members of the genus. [4]
Berried females (those that are carrying eggs) have been collected in late October through November. The eggs are burgundy with white patches where the developing embryo was located and each female carries 43 to 164. [4]
The species is listed as endangered in Victoria [3] otherwise least concern. [1] [2]
Variable spiny cray are unsuitable for human consumption due to their small size. They do not reach the minimum legal size in both Victoria and New South Wales of 90 mm (3.5 in) OCL. [5] [6]
Tenuibranchiurus is a genus of diminutive freshwater crayfish that live in the Australian state of Queensland. Only one species has been described, the swamp crayfish, T. glypticus.
The Murray crayfish, Euastacus armatus, is a species of freshwater crayfish endemic to Australia that belongs to the family Parastacidae. The Murray crayfish has the largest geographic range of any of the Euastacus crayfish in Australia, being found in the Murray and Murrumbidgee Rivers as well as many of their tributaries. Murray crayfish are also known as "Murray River crayfish", "Murray crays", "freshwater crays", "spiny freshwater crays", "spinies" and in the Wagga Wagga region of southern New South Wales they are simply known as "lobsters".
Euastacus is a genus of freshwater crayfish known as "spiny crayfish". They are found in the south-east of the Australian mainland, along with another genus of crayfish, Cherax. Both genera are members of the family Parastacidae, a family of freshwater crayfish restricted to the Southern Hemisphere.
Euastacus bindal is a species of southern crawfish in the family Parastacidae.
Euastacus bispinosus, the Glenelg spiny crayfish, is a species of southern crawfish in the family Parastacidae.
Euastacus crassus is a species of southern crayfish in the family Parastacidae. It is commonly known as the Alpine spiny crayfish.
Euastacus eungella is a species of southern crawfish in the family Parastacidae.
Euastacus fleckeri is a species of southern crawfish in the family Parastacidae.
Euastacus hystricosus is a species of southern crawfish in the family Parastacidae.
Euastacus jagara is a species of Australian crayfish in the family Parastacidae. It is known from only six specimens, all collected at the type locality in the Mistake Mountains in the State of Queensland, Australia. The streams inhabited by the species are surrounded by Upland Subtropical Rainforest, and drain into the Brisbane River. The species is listed as critically endangered on the IUCN Red List.
Euastacus maidae is a species of Australian crayfish in the family Parastacidae. It is known only from a single catchment in the Gold Coast hinterland in the State of Queensland, Australia, and is listed as critically endangered on the IUCN Red List. The stream is surrounded by Subtropical Rainforest. This species may also occur in adjacent high rainfall catchments.
Euastacus neodiversus is a species of southern crawfish in the family Parastacidae.
Euastacus robertsi is a species of southern crawfish in the family Parastacidae.
Euastacus setosus is a species of southern crawfish in the family Parastacidae.
Euastacus urospinosus is a species of southern crawfish in the family Parastacidae.
Euastacus sulcatus, also known as the Lamington crayfish, is a freshwater crayfish, or "yabby", native to Australia. It is commonly bright blue in colour although also existing in a red and white, rusty red, brown, green, orange and completely white variations are found all around its known region. They can be found roaming the forest floor when conditions are damp, usually after substantial rainfall. Actively searching for a mate, new territory or food. When threatened, it raises its front two powerful pincers and will readily pinch any potential predator. The spiny crayfish has zero native predators by the time it reaches full-size maturity, although since the introduction of feral animals such as foxes and cats, it has suffered from predation not evolved to defend itself against. Due it its magnificent coloration it has also been targeted as a aquarium pet or even winding up on barbecues. This species is listed as protected and is an offence to trap/remove or harm this species, with on-the-spot fines of up to $522.
Euastacus spinifer is a species of freshwater crayfish endemic to Australia that belongs to the family Parastacidae.
Euastacus guruhgi is a species of freshwater crayfish found in the Australian state of New South Wales. It has an estimated extent of occurrence of 80 square kilometres (31 sq mi) and an area of occupancy of 7.5 square kilometres (2.9 sq mi) where it occurs fragmentedly. The species has been assessed as a critically endangered species due to a continuing decline in the quality of its habitat due to the invasive exotic species in the area, some of which predate upon this species. Furthermore, there is a continual destruction of its suitable rainforest habitat. E. guruhgi also faces the consequences of global warming; as a restricted range species, it is dependent on cool headwater streams and a slight increase in the temperature of the water could rapidly eradicate the species. There are no specific conservation measures for this species in place but the distribution range of the E. guruhgi falls within the Mount Warning and Wollumbin national parks. In New South Wales, there is a minimum recreational size limit of 90 mm orbital carpace length for any spiny crayfish. E. guruhgi does not attain that size, and is thus, indirectly protected by this restriction.
Euastacus dalagarbe is a species of freshwater crayfish endemic to Australia that belongs to the family Parastacidae. It has a small range in New South Wales and is regarded by the International Union for Conservation of Nature as "critically endangered".
Euastacus bidawalus, the East Gippsland spiny crayfish, is an Australian freshwater crayfish endemic to the East Gippsland area of Victoria and the far south coast of New South Wales.
