This crayfish species is endemic to central southern Tasmania. (TAS).Features:
This species of endemic Tasmanian freshwater crayfish is one of only two Tasmanian species that possess a single terminal spine on the tailfan. It is easy to distinguish from the other spiny-tailed species by the shape of its chelae (claw), which is much stouter in appearance, also the ranges of the two species do not overlap. Terminal spines on the tailfans of freshwater crayfish is not common. Only 14 species (nine North American and five Australian) of the approximately 500 species worldwide possess them. Four of the five Australian species are found only in Tasmania.Ecology/Way of Life:
These crayfish are found in the wet heathlands, rainforests and wet sclerophyll forests of the far south and south-east of Tasmania. Although usually associated with burrows they are also found in streams and lakes. They occur from sea level to high alpine regions (above 1000 metres). The burrows made by these crayfish range from relatively simple (a single entrance leading to the main water-filled chamber) to complex (multiple entrances and tunnels ramifying through the substrate). Although found throughout the usual range of habitats occupied by Tasmanian burrowing crayfish, such as creeks and swampy plains, these crayfish appear able to tolerate drier conditions than other species in the genus. Where they occur in sympatry (share the habitat) with other species, they are usually found on the drier, better-drained slopes with the other species occupying the wetter plains. In these conditions they build simple burrows, sometimes with only a single entrance. These burrows may occasionally dry out completely in the summer months. The crayfish can survive for several weeks in these dry burrows provided the humidity level within them remains high.
Females moult and produce young only every second year. Mating and spawning occurs between autumn and spring, and females carry the eggs from June to November. The eggs hatch in early summer, and the young remain attached to the female through two moults. The young are released in late summer and remain in the female's burrow system until her next hatchlings are released.Interaction with Humans/Threats:
It is unlikely that Aboriginal people made much use of these animals as a food source, as the only practical method for obtaining them is to excavate the burrows. This species are relatively slow-growing, and reach a maximum size of only 80 mm. Their burrowing habit, slow growth rate and small size also make them unsuitable for intensive rearing through aquaculture. The majority of the range of this species extends into the Tasmanian World Heritage Area, therefore little of the range has been affected by such human interactions as land-clearance for agriculture or logging, and the species is consequently well protected.Other Comments:
Variations within the species are yet to be formally described. Refer to Hansen and Richardson (2002).Further Reading:
Crandall, K.A. & Fetzner, J.W. (2004). Crayfish Home Page. http://crayfish.byu.edu/
Richardson, A. M. M. & Swain, R. (1980). Habitat requirements and geographical distribution of three subspecies of Parastacoides tasmanicus, and Engaeus cisternarius (Crustacea; Decapoda: Parastacidae), burrowing crayfish from south west Tasmania. Australian Journal of Marine and Freshwater Research 31, 475 – 484.
Hansen, B. and Richardson, A. M. M. (1999). Interpreting the geographic range, habitat and evolution of the Tasmanian freshwater crayfish genus Parastacoides from a museum collection. In: W. Ponder & D. Lunney, (eds) The Other 99% – the Conservation and Biodiversity of Invertebrates. Transactions of the Royal Society of New South Wales, Mosman. pp 210 – 218.
Hansen, B., Adams, M., Krasnicki, T. & Richardson, A. M. M. (2001). Substantial allozyme diversity in the freshwater crayfish Parastacoides tasmanicus supports extensive cryptic speciation. Invertebrate Taxonomy 15:667 – 679.
Hansen, B. & Richardson , A.M.M. (2002). Geographic ranges, sympatry and the influence of environmental factors on the distribution of species of an endemic Tasmanian freshwater crayfish. Invertebrate Systematics. 16(4) pp621 – 629.
Text and distribution map by Brita Hansen. Photography by A.M.M. Richardson.Sponsorship welcomed:
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