This freshwater crayfish species is found in regions around the shoreline of Macquarie Harbour, in western Tasmania. (TAS).Features:
This freshwater crayfish species can have seven or eight corneous denticles (teeth) on each mandible. It has an unusually large number of tubercles on the carpus of the great chela (claw), usually more than four.Ecology/Way of Life:
These crayfish often dig shallow burrows in seepages, but in drier areas they are capable of digging deep, ramifying burrows. Burrows may serve a number of functions for animals such as crayfish. Firstly, they provide shelter, both from the elements and from predators, particularly for females with eggs or young attached. Burrows also provide a source of water to moisten the gills for respiration. This species, along with others in this genus, of crayfish is known to dig Type 2 burrows. Type 2 burrows are not connected to surface water such as streams or lakes, but rather the water in them comes from surface runoff or water in the surrounding soil. Burrows also provide a place where food may be obtained. Vegetation provides the major source of food for these animals; they eat roots, rotting vegetation, decaying wood, detritus, and small amounts of animal matter. Burrows often ramify extensively, with tunnels forming blind chambers. These chambers often end at the base of plants. Plants growing near burrows send fine roots into the burrows, and the crayfish feed off these. These crayfish are most commonly associated with graminoid heaths (heaths and shrubs with monocotyledons co-dominant) and melaleuca scrub.
Females moult and produce young only every second year. There is some variation between species in this genus, however mating and spawning generally occurs between autumn and spring. The females carry the eggs from June to November and the eggs will hatch in early summer. The young remain attached to the female through two moults and are released in late summer, although they remain in the female's burrow system until her next hatchlings are released.Interaction with Humans/Threats:
Animals in this species are relatively slow-growing, reach a maximum size of only 80 mm and are burrowers. This combination means they are not suitable for intensive rearing for aquaculture. Although the range of this species extends into the Tasmanian World Heritage Area, large parts of the range lie outside this reserve.Other Comments:
Variations within the species 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/
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.
Horwitz, P.H.J. & Richardson, A.M.M. (1986). An ecological classification of the burrows of Australian freshwater crayfish. Australian Journal of Marine and Freshwater Research 37: 237 – 242.
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.
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.
Text and distribution map by Brita Hansen. Photography by A. M. M. Richardson.Sponsorship welcomed:
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