Engaeus fossor occur throughout north-western Tasmania and on Hunter Island, off the north-west corner of Tasmania. (TAS, Hunter Island)Features:
As with other burrowing crayfish, the cephalothorax (head/middle section) is relatively large in comparison to the abdomen (tail section). The claws are large, and the movable finger moves up and down in the vertical plane. The body is smooth, and a red-brown colour.Ecology/Way of Life:
Engaeus fossor feed mostly on plants and semi-decayed wood, as well as small water insects or worms. Breeding takes place in spring or summer. Eggs are attached to the underside of the abdomen of the female and probably incubate for about 4 months. After hatching from the eggs, larvae remain with the female and moult 3 times before becoming independent. Burrows are made in a wide variety of habitats ranging from Acacia or Tea-tree swamps, coastal plains, buttongrass plains, wet sclerophyll forest or Nothofagus rainforest. Usually, each burrow contains only one adult crayfish. However, in the case of females, newly hatched young and juveniles stay in the burrow with the mother, and eventually disperse by constructing their own burrows. At the surface, each adult crayfish has several burrow entrances. The tunnels from these entrances join the main burrow shaft that reaches down to a living chamber, below the water table. Thus the living chamber always contains water. The soil and debris that is excavated from inside the burrow is thrown out on the surface, and often forms a chimney or mound at each surface opening. In swampy areas, these chimneys may be up to 40 cm high.Interaction with Humans/Threats:
Engaeus fossor is widely distributed, occurring in a wide variety of habitats, it is therefore not presently considered under threat. As with other burrowing crayfish, the major threat to Engaeus fossor is habitat degradation, from activities such as forest clearing and land reclamation.Other Comments:
Engaeus fossor was named fossor by Erichson in 1846.Further Reading:
Horwitz, P. (1990). A taxonomic revision of species in the freshwater crayfish genus Engaeus Erichson (Decapoda: Parastacidae). Invertebrate Taxonomy 4(3): 427–614.
Jones, D. S. & Morgan, G. J. (1994). A Field Guide to Crustaceans of Australian Waters. Reed Books, Sydney.
Suter, P. J. & Richardson, A. M. M. (1977). The biology of two species of Engaeus (Decapoda: Parastacidae) in Tasmania III. Habitat, food, associated fauna and distribution. Australian Journal of Marine and Freshwater Research 28: 95–103.
Text and map by Shane Ahyong. Photograph by Patrick Johnson.Sponsorship welcomed:
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