The Eastern swamp crayfish, Gramastacus lacus. Image credit: McCormack RB.
Gramastacus lacus : New Crayfish Species Discovered in Australia
Dr Robert McCormack from the Australian Aquatic Biological Pty’s Australian Crayfish Project has described a new species of crayfish from the swamps and creeks of coastal New South Wales, Australia.
Crayfish, also known as crawfish, crawdads, or mudbugs, are aquatic arthropods resembling small lobsters.
The newly described species has been scientifically named Gramastacus lacus. The common name is the Eastern swamp crayfish.
Gramastacus lacus is a small freshwater crayfish, reaching a maximum weight of 7 gr and 21.3 mm in length. It is distinguished by a large male genital papilla, large raised post orbital ridges, laterally compressed carapace and elongated chelae.
“Color varying with population,” Dr McCormack wrote in a paper published in the journal Zookeys. “First chelipeds very dark, black to black-blue with bright blue highlights along propodal, carpal and meral lateral edges, light blue tint ventrally with articulations dull to bright red. Cephalon dark black-brown dorsally, lightening laterally, many with blue highlight on lateral surface. Thorax and abdomen light brown, green, tan or steel blue, usually with small, light cream or red speckles. Body clear to cream ventrally. Juveniles light blue.”
Gramastacus lacus is found in lowland ephemeral habitats surrounding coastal lakes and lagoons from Wamberal Lagoon, north along the coastal strip to Wallis Lake.
Being dependent on regular natural flooding and drying cycles, only lowland, swampy areas are suitable for this crayfish species.
Each crayfish digs a small rounded cross-section burrow up to 1 m deep into the water table to survive the drying cycle. Some areas are riddled with these small burrows as they are a very prolific species and can occur in very high numbers in small habitat areas.
Now, being found and officially described, Gramastacus lacus must be considered in any further developments and hopefully future habitat loss will be reduced.