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Euastacus guwinus (Family Parastacidae)

Tianjara Crayfish


Euastacus guwinus is known only from Tianjara Creek, Morton National Park, New South Wales. It may occur elsewhere in unexplored or seldom visited parts of Morton National Park. (NSW)


Euastacus guwinus is a dark green-brown colour above and a pale yellow-brown colour below. The body reaches a length of about 80 mm. The spines on the abdomen are small, even in adults, but as in other spiny crayfish, the lower edges of the claws are serrated. The wrists of the claws have two spines on the inner edge. The joints of the claws are red and the serrations and spines of the hand of the claw are light yellow-orange. Males and females are similar.

Ecology/Way of Life:

The only known habitat of Euastacus guwinus is Tianjara Creek. Tianjara Creek is a small stream with sandstone bedrock bordered by dry sclerophyll and heath forest. Stream water is typically tannin-stained. Crayfish are most common beneath boulders and logs on the stream-bed, but also burrow in the stream banks. During daylight, the crayfish generally spend most of their time sheltered under rocks or in burrows, although sometimes they will forage in the shaded parts of the stream. At night, the crayfish actively forage in the open. As with other spiny crayfish, Euastacus guwinus feed on semi-decayed plant matter and any type of animal matter that they can scavenge or capture. Males and females are sexually mature at about 60 mm body length, slightly smaller for males. Euastacus guwinus share their habitat with Euastacus yanga.

Interaction with Humans/Threats:

Like other species of freshwater crayfish, Euastacus guwinus is at risk from habitat destruction, such as land clearing. This is especially noteworthy in the case of Euastacus guwinus as it is presently known from such a limited area. However, because Euastacus guwinus occurs within Morton National Park, its status is probably relatively secure.

Other Comments:

Euastacus guwinus was named by Morgan in 1997. The name is based on the word “guwin”, meaning ghost in the Dharawal language of the region.

Further Reading:

Morgan, G. (1997). Freshwater crayfish of the genus Euastacus Clark (Decapoda: Parastacidae) from New South Wales, with a key to all species of the genus. Records of the Australian Museum, Supplement 23: 1–110.


Text, map and photograph by Shane Ahyong.

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