Cherax parvus facts for kids
Quick facts for kids Cherax parvus |
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| Conservation status | |
| Scientific classification | |
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| Phylum: | |
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Parastacidae
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| Genus: |
Cherax
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| Species: |
C. parvus
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| Binomial name | |
| Cherax parvus Short & Davey, 1993
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Cherax parvus is a tiny type of crayfish that belongs to the Parastacidae family. It was discovered in 1992 during an expedition to the upper Tully River area in Queensland, Australia. This special crayfish is only found in the high rainforests of the Cardwell Range in north-eastern Queensland.
It is one of the smallest crayfish in its group, the Cherax genus. What makes Cherax parvus unique is that it lives in wet, high-altitude areas, which is unusual for other Cherax species. Most other crayfish in this group live in lower areas. Scientists think it has been geographically isolated for a very long time because it has several features not seen in other crayfish.
Cherax parvus is currently listed as "data deficient" on the IUCN Red List. This means scientists need more information about how many there are and where else they might live to understand if they are safe or at risk.
Contents
What it Looks Like
Cherax parvus is a small crayfish. Its body is mostly dark brown.
Its Claws
The main claws, called chelipeds, are dark brown on top. They have an orange pattern on the tips and near the body. The underside of the claws is a creamy color.
Its Legs
Its other legs are greenish-cream on top and light cream underneath.
Where it Lives
This crayfish lives in fresh water. You can find it in short burrows under rocks. It also hides among fallen leaves in shallow water, usually about 1 meter deep.
It prefers to live on rocks, sand, or clay at the edge of rainforests. These crayfish live at high altitudes, between 720 and 750 meters above sea level. The water they live in is usually clear, with little to moderate flow.
Cherax parvus can live in water with specific conditions:
- A pH of about 5.5 (slightly acidic).
- Low water hardness (less than 10 parts per million).
- Temperatures between 18 and 20°C.
- Good levels of dissolved oxygen (5.8 to 6.0 parts per million).
This crayfish shares its habitat with other water creatures. These include another crayfish called E. yigara, a type of shrimp called Caridina zebra, and an undescribed Macrobrachium shrimp species.
Where it is Found
Cherax parvus is only known from the upper Tully River and one of its smaller streams, O’Leary Creek. These locations are above the Koombooloomba Dam, in the Cardwell Range of Queensland, Australia.
Its Special Features
Crayfish from the Cherax group are found across the humid tropical areas of north Queensland. Even though Cherax parvus lives in the same general area as another species, C. depressus, it doesn't seem closely related to it. This suggests it has been isolated for a very long time.
Here are some unique features of Cherax parvus:
- Its postorbital carinae (ridges near its eyes) are almost gone. They start very close to the eye area.
- A part of its first claw (the distodorsal condyle on the carpus) is very strong. It forms a wide, hard plate.
- The pleurocoxal lappet (a flap-like part) between its fourth and fifth legs is unusually thin. It has very long, feathery hairs.
- Its branchiostegites (parts of its shell covering the gills) are not inflated. This is different from some other crayfish.
The fact that its branchial chambers (where the gills are) are relatively small might mean it prefers cool, well-oxygenated rainforest streams. This is because crayfish living in water with less oxygen often have larger gill chambers.
Also, unlike most other highland crayfish from New Guinea, C. parvus has a smooth rostrum (a spine-like part on its head) without bumps or spines.
Name Meaning
The name parvus comes from Latin. It is an adjective that means "small." This name perfectly describes this tiny crayfish!
- J.W. Short and P.J.F. Davie (1993). Two new species of freshwater crayfish (Crustacea: Decapoda: Parastacidae) from northeastern Queensland rainforest. Memoirs of the Queensland Museum. Queensland Museum, pp. 68–80. ISSN 0079-8835.
