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 Major Groups | Crustacea (crustaceans) | Malacostraca (malacostracans) | Decapoda (yabbies plus) | Hymenosomatidae

Amarinus lacustris

Major Group: Crustacea
Minor Group: Malacostraca
Order: Decapoda
Genus: Amarinus
Species: lacustris
This family is represented in Australia by a single freshwater species, Amarinus lacustris Chilton.

Descriptive Features:

  • cephalothorax dorso-ventrally thin, cuticle not heavily calcified, without hooked setae
  • dorsal carapace surface flat or nearly flat, often with strong gastro-cardiac groove and contiguous grooves
  • without orbits or with very incomplete orbits, eyes exposed and a little retractile
  • antennular fossae shallow and poorly defined, antennae fused with epistome (when present), 2nd segment slender
  • ischium of 3rd maxillipeds well developed, palp articulating near anterolateral angle of merus
  • chelipeds not longer than 2x carapace width in females and most males, fingers not bent at an angle to palm
  • male and female abdomens with not more than 5 segments, excluding telson
  • Carapace width: 2 - 26 mm

    Amarinus lacustris

    Taxonomic Checklist: Amarinus lacustris Chilton

    Distribution: SA, Vic, Tas

    Sensitivity Rating: SIGNAL grade 3. Amarinus lacustris is commonly found in freshwater with higher salinities.

    Functional Feeding Group: gathering collectors


    Murray River, near Hindmarsh Island SA

    Ecology: Hymenosomatidae species are commonly known as 'false spider crabs'.
    Instream habitat: Hymenosomatid crabs generally occur in shallow marine coastal waters and estuaries, however, Amarinus lacustris is the only species noted as occurring in freshwater streams and lakes. This species is found in large numbers on snags, amongst vegetation or under and around rocks.
    Feeding ecology: These crabs are detritivores and omnivores.
    Habit: The pointed terminal leg segment enables them to climb freely on logs. They are crawlers and burrowers.
    Life history:


    Information Sources: Davie 2002b, Gooderham & Tsyrlin 2002, Hawking & Smith 1997