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


Major Group: Crustacea
Minor Group: Malacostraca
Order: Decapoda

Descriptive Features:

  • rostrum, if present, inflexibly attached to rest of carapace
  • carapace without longitudinal lateral ridges or suture, without cardiac notch in posterior margin
  • eyes neither unusually long nor concealed beneath carapace
  • antennule with 2 flagella, neither with accessory branch
  • mandible with palp, with subtruncate molar process not distinctly separated from incisor process
  • 2nd maxilla with endite well developed, scaphognathite with proximal lobe tapering, bearing series of long setae, and extending far into branchial chamber
  • 1st maxilliped with exopod terminating in lash, not in broad, partially detached lobe
  • caridean lobe not acutely produced, not over-reaching distally produced endite
  • 2nd maxilliped with exopod, endopod 4-segmented, not terminating in 2 segments attached side-by-side to preceding segment, terminal segment attached to slender, sickle shaped extension of preceding segment
  • 3rd maxilliped 5-segmented, slender, pereopod-like
  • pereopods usually with strap-like epipods (mastigobranchs) on at least 3 anterior pairs, epipods without naked appendix extending vertically into branchial chamber
  • 2 anterior pairs of pereiopods similar, with fingers of chela usually terminating in tuft of setae; 2nd pereiopod with carpus undivided
  • Total length: less than 35 mm, except Australatya striolata at 60 mm
  • Taxonomic Checklist: Genera

    Distribution: all states 

    Sensitivity Rating: SIGNAL grade 3  

    Functional Feeding Group: gathering collectors, filtering collectors, predators

    Ecology: Instream habitat: Atyidae species in freshwater, estuarine and brackish surface waters as well as underground waters. Australatya, Caridina, Caridinides and Paratya occur in surface aquatic habitats, including; lakes, creek pools, temporary pools, stagnant water pools in the outflow tunnel of caves and streams flowing through open grassland and forested areas. Larvae are most common in billabongs and slackwaters. Parisia, Pycneus, Pycnisia and Stygiocaris occur in underground aquatic habitats, including; in freshwater wells subject to tidal influence and limestone caves at depths from nine to thirty three metres below ground surface. In surface habitats, atyid shrimp are found in leaf litter packs on rock, gravel or sand substrata and under rocks, logs or amongst vegetation in littoral areas.
    Feeding ecology: Generally, atyid shrimp are collectors feeding on plant and animal detritus or bacteria or algal particles. Most species feed by gathering food particles off rocks and plants using the brush-like setae on the tips of the claws of their first and second legs. Paratya, the most common inland atyid shrimp, is an omnivore. Australatya striolata is a filter feeder. Pycnisia raptor is believed to be a predator.
    Habit: Australatya striolata are migratory.
    Life history: Some Atyidae species require marine influence (estuarine waters) for larval development. Paratya can only breed successfully in fresh waters. Females carry the eggs under their abdomen. The pleopods are used to keep fresh oxygenated water flowing over the eggs. Atyid shrimp are planktonic in the first months of life (summer). The life span of Paratyais two years with females breeding in the second summer. The planktonic larval stage lasts for twenty eight to forty five days.
    Information Sources: Davie 2002a, Gooderham & Tsyrlin 2002
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