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 Major Groups | Insecta (insects) | Coleoptera (beetles) | Georissidae


Major Group: Insecta
Order: Coleoptera
Family: Georissidae (formerly within Hydrophilidae)
Genus: This family is represented by a single genus worldwide, Georissus.

Descriptive Features:

  • antennae 7- to 9-segmented with 3- or 4-segmented club
  • 2nd segment of maxillary palpi slender
  • body broad, compact, round, black
  • abdomen with more than 3 ventrites
  • ventrite 1 divided into 2 or 3 parts by hind coxae
  • elytra highly sculptured, exposing less than 2 complete abdominal tergites
  • prothorax with pair of notopleural sutures separating notum from externally visible pleuron on each side
  • tarsi 5-segmented
  • basal segment of hind tarsi shorter than 2nd
  • size: <2mm
  • labrum completely fused to head capsule
  • legs 3-segmented
  • abdominal tergum 8 usually subterminal, not forming spiracular siphon or spiracular chamber
  • size: 

    Georissus adult

    Taxonomic Checklist: Species
    Georissus australis
    Georissus kingi Blackburn
    Georissus occidentalis Carter

    Distribution: N Aus, SW Aus, Vic

    Sensitivity Rating: none; formerly within Hydrophilidae - SIGNAL grade 2

    Functional Feeding Group: shredders (adults), predators (larvae)


    Mitta Mitta River at Eskdale, Vic

    Ecology: Little is known about Australian species, all of the ecological information below is from the Northern Hemisphere.
    Instream habitat: Georissidae is one of a group of beetle families commonly known as ‘shore beetles’. Adults and larvae are generally viewed as terrestrial beetles that are found almost exclusively very close to the edges of pools or rivers where they occur in moist mud or fine sand, especially in places with little vegetation.
    Feeding ecology: Adults feed on plant material and decaying organic matter. Larvae are predators.
    Life history: Eggs are enclosed within a densely woven silk cocoon.There are two larval instars.


    Information Sources: Watts 2002, Hansen 2000, Jach 1998, Bernhard et al. 2006, Calder 2004, Williams 1980
    Key to Species: none