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


Major Group: Insecta
Order: Coleoptera
Family: Ptilodactylidae
Genus: Byrrocryptus
In Australia, this family contains a single semi-aquatic genus, Byrrocryptus.

Descriptive Features:

  • antennae 11-segmented, no distinct club
  • prosternum in front of coxae as long as or shorter than intercoxal process
  • ventral portion of the notum, (hypomeron) on each side joined directly to the sternum by notosternal suture
  • pleuron reduced and concealed
  • elytra exposing less than 2 complete abdominal tergites
  • body finely pubescent
  • abdomen with at least 3 connate ventrites
  • mesocoxal cavities narrowly separated (by less than 0.4 times coxal width)
  • intercoxal process on ventrite 1 acute
  • tarsi simple
  • body length 1.5 X width
  • size: 5mm
  • head prognathous or slightly declined
  • antennal length > head width
  • apex of antennal segment 2 truncate
  • labrum separated from head capsule by complete suture
  • maxillary palp 4-segmented
  • postmentum divided longitudinally into 3 parts
  • mesal surface of mandibular base with brush of hairs or spines
  • maxillary articulating area present but more or less concealed behind expanded postmentum
  • spiracles biforous, with 2 parallel openings
  • stemmata closely clustered, sometimes fused into a single mass
  • cardines separated from each other by labium
  • ecdysial scar preszent
  • body elongate
  • legs 5-segmented, including claw
  • size: up to 15mm

    Byrrocryptus larva


    Byrrocryptus oblongus adult

    Taxonomic Checklist: Species
    Byrrocryptus nigrinus Carter
    Byrrocryptus oblongus Carter
    Byrrocryptus serraticornis Carter
    Byrrocryptus variegatus Carter

    B. nigrinus
    B. oblongus NSW
    B. serraticornis & B. variegatus Qld

    Sensitivity Rating: SIGNAL grade 10

    Functional Feeding Group: shredders (larvae); terrestrial adults


    Mt Wills Creek near Granite Flat, Vic

    Ecology: Instream habitat: Only the larvae of Byrrocryptus are aquatic. They are common amongst stones in rivers and creeks, especially where there is leaf litter and rotten wood. Byrrocryptus adults are terrestrial and are found in riparian foliage alongside streams and rivers.
    Feeding ecology: Larvae feed on decaying plant matter, including wood.
    Habit: Byrrocryptus adults are nocturnal.
    Life history:


    Information Sources: Lawrence & Britton 1991, Lawrence 1992, Watts 2002, Calder 1999d, Williams 1980
    Key to Species: none