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 Major Groups | Insecta (insects) | Ephemeroptera (mayflies) | Caenidae


Major Group: Insecta
Order: Ephemeroptera
Family: Caenidae

Descriptive Features:

  • head prognathous
  • antennae longer than head width
  • body pinkish to brown
  • thorax and abdomen dorso-ventrally flattened
  • gills present on abdominal segments 1-6, 1st gills are monofilamentous, 2nd gills are operculate (i.e. form a covering over other gills), rectangular, fringed with fine hairs, not fused at mid-line, gills 3-6 with multifid tracheal filaments
  • hind wing pads absent
  • caudal filaments with whorls of setae at apex of each segment
  • Total length: up to 6 mm
  • Taxonomic Checklist: Genera

    Distribution: Australia wide

    Sensitivity Rating: SIGNAL grade 4. Caenid nymphs are more pollution tolerant than other families of Ephemeroptera. Tasmanocoenis can be found in eutrophic lakes suggesting a tolerance to nutrient enrichment. Caenidae species have not been found in saline waters.

    Functional Feeding Group: gathering collectors

    Ecology: Instream habitat: Caenid nymphs occur in slow flowing silty areas of stony streams, rivers, billabongs and lakes. They typically dwell in leaf packs, on logs or macrophytes.
    Feeding ecology: Nymphs feed on fine particulate detritus.
    Habit: The operculate gills (gill covers) are thought to protect the other delicate posterior gills from becoming clogged by fine sediment. They are sprawling nymphs and poor swimmers that mostly crawl along the riverbed. The body is covered in a layer of fine hairs which can give them a “fuzzy” appearance when fine algae or detritus is trapped.
    Life history: Caenidae species typically have one or two generations per year with adults emerging in spring and summer. A tropical species of Tasmanocoenis has a short nymphal stage of two to four weeks with adults emerging throughout the year.

    Information Sources: Dean & Suter 1996, Peters & Campbell 1991, Gooderham & Tsyrlin 2002, Davis & Christidis 1997
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