Sampling stygofauna down a bore hole.
Photo - Parks and Wildlife

What are stygofauna?

  • Ground water fauna, or stygofauna, are animals that live permanently underground in water.
    • Most are small crustaceans between 0.3 to 10 millimetres in length.
    • Other stygofauna include fish, worms, snails, mites and insects.
  • Stygofauna live in a range of groundwater habitats—from tiny spaces between sand grains to pools and streams in caves.
  • As stygofauna have evolved in the dark, they lack eyes and pigmentation but compensate for this by having well elongated feelers.
  • Western Australia has three threatened stygofaunal fish species, the blind cave eel (Ophisternon candidum) and two blind gungeons (Milyeringa veritas and M. justitia), found in the Cape Range area near Exmouth or on Barrow Island.
  • Some stygofauna have origins dating back to a time before the main land masses of the earth broke apart and became today's continents, and are thought to have become  underground-dwellers to avoid drying out in areas that once had much higher rainfall .
  • Studying stygofauna gives researchers further insight on this 'continental drift' theory and the evolution of stygofauna since then.
  • Very little is known about their ecology as they are difficult to observe in their natural environment or keep alive in the laboratory.

pdfBeasts of the Underworld LANDSCOPE 2006928.48 KB

Role in maintaining water quality.

  • Stygofauna communities obtain their food from organic matter percolating down from the ground's surface. This regulates the concentration of this material in water.
  • Stygofauna also keep ground water flowing by maintaining the spaces between soil particles.

Threats to stygofauna

using video camera stygafauna
Using a video camera to research
stygofauna down a bore hole.
Photo - Parks and Wildlife

Stygofauna have evolved and specialised over time to live in particular underground water habitats.

Major changes to these habitats pose significant risks to the ongoing survival of their species.

Threats to stygofauna include:

  • changes in the water quality of groundwater
  • changes to water levels or removal of groundwater
  • compaction of sediment
  • lack of scientific knowledge which limits our understanding of the impacts of these threats.

Stygofauna survey in the Pilbara

Increasing our knowledge about stygofauna was a major focus of the Pilbara Region Biological Survey 2002-2013. This survey has shown that stygofauna are an important part of the Pilbara's biodiversity.

The survey found 350 species of stygofauna in the Pilbara, with the total number of species estimated to be up to 550, most of which are new to science and restricted to the Pilbara region. This survey has shown that the Pilbara is a globally important region for stygofauna.

pdfImages of Pilbara stygofauna236.38 KB

Contact information

Adrian Pinder

  • ostracod stygofauna
    Photo: ©  Parks and Wildlife
  • new stygofauna
    New Pilbara stygofauna species.
    Photo: ©  Parks and Wildlife

  • Stygofauna
    Photo: © Parks and Wildlife