Troglobitic silverfish, Trinemura sp. Pilbara

Troglofauna are animals inhabiting air-filled caves or smaller cavities below the ground. Most troglofauna are invertebrates such as spiders, pseudoscorpions, millipedes, beetles and other invertebrates.

Troglofauna that live permanently and exclusively underground are termed troglobites, from troglos (cave) and bios (life). Typical troglobites are pale and blind, with elongated appendages. The term troglomorph refers to any morphological, physiological, or behavioral feature that characterizes cave animals (Christiansen 1962).

Though characteristic of cave animals, many of the regressive features associated with living in darkness are found in other non-cave environments such as soil and the deep sea. Animals in these environments may exhibit “troglomorphic” traits but they are not troglobites. The term troglomorph serves to identify potential cave-adapted organisms without the possibly erroneous designation of troglobite (Christiansen 2005).

Where are troglofauna found?

Troglofauna are found in geologic environments with air-filled subsurface cavities that are humid and dark. A critical habitat requirement for troglobitic species is the maintenance of a high relative humidity because of their generally reduced ability to retain moisture inside their bodies (Howarth 1983).

Diverse troglobitic communities are most commonly recorded in karst terrains in carbonate rocks such as limestone, dolomite and calcrete where caves and meso-caverns are often well developed. Until relatively recently it was thought that troglobites were more or less restricted to caves in karst terrains, however in montane environment  in Europe diverse troglomorphic faunae have been recorded from the zone of fractured rocks between the soil and non-calcareous bedrock, the so-called mileau souterrain superficiel (MSS) (Juberthie et al. 1980).

Diverse troglobitic faunas have also been recorded from lava caves and smaller voids (meso-caverns) in fractured basalts in Hawaii (Howarth 1983) and the Canary Islands (Oromi and Martin 1992) for example. In Australia there has been little sampling of troglofauna in non-karstic terrains but troglobitic species have been recorded from lava caves in Queensland (Howarth 1988), and dolerite talus caves in Tasmania (Eberhard et al. 1991) for example. The emerging understanding in Australia is that species specialised to subterranean existence are not necessarily restricted to caves and karst but are more widely distributed and may potentially occur where suitable habitat exists (Eberhard and Humphreys 2003).

In Western Australia, historically, troglofauna have been recorded from caves in karstic limestones in the Kimberley, Cape Range, Barrow Island, Perth Basin (eg. Eneabba, Jurien, Yanchep), the Leeuwin Naturaliste Ridge and the Nullarbor Plain. Until the last few years there had been little searching for troglofauna in non-karstic terrains, however, rich troglobitic communities have recently been discovered in Quaternary pisolite (Biota 2006), calcrete (Barranco & Harvey 2008) and Archaean fractured rocks (Subterranean Ecology 2007; Eberhard et al. 2008). 

Troglofauna habitats