Obligate cave dwelling organisms are frequently characterised by a peculiar morphological syndrome, named troglomorphosis or troglobiomorphosis. This hypothesis, which deals with the evolutionary influence of the subterranean environment on cave organisms is far from being universally accepted. Yet it has been adopted by many authors and is often included in the definitions of the current classification of cave taxa. In this paper I present a test of the troglobiomorphosis hypothesis, using the case study of the cricket clade Amphiacustae (Orthoptera, Grylloidea, Phalangopsidae). Such a test preliminarily requires that observations of the habitat of the taxa (achieved on present-day populations) are clearly separated from hypotheses on the evolutionary transformations of cave taxa (troglobiomorphosis hypothesis s. str.). The evolutionary hypotheses on troglobite morphology are tested using phylogenetic inference, that is by parsimoniously mapping the states of several morphological characters (eye size, body colour, relative hindleg size) onto the cladogram of the Amphiacustae. According to these phylogenetic analyses, the troglobiomorphosis hypothesis is corroborated by the patterns reconstructed for eye size and body coloration characters, but is refuted by the patterns built for hindleg size.
Are troglobitic taxa troglobiomorphic? A test using phylogenetic inference.
International Journal of Speleology,
Available at: http://scholarcommons.usf.edu/ijs/vol26/iss1/1