Molecular phylogeny and biogeography of spring-associated hydrobiid snails of the Great Artesian Basin, Australia.

The Great Artesian Basin (GAB) of Australia underlies some of the driest parts of South Australia and Queensland and feeds numerous freshwater springs. Prominent and endangered components of the GAB spring community are snails of the family Hydrobiidae. This paper examines the evolutionary relationships of the entire hydrobiid fauna associated with the GAB, and includes appropriate non-GAB species to place the GAB fauna in a broader phylogenetic context. The Queensland genus Jardinella is a focus of this paper, providing a fine scale examination of relationships between spring supergroups in the northeastern regions of the GAB. Maximum parsimony and Bayesian analyses performed on 16S, CO1, and combined sequence data from 40 hydrobiid taxa found four major clades of Australian taxa. The analysis revealed that at least three separate colonization events of the GAB spring fauna have occurred. Two of these are represented by considerable radiations, (1) Jardinella to the north and east and (2) Caldicochlea, Fonscochlea, and possibly Trochidrobia in South Australia. The phylogenetic position of the latter is uncertain so it may represent yet another invasion. The third definite invasion is represented by a single species of the speciose SE Australian genus Austropyrgus in the Dalhousie Springs in South Australia. Jardinella is found to be monophyletic, and with one exception, its members in each of the Queensland spring supergroups are found to be monophyletic.