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EVOLUTION OF SUBTERRANEAN DIVING BEETLES (COLEOPTERA: DYTISCIDAE HYDROPORINI, BIDESSINI) IN THE ARID ZONE OF AUSTRALIA
Author(s) -
Leys Remko,
Watts Chris H. S.,
Cooper Steve J. B.,
Humphreys William F.
Publication year - 2003
Publication title -
evolution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.84
H-Index - 199
eISSN - 1558-5646
pISSN - 0014-3820
DOI - 10.1111/j.0014-3820.2003.tb01523.x
Subject(s) - biology , dytiscidae , aridification , sympatric speciation , arid , ecology , molecular clock , phylogenetic tree , biochemistry , gene
Abstract Calcrete aquifers in arid inland Australia have recently been found to contain the world's most diverse assemblage of subterranean diving beetles (Coleoptera: Dytiscidae). In this study we test whether the adaptive shift hypothesis (ASH) or the climatic relict hypothesis (CRH) is the most likely mode of evolution for the Australian subterranean diving beetles by using a phylogeny based on two sequenced fragments of mitochondrial genes ( CO1 and 16S‐tRNA‐ND1 ) and linearized using a relaxed molecular clock method. Most individual calcrete aquifers contain an assemblage of diving beetle species of distantly related lineages and/or a single pair of sister species that significantly differ in size and morphology. Evolutionary transitions from surface to subterranean life took place in a relatively small time frame between nine and four million years ago. Most of the variation in divergence times of the sympatric sister species is explained by the variation in latitude of the localities, which correlates with the onset of aridity from the north to the south and with an aridity maximum in the Early Pliocene (five mya). We conclude that individual calcrete aquifers were colonized by several distantly related diving beetle lineages. Several lines of evidence from molecular clock analyses support the CRH, indicating that all evolutionary transitions took place during the Late Miocene and Early Pliocene as a result of aridification.