A new genus of phreatoicidean isopod (Crustacea) from the north Kimberley region, Western Australia

Abstract

A new genus and species of phreatoicidean isopod, Crenisopus acinifer, has been collected from a freshwater spring in the northern Kimberley region of Western Australia. Empirical cladistic analysis of 10 exemplars of phreatoicidean genera found a single cladogram. The new genus and species assumed a basal position in the Phreatoicidea, placing it within the family Amphisopodidae sensu lata. This family, however, was not monophyletic in the preliminary cladogram, suggesting that the taxonomic structure of the suborder must be revised. The cladogram provided evidence for the monophyly of the Phreatoicidae and its New Zealand clade. The analysis suggested that clades of modern phreatoicideans diverged from one another during the Mesozoic Era after they entered fresh water, but prior to the fragmentation of East Gondwana.

VIEWPOINT. Is the Australian subterranean fauna uniquely diverse?

“…This extrapolation was carried out in different ways for different regions, for which we give two examples. First, in the Pilbara region it is likely that most of the landscape provides potential habitat for troglofauna and stygofauna and, hence, it is difficult to assign sampled/unsampled area estimates based on Wilson and Ponder (1992), Bruce and Humphreys (1993), Wilson and Johnson (1999), Wilson and Keable (1999), Taiti and Humphreys (2001), Wilson (2001Wilson ( , 2003Wilson ( , 2008…”

“…There are established links with Australia for some stygal lineages from India (Phreatoicidea (Wilson 2008); Atopobathynella (Cho et al 2006b)), Africa (Phreatoicidea (Wilson and Keable 1999)), and more widely with Gondwana (Candoninae (Karanovic 2004(Karanovic , 2005a(Karanovic , 2005b; Spelaeogriphacea Humphreys 1998, 2003)). Further these Gondwanan links between the major continents (e.g.…”

Three new species ofBillibathynellafrom Western Australia (Crustacea, Syncarida, Parabathynellidae)

“…Recent studies on the subterranean biotopes of the arid region of Western Australia have revealed diverse crustacean taxa of ancient lineages (Poore and Humphreys 1992;Bruce and Humphreys 1993;Humphreys 1993;Yager and Humphreys 1996;Bradbury and Williams 1997;Wilson and Johnson 1999;Wilson and Keable 1999;Wilson 2001Wilson , 2003. Numerous bathynellacean syncarids have also been collected from limestone, calcrete, sedimentary and regolith substrata in fresh, saline and anchialine waters in this region.…”

From genetic structure to wetland conservation: a freshwater isopod Paramphisopus palustris (Phreatoicidea: Amphisopidae) from the Swan Coastal Plain, Western Australia

“…These genera, mostly included within the families Hypsimetopidae and Amphisopidae senso stricto (see Wilson & Edgecombe, 2003), are phylogenetically distinct and are an important component of Western Australia's relictual and diverse Gondwanan fauna (Wilson & Keable, 1999, 2002Wilson & Edgecombe, 2003). While overall phreatoicidean diversity is greatest in Australia, the generic diversity in Western Australia is nonetheless remarkable when considering the region's aridity and rivals that of the wetter southeast (Wilson & Keable, 2002;Wilson & Edgecombe, 2003).…”

“…By contrast, species diversity is low in Western Australia. Six of these genera are presently monotypic and have narrow distributions (see Nicholls & Milner, 1923;Knott & Halse, 1999;Wilson & Keable, 1999, 2002. Only Amphisopus and Paramphisopus, both restricted to the southwestern portion of the state, contain multiple recognized species (Nicholls, 1943).…”