title: Molecular systematics and biodiversity of oniscidean isopods in the groundwater calcretes of central Western Australia.
abstract: Groundwater calcrete aquifers of central Western Australia have been shown to contain a high diversity of stygobiont (subterranean aquatic) invertebrates, with each species confined to an individual calcrete and the entire system resembling a 'subterranean archipelago' containing hundreds of isolated calcretes. Here, we utilised alternative sampling techniques above the water table and uncovered a significant fauna of subterranean terrestrial oniscidean isopods from the calcretes. We explored the diversity and evolution of this fauna using molecular analyses based on one mitochondrial gene, Cytochrome C Oxidase Subunit I (COI), two Ribosomal RNA genes (28S and 18S), and one protein coding nuclear gene, Lysyl-tRNA Synthetase (LysRS). The results from 12 calcretes showed the existence of 36 divergent DNA lineages belonging to four oniscidean families (Paraplatyarthridae, Armadillidae, Stenoniscidae and Philosciidae). Using a combination of phylogenetic and species delimitation methods, we hypothesized the occurrence of at least 27 putative new species of subterranean oniscideans, of which 24 taxa appeared to be restricted to an individual calcrete, lending further support to the "subterranean island hypothesis". Three paraplatyarthrid species were present on adjacent calcretes and these exceptions possessed more ommatidia and body pigments compared with the calcrete-restricted taxa, and are likely to represent troglophiles. The occurrence of stenoniscid isopods in the calcretes of central Western Australia, a group previously only known from the marine littoral zone, suggests a link to the marine inundation of the Eucla basin during the Late Eocene. The current oniscidean subterranean fauna consists of groups known to be subtropical, littoral and benthic, reflecting different historical events that have shaped the evolution of the fauna in the calcretes.
authors.affiliation: Australian Centre for Evolutionary Biology and Biodiversity, School of Biological Sciences, The University of Adelaide, Adelaide, South Australia 5005, Australia. Electronic address: m.javidkar@gmail.com.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Javidkar
authors.affiliation: Australian Centre for Evolutionary Biology and Biodiversity, School of Biological Sciences, The University of Adelaide, Adelaide, South Australia 5005, Australia; Evolutionary Biology Unit, South Australian Museum, North Terrace, Adelaide, South Australia 5000, Australia. Electronic address: steve.cooper@samuseum.sa.gov.au.
authors.forename: Steven J B
authors.initials: SJB
authors.lastname: Cooper
authors.affiliation: Australian Centre for Evolutionary Biology and Biodiversity, School of Biological Sciences, The University of Adelaide, Adelaide, South Australia 5005, Australia; Evolutionary Biology Unit, South Australian Museum, North Terrace, Adelaide, South Australia 5000, Australia.
authors.forename: Rachael A
authors.initials: RA
authors.lastname: King
authors.affiliation: Western Australian Museum, Welshpool DC, Western Australia 6986, Australia; School of Animal Biology, University of Western Australia, Crawley, Western Australia 6009, Australia.
authors.forename: William F
authors.initials: WF
authors.lastname: Humphreys
authors.affiliation: Australian Centre for Evolutionary Biology and Biodiversity, School of Biological Sciences, The University of Adelaide, Adelaide, South Australia 5005, Australia; Evolutionary Biology Unit, South Australian Museum, North Terrace, Adelaide, South Australia 5000, Australia.
authors.forename: Terry
authors.initials: T
authors.lastname: Bertozzi
authors.affiliation: Evolutionary Biology Unit, South Australian Museum, North Terrace, Adelaide, South Australia 5000, Australia; School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, South Australia 5000, Australia.
authors.forename: Mark I
authors.initials: MI
authors.lastname: Stevens
authors.affiliation: Australian Centre for Evolutionary Biology and Biodiversity, School of Biological Sciences, The University of Adelaide, Adelaide, South Australia 5005, Australia.
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Austin
mesh_terms: D000818:Animals; D044822:Biodiversity; D045304:Cytochromes c / Q000145:classification / Q000235:genetics / Q000378:metabolism; D004247:DNA / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D030541:Databases, Genetic; D060587:Groundwater / Q000469:parasitology; D033321:Isopoda / Q000145:classification* / Q000235:genetics; D008250:Lysine-tRNA Ligase / Q000145:classification / Q000235:genetics / Q000378:metabolism; D010802:Phylogeny; D012337:RNA, Ribosomal, 18S / Q000145:classification / Q000235:genetics / Q000378:metabolism; D012339:RNA, Ribosomal, 28S / Q000145:classification / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D014904:Western Australia
chemical_list: D012337:RNA, Ribosomal, 18S; D012339:RNA, Ribosomal, 28S; D045304:Cytochromes c; D004247:DNA; D008250:Lysine-tRNA Ligase
keywords: Groundwater calcretes; Molecular systematics; Oniscidean isopods; Species delimitation; Subterranean fauna