Pilbarana, a new subterranean amphipod genus (Hadzioidea: Eriopisidae) of environmental assessment importance from the Pilbara, Western Australia

The Pilbara and nearby regions in north-western Western Australia have an exceptionally high diversity of short-range endemic invertebrates inhabiting threatened groundwater-dependent habitats. Amphipod crustaceans, in particular, are dominant in these communities, but are poorly understood taxonomically, with many undescribed species. Recent molecular phylogenetic analyses of Pilbara eriopisid amphipods have, nonetheless, uncovered a previously unknown biodiversity. In this study, we formally establish a new genus, Pilbarana Stringer & King gen. nov., and describe two new species, P. grandis Stringer & King sp. nov. from Cane River Conservation Park and P. lowryi Stringer & King sp. nov. from the Fortescue River Basin near the Hamersley Range, using a combination of molecular and morphological data. The new genus is similar morphologically to the two additional Western Australian eriopisid genera, Nedsia Barnard & Williams, 1995 and Norcapensis Bradbury & Williams, 1997, but represents a genetically divergent, reciprocally monophyletic lineage, which can be differentiated by its vermiform body shape, the presence of an antennal sinus, and by the length and form of the antennae and uropods. This research signifies an important contribution to knowledge of Pilbara subterranean communities and has critical implications for future environmental impact assessments and conservation management.Danielle N. Stringer, Rachael A. King, Andrew D. Austin, Michelle T. Guzi

Systematics of Haloniscus Chilton, 1920 (Isopoda: Oniscidea: Philosciidae), with description of four new species from threatened Great Artesian Basin springs in South Australia

Recent surveys of Australian arid-zone groundwater ecosystems have uncovered considerable species diversity and extreme endemism for the oniscidean isopod genus Haloniscus Chilton, 1920. Phylogenetic and species delimitation analyses have recognised several distinct species from the Great Artesian Basin springs in South Australia, inspiring a morphological reassessment of the genus and examination of specimens from the iconic Lake Eyre and Dalhousie Springs. We present a revised diagnosis of Haloniscus, transfer the genus from the family Scyphacidae to Philosciidae and describe four new species, H. fontanus Stringer, King & Taiti n. sp., H. microphthalmus Stringer, King & Taiti n. sp., H. rotundus Stringer, King & Taiti n. sp., and H. yardiyaensis Stringer, King & Taiti n. sp., based on combined morphological and molecular evidence. We compare the results of molecular-based species delimitation analyses with morphological data, provide distribution information, and present a key to the described species of Haloniscus. Two species presently included in Andricophiloscia Vandel, 1973, A. stepheni (Nicholls & Barnes, 1926) and A. pedisetosa Taiti & Humphreys, 2001, from Western Australia are also transferred to Haloniscus.Danielle N. Stringer, Rachael A. King, Stefano Taiti, Michelle T. Guzik, Steven J.B. Cooper, and Andrew D. Austi

Molecular phylogenetic analysis of Australian arid-zone oniscidean isopods (Crustacea: Haloniscus) reveals strong regional endemicity and new putative species

During the Miocene, central and western Australia shared a warm–wet environment that harboured a mesic rainforest fauna. Now, although the area is within the arid climate zone, it provides a habitat for highly diverse groundwater-associated invertebrates. Periods of global cooling and aridification during the late Miocene resulted in isolated desert refuges that retained ancient lineages. We aimed to characterise oniscidean isopod crustaceans from three refugial locations in the arid zone, and salt lakes, to identify new putative species. Extensive sampling and sequencing of the mitochondrial Cytochrome Oxidase c subunit 1 gene and the 18S rRNA gene were conducted. A molecular phylogenetic analysis of the oniscidean genus Haloniscus showed results consistent with a relictualisation hypothesis of widespread populations from across South Australia to Western Australia with subsequent geographic isolation and diversification of new species within habitats. We observed significant regional endemicity, but some lineages were not regionally monophyletic, pointing to past connectivity. We expand the range of Haloniscus and identify at least 26 putative species from arid-zone locations in Australia, with substantial phylogeographic structure within locations. These findings highlight the importance of relictual groundwater habitats as refugia for a diverse fauna representing early climatic history in Australia’s arid zone.Michelle T. Guzik, Danielle N. Stringer, Nicholas P. Murphy, Steven J.B. Cooper, Stefano Taiti, Rachael A. King, William F. Humphreys and Andrew D. Austi

Evidence for speciation underground in diving beetles (Dytiscidae) from a subterranean archipelago

Most subterranean animals are assumed to have evolved from surface ancestors following colonisation of a cave system, however very few studies have raised the possibility of 'subterranean speciation' in underground habitats (i.e. obligate cave-dwelling organisms (troglobionts) descended from troglobiotic ancestors). Numerous endemic subterranean diving beetle species from spatially-discrete calcrete aquifers in Western Australia (stygobionts) have evolved independently from surface ancestors; however, several cases of sympatric sister species raises the possibility of subterranean speciation. We tested this hypothesis using vision (phototransduction) genes that are evolving under neutral processes in subterranean species and purifying selection in surface species. Using sequence data from 32 subterranean and five surface species in the genus Paroster (Dytiscidae), we identified deleterious mutations in: long wavelength opsin (lwop), arrestin 1 (arr1), and arrestin 2 (arr2) shared by a sympatric sister-species triplet, arr1 shared by a sympatric sister-species pair, and lwop and arr2 shared among closely related species in adjacent calcrete aquifers. In all cases, a common ancestor possessed the function-altering mutations, implying they were already adapted to aphotic environments. Our study represents one of the first confirmed cases of subterranean speciation in cave insects. The assessment of genes undergoing pseudogenisation provides a novel way of testing modes of speciation and the history of diversification in blind cave animals. This article is protected by copyright. All rights reserved.Barbara L. Langille ... Danielle N. Stringer, Simon M. Tierney, William F. Humphreys, Andrew D. Austin, Steven J. B. Cooper ... et al

A fucose containing polymer-rich fraction from the brown alga Ascophyllum nodosum mediates lifespan increase and thermal-tolerance in Caenorhabditis elegans, by differential effects on gene and protein expression

The extracts of the brown alga, Ascophyllum nodosum, which contains several bioactive compounds, have been shown to impart biotic and abiotic stress tolerance properties when consumed by animals. However, the physiological, biochemical and molecular mechanism underlying such effects remain elusive. We investigated the effect of A. nodosum fucose-containing polymer (FCP) on tolerance to thermally induced stress using the invertebrate animal model, Caenorhabditis elegans. FCP at a concentration of 150 \u3bcg mL-1 significantly improved the life span and tolerance against thermally induced stress in C. elegans. The treatment increased the C. elegans survival by approximately 24%, when the animals were under severe thermally induced stress (i.e. 35 \ub0C) and 27% under mild stress (i.e. 30 \ub0C) conditions. The FCP induced differential expression of genes and proteins is associated with stress response pathways. Under thermal stress, FCP treatment significantly altered the expression of 65 proteins (54 up-regulated & 11 down-regulated). Putative functional analysis of FCP-induced differential proteins signified an association of altered proteins in stress-related molecular and biochemical pathways of the model worm. \ua9 2014 The Royal Society of Chemistry.Peer reviewed: YesNRC publication: Ye

Parallel decay of vision genes in subterranean water beetles

In the framework of neutral theory of molecular evolution, genes specific to the development and function of eyes in subterranean animals living in permanent darkness are expected to evolve by relaxed selection, ulti- mately becoming pseudogenes. However, definitive empirical evidence for the role of neutral processes in the loss of vision over evolutionary time remains controversial. In previous studies, we characterized an assemblage of independently-evolved water beetle (Dytiscidae) species from a subterranean archipelago in Western Australia, where parallel vision and eye loss have occurred. Using a combination of transcriptomics and exon capture, we present evidence of parallel coding sequence decay, resulting from the accumulation of frameshift mutations and premature stop codons, in eight phototransduction genes (arrestins, opsins, ninaC and transient receptor potential channel genes) in 32 subterranean species in contrast to surface species, where these genes have open reading frames. Our results provide strong evidence to support neutral evolutionary processes as a major contributing factor to the loss of phototransduction genes in subterranean animals, with the ultimate fate being the irreversible loss of a light detection system.Barbara L. Langille, Simon M. Tierney, Terry Bertozzi, Perry G. Beasley-Hall, Tessa M. Bradford, Erinn P. Fagan-Jeffries, Josephine Hyde, Remko Leijs, Matthew Richardson, Kathleen M. Saint, Danielle N. Stringer, Adrian Villastrigo, William F. Humphreys, Andrew D. Austin, Steven J.B. Coope