Jennifer Chaplin

Australian salt lakes contain a high proportion of endemic taxa. This includes giant ostracods in the subfamily Mytilocypridinae (Cyprididae), which appears to have undergone radiation in these environments. Although the morphological taxonomy of this subfamily is relatively advanced, it has not been verified with molecular data. We, therefore, used molecular (mitochondrial COI and 16S and nuclear 28S markers) as well morphological evidence to evaluate the current taxonomy of Mytilocypridinae. Our study included 18 of 21 described species and seven of eight undescribed species. The results confirm the monophyly of the Mytilocypridinae. Five major clades (putative genera) were apparent within this subfamily, two of which corresponded to currently recognized genera but the remaining three contained admixtures of species from more than one current genus, i.e. the current genera do not represent monophyletic species groups. Molecular and morphological data supported most species’ designations; however, two putative new species, one synonymy, and one complex of cryptic species were identified. By enhancing our understanding of the taxonomy and systematics of Mytilocypridinae, the results of this study will support future research on this taxon and on the evolution of salt-lake invertebrates.

This study investigates the impact of paleoclimate on the evolutionary history of Coxiella (Tomichiidae), a group of 15 species of aquatic snail in four putative genera that are endemic to Australian salt lakes. It used a time-calibrated phylogeny, based on mitochondrial DNA ( COI ) sequence variation from 938 individuals from 14 species, to estimate the timing of diversification events in Coxiella . The four putative genera of Coxiella were estimated to have evolved in the late Miocene to late Pliocene, followed by speciation within these genera during late Pliocene to Pleistocene and subsequent divergence within species during the Pleistocene. We also used COI data from 872 individuals to compare the phylogeographic patterns and genetic diversities amongst six species. These species showed three distinctly different phylogeographic patterns, ranging from deep phylogeographic structuring to a very shallow structure in a species that appears to have undergone a range expansion after a severe bottleneck. Overall, the recent evolutionary history of Coxiella shows important parallels with those of many other taxa from southern Australia which implies a common cause, which is usually identified as the trend of increasing aridification of the Australian climate over the last ~ 15 mya.

Understanding connectivity in high impact corallivores is crucial for coral reef management. The obligate corallivorous Drupella cornus (Röding, 1798) has caused extensive damage to some Indian Ocean coral reef areas in the last four decades. This study used novel and previously published Cytochrome Oxidase I (COI) sequences to reveal patterns of genetic diversity, phylogeography and connectivity within D. cornus across the Indian Ocean. The genetic compositions of the Western Australian D. cornus groups from Ningaloo Reef, Houtman Abrolhos Islands, and a recently discovered group at Rottnest Island, were analysed and compared to D. cornus groups from the western Indian Ocean (Tanzania and the Gulf of Eilat). The findings indicated that these groups all belong to the same species, except for a few individuals from Rottnest Island, which were excluded from subsequent analyses. No genetically distinct D. cornus groups along the Western Australian coastline were found, whereas molecular population differences were seen between the western Indian Ocean D. cornus groups and the Western Australian D. cornus groups. The molecular differences between the Western Australian and Tanzanian groups were statistically significant; however, there was evidence of historic connections and possibly also occasional long-distance gene flow between these groups. We hypothesise that high-density D. cornus outbreaks have played an important role in the dispersal of this species across Western Australia and, more broadly, the Indian Ocean. This is important as Drupella spp. outbreaks are being reported more frequently in the Indo-Pacific, affecting coral reef health and ecosystem function.

Invertebrate coral predators can have a great impact on coral reef communities. Understanding the taxonomy of these corallivorous species, their distributions, behaviour, and ecology, is crucial for effective management of coral reefs. The six currently recognised species of Drupella (Gastropoda: Muricidae) occur in the Indo-Pacific, where they are predominantly obligate corallivores, and three of these species, including D. cornus, are sometimes associated with high levels of coral reef destruction when in elevated densities. Here, we used an integrative approach to delimit species of Drupella. We found evidence to support the presence of two species within the described species D. cornus, one which is widespread across the Indian Ocean and another that is widespread across the Pacific Ocean. We also found support for a previous suggestion that separated D. margariticola into ‘oceanic’ and ‘continental’ species. Our results also show wider geographic distribution for D. fragum and document new distribution records for D. eburnea on the Great Barrier Reef. These findings demonstrate the need for further research to understand the ecological differences between these species. Furthermore, it is important to assess the causes of proposed distributional changes in high-impact Drupella species, including the potential influence of increasing water temperatures.

Australian salt lakes contain a diverse range of endemic invertebrates. The brine shrimp Parartemia is among the most speciose and salt-tolerant of these invertebrates. The morphotaxonomy of Parartemia is well established but there has only been limited molecular assessment of the phylogenetic relationships and boundaries of the morphospecies. We used multiple genetic markers (nuclear 28S and mitochondrial 16S and COI ) and tree-building methods (Bayesian inference and maximum likelihood) to investigate the phylogeny of Parartemia . We also used species delimitation methods to test the validity of morphological species designations. The data set included all but 2 of the 18 described Parartemia morphospecies, collected from a total of 93 sites from across southern Australia plus some sequences from GenBank. The results identified large amounts of molecular divergence (e.g. COI P- values of up to 25.23%), some groups of closely related species (which also usually shared some morphological similarities) and some distinctive species, although the relationships among divergent lineages were generally not well resolved. The most conservative set of results from the species delimitation analyses suggests that the morphotaxonomy is largely accurate, although many morphospecies comprised divergent genetic lineages separated by COI P- values of up to 17.02%. Two putative new morphospecies, three cryptic species and one synonymy were identified. Our findings improve the knowledge of Parartemia taxonomy and will facilitate the development of future studies and conservation of this taxon.Australian salt lakes contain a diverse range of endemic invertebrates. The brine shrimp Parartemia is among the most speciose and salt-tolerant of these invertebrates. The morphotaxonomy of Parartemia is well established but there has only been limited molecular assessment of the phylogenetic relationships and boundaries of the morphospecies. We used multiple genetic markers (nuclear 28S and mitochondrial 16S and COI ) and tree-building methods (Bayesian inference and maximum likelihood) to investigate the phylogeny of Parartemia . We also used species delimitation methods to test the validity of morphological species designations. The data set included all but 2 of the 18 described Parartemia morphospecies, collected from a total of 93 sites from across southern Australia plus some sequences from GenBank. The results identified large amounts of molecular divergence (e.g. COI P- values of up to 25.23%), some groups of closely related species (which also usually shared some morphological similarities) and some distinctive species, although the relationships among divergent lineages were generally not well resolved. The most conservative set of results from the species delimitation analyses suggests that the morphotaxonomy is largely accurate, although many morphospecies comprised divergent genetic lineages separated by COI P- values of up to 17.02%. Two putative new morphospecies, three cryptic species and one synonymy were identified. Our findings improve the knowledge of Parartemia taxonomy and will facilitate the development of future studies and conservation of this taxon.

Giant ostracods in the subfamily Mytilocypridinae are an important component of the biota of Australian salt lakes, which are predominantly temporary, and often located in remote arid areas. Mytilocypridines produce desiccation-resistant eggs to persist in these habitats during unfavourable conditions. In this study, we used mytilocypridine eggs collected from sediments in salt lakes in Western Australia to analyse aspects of the ecology of these ostracods. We conducted two rehydration trials, where sediment was collected from dry lakes or the dry margins of lakes, rehydrated in a laboratory setting, and selected mytilocypridine species hatched and raised in cultures. The first trial found that the eggs of mytilocypridine species were unevenly distributed in a dry lake and could be hatched even after 27 months of dry storage with no discernible loss of viability. The second trial assessed the capacity of selected mytilocypridines to hatch and develop into adults under different salinity treatments. One species, Australocypris insularis , hatched and developed across a very wide salinity range (0–100 g/L). Egg/sediment samples provide a means for testing species’ tolerance to physical and chemical variables throughout their entire life cycle, as well as for surveying the mytilocypridines in remote lakes that rarely hold water.

With increasing sea water temperatures, higher latitude temperate and sub-tropical coral reefs are becoming increasingly tropicalised. Although these cooler areas might offer refuge to tropical species escaping the heat, the reshaping of ecosystems can have devastating effects on the biodiversity in these areas, especially when habitat structure is affected. Recently, feeding aggregations of corallivorous gastropod Drupella cornus, a tropical species capable of large-scale reef degradation, were found at Rottnest Island in Western Australia (32°S). We provide evidence that D. cornus spawned at Rottnest Island for 2 consecutive years in 2021 and 2022, and Drupella veligers from an egg case collected at the island hatched and grew at temperatures in the laboratory that were predominantly lower than those at Rottnest Island at the same time. The spawning was possibly triggered by higher than usual La Niña-associated SSTs during the survey period, or the long period of high sea water temperature anomalies recorded around Rottnest Island. A spawning population of D. cornus can greatly affect these higher latitude reef areas, especially when accompanied by increased heat stress. Monitoring and management should be implemented to further understand what effects a breeding population of D. cornus has on Rottnest Island.

This study uses published and unpublished data to create a comprehensive and up-to-date synthesis of available information on a little-known group of invertebrates, namely, non-marine giant ostracods (cypridids >= 3 mm long). Approximately 8% of the similar to 1000 living cypridid species are identified as 'giant'. They occur in a range of subfamilies, in all zoogeographic regions, except Antarctica, and mainly in small standing-water ecosystems. Only those in the subfamily Mytilocypridinae are reasonably well studied. This subfamily is endemic to Australia and comprises a diverse range of giant species (similar to 29 species in 6 genera), mainly in temporary habitats, mostly salt lakes, including in extreme conditions. We evaluate the current taxonomy of the Mytilocypridinae, analyse patterns in the field distributions and abiotic tolerances of species, and review the general biology of these ostracods. We also identify those species most in need of consideration in conservation planning, highlight critical gaps in knowledge and show how these ostracods could serve as useful models for testing ecological and evolutionary theories. The results of this study can be used to inform conservation planning for giant ostracods and direct further study of these unique invertebrates, which are an important component of the biodiversity of small standing-water ecosystems.

This study aimed to determine salinity tolerances in Coxiella gastropods from Australian salt lakes and whether different species exhibit characteristically different tolerances. Controlled gradual accumulation experiments were conducted to estimate both the maximum and minimum salinity levels at which 50% of individuals (IC50) remained active for 25 populations representing six species. All studied species showed remarkable euryhalinity and were tolerant of very high levels of salinity, some more than others, while minimum salinity tolerance varied little among populations and species. The experimental trends in salinity tolerances were consistent with the salinity distributions of species in the field, although the former were typically broader than latter. The findings suggest that Coxiella comprises some of the most salt tolerant gastropods globally.

Sharks and rays evolved 450 million years ago, during the Late Ordovician Period. However, during the modern Anthropocene, shark populations have declined at considerable rates, and recent global assessments indicate about one in three species is threatened with extinction. A notable reason for this elevated extinction risk is overfishing linked to increased demand for shark fins and other products. Here, we review multiple dimensions of consuming shark products, ranging from stock sustainability, product (mis)labelling and trade, the human health implications of consuming shark products, and illegal, unreported and unregulated fishing and slavery and labour abuses in the fishing industry. We conclude that traceability and increased transparency in seafood supply chains is essential to overcome obstacles to consumption of sustainable, ethical and healthy shark products. We also provide a decision tree outlining steps in consumer choice that would foster such consumption. Our aim is to provide a holistic view on issues concerning the consumption of shark products that will help policymakers, the public, management and law enforcement agencies to advocate for ecologically- and ethically sustainable consumption of shark products and thereby empower the general public to make informed decisions on which shark products they consume.