Nine new species of Bennelongia De Deckker & McKenzie, 1981 (Crustacea, Ostracoda) from Western Australia, with the description of a new subfamily

The genus Bennelongia De Deckker & McKenzie, 1981 is most likely endemic to Australia and New Zealand and, up to now, only two described species in this genus had been reported from Western Australia. Extensive sampling in Western Australia revealed a much higher specifi c diversity. Here, we describe nine new species in three lineages, within the genus Bennelongia: B. cygnus sp. nov. and B. frumenta sp. nov. in the B. cygnus lineage, B. gwelupensis sp. nov., B. coondinerensis sp. nov., B. cuensis sp. nov., B. lata sp. nov. and B. bidgelangensis sp. nov. in the B. australis lineage, and B. strellyensis sp. nov. and B. kimberleyensis sp. nov. (from the Pilbara and Kimberley regions respectively) in the B. pinpi-lineage. For six of the nine species, we were also able to construct molecular phylogenies and to test for cryptic diversity with two different methods based on the evolutionary genetic species concept, namely Birky’s 4 x rule and the GYMC model. These analyses support the specifi c nature of at least four of the fi ve new species in the B. australis lineage and of the two new species in the B. pinpi lineage. We also describe Bennelongiinae n.subfam. to accommodate the genus. With the nine new species described here, the genus Bennelongia now comprises 15 species, but several more await formal description

On the Bennelongia barangaroo lineage (Crustacea, Ostracoda) in Western Australia, with the description of seven new species

The ostracod genus Bennelongia De Deckker & McKenzie, 1981 is endemic to Australia and New Zealand. Extensive sampling in Western Australia (WA) revealed a high specific and largely undescribed diversity. Here, we describe seven new species belonging to the B. barangaroo lineage: B. timmsi sp. nov., B. gnamma sp. nov., B. hirsuta sp. nov., B. ivanae sp. nov., B. mcraeae sp. nov., B. scanloni sp. nov. and B. calei sp. nov., and confirm the presence of an additional species, B. dedeckkeri, in WA. For five of these eight species, we could construct molecular phylogenies and parsimonious networks based on COI sequences. We also tested for cryptic diversity and specific status of clusters with a statistical method based on the evolutionary genetic species concept, namely Birky’s 4 theta rule. The analyses support the existence of these five species and a further three cryptic species in the WA B. barangaroo lineage. The molecular evidence was particularly relevant because most species described herein have very similar morphologies and can be distinguished from each other only by the shape, size and position of the antero-ventral lapel on the right valve, and, in sexual populations, by the small differences in shape of the hemipenes and the prehensile palps in males. Four species of the WA B. barangaroo lineage occur in small temporary rock pools (gnammas) on rocky outcrops. The other four species are mainly found in soft bottomed seasonal water bodies. One of the latter species, B. scanloni sp. nov., occurs in both claypans and deeper rock pools (pit gnammas). All species, except for B. dedeckkeri, originally described from Queensland, have quite clearly delimited distributions in WA. With the seven new species described here, the genus Bennelongia now comprises 25 nominal species but several more await formal description

A review of Bennelongia De Deckker & McKenzie, 1981 (Crustacea, Ostracoda) species from eastern Australia with the description of three new species

Australia is predicted to have a high number of currently undescribed ostracod taxa. The genus Bennelongia De Deckker & McKenzie, 1981 (Crustacea, Ostracoda) occurs in Australia and New Zealand, and has recently shown potential for high speciosity, after the description of nine new species from Western Australia. Here, we focus on Bennelongia from eastern Australia, with the objectives of exploring likely habitats for undiscovered species, genetically characterising published morphological species and scanning classical species for cryptic diversity. Two traditional (morphological) species are confi rmed to be valid using molecular evidence (B. harpago De Deckker & McKenzie, 1981 and B. pinpi De Deckker, 1981), while three new species are described using both morphological and molecular evidence. Two of the new species belong to the B. barangaroo lineage (B. dedeckkeri sp. nov. and B. mckenziei sp. nov.), while the third is a member of the B. nimala lineage (B. regina sp. nov.). Another species was found to be genetically distinct, but is not formally described here owing to a lack of distinguishing morphological features from the existing species B. cuensis Martens et al., 2012. Trends in diversity and radiation of the genus are discussed, as well as implications these results have for the conservation of temporary pool microfauna and our understanding of Bennelongia’s evolutionary origin

Hurdles in investigating UVB damage in the putative ancient asexual Darwinula stevensoni (Ostracoda, Crustacea)

Ostracoda or mussel-shrimps are small, bivalved Crustacea. Because of their excellent fossil record and their broad variety of reproductive modes, ostracods are of great interest as a model group in ecological and evolutionary research. Here, we investigated damage and repair of one of the most important biological mutagens, namely UVB radiation in the putative ancient asexual ostracod Darwinula stevensoni from Belgium. We applied three different methods: the Polymerase Inhibition (PI) assay, Enzyme-Linked Immuno Sorbent Assay (ELISA) and dot blot. All three techniques were unsuccessful in quantifying UVB damage in D. stevensoni. Previous experiments have revealed that the valves of D. stevensoni provide an average UVB protection of approximate 60%. Thus, UVB damage could be too little to make quantitative experiments work. Additional variation between individual ostracods due to season and age most likely contributed further to the failure of the three used experimental approaches. In a second experiment, we investigated the influence of temperature on survival of D. stevensoni during UVB exposure. The estimated lethal UVB dose at 4°C was with 50 kJ/m2 significantly lower than at room temperature with 130 kJ/m2. This could either indicate adaptation to low temperatures and/or the presence of metabolic processes against UVB damage in D. stevensoni. These results could also explain why the estimated lethal UVB dose of D. stevensoni is similar to that of other non-marine ostracods where valves provide around 80% protection, although the valves of D. stevensoni provide less protection. If such metabolic processes can repair UVB damage fast, they might be an alternative explanation why we could not quantify UVB damage in D. stevensoni

On the Bennelongia nimala and B. triangulata lineages (Crustacea, Ostracoda) in Western Australia, with the description of six new species

The ostracod genus Bennelongia De Deckker & McKenzie, 1981 occurs in Australia and New Zealand. We redescribe B. nimala from the Northern Territory and describe six new species from Western Australia belonging to the B. nimala (five species) and B. triangulata sp. nov. (one species) lineages: B. tirigie sp. nov., B. koendersae sp. nov., B. pinderi sp. nov., B. muggon sp. nov., B. shieli sp. nov. and B. triangulata sp. nov. For six of these seven species, we could construct molecular phylogenies and parsimonious networks based on COI sequences. We tested for specific status and for potential cryptic diversity of clades with Birky's 4 theta rule. The analyses support the existence of these six species and the absence of cryptic species in these lineages. Bennelongia triangulata sp. nov. is a common species in the turbid claypans of the Murchison/ Gascoyne region. Bennelongia nimala itself is thus far known only from the Northern Territory. Bennelongia tirigie sp. nov., B. pinderi sp. nov. and B. muggon sp. nov. occur in the Murchison/ Gascoyne region, whereas B. koendersae sp. nov. and B. shieli sp. nov. are described from the Pilbara. With the six new species described here, the genus Bennelongia now comprises 31 nominal species

Ostracod valves as efficient UV protection

One of the major consequences of climate change is the increase of ultraviolet radiation, especially UVB (280-315 nm). This has important consequences for organisms and ecosystems. In surface freshwater ecosystems with transparent water, UV can easily penetrate deeply. Here, we used three different experimental approaches to examine the response of non-marine ostracods and cladocerans to UVB radiation: estimating lethal doses, determining how much UVB is blocked by the valves, and analysing valve chemical compositions. For most investigated crustaceans, we found a strong correlation between the amount of UVB that is blocked by the valves and the lethal UVB doses. Most ostracod valves blocked between 60% and 80% of UVB radiation, thus providing effective shielding. Pigmented species from temporary habitats were best protected. These species also showed high lethal UVB doses of 110 kJ m 2 to 214 kJ m 2. In the waterflea Daphnia magna, valves only stopped ca 35% of UVB radiation, and the lethal dose was half that of the doses estimated for ostracods. Since there were no significant differences in chemical composition of the valves between the investigated species, other factors must be responsible for the observed differences, which remain to be identified

Sedimentary evidence of the Late Holocene tsunami in the Shetland Islands (UK) at Loch Flugarth, northern Mainland

Tsunami deposits around the North Sea basin are needed to assess the long-term hazard of tsunamis. Here, we present sedimentary evidence of the youngest tsunami on the Shetland Islands from Loch Flugarth, a coastal lake on northern Mainland. Three gravity cores show organic-rich background sedimentation with many sub-centimetre-scale sand layers, reflecting recurring storm overwash and a sediment source limited to the active beach and uppermost subtidal zone. A basal 13-cm-thick sand layer, dated to 426–787 cal. a CE based on 14C, 137Cs and Bayesian age–depth modelling, was found in all cores. High-resolution grain-size analysis identified four normally graded or massive sublayers with inversely graded traction carpets at the base of two sublayers. A thin organic-rich ‘mud’ drape and a ‘mud’ cap cover the two uppermost sublayers, which also contain small rip-up clasts. Grain-size distributions show a difference between the basal sand layer and the coarser and better sorted storm layers above. Multivariate statistical analysis of X-ray fluorescence core scanning data also distinguishes both sand units: Zr, Fe and Ti dominate the thick basal sand, while the thin storm layers are high in K and Si. Enriched Zr and Ti in the basal sand layer, in combination with increased magnetic susceptibility, may be related to higher heavy mineral content reflecting an additional marine sediment source below the storm-wave base that is activated by a tsunami. Based on reinterpretation of chronological data from two different published sites and the chronostratigraphy of the present study, the tsunami seems to date to c. 1400 cal. a BP. Although the source of the tsunami remains unclear, the lack of evidence for this event outside of the Shetland Islands suggests that it had a local source and was smaller than the older Storegga tsunami (8.15 cal. ka BP), which affected most of the North Sea basin.</p

A 1500‐year record of North Atlantic storm flooding from lacustrine sediments, Shetland Islands (UK)

Severe storm flooding poses a major hazard to the coasts of north‐western Europe. However, the long‐term recurrence patterns of extreme coastal flooding and their governing factors are poorly understood. Therefore, high‐resolution sedimentary records of past North Atlantic storm flooding are required. This multi‐proxy study reconstructs storm‐induced overwash processes from coastal lake sediments on the Shetland Islands using grain‐size and geochemical data, and the re‐analysis of historical data. The chronostratigraphy is based on Bayesian age–depth modelling using accelerator mass spectrometry 14 C and 137 Cs data. A high XRF‐based Si/Ti ratio and the unimodal grain‐size distribution link the sand layers to the beach and thus storm‐induced overwash events. Periods with more frequent storm flooding occurred 980–1050, 1150–1300, 1450–1550, 1820–1900 and 1950–2000 ce, which is largely consistent with a positive North Atlantic Oscillation mode. The Little Ice Age (1400–1850 ce ) shows a gap of major sand layers suggesting a southward shift of storm tracks and a seasonal variance with more storm floods in spring and autumn. Warmer phases shifted winter storm tracks towards the north‐east Atlantic, indicating a possible trend for future storm‐track changes and increased storm flooding in the northern North Sea region

Biogeography and community structure of abyssal scavenging Amphipoda (Crustacea) in the Pacific Ocean

In 2015, we have collected more than 60,000 scavenging amphipod specimens during two expeditions to the Clarion-Clipperton fracture Zone (CCZ), in the Northeast (NE) Pacific and to the DISturbance and re-COLonisation (DisCOL) Experimental Area (DEA), a simulated mining impact disturbance proxy in the Peru basin, Southeast (SE) Pacific. Here, we compare biodiversity patterns of the larger specimens (>15mm) within and between these two oceanic basins. Nine scavenging amphipod species are shared between these two areas, thus indicating connectivity. We further provide evidence that disturbance proxies seem to negatively affect scavenging amphipod biodiversity, as illustrated by a reduced alpha biodiversity in the DEA (Simpson Index (D)=0.62), when compared to the CCZ (D=0.73) and particularly of the disturbance site in the DEA and the site geographically closest to it. Community compositions of the two basins differs, as evidenced by a Non-Metric Dimensional Scaling (NMDS) analysis of beta biodiversity. The NMDS also shows a further separation of the disturbance site (D1) from its neighbouring, undisturbed reference areas (D2, D3, D4 and D5) in the DEA. A single species, Abyssorchomene gerulicorbis, dominates the DEA with 60% of all individuals