Removal of extracellular coat from giant sperm in female receptacle induces sperm motility in Mytilocypris mytiloides (Cyprididae, Ostracoda, Crustacea).

Previous studies of cypridoidean ostracods have noted that (1) their giant spermatozoa are immotile inside the male, (2) these spermatozoa are motile in the female seminal receptacle and (3) these receptacles are often filled with empty sperm coats. Such findings have led previous authors to hypothesize that sperm must shed their coats in the female receptacle to become motile. We present light and electron microscopy results and video recordings of mating experiments with virgin specimens of Mytilocypris mytiloides. We show that the empty sperm coats frequently found in the female receptacles are not the result of sperm molting but are the resistant inner coats of exhausted sperm not used for egg fertilization. In contrast, we show that an outer granular coating material is successively removed from the sperm while resident inside the female receptacles before first oviposition occurs. During this period, previously immotile sperm gain motility, showing strong movement shortly before first oviposition takes place. By correlation of these phenomena, we suggest that dissolution of the outer coat material is required for motility to develop.

Sperm length variations in five species of cypridoidean non-marine ostracods (Crustacea).

Spermatozoa of the ostracod superfamily Cypridoidea include some of the longest in the animal kingdom, but unlike other so-called giant spermatozoa, they are aflagellate, probably evolved only once, and represent an exceptionally old trait. Sperm length variations within cypridoidean species remain poorly known, a lack that hinders the development of hypotheses to explain their length and variation. For this study, the lengths of 500 spermatozoa from each of five species of freshwater cypridoidean ostracods, Candonopsis tenuis (Brady, 1886), Fabaeformiscandona subacuta (Yang, 1982), Heterocypris rotundata (Bronshtein, 1928), Ilyocypris japonica Okubo, 1990, and Notodromas trulla Smith and Kamiya, 2014, were measured, including the lengths of the posterior and anterior regions. No overall pattern in sperm variation was discernible. Length variations between species, between males of the same species, and within individual males varied from low (Candonopsis tenuis) to extraordinarily large (Notodromas trulla and Fabaeformiscandona subacuta). Sperm competition, cryptic female choice, sperm heteromorphism, and testis size are unlikely to explain all of the variations observed. Age structures of the populations sampled might play a role in explaining some intraspecific variation. The differing amounts of variation in sperm characters revealed in this study suggest that multiple evolutionary trends and pressures shape sperm lengths in this superfamily.

Subcellular preservation in giant ostracod sperm from an early Miocene cave deposit in Australia.

Cypridoidean ostracods are one of a number of animal taxa that reproduce with giant sperm, up to 10 000 µm in length, but they are the only group to have aflagellate, filamentous giant sperm. The evolution and function of this highly unusual feature of reproduction with giant sperm are currently unknown. The hypothesis of long-term evolutionary persistence of this kind of reproduction has never been tested. We here report giant sperm discovered by propagation phase contrast X-ray synchrotron micro- and nanotomography, preserved in five Miocene ostracod specimens from Queensland, Australia. The specimens belong to the species Heterocypris collaris Matzke-Karasz et al. 2013 (one male and three females) and Newnhamia mckenziana Matzke-Karasz et al. 2013 (one female). The sperm are not only the oldest petrified gametes on record, but include three-dimensional subcellular preservation. We provide direct evidence that giant sperm have been a feature of this taxon for at least 16 Myr and provide an additional criterion (i.e. longevity) to test hypotheses relating to origin and function of giant sperm in the animal kingdom. We further argue that the highly resistant, most probably chitinous coats of giant ostracod sperm may play a role in delaying decay processes, favouring early mineralization of soft tissue.

Exploring the effect of case management in homelessness per components: A systematic review of effectiveness and implementation, with meta-analysis and thematic synthesis.

Background: Adequate housing is a basic human right. The many millions of people experiencing homelessness (PEH) have a lower life expectancy and more physical and mental health problems. Practical and effective interventions to provide appropriate housing are a public health priority. Objectives: To summarise the best available evidence relating to the components of case-management interventions for PEH via a mixed methods review that explored both the effectiveness of interventions and factors that may influence its impact. Search Methods: We searched 10 bibliographic databases from 1990 to March 2021. We also included studies from Campbell Collaboration Evidence and Gap Maps and searched 28 web sites. Reference lists of included papers and systematic reviews were examined and experts contacted for additional studies. Selection Criteria: We included all randomised and non-randomised study designs exploring case management interventions where a comparison group was used. The primary outcome of interest was homelessness. Secondary outcomes included health, wellbeing, employment and costs. We also included all studies where data were collected on views and experiences that may impact on implementation. Data Collection and Analysis: We assessed risk of bias using tools developed by the Campbell Collaboration. We conducted meta-analyses of the intervention studies where possible and carried out a framework synthesis of a set of implementation studies identified by purposive sampling to represent the most 'rich' and 'thick' data. Main Results: We included 64 intervention studies and 41 implementation studies. The evidence base was dominated by studies from the USA and Canada. Participants were largely (though not exclusively) people who were literally homeless, that is, living on the streets or in shelters, and who had additional support needs. Many studies were assessed as having a medium or high risk of bias. However, there was some consistency in outcomes across studies that improved confidence in the main findings. Case Management and Housing Outcomes: Case management of any description was superior to usual care for homelessness outcomes (standardised mean difference [SMD] = -0.51 [95% confidence interval [CI]: -0.71, -0.30]; p < 0.01). For studies included in the meta-analyses, Housing First had the largest observed impact, followed by Assertive Community Treatment, Critical Time Intervention and Intensive Case Management. The only statistically significant difference was between Housing First and Intensive Case Management (SMD = -0.6 [-1.1, -0.1]; p = 0.03) at ≥12 months. There was not enough evidence to compare the above approaches with standard case management within the meta-analyses. A narrative comparison across all studies was inconclusive, though suggestive of a trend in favour of more intensive approaches. Case Management and Mental Health Outcomes: The overall evidence suggested that case management of any description was not more or less effective compared to usual care for an individual's mental health (SMD = 0.02 [-0.15, 0.18]; p = 0.817). Case Management and Other Outcomes: Based on meta-analyses, case management was superior to usual care for capability and wellbeing outcomes up to 1 year (an improvement of around one-third of an SMD; p < 0.01) but was not statistically significantly different for substance use outcomes, physical health, and employment. Case Management Components: For homelessness outcomes, there was a non-significant trend for benefits to be greater in the medium term (≤3 years) compared to long term (>3 years) (SMD = -0.64 [-1.04, -0.24] vs. -0.27 [-0.53, 0]; p = 0.16) and for in-person meetings in comparison to mixed (in-person and remote) approaches (SMD = -0.73 [-1.25,-0.21]) versus -0.26 [-0.5,-0.02]; p = 0.13). There was no evidence from meta-analyses to suggest that an individual case manager led to better outcomes then a team, and interventions with no dedicated case manager may have better outcomes than those with a named case manager (SMD = -0.36 [-0.55, -0.18] vs. -1.00 [-2.00, 0.00]; p = 0.02). There was not enough evidence from meta-analysis to assess whether the case manager should have a professional qualification, or if frequency of contact, case manager availability or conditionality (barriers due to conditions attached to service provision) influenced outcomes. However, the main theme from implementation studies concerned barriers where conditions were attached to services. Characteristics of Persons Experiencing Homelessness: No conclusions could be drawn from meta-analysis other than a trend for greater reductions in homelessness for persons with high complexity of need (two or more support needs in addition to homelessness) as compared to those with medium complexity of need (one additional support need); effect sizes were SMD = -0.61 [-0.91, -0.31] versus -0.36 [-0.68, -0.05]; p = 0.3. The Broader Context of Delivery of Case Management Programmes: Other major themes from the implementation studies included the importance of interagency partnership; provision for non-housing support and training needs of PEH (such as independent living skills), intensive community support following the move to new housing; emotional support and training needs of case managers; and an emphasis on housing safety, security and choice. Cost Effectiveness: The 12 studies with cost data provided contrasting results and no clear conclusions. Some case management costs may be largely off-set by reductions in the use of other services. Cost estimates from three North American studies were $45-52 for each additional day housed. Authors' Conclusions: Case management interventions improve housing outcomes for PEH with one or more additional support needs, with more intense interventions leading to greater benefits. Those with greater support needs may gain greater benefit. There is also evidence for improvements to capabilities and wellbeing. Current approaches do not appear to lead to mental health benefits. In terms of case management components, there is evidence in support of a team approach and in-person meetings and, from the implementation evidence, that conditions associated with service provision should be minimised. The approach within Housing First could explain the finding that overall benefits may be greater than for other types of case management. Four of its principles were identified as key themes within the implementation studies: No conditionality, offer choice, provide an individualised approach and support community building. Recommendations for further research include an expansion of the research base outside North America and further exploration of case management components and intervention cost-effectiveness.

Ilyocyprisleptolinea Wang & Zhai, sp. nov., an ostracod (Ostracoda, Crustacea) from the late Quaternary of Inner Mongolia, northern China.

Ilyocyprisleptolinea Wang & Zhai, sp. nov. is described from late Quaternary sediments in central-eastern Inner Mongolia, northern China. The new species, which has a carapace shape and pitted surface typical of the genus, is characterised by double rows of fine, densely arranged marginal ripplets, separated by an inner list, along both anterior and posterior calcified inner lamellae in the left valve. Outline analysis and Principal Component Analysis indicate that its morpho-space overlaps with I.bradyi Sars, 1890, I.japonica Okubo, 1990, and I.mongolica Martens, 1991, which have living or fossil representatives in Inner Mongolia, but it is clearly discriminated from I.innermongolica Zhai & Xiao, 2013. Judging from the relatively coarse lithology dominated by silt and sand, and the lack of accompanying brackish-water ostracods, I.leptolinea Wang & Zhai, sp. nov. may have lived in a relatively shallow freshwater lake. It perhaps can be added to the list of species that went extinct during the Quaternary, but the timing and process of extinction await further investigation.

PROTOCOL: Exploring the effect of case management in homelessness per components: A systematic review of effectiveness and implementation, with meta-analysis and thematic synthesis.

This is the protocol for a Campbell review. The objectives are as follows: To carry out a mixed methods review to summarise current evidence relating to the components of case-management interventions for people experiencing homelessness.

On some modern Ostracoda (Crustacea) from the Tibetan Plateau in SW China, with descriptions of three new species.

Studies of Holocene ostracods of the Tibetan Plateau have mostly centred around valves and carapaces collected from lake sediments, some at or near the substrate surface and others from short cores. Reports from habitats other than lakes are scarce, and few living species found in this region have appendages described, hindering further taxonomic and phylogenetic work. For this study collections of living ostracods were made in mostly ponds, as well as two rivers and one lake. Six species, including three previously undescribed, were recovered: Tonnacypris estonica (Järvekülg, 1960), Arctocypris edita n. sp., Cypris pubera O.F. Müller, 1776, Potamocypris variegata (Brady Norman, 1889), Ilyocypris tibeta n. sp., and Fabaeformiscandona monticulus n. sp. Specimens of Tonnacypris estonica include males, previously unknown for this species, and suggesting it is a geographical parthenogen. A revision of the fifth limb morphology of the genus Arctocypris, and a subsequent amended diagnosis of the genus are given. Based on carapace and appendage features, Eucypris mareotica (Fischer, 1855) is transferred to this genus: Arctocypris mareotica (Fischer, 1855) com. nov. There are now ca. 100 ostracod species reported from modern or subsurface sediments on the Tibetan Plateau, but only 19 of those can be confirmed as alive when collected (i.e. had appendages intact). The families Limnocytheridae and Ilyocyprididae are both relatively diverse on the plateau compared with the Palaearctic zoogeographical region generally. About one third of ostracod species reported from the Tibetan Plateau are only known from there, suggesting a potentially very high rate of endemism.

Three-dimensionally preserved decapod larval compound eyes from the Cretaceous Santana Formation of Brazil.

Compound eyes are common in decapod crustaceans. Decapods have an abundant post-Palaeozoic fossil record, but hitherto morphological information about their eyes has been mainly restricted to Recent material. Here we report the discovery of compound eyes recovered from acetic acid residues of two fish-bearing nodules from the Cretaceous Santana Formation of Brazil; they include what are identified as decapod larval compound eyes. The fossil eyes are comparable to phyllosoma larval eyes because of the following characters: the hemispherical visual surface on a stalked eye; the relatively small-size of the visual surface of the eye; rounded facets are arranged in square arrays in the anterior region; the fact that the neighboring ommatidia are bounded by ridges and/ or grooves; and the more convex inner surface of the cornea lens. This report represents the first description of a three-dimensionally preserved fossil decapod eye. We conclude that the eyes probably represent palinuroid phyllosoma larval eyes and were an adaptation to a planktonic lifestyle.

Living males of the 'ancient asexual' Darwinulidae (Ostracoda: Crustacea).

Three living male darwinulid ostracods of a new species of the genus Vestalenula have been found in Yakushima, Japan. This is the first report of living darwinulid males for over 100 years and their morphology casts doubt on the two previous records from the late 1800' s. The presence of male darwinulids also calls into question the hypothesis that the family Darwinulidae is an exclusively ancient asexual group, reproducing without sex for over 200 million years (Myr). Male carapaces are of similar size and shape to A-1 juvenile females of the same species, suggesting that males may have been dismissed as A-1 juveniles in other living and fossil species. The antennae and fifth limbs are sexually dimorphic: the male antennae have six segments compared with five in the female and a series of putative chemical receptors originating at the extra segment boundary, while the male fifth limbs have well-developed grasping hooks, as in males of many ostracod groups. The lack of Zenker's Organ and of complex internal structures within the hemipenis contradicts previous hypotheses of the phylogenetic position of darwinulids.

The freshwater ostracod (Crustacea) genus Notodromas Lilljeborg, 1853 (Notodromadidae) from Japan; taxonomy, ecology and lifestyle.

Although Notodromas monacha (O. F. Müller, 1776) was first reported from Japan over 85 years ago, detailed comparisons between Japanese and European specimens reveal that the Japanese specimens have been misidentified. The Japanese specimens are described as a new species, Notodromas trulla n. sp., herein. This species differs from Notodromas monacha by the morphology of the male fifth limbs and sexual organs, and the morphology of the female carapace. Like other Notodromas species, it is at least partially neustonic, spending considerable amounts of time hanging upside down from the water surface, facilitated by an oval concavity on its ventral surface. It is found in rice fields and small, shallow ponds with few or no floating plants and a muddy substrate, and in suitable habitats can be very abundant. However, evidence suggests that this conspicuous species has experienced a significant and widespread population decline in Japan; reported as abundant in rice fields, swamps and ponds in the 1940s-70s, this species has been collected from only a small number of localities in recent years.