Quantitative macroinvertebrate bioassessment in seasonally astatic aquatic habitats, Part I. Quantitative method.

Seasonally astatic aquatic habitats are important ecologically, municipally, and agriculturally. Regulatory agencies and conservation organizations have developed various plans for protecting or constructing temporary wetlands, resulting in habitat monitoring requirements, particularly as relates to restoration and constructed habitats. Unfortunately, there has been no effort to develop a unified, consistent method for wetland biological monitoring. This is particularly true for habitats important in a regulatory sense. We conducted macroinvertebrate bioassessment in constructed vernal pools in California, USA, to assess habitat functionality. This tool is modified from aquatic bioassessment; a primary tool of regulatory agencies in measuring habitat health and water quality and should be equally applicable to seasonally astatic wetlands globally.

Quantitative macroinvertebrate bioassessment in seasonally astatic aquatic habitats, Part II. Applying the method.

Seasonally astatic aquatic habitats are important ecologically, municipally, and agriculturally. Regulatory agencies and conservation organizations have developed various plans for protecting or constructing temporary wetlands, resulting in habitat monitoring requirements, particularly as relates to restoration and constructed habitats. Unfortunately, there has been no effort to develop a unified, consistent method for wetland biological monitoring. In Part I, we presented a quantifiable, replicable method for assessing seasonally astatic wetlands, which would allow for direct comparison between individual wetlands, wetland sites, and wetland types. Here in Part II, we apply the method and present the results from more than a decade of a data on two disparate sites that support California vernal pool habitats. These habitats include natural, restored, and constructed vernal pools. Our results demonstrate that the method we present yields reliable, statistically useful, and actionable data and provides a better method for assessing astatic wetland ecological health and the persistence of federally listed vernal pool crustaceans than other methods so far employed.

The complex study of complexes: The first well-supported phylogeny of two species complexes within genus Caridina (Decapoda: Caridea: Atyidae) sheds light on evolution, biogeography, and habitat.

Atyid shrimps, a key component of tropical freshwater ecosystems, face multiple anthropogenic threats and thus need special attention. With more than 300 described species, the genus Caridina is the most speciose of all the Caridea infra-order. Caridina spp. occupy diverse habitats in tropical freshwaters of the Indo-West Pacific region. Several species complexes have been recognized, based on common morphological features, but little is known about how well these morphological characteristics align with phylogenetic characteristics. Furthermore, no phylogeny of the genus Caridina published so far has provided well-resolved and supported relationships among different species, thus impeding the possibility of proposing evolutionary hypotheses. In this study we used next generation sequencing (NGS) to provide new insights into the phylogenetic relationships among the genus Caridina, focusing on two complexes: 'Caridina nilotica' and 'Caridina weberi'. We collected 92 specimens belonging to these two groups from most of their known geographical range, representing 50 species, for which we sequenced seven mitochondrial genes and two nuclear markers using ion torrent NGS. We performed a phylogenetic analysis, which yielded the first well-supported tree for the genus Caridina. On this tree were mapped the geographic ranges and the habitats used by the different species, and a time calibration was tested. We found the driving factors that most likely account for separation of clades are differences in habitat and to a lesser extent geography. This work provides new insights into the taxonomy of this group and identifies opportunities for further studies in order to fill knowledge gaps that currently impede the management and conservation of atyid species.

Tetraconatan phylogeny with special focus on Malacostraca and Branchiopoda: highlighting the strength of taxon-specific matrices in phylogenomics.

Understanding the evolution of Tetraconata or Pancrustacea-the clade that includes crustaceans and insects-requires a well-resolved hypothesis regarding the relationships within and among its constituent taxa. Here, we assembled a taxon-rich phylogenomic dataset focusing on crustacean lineages based solely on genomes and new-generation Illumina-generated transcriptomes, including 89 representatives of Tetraconata. This constitutes, to our knowledge, the first phylogenomic study specifically addressing internal relationships of Malacostraca (with 26 species included) and Branchiopoda (36 species). Seven matrices comprising 81-684 orthogroups and 17 690-242 530 amino acid positions were assembled and analysed under five different analytical approaches. To maximize gene occupancy and to improve resolution, taxon-specific matrices were designed for Malacostraca and Branchiopoda. Key tetraconatan taxa (i.e. Oligostraca, Multicrustacea, Branchiopoda, Malacostraca, Thecostraca, Copepoda and Hexapoda) were monophyletic and well supported. Within Branchiopoda, Phyllopoda, Diplostraca, Cladoceromorpha and Cladocera were monophyletic. Within Malacostraca, the clades Eumalacostraca, Decapoda and Reptantia were well supported. Recovery of Caridoida or Peracarida was highly dependent on the analysis for the complete matrix, but it was consistently monophyletic in the malacostracan-specific matrices. From such examples, we demonstrate that taxon-specific matrices and particular evolutionary models and analytical methods, namely CAT-GTR and Dayhoff recoding, outperform other approaches in resolving certain recalcitrant nodes in phylogenomic analyses.

Bet hedging in stochastic habitats: an approach through large branchiopods in a temporary wetland.

Organisms evolve to maintain fitness across generations, while short-term fitness in stochastic habitats such as temporary wetlands may be highly varied. As typical temporary wetland inhabitants, large branchiopods rely on bet hedging hatching that helps them survive throughout generations. An optimal hatching rate is predicted to be approximate to the successful reproduction probability (SRP). We tested the difference between hatching rate and SRP of large branchiopods Branchinella kugenumaensis and Eulimnadia braueriana in a temporary wetland in Taiwan, through field surveys and climatic records to evaluate their SRP. Comparisons were performed under two proposed scenarios, where a population's hatching was bet hedged for a hydroperiod or for a wet season (with several hydroperiods), respectively. Population size fluctuations were simulated for these two scenarios under assumed egg mortalities and reproductive replenishments. Results showed that the hatching rates only fitted to SRP for E. braueriana under the scenario of bet hedging on a wet season, not for B. kugenumaensis, nor for both species under the scenario of bet hedging on a hydroperiod. Bet hedging on a wet season would have a smaller range of population size fluctuation and a lower rate of population size decrease. This implies that large branchiopods adopt a conservative hatching strategy, lowering the hatching fraction in each hydroperiod to reduce long-term egg bank size fluctuation. Bet hedging strategies could occur during other life cycle stages, coexist with other life history strategies, and lead to the diversified hatching fraction distribution rather than a single, optimal fraction throughout hydroperiods.

A new species of Streptocephalus (Crustacea: Anostraca: Streptocephalidae) from the Western Ghats, India, with a key to the Asian species.

We present and describe the fairy shrimp Streptocephalus sahyadriensis sp. nov. from the Western Ghats of India. This species is most similar to S. simplex Gurney, 1906 and S. dichotomus Baird, 1860 sharing similar basic antennal appendage morphology. However, S. sahyadriensis sp. nov. differs in the form of the ornamentation on the peduncle and the arrangement and form of spines on the antennal appendage. The three species also have different egg surface morphologies. The Asian species of Streptocephalus are discussed and a key to species is provided.

Assessment of the USDA Biomass Harvest Trap (USDA-BHT) device as an insect harvest and mosquito surveillance tool.

Insects are a promising source of high-quality protein, and the insect farming industry will lead to higher sustainability when it overcomes scaling up, cost effectiveness, and automation. In contrast to insect farming (raising and breeding insects as livestock), wild insect harvesting (collecting agricultural insect pests), may constitute a simple sustainable animal protein supplementation strategy. For wild harvest to be successful sufficient insect biomass needs to be collected while simultaneously avoiding the collection of nontarget insects. We assessed the performance of the USDA Biomass Harvest Trap (USDA-BHT) device to collect flying insect biomass and as a mosquito surveillance tool. The USDA-BHT device was compared to other suction traps commonly used for mosquito surveillance (Centers for Disease Control and Prevention (CDC) light traps, Encephalitis virus surveillance traps, and Biogents Sentinel traps). The insect biomass harvested in the USDA-BHT was statistically higher than the one harvested in the other traps, however the mosquito collections between traps were not statistically significantly different. The USDA-BHT collected some beneficial insects, although it was observed that their collection was minimized at night. These findings coupled with the fact that sorting time to separate the mosquitoes from the other collected insects was significantly longer for the USDA-BHT, indicate that the use of this device for insect biomass collection conflicts with its use as an efficient mosquito surveillance tool. Nevertheless, the device efficiently collected insect biomass, and thus can be used to generate an alternative protein source for animal feed.

Annotated Checklist of the large branchiopod crustaceans of Idaho, Oregon and Washington, USA, with the "rediscovery" of a new species of Branchinecta (Anostraca: Branchinectidae).

We present a checklist of the large branchiopod crustaceans of Idaho, Oregon and Washington, USA. New distributional records are presented for most species, including the first records of Branchinecta constricta Rogers, 2006 and Lepidurus cryptus Rogers, 2001 from Idaho, the first record of B. oriena Belk & Rogers 2002 from Oregon, the first record of B. mackini Dexter, 1956 and Artemiafranciscana Kellogg, 1906 co-occurring, and the first record of L. cryptus from Washington. Furthermore, we present the first record of Eulimnadia diversa Mattox, 1937 from west of the continental divide, which we interpret as an accidental introduction. In 1959, Lynch collected a new fairy shrimp species from Washington, deposited that material in the US National Museum, labeled "muddy fairy shrimp, Branchinecta lutulenta", but never described it. Numerous efforts have been made to rediscover extant populations since 1999. We rediscovered this species in 2011, from two small pools from the vicinity of Lynch's original collection site, which appears to have been destroyed. Branchinecta lutulenta sp. nov. is most closely related to B. lindahli Packard, 1883 and B. oterosanvicentei Obregón-Barboza et al., 2002. Branchinecta lutulenta sp. nov. is readily separable from all other Branchinecta species by the form of the male second antennal distal antennomere and the ornamentation of the female dorsum.

A new species of Chirocephalus (Crustacea: Anostraca) from Iran.

Chirocephalus soulukliensis, an insular new species of fairy shrimp, is described from the Soulukli Wetland in Golestan National Park in northeastern Iran. The new species shares several characters with the loosely organized "Pristicephalus" group. It is readily separated from all congeners by the short, monolamellar form of the antennal appendage, which is un-armed, the distally expanded form of the apophyses, and the sinuate form of the second antennal distal antennomere.

Parartemiopsisshangrilaensis, a new species of fairy shrimp (Branchiopoda, Anostraca) from Yunnan, with a key to the Chirocephalidae of China.

The fairy shrimp genus Parartemiopsis Rogers, 2005 currently contains a single species reported from Russia and Mongolia. In 2013, an unidentified Parartemiopsis population was reported from the eastern margin of the Tibetan Plateau in China's Yunnan Province, from Patatson National Park in Shangri-La County. Here, we describe the Chinese populations as a new species, Parartemiopsisshangrilaensissp. nov. This new species is distinguished from its congener, P.longicornis (Smirnov, 1930), by the form of the male second antennae and the gonopod. The discovery of P.shangrilaensissp. nov. extends the known distribution of the genus, and more Parartemiopsis species may be found in the future. We present a key to the genera and species of Chirocephalidae in China as an aid to future research.

Investigating Vernal Pool Fairy Shrimp Exposure to Organophosphate Pesticides: Implications for Population-Level Risk Assessment.

Vernal pool fairy shrimp, Branchinecta lynchi, is a freshwater crustacean endemic to California and Oregon, including California's Central Valley. B. lynchi is listed as a Federally Threatened species under the US Endangered Species Act, and as a vulnerable species on the IUCN Red List. Threats that may negatively impact vernal pool fairy shrimp populations include pesticide applications to agricultural land use (e.g., agrochemicals such as organophosphate pesticides) and climate changes that impact vernal pool hydrology. Pop-GUIDE (Population model Guidance, Use, Interpretation, and Development for Ecological risk assessment) is a comprehensive tool that facilitates development and implementation of population models for ecological risk assessment and can be used to document the model derivation process. We employed Pop-GUIDE to document and facilitate the development of a population model for investigating impacts of organophosphate pesticides on vernal pool fairy shrimp populations in California's Central Valley. The resulting model could be applied in combination with field assessment and laboratory-based chemical analysis to link effects from pesticide exposure to adverse outcomes in populations across their range. B. lynchi has a unique intra-annual life cycle that is largely dependent upon environmental conditions. Future deployment of this population model should include complex scenarios consisting of multiple stressors, whereby the model is used to examine scenarios that combine chemical stress resulting from exposure to pesticides and climate changes.

Review of the southern African Leptestheriidae (Branchiopoda: Spinicaudata) I: redescription of Leptestheria brevirostris Barnard, 1924 with comments on diagnostic characters.

We present the first records of Leptestheria brevirostris since its discovery in Namibia by Barnard in 1924. Our records come from Botswana and South Africa, and present significant range extensions. We redescribe L. brevirostris according to modern standards and present the first description of the male. We also discovered that L. brevirostris is likely a rock pool specialist, specific to sandstone and gneiss outcrops; this is the first record of a rock pool specialist clam shrimp from Africa and the second rock pool specialist described for Leptestheriidae. Finally, we depict and discuss the validity and usefulness of diagnostic characters for Leptestheria species in southern Africa, especially the usefulness of carapace interval ornamentation.

Preliminary Study of Temperature Effects on Size and Shape in the Modern Spinicaudatan Eulimnadia texana (Crustacea: Branchiopoda).

Studies of temperature effects on morphology in Spinicaudata have focused on length, with no data on shape. To fill this gap, size and shape variability in response to temperature fluctuations was investigated by rearing the modern spinicaudatan Eulimnadia texana. Two days after hydration, juvenile individuals were separated into four different temperature treatments: 20°C, 23°C, 26°C, and 29°C. Hermaphrodite size and shape were analysed by looking at linear combinations of size variables and using Fourier shape analysis; methods that are also used to describe fossil size and shape for better comparison. Size differences were considerable, with reduced growth at low and high temperatures and accelerated growth at the optimum temperature of 26°C, revealing that the reaction of size to increasing temperature is non-linear. The height of the dorsal margin, which is associated with space for egg production in Eulimnadia texana, accounts for a high amount of size variability in this species and, presumably, in most of the Limnadiidae. Hermaphrodite shapes reared under temperatures of 20°C and 29°C are statistically distinct, while intermediate temperatures yield intermediate shapes. The rate of shape change along temperature is comparatively low between 23°C and 26°C and accelerated at lower and higher temperatures. With increasing temperature, the highest point of the dorsal margin is shifted towards the anterior of the carapace, while it assumes a median position at 20°C. Our result that temperature has strong effects on carapace size and shape implies considerable ecophenotypic variability in Spinicaudata.

The complete mitogenome of Leptestheria brevirostris Barnard, 1924, a rock pool clam shrimp (Branchiopoda: Spinicaudata) from Central District, Botswana.

Spinicaudatan clam shrimp are a widespread and diverse group of branchiopod crustaceans, yet few mitochondrial genomes have been published for this taxonomic group. Here, we present the mitogenome of Leptestheria brevirostris from a rock pool ecosystem in Botswana. Massively parallel sequencing of a single specimen facilitated the reconstruction of the species' 15,579 bp circularized mitogenome. The reconstructed phylogenetic tree confirms that L. brevirostris forms a monophyletic group with other diplostracan branchiopods, and that these are the sister taxon to Notostraca. The mitogenome reconstructed here is the first to be reported from a leptestherid clam shrimp.

Spinicaudata Catalogus (Crustacea: Branchiopoda).

The Spinicaudata (spiny clam shrimp) are a large group of freshwater, bivalved branchiopod crustaceans in need of taxonomic revision. Herein, the extant Spinicaudata families and genera are defined and diagnosed according to modern standards. An annotated catalogue of the Spinicaudata taxa is presented with synonyms. More than 747 spinicaudatan taxa are presented, of which 215 are considered valid families, genera and species. Chresonyms are provided for taxa redescribed according to modern standards. It is hoped that this catalogue will provide a basis for further taxonomic revision and phylogenetic work within the Spinicaudata.

Molecular Evaluation of the Fairy Shrimp Family Branchinectidae (Crustacea: Anostraca) Supports Peripatric Speciation and Complex Divergence Patterns.

The Branchinectidae is a diverse and widely distributed group of anostracans. The majority of work on the group has focused on the morphological delineation of taxa and biogeography. Here we present a molecular phylogeny for select members of the family to better understand the distribution of morphological variation among species, and test biogeographic models of speciation for the group. Although we conducted both molecular and morphological phylogenies for the Branchinectidae, the morphological analysis did not support our molecular phylogeny and it did not support previous species group concepts based on geography. Our molecular phylogenetic analysis suggests that the family may have originated in Eurasia and found support for numerous species groups. These phylogenetic groups assisted in delineating species groups that are all definable morphologically and/or ecologically. The peripatric speciation model was supported from our analysis, offering credence to previously published speciation models in anostracans. This suggests that these processes may be important in other Branchiopoda and should be rigorously evaluated when delineating species.

Fossil and Modern Clam Shrimp (Branchiopoda: Spinicaudata, Laevicaudata): The World's First Clam Shrimp Symposium and a Celebration of Brian V. Timms.

This special volume of Zoological Studies is the result of a symposium entitled "Fossil and Modern Clam Shrimp" held at the midyear meeting of The Crustacean Society in May of 2019. This symposium is the first ever focusing on clam shrimp, and the first conference where both palaeontologists and biologists specialising in these animals were able to come together. The papers presented here provide insight into the palaeontology, biology, ecology, taxonomy and phylogeny of the clam shrimp. This chapter introduces the symposium, its aims, and the resulting research, presented in the subsequent chapters. In addition, in this symposium we celebrate our great friend Brian V. Timms, who has mentored so many of us, brought us on various excursions across Australia, and has done more to advance Australian branchiopod studies than anyone else in history.

Diagnosing Eulimnadia and Paralimnadia (Branchiopoda: Spinicaudata: Limnadiidae).

Eulimnadia and Paralimnadia are both strongly supported, monophyletic limnadiid lineages based on molecular studies. However, defining the two taxa morphologically relies on the presence/absence of a subcercopodal spiniform projection; otherwise there is considerable overlap and confusion in morphological characters between the two taxa. The most discriminatory of these characters are examined here and applied to Australasian species. As a result, five Eulimnadia species are transferred to Paralimnadia. These characters are then applied to world Eulimnadia species and other limnadiid genera which share key features with Eulimnadia.

A New Eulimnadia (Branchiopoda: Spinicaudata: Limnadiidae) from the US Virgin Islands.

We describe a new species of Eulimnadia from the Caribbean using fresh material from the island of St Thomas. Originally reported in 2003 as a Eulimnadia cf. texana (Packard, 1871) based on egg morphology, this species egg distinctly differs from E. texana by the number of lateral grooves and by the single domed end.

The World's First Clam Shrimp Symposium: Drawing Paleontology and Biology Together.

After a symposium and special issue devoted to the study of clam shrimp, it is tempting to ask what is next... where is the study of clam shrimp going? Rather than try to read the tea leaves to predict the future, we will instead offer some closing thoughts on where the study of clam shrimp should go and what areas are ripe for investigation. Many of these ideas integrate both fossil and modern clam shrimp to get at a more complete view of their evolution and ecology.