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The size and sex structure, the dependence of the state of the gonads of females on the size of the individual, and the composition of the food of the shrimp Sabinea septemcarinata (Sabine 1824) (Crustacea, Crangonidae) from the Laptev Sea, from Khatanga Bay in the Laptev Sea, and from the Kara Sea are described (598 individuals: 230 of them had empty stomachs, 368 contained food in their stomachs, and 34 were full). The shrimp were collected in August–September 2016. The total body length of the shrimp examined varied from 31 to 103 mm: 32–103 mm in females and 31–74 mm in males. The lifespan seems to last 3–4 years in females and 2–3 years in males. Based on the condition of the gonads of the females, the time of material collection coincided with spawning. Among the females there are individuals at all stages of the reproductive cycle: feeding, spawning, and preparing for the next spawning. This indicates extended population spawning. Sabinea septemcarinata belongs to the life form of burrowing shrimp. According to the frequency of occurrence in the stomachs, detritus occupies first place (92.2%). The second and third places are taken up by cumaceans and sedentary polychaetes, which occur in almost every second and third stomach (frequency of occurrence 37.7 and 23.9%, respectively). Sand shows a frequency of occurrence of 50.3%. In the virtual food lump, a little more than a third of its volume is taken up by detritus (39.7%), followed by cumaceans and polychaetes that take second and third places (23.6 and 22.6%, respectively). Consequently, S. septemcarinata feed on infauna. Thus, S. septemcarinata are characterized by elements of an attacking predator and a detritophage. [ABSTRACT FROM AUTHOR]

Grimothea monodon, an important fishery resource in the Humboldt Current marine ecosystem (HCE), present two contrasting morphotypes (PM, pelagic morphotype; BM, benthic morphotype). The fishery management of G. monodon is focused on understanding only fishery aspects that apply to a limited area, and there are currently no studies that evaluate the nutritional status of these morphotypes. This study evaluated the biological performance of PM and BM, analyzing the body (size, CL; weight, W; condition factor, Kn) and biochemical condition (glucose, G; proteins, P; lipids, L; fatty acids, FAs). The results reveal that G. monodon showed differences in CL and W between morphotypes, with higher values in BM than PM. The Kn was different between morphotypes with a tendency of isometric growth. In turn, the G contents were higher in PM than BM, while the contents of P, L, and FAs showed an opposite tendency, with higher contents recorded in BM than PM. Our findings suggest that the Kn should be included to strengthen the biological parameters and their relationships used in fishery management models. Differences in the biochemical condition between morphotypes can be considered potentially adaptive, in response to the combined effect of environmental factors that vary in the HCE. [ABSTRACT FROM AUTHOR]

Crustacean aquaculture, especially monosex culture, requires a comprehensive knowledge of the mechanisms regulating sex determination and differentiation. Decapod crustaceans display either female heterogamety (ZW/ZZ) or male heterogamety (XY/XX) as their mode of genotypic sex determination. However, some decapod species exhibit sexual plasticity via removing the androgenic gland, knockdown insulin receptor transcripts, administrating exogenous sex steroids, and altering environmental factors. Although the master sex‐determining gene in decapods remains elusive, various sexual genes, hormones, and neurotransmitter are emerging as important factors in sex differentiation. This review looks into recent advancements in studies related to the genetic sex determination system and factors that trigger sex reversal. Moreover, the elucidation of the role of genetic factors in sex differentiation in both females and males, as well as their underlying interrelated regulatory mechanisms, provides justification for three levels of application: the induction of monosex populations, detection of precocious sex and genotype, and prevention of uncontrolled reproduction. Finally, we proposed future directions of bioinformatics analysis and genome editing coupled with sex control to increase the yield for economic decapods. In conclusion, this review provides a foundation for future research on the reproductive biology and sexual regulation of decapods, with the aim of aiding practitioners in advancing the crustacean aquaculture industry. [ABSTRACT FROM AUTHOR]

The sand bubbler crab, Scopimera longidactyla Shen, 1932 (Arthropoda: Malacostraca: Decapoda: Thoracotremata: Dotillidae), is commonly found along tropical and subtropical sandy shores of China, Korea, and Taiwan. Ecologically, it plays an important role in the productivity of sandy shores through their feeding and burrowing activities. In this study, the first complete mitochondrial genome (mitogenome) of S. longidactyla was analyzed using next-generation sequencer. Its mitogenome, circular in structure, spans 15,965 bp with a GC content of 29.97%, consisting of 13 protein-coding genes, two ribosomal RNA genes, 22 transfer RNA genes, and one putative control region. Its mitogenome arrangement and composition are identical to its two congeners, S. globosa and S. intermedia. Phylogenetic analysis fully supports for the monophyly of the genus Scopimera and the sister relationship between S. longidactyla and S. globosa. The complete mitogenome of S. longidactyla and its phylogenetic implications will provide valuable insights for further studies in phylogenetic and evolutionary biology.

Decapod crustaceans provide a valuable food source worldwide, both through wild capture and captive rearing. They are also used extensively in scientific research, both as subjects for the investigation of basic biological processes and as model organisms for the detection of environmental changes. There is now an increasing acceptance that decapod crustaceans are sentient, and legislation is being introduced in numerous countries to ensure crustacean welfare when they are harvested or held captive. Moreover, methods for the humane slaughter of these animals are being developed, and of these electrical stunning is a prime candidate. Optimisation of electrical stunning is underway for a range of commercially-exploited or scientifically-important species, and the present study contributes to that process by examining further crab (Carcinus maenas) and lobster (Homarus gammarus) species using a rigorous neurophysiological approach. By recording nerve activity in both the central and peripheral nervous systems, we have found that electrical stunning with a standard commercial instrument arrests nerve activity in both these species at all levels: sensory, motor and central, rendering the animals neurologically insensible. This methodology is the most direct and effective way to establish if insensibility is successfully achieved. However, ultimately the routine monitoring of effective stunning in commercial and laboratory settings will have to depend on simple, yet reliable physiological or behavioural indicators, following their calibration against neurological methods. Monitoring heartbeat is used widely to establish metabolic activity, locomotory performance, agonistic interactions and responses to environmental conditions. We have therefore assessed the potential to use cardiac activity as an indicator for the state of sensibility. We recorded the heartbeat in both C. maenas and H. gammarus before and after electrical stunning, but find that in many cases even though nerve activity has ceased both centrally and peripherally, cardiac activity actually continues (though at a reduced rate) for a substantial time (>1h). The heartbeat is therefore not a reliable indicator of the state of sensibility, making it an unsuitable indicator of effective stunning. Possible reasons for these findings, and ways to validate behavioural measures that may be more appropriate for routinely establishing effective electrical stunning, are discussed. [ABSTRACT FROM AUTHOR]

Grimothea monodon, an important fishery resource in the Humboldt Current marine ecosystem (HCE), present two contrasting morphotypes (PM, pelagic morphotype; BM, benthic morphotype). The fishery management of G. monodon is focused on understanding only fishery aspects that apply to a limited area, and there are currently no studies that evaluate the nutritional status of these morphotypes. This study evaluated the biological performance of PM and BM, analyzing the body (size, CL; weight, W; condition factor, Kn) and biochemical condition (glucose, G; proteins, P; lipids, L; fatty acids, FAs). The results reveal that G. monodon showed differences in CL and W between morphotypes, with higher values in BM than PM. The Kn was different between morphotypes with a tendency of isometric growth. In turn, the G contents were higher in PM than BM, while the contents of P, L, and FAs showed an opposite tendency, with higher contents recorded in BM than PM. Our findings suggest that the Kn should be included to strengthen the biological parameters and their relationships used in fishery management models. Differences in the biochemical condition between morphotypes can be considered potentially adaptive, in response to the combined effect of environmental factors that vary in the HCE.

Decapod crustaceans provide a valuable food source worldwide, both through wild capture and captive rearing. They are also used extensively in scientific research, both as subjects for the investigation of basic biological processes and as model organisms for the detection of environmental changes. There is now an increasing acceptance that decapod crustaceans are sentient, and legislation is being introduced in numerous countries to ensure crustacean welfare when they are harvested or held captive. Moreover, methods for the humane slaughter of these animals are being developed, and of these electrical stunning is a prime candidate. Optimisation of electrical stunning is underway for a range of commercially-exploited or scientifically-important species, and the present study contributes to that process by examining further crab (Carcinus maenas) and lobster (Homarus gammarus) species using a rigorous neurophysiological approach. By recording nerve activity in both the central and peripheral nervous systems, we have found that electrical stunning with a standard commercial instrument arrests nerve activity in both these species at all levels: sensory, motor and central, rendering the animals neurologically insensible. This methodology is the most direct and effective way to establish if insensibility is successfully achieved. However, ultimately the routine monitoring of effective stunning in commercial and laboratory settings will have to depend on simple, yet reliable physiological or behavioural indicators, following their calibration against neurological methods. Monitoring heartbeat is used widely to establish metabolic activity, locomotory performance, agonistic interactions and responses to environmental conditions. We have therefore assessed the potential to use cardiac activity as an indicator for the state of sensibility. We recorded the heartbeat in both C. maenas and H. gammarus before and after electrical stunning, but find that in many cases even though nerve activity has ceased both centrally and peripherally, cardiac activity actually continues (though at a reduced rate) for a substantial time (>1h). The heartbeat is therefore not a reliable indicator of the state of sensibility, making it an unsuitable indicator of effective stunning. Possible reasons for these findings, and ways to validate behavioural measures that may be more appropriate for routinely establishing effective electrical stunning, are discussed.

This research focuses on studying the narrow-clawed crayfish in the Dnipropetrovsk region. The narrow-clawed crayfish, Astacus leptodactylus, is a crucial component of industrial fisheries and plays a significant role in the development of aquatic ecosystems. Within the territory of the Dnipropetrovsk region, crayfish inhabit various freshwater bodies, including rivers, lakes, floodplains, and ponds. It is known that water bodies in the Dnipro region undergo substantial anthropogenic impact, leading to alterations in the life cycles and reproductive features of hydrobionts. Investigated areas of reservoirs were characterized by diverse levels and factors of pollution, such as contamination of water with chemical and radioactive substances, oil products, wastewater, and the use of nitrogen and phosphorus fertilizers. These anthropogenic interventions may result in a decrease in populations of aquatic organisms, posing a serious threat to water ecosystems. The sensitivity to environmental changes makes crayfish a valuable bioindicator species. Fertility indicators and morphometric characteristics can be considered as bioindicators. The analysis of linear-weight parameters revealed that crayfish extracted from the Zaporizhzhia Reservoir had a body length 15–18% greater than those from the Kamianske and Samara Bay. Additionally, they exhibited larger cephalothorax dimensions by 18–20%, and their mass was almost 50% higher compared to individuals from other water bodies. Samara Bay demonstrated significantly lower fertility indicators compared to the Zaporizhzhia Reservoir, with crayfish fertility being reliably 63% lower. The established differences in morphometric indicators between crayfish from the Zaporizhzhia Reservoir, Samara Bay and Kamianske Reservoir may indicate heterogeneity in the living conditions within the water bodies of Dnipropetrovsk and might be induced by anthropogenic pressures.

The Norway lobster, Nephrops norvegicus, is an important representative of the benthos and also supports valuable fisheries across Europe. Nephrops are susceptible to infection by Hematodinium sp., an endoparasitic dinoflagellate that causes morbidity and mortality. From an epizootiological perspective, the Clyde Sea Area (CSA; west of Scotland) is the best-studied Hematodinium–Nephrops pathosystem, with historical data available between 1988 and 2008. We have revisited this pathosystem by curating and updating prevalence values, differentiating host traits associated with disease exposure and progression, and comparing Hematodinium sp. disease dynamics in the CSA to other locations and to other decapod hosts (Cancer pagurus, Carcinus maenas). Prevalence from a 2018/2019 survey (involving 1739 lobsters) revealed Hematodinium sp. still mounts a synchronized patent infection in the CSA; hence this pathogen can be considered as enzootic in this location. We highlight for the first time that Nephrops size is associated with high severity infection, while females are more exposed to Hematodinium sp. More generally, regardless of the host (Norway lobster, brown and shore crabs) or the geographical area (Ireland, Wales, Scotland), Hematodinium sp. patent infections peak in spring/summer and reach their nadir during autumn. We contend that Hematodinium must be considered one of the most important pathogens of decapod crustaceans in temperate waters.

Establishment of artificial reefs and no-take areas are management measures available for restoring deteriorated marine ecosystems, compensating for habitat loss and strengthening harvested populations. Following the establishment of no-take artificial reefs in western Sweden to compensate for hard bottoms lost to a shipping lane, we detected rapid positive effects on crustaceans and demersal fish compared to fished reference areas. The relative abundance and size structure of European lobster (Homarus gammarus) increased strongly in the no-take area indicating more than doubled and tripled egg production in 5 and 10 years, respectively. For benthic fish and crustacean communities, the abundances of gadoids and wrasses increased and the abundances of small decapod crustaceans decreased in the no-take area, likely indicating cascading effects of increased predation. The study demonstrates that relatively small no-take areas, enhanced by artificial reefs, can rapidly invigorate populations of lobster and fish that in turn may re-initiate local top-down control. [ABSTRACT FROM AUTHOR]

The Canary Islands constitute one of the major marine biodiversity hotspots in the eastern-central Atlantic, with decapod crustaceans being a highly representative group in the benthic environment due to their vast diversity of taxa and occupied ecosystems. This study identifies three significant milestones corresponding to the publication of comprehensive decapod checklist for the Canary Islands in 1973, 1995, and 2018. The lists of coastal benthic decapod species (0–300 m depth) were revised and updated, indicating the biogeographic pattern and vertical distribution range of each species in the region. Changes in the composition of the biogeographic patterns of coastal decapods in the Canary Islands were analysed to evaluate whether they could be considered as a useful indicator of the tropicalization process in the region. Particular attention was paid to variations in the percentages of species with warm water affinity versus those with Atlanto-Mediterranean preferences, with the former showing a clear upward trend. • The list of coastal benthic decapods (0–300 m) in the Canary Islands has been updated. • Changes in the composition of biogeographical patterns over the last 50 years are analysed. • The percentages of species with an affinity for warm waters have increased. • The percentages of Atlanto-Mediterranean species have decreased. • These changes are a valid indicator of topicalization in the Canary Islands region. [ABSTRACT FROM AUTHOR]

The fossil records of decapod crustaceans (Malacostraca) from Oligocene and Miocene fish beds (i.e. laminated deposits with exceptional fish preservation and high organic content) of Europe have lacked a uniform taxonomic approach, prohibiting assessments of their diversity and distribution. Therefore, we revisited the systematics of brachyuran crabs from these deposits preserved in the Great Caucasian Basin, the Outer Carpathian Basin, and the Pannonian Basin. The revised material originates from the Lower Oligocene of Hungary (Tard Clay Formation), Poland (Menilite Formation), Romania (Dysodilic Shale Formation), and Ukraine (Menilite Formation); Upper Oligocene of Poland (Menilite Formation); and the Lower Miocene of Azerbaijan (Maikopian Series), the Czech Republic (Ždánice-Hustopeče Formation), and Russia (Maikopian Series). Previously unreported material includes decapod specimens from the Lower Oligocene of Abadzekhskaya, Russia. In total, three crab species were distinguished, including Platymaia lethaea (Smirnov, 1929), Liocarcinus oligocenicus (Paucă, 1929), and Necronectes sp. Among them, L. oligocenicus occurs at all studied localities and is the most widespread taxon. Although earlier records of this species were often recognized as separate taxa, we propose that Portunus musceli Paucă, 1929; Portunus lancetidactylus Smirnov, 1929; Portunus arcuatus var. priscus Smirnov, 1929; Nautilograpsus prior Smirnov, 1929; and Portunus atropatanus Aslanova & Dzhafarova, 1975, are junior subjective synonyms of Liocarcinus oligocenicus. Although decapod specimens preserved in Oligocene and Miocene fish beds are often represented by complete or near-complete articulated bodies, their extreme flattening distorts the outline of exoskeleton elements and obscures diagnostic characters on the dorsal carapaces, such as the development of grooves, regions, and cuticular ornamentation, posing a major problem in taxonomic evaluation of these decapods. Other traits commonly not preserved in the fossil record, such as eyes, antennae, and even gonopods can be observed, although their comparison with modern counterparts is limited. [ABSTRACT FROM AUTHOR]

RNA interference (RNAi) has been widely utilised in many invertebrate models since its discovery, and in a majority of instances presents as a highly efficient and potent gene silencing mechanism. This is emphasized in crustaceans with almost all taxa having the capacity to trigger effective silencing, with a notable exception in the spiny lobsters where repeated attempts at dsRNA induced RNAi have demonstrated extremely ineffective gene knockdown. A comparison of the core RNAi machinery in transcriptomic data from spiny lobsters (Panulirus ornatus) and the closely related slipper lobsters (Thenus australiensis, where silencing is highly effective) revealed that both lobsters possess all proteins involved in the small interfering and microRNA pathways, and that there was little difference at both the sequence and domain architecture level. Comparing the expression of these genes however demonstrated that T. australiensis had significantly higher expression in the transcripts encoding proteins which directly interact with dsRNA when compared to P. ornatus, validated via qPCR. These results suggest that low expression of the core RNAi genes may be hindering the silencing response in P. ornatus, and suggest that it may be critical to enhance the expression of these genes to induce efficient silencing in spiny lobsters. [ABSTRACT FROM AUTHOR]

Hydrothermal vent ecosystems are home to a wide array of symbioses between animals and chemosynthetic microbes, among which shrimps in the genus Rimicaris is one of the most iconic. So far, studies of Rimicaris symbioses have been restricted to Atlantic species, including Rimicaris exoculata, which is totally reliant on the symbionts for nutrition, and the mixotrophic species Rimicaris chacei. Here, we expand this by investigating and characterizing the symbiosis of the Indian Ocean species Rimicaris kairei using specimens from two vent fields, Kairei and Edmond. We also aimed to evaluate the differences in mineralogy and microbial communities between two cephalothorax color morphs, black and brown, through a combination of 16S metabarcoding, scanning electron microscopy, fluorescent in situ hybridization, energy-dispersive X-ray spectroscopy, and synchrotron near-edge X-ray absorption structure analyses. Overall, our results highlight that R. kairei exhibits similar symbiont lineages to those of its Atlantic congeners, although with a few differences, such as the lack of Zetaproteobacteria. We found distinct mineralization processes behind the two color morphs that were linked to differences in the vent fluid composition, but the symbiotic community composition was surprisingly similar. In R. exoculata, such mineralogical differences have been shown to stem from disparity in the microbial communities, but our results indicate that in R. kairei this is instead due to the shift of dominant metabolisms by the same symbiotic partners. We suggest that a combination of local environmental factors and biogeographic barriers likely contribute to the differences between Atlantic and Indian Ocean Rimicaris symbioses. [ABSTRACT FROM AUTHOR]

The establishment of fisheries no-take areas is considered an effective method for the recovery of populations of exploited species and their habitats. Here we study the faunistic composition of decapod crustaceans after the implementation of a no-take area in the Gulf of Roses (NW Mediterranean) in 2014. We studied the occurrence (presence/absence) and density of all decapod crustaceans sampled by trawling inside and outside a no-take area from March 2015 to July 2018. Sizes were assessed for all common species. A total of 33 species of decapod crustaceans were recorded. Four species showed significantly higher occurrences in the no-take area and three in the open area, while significantly higher densities were found for four species in the no-take area and three in the open area. Multivariate analysis showed marked differences between the no-take area and the open area, while also showing that the two areas were undergoing a divergence. The comparison of sizes between the two zones showed species-specific patterns that in many cases showed that both the smallest and the largest individuals were present in the no-take area, suggesting that the closing of this area would be important for recruitment and juvenile development, as well as for protection of large-sized individuals. All evidence indicates that the establishment of the no-take area has led to an improvement in biodiversity and species population descriptors.

To maximise productivity, a better understanding of the underlying causes of subfertility that lead to inferior offspring and high mortality is imperative. In decapod crustaceans, most research has focused on female reproductive performance, with little attention given to male fertility. Paternal genetic contribution is critical to both successful embryonic and post‐embryonic development. Assessment of sperm quality can be a direct method to determine male subfertility in decapods. Sperm quality parameters such as sperm concentration and morphology have traditionally been used to determine male reproductive performance, but these procedures are time‐consuming and can only assess a limited number of sperm cells and males. Alternative diagnostic biomarkers used widely in humans and other mammals could be adapted to decapod crustaceans and may be more indicative of sperm fertilisation competence and male reproductive performance. These predictive biomarkers use fluorescent cellular dyes and high‐throughput flow cytometry or computer‐assisted sperm microscopic analysis to evaluate sperm viability, mitochondrial function, acrosome reaction and DNA fragmentation. This review examines current and advanced biomarkers to evaluate sperm quality and further explores state‐of‐the‐art procedures of sperm cryopreservation (conventional vs. vitrification techniques) and artificial fertilisation in decapod crustaceans. Sperm freezing coupled with artificial fertilisation in decapods permits the long‐term storage, controlled timing and selection of individuals for reproduction. Collectively, these tools can be applied to commercial broodstock management to improve productivity and accelerate selective breeding in the crustacean aquaculture industry. [ABSTRACT FROM AUTHOR]

Based on the information provided in the 2nd and 3rd editions of the Red Book of Mongolia, the current state of the rare and endangered species of mollusks, crustaceans and insects of Mongolia and the threat to their existence are analyzed: water pollution and accidental catch during fishing (for aquatic species); degradation of habitats (haying, draining of swamps); overgrazing; collecting. The effectiveness of protection measures has been identified: the habitats of some species are included in the boundaries of specially protected natural territories; some species are listed in Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora which will establish strict control over the international trade of rare and endangered species of invertebrates in Mongolia. It is indicated that the conservation of certain species of mollusks, crustaceans and insects requires additional and more specific measures: prevention of habitat degradation, including overgrazing and pollution of water bodies; a ban on collecting; conducting research to identify the concentration of populations, as well as assess the resources of food plants.

The crab species Plagiolophus sulcatus Beurlen, 1939 from the Oligocene (Rupelian) Kiscell Clay of Hungary is revised and its holotype is reillustrated for the first time since its original publication. Material from the upper Oligocene (Chattian) of Trbovlje (Slovenia) is here considered conspecific with P. sulcatus. Attribution of this species to the genus Glyphithyreus, as proposed by Hiroaki Karasawa and Carrie Schweitzer in 2004, is confirmed. Glypthithyreus sulcatus differs from congeners in possessing protogastric regions that are subtriangular in outline and in having fewer and coarser tubercles on elevated carapace regions.

Abstract Background G-protein coupled receptors (GPCRs) are ancient, ubiquitous, constitute the largest family of transducing cell surface proteins, and are integral to cell communication via an array of ligands/neuropeptides. Molt inhibiting hormone (MIH) is a key neuropeptide that controls growth and reproduction in crustaceans by regulating the molt cycle. It inhibits ecdysone biosynthesis by a pair of endocrine glands (Y-organs; YOs) through binding a yet uncharacterized GPCR, which triggers a signalling cascade, leading to inhibition of the ecdysis sequence. When MIH release stops, ecdysone is synthesized and released to the hemolymph. A peak in ecdysone titer is followed by a molting event. A transcriptome of the blackback land crab Gecarcinus lateralis YOs across molt was utilized in this study to curate the list of GPCRs and their expression in order to better assess which GPCRs are involved in the molt process. Results Ninety-nine G. lateralis putative GPCRs were obtained by screening the YO transcriptome against the Pfam database. Phylogenetic analysis classified 49 as class A (Rhodopsin-like receptor), 35 as class B (Secretin receptor), and 9 as class C (metabotropic glutamate). Further phylogenetic analysis of class A GPCRs identified neuropeptide GPCRs, including those for Allatostatin A, Allatostatin B, Bursicon, CCHamide, FMRFamide, Proctolin, Corazonin, Relaxin, and the biogenic amine Serotonin. Three GPCRs clustered with recently identified putative CHH receptors (CHHRs), and differential expression over the molt cycle suggests that they are associated with ecdysteroidogenesis regulation. Two putative Corazonin receptors showed much higher expression in the YOs compared with all other GPCRs, suggesting an important role in molt regulation. Conclusions Molting requires an orchestrated regulation of YO ecdysteroid synthesis by multiple neuropeptides. In this study, we curated a comprehensive list of GPCRs expressed in the YO and followed their expression across the molt cycle. Three putative CHH receptors were identified and could include an MIH receptor whose activation negatively regulates molting. Orthologs of receptors that were found to be involved in molt regulation in insects were also identified, including LGR3 and Corazonin receptor, the latter of which was expressed at much higher level than all other receptors, suggesting a key role in YO regulation.

The presence of decapod crustaceans in the Pliocene and Pleistocene (MIS 5e) fossil record of Santa Maria Island (Azores Archipelago) is herein reviewed. Our study raises the number of fossil decapods from this island from one species to 10 taxa (three for the Pliocene and seven for the Last Interglacial). Four of these 10 taxa are reported for the first time in the fossil record, worldwide. A new species of a mud shrimp is also described (Upogebia azorensis n. sp.). Our study suggests that the Plio–Pleistocene decapod assemblages of the Azores did not differ significantly from modern ones, being dominated by species that are today widespread across the Webbnesia ecoregion, the Mediterranean Sea, and the eastern Atlantic shores, including the Azores. As far as can be judged from the limited fossil record, apparently no tropical crab species with a Cabo Verdean/Senegalese provenance reached the Azores during windows of opportunity associated with Glacial Termination 2 or with the initial setting of the Last Interglacial period. This contribution increases the total number of marine taxa reported for the Pliocene and Pleistocene outcrops of Santa Maria Island to 218 and 155, respectively, highlighting the scientific relevance of its palaeontological heritage. [ABSTRACT FROM AUTHOR]

The sand bubbler crab, Scopimera longidactyla Shen, 1932 (Arthropoda: Malacostraca: Decapoda: Thoracotremata: Dotillidae), is commonly found along tropical and subtropical sandy shores of China, Korea, and Taiwan. Ecologically, it plays an important role in the productivity of sandy shores through their feeding and burrowing activities. In this study, the first complete mitochondrial genome (mitogenome) of S. longidactyla was analyzed using next-generation sequencer. Its mitogenome, circular in structure, spans 15,965 bp with a GC content of 29.97%, consisting of 13 protein-coding genes, two ribosomal RNA genes, 22 transfer RNA genes, and one putative control region. Its mitogenome arrangement and composition are identical to its two congeners, S. globosa and S. intermedia . Phylogenetic analysis fully supports for the monophyly of the genus Scopimera and the sister relationship between S. longidactyla and S. globosa . The complete mitogenome of S. longidactyla and its phylogenetic implications will provide valuable insights for further studies in phylogenetic and evolutionary biology., Competing Interests: No potential conflict of interest was reported by the author(s)., (© 2024 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.)

The crab species Plagiolophus sulcatus Beurlen, 1939 from the Oligocene (Rupelian) Kiscell Clay of Hungary is revised and its holotype is reillustrated for the first time since its original publication. Material from the upper Oligocene (Chattian) of Trbovlje (Slovenia) is here considered conspecific with P. sulcatus. Attribution of this species to the genus Glyphithyreus, as proposed by Hiroaki Karasawa and Carrie Schweitzer in 2004, is confirmed. Glypthithyreus sulcatus differs from congeners in possessing protogastric regions that are subtriangular in outline and in having fewer and coarser tubercles on elevated carapace regions. [ABSTRACT FROM AUTHOR]

It has become a common expectation for an animal's guts to be a site for bacterial symbiosis, which may play a role in influencing various aspects of physiology including digestion and immune responses. The presence of a microbiome in the digestive tracts of crustaceans has been demonstrated in the past using molecular techniques and has encouraged manipulations including probiotics to enhance growth rates in cultured species. We suggest, however, that bacteria are restricted to the lumen of the gut and separated from the epithelium by the peritrophic matrix, which prevents their establishment as a permanent component of the gut. The peritrophic matrix, found in most arthropods, is a chitinous sheet containing accessory molecules, and is continuously formed by delamination from the epithelium of the midgut such that the actual surface is constantly being cleaned. The lifted layer then surrounds ingested materials, including microbes, in an impenetrable wrapper compartmentalizing digestive and immune functions. The ectoperitrophic space, lying between the peritrophic matrix and the epithelium, was examined in six species representatives of six groups of crustaceans (Branchiopoda, Amphipoda, Copepoda, and Decapoda) for the presence of microbes using light and transmission electron microscopy as well as fluorescent probes for bacteria. The results suggest that a microbiome is lacking in several common groups of crustaceans. [ABSTRACT FROM AUTHOR]

Peritrichs usually settle on the external surface and gills of crustaceans. However, their physiological effect on the host has not been studied. Respiratory rate is a susceptible index for some factors that affect an organism. To test if ciliates attached to the crustacean gills have a physiological effect, we measured crustacean oxygen consumption in a closed system. Crayfish Cambarellus (Cambarellus) montezumae were collected in Lago Xochimilco in Mexico City and were isolated in chambers. Two peritrich species, Cothurnia variabilis (32.5%) and Epistylis gammari (67.5%), were observed on the gills. The metabolic rate was evaluated by oxygen consumption with a polarimetric oximeter. Statistical analyses demonstrated that a density of ciliates attached to the gills of the crayfish above ~50 individuals increased oxygen consumption with a positive correlation to epibiont density. We conclude that C. variabilis and E. gammari ciliate epibionts attached to the gill of the crayfish Cambarellus (Cambarellus) montezumae cause an increase in metabolic rate.

The Norway lobster, Nephrops norvegicus , is an important representative of the benthos and also supports valuable fisheries across Europe. Nephrops are susceptible to infection by Hematodinium sp., an endoparasitic dinoflagellate that causes morbidity and mortality. From an epizootiological perspective, the Clyde Sea Area (CSA; west of Scotland) is the best-studied Hematodinium - Nephrops pathosystem, with historical data available between 1988 and 2008. We have revisited this pathosystem by curating and updating prevalence values, differentiating host traits associated with disease exposure and progression, and comparing Hematodinium sp. disease dynamics in the CSA to other locations and to other decapod hosts ( Cancer pagurus , Carcinus maenas ). Prevalence from a 2018/2019 survey (involving 1739 lobsters) revealed Hematodinium sp. still mounts a synchronized patent infection in the CSA; hence this pathogen can be considered as enzootic in this location. We highlight for the first time that Nephrops size is associated with high severity infection, while females are more exposed to Hematodinium sp. More generally, regardless of the host (Norway lobster, brown and shore crabs) or the geographical area (Ireland, Wales, Scotland), Hematodinium sp. patent infections peak in spring/summer and reach their nadir during autumn. We contend that Hematodinium must be considered one of the most important pathogens of decapod crustaceans in temperate waters., Competing Interests: We declare we have no competing interests., (© 2024 The Authors.)

The El Niño phenomenon refers to a warming of the tropical Pacific basin whose meteorological effects influence the dynamics of aquatic ecosystems around the world. Prior studies have shown that strong El Niño events are highly correlated with high rainfall episodes and high freshwater discharge into subtropical estuaries, with subsequent changes in species composition, abundance, and diversity of their biota. In this work, we evaluated the hypothesis that riverine allochthonous matter associated with the strong 2015 El Niño event is assimilated by decapod crustaceans and fishes of a southwestern Atlantic estuary. We analyzed carbon (δ13C) and nitrogen (δ15N) stable isotope ratios of primary food sources and consumers in the estuary and of riverine allochthonous matter. Our findings revealed that higher water surplus and lower salinity associated with the 2015 El Niño coincided with an increase in the number of freshwater fish species and a decrease in the number of marine- and estuarine-dependent fishes inside the estuary. In addition, most estuarine consumers had lower average δ13C values during the wet period associated with the 2015 El Niño. This seemed to reflect the assimilation of 13C-depleted riverine matter, which according to Bayesian isotope mixing models ranged from 11% (adult resident decapod crustaceans) to 60% (adult resident fishes) during the wet season. Further studies are needed to evaluate the role of El Niño events on structuring food web organization in estuaries under the influence of this climatic phenomenon, which may become more frequent and intense in a global warming scenario. [ABSTRACT FROM AUTHOR]

Background: G-protein coupled receptors (GPCRs) are ancient, ubiquitous, constitute the largest family of transducing cell surface proteins, and are integral to cell communication via an array of ligands/neuropeptides. Molt inhibiting hormone (MIH) is a key neuropeptide that controls growth and reproduction in crustaceans by regulating the molt cycle. It inhibits ecdysone biosynthesis by a pair of endocrine glands (Y-organs; YOs) through binding a yet uncharacterized GPCR, which triggers a signalling cascade, leading to inhibition of the ecdysis sequence. When MIH release stops, ecdysone is synthesized and released to the hemolymph. A peak in ecdysone titer is followed by a molting event. A transcriptome of the blackback land crab Gecarcinus lateralis YOs across molt was utilized in this study to curate the list of GPCRs and their expression in order to better assess which GPCRs are involved in the molt process. Results: Ninety-nine G. lateralis putative GPCRs were obtained by screening the YO transcriptome against the Pfam database. Phylogenetic analysis classified 49 as class A (Rhodopsin-like receptor), 35 as class B (Secretin receptor), and 9 as class C (metabotropic glutamate). Further phylogenetic analysis of class A GPCRs identified neuropeptide GPCRs, including those for Allatostatin A, Allatostatin B, Bursicon, CCHamide, FMRFamide, Proctolin, Corazonin, Relaxin, and the biogenic amine Serotonin. Three GPCRs clustered with recently identified putative CHH receptors (CHHRs), and differential expression over the molt cycle suggests that they are associated with ecdysteroidogenesis regulation. Two putative Corazonin receptors showed much higher expression in the YOs compared with all other GPCRs, suggesting an important role in molt regulation. Conclusions: Molting requires an orchestrated regulation of YO ecdysteroid synthesis by multiple neuropeptides. In this study, we curated a comprehensive list of GPCRs expressed in the YO and followed their expression across the molt cycle. Three putative CHH receptors were identified and could include an MIH receptor whose activation negatively regulates molting. Orthologs of receptors that were found to be involved in molt regulation in insects were also identified, including LGR3 and Corazonin receptor, the latter of which was expressed at much higher level than all other receptors, suggesting a key role in YO regulation. [ABSTRACT FROM AUTHOR]

Decapod associations have been significant components of marine habitats throughout the Cenozoic when the major diversification of the group occurred. In this respect, the circum-Mediterranean area is of particular interest due to its complex palaeogeographic history. During the Oligo-Miocene, it was divided in two major areas, Mediterranean and Paratethys. Decapod crustaceans from the Paratethys Sea have been reported in the literature since the 19th century, but only recent research advances allow evaluation of the diversity and distribution patterns of the group. Altogether 176 species-level taxa have been identified from the Oligocene and Miocene of the Western and Central Paratethys. Using the three-dimensional NMDS analysis, the composition of decapod crustacean faunas of the Paratethys shows significant differences through time. The Ottnangian and Karpatian decapod associations were similar to each other both taxonomically and in the mode of preservation, and they differed taxonomically from the Badenian ones. The Early Badenian assemblages also differed taxonomically from the Late Badenian ones. The time factor, including speciation, immigration from other provinces and/or (local or global) extinction, can explain temporal differences among assemblages within the same environment. High decapod diversity during the Badenian was correlated with the presence of reefal settings. The Badenian was the time with the highest decapod diversity, which can, however, be a consequence of undersampling of other time slices. Whereas the Ottnangian and Karpatian decapod assemblages are preserved virtually exclusively in the siliciclastic “Schlier”-type facies that originated in non-reefal offshore environments, carbonate sedimentation and the presence of reefal environments during the Badenian in the Central Paratethys promoted thriving of more diverse reef-associated assemblages. In general, Paratethyan decapods exhibited homogeneous distribution during the Oligo-Miocene among the basins in the Paratethys. Based on the co-occurrence of certain decapod species, migration between the Paratethys and the North Sea during the Early Miocene probably occurred via the Rhine Graben. At larger spatial scales, our results suggest that the circum-Mediterranean marine decapod taxa migrated in an easterly direction during the Oligocene and/or Miocene, establishing present-day decapod communities in the Indo-West Pacific.

Abstract Extreme events associated with global warming, such as ocean heat waves, can have contrasting fitness consequences for different species, thereby modifying the structure and composition of marine communities. Here, we examined the effects of a laboratory simulated heat wave on the physiology and performance of two Indo-Pacific crustacean species: the shrimp Rhynchocinetes durbanensis and the hermit crab Calcinus laevimanus. We exposed the crustaceans to a control temperature or to a +5 °C temperature (25 °C vs 30 °C) for two consecutive weeks, and weekly analyzed protective proteins, antioxidant activity, and lipid peroxides in muscle and visceral mass. Fulton's K, total protein, %C, and C:N molar ratio of muscle tissue were also analyzed at the end of the experiment. Results showed that 1) the most responsive tissues were the muscle in the shrimp species and the visceral mass in the hermit crab species; 2) biomarker responses in both species occurred mostly after 7 days of exposure; 3) temperature stress led to an increase in biomarker levels; 4) highest biomarker fold-changes were detected in protective chaperones and antioxidants superoxide dismutase and glutathione-S-transferase; 4) integrated biomarker indices suggested poorer health status in individuals subjected to the heat wave; 5) performance changes at the organism level were only detected in R. durbanensis ; and 6) mortality rates of both species remained unchanged with the heat wave. Finally, we concluded that these species are capable of physiological adjustments in response to rapid environmental changes, which ultimately confers them with enough thermal tolerance to withstand this simulated heat wave without major consequences for fitness. Graphical abstract Image 1 Highlights • Effects of a marine heat wave were tested in two tropical crustaceans. • Heat wave elicited a cellular stress response that was time-dependent. • Specimens subjected to a heat wave showed poorer health condition. • Heat wave did not affect mortality rates in neither species. [ABSTRACT FROM AUTHOR]

The study was to find out the effect of cadmium and mercury on levels of hemolymph glucose, crustacean hyperglycemic hormone (CHH) and hepatopancreas glycogen in the blue swimmer crab Portunus pelagicus. The experiments were performed in both intact and eyestalk ablated crabs. Quantification of CHH was done by the indirect ELISA with the aid of primary anti-Carcinus maenas-CHH antibody. Higher glucose concentration was observed on exposure to 8×10-6 of cadmium ((825.6±5.42) μg/mL) and 6×10-6 of mercury ((90.5±6.25) μg/mL) after 48 h and 24 h respectively. Higher level of hemolymph glucose was observed in eyestalk intact crabs on exposure to cadmium and mercury than eyestalk ablated crabs. Decrease in the levels of CHH was observed in both eyestalk intact and ablated crabs on heavy metal exposure. Decline of the hepatopancreas glycogen level was also witnessed with the exposure to heavy metal, which validated its utilization in the production of glucose. Thus this study brings to light, the variations in hemolymph glucose, CHH and hepatopancreas glycogen on heavy metal stress. These carbohydrate metabolites can be used as biomarkers in assessing heavy metal contamination in water bodies. [ABSTRACT FROM AUTHOR]

Metabolic rates provide an estimate of the cost of living for different organisms that can readily be compared across species to provide an estimate of their relative requirements for survival. As such, metabolic rates have been measured for decades on a wide range of organisms. Here, we review published estimates of metabolic rates for brachyuran crabs, a ubiquitous and ecologically and economically important group of consumers. Consistent with ecological theory and results in many other groups of animals, and after controlling for phylogenetic relationships, crab metabolic rates scale with body mass with a scaling exponent of 0.65. Similarly, as with other groups of poikilotherms, crab metabolic rates increase strongly with temperature, with a Q10 of 1.26. Additionally, we found that metabolic rates were correlated with ecological niche, varying with both the diet strategy and the habitat occupied. These results help clarify the relative risk to crabs from environmental changes that impose metabolic stress, including climate change and the proliferation of hypoxic zones. [ABSTRACT FROM AUTHOR]

Temporal variation in pelagic food supply may affect the larval development and recruitment success of many decapod crustaceans in marine coastal ecosystems. In the present study, we experimentally investigated the degree of nutritional vulnerability in megalopa larvae of two sesarmid crab species ( Sesarma curacaoense and S. rectum ) subjected to different conditions of nutritional stress. In the laboratory, Sesarma megalopae were initially starved for up to 9 days followed by a constant feeding period in one experiment (i.e., point of no return), or they were fed at the beginning of their development for up to 9 days followed by a continuous period of food deprivation in a second experiment (i.e., point of reserve saturation). Megalopae were also constantly reared in the absence and presence of food ( Artemia sp. nauplii) in two control groups. The larval response to the different experimental conditions was evaluated through the percentage of survival (= % metamorphosed larvae), developmental time to metamorphosis, and Nutritional Vulnerability Index (= PRS 50 / PNR 50 ). All megalopae died when reared under constant starvation whereas 100% of the larvae metamorphosed into the first juvenile crab stage after 13.1 ± 4.4 days ( S. curacaoense ) or 12.4 ± 1.2 days ( S. rectum ) when continuously fed. In the first experiment, the starvation periods did not affect the mean developmental time of the megalopae through metamorphosis (13.6 ± 4.3 days) of S. curacaoense and only those larvae initially starved for 7 days presented the lowest percentage of metamorphosis to juvenile crab (73%). In S. rectum , by contrast, megalopae starved from 5 to 9 days exhibited lower percentages of metamorphosis (≤ 86%) compared to larvae starved for 1 or 3 days or those constantly fed. Furthermore, megalopae starved for 7 and 9 days delayed by 1.6 and 3.5 days their metamorphosis, respectively, compared to larvae constantly fed. In the second experiment, the Sesarma megalopae initially fed for only 1 day presented lower percentages of metamorphosis (≤ 73%) than megalopae fed for 3 or more days or continually (≥ 93%). The mean developmental time to metamorphosis was shorter with 1 day (8.1 ± 0.7 days in S. curacaoense ) or 3 days (11.3 ± 1.6 days in S. rectum ) of temporary feeding. The estimated values of the PNR 50 and PRS 50 indices were respectively 7.34 and 0.93 days for S. curacaoense and 9.01 and 1.78 days for S. rectum . These values provided a Nutritional Vulnerability Index of 0.13 for S. curacaoense and 0.2 for S. rectum , indicating a reduced dependence on exogenous food by the megalopae of these two sesarmid crab species. This starvation tolerance associated with a short megalopal development should increase the likelihood of successful survival into the benthic life phase and avoid latent effects of the larval nutritional stress and/or delayed metamorphosis on early juvenile performance of both Sesarma species. [ABSTRACT FROM AUTHOR]

The aim of this study was to assess the regulatory process of digestive peptidases of crustaceans in the presence of soybean trypsin inhibitor ( SBTI). This naturally occurring inhibitor in soybean meal was used to inhibit the activity of digestive serine peptidases of the whiteleg shrimp Litopenaeus vannamei. In vitro, SBTI inhibited the total proteolytic activity and chymotrypsin activity by 65%. Trypsin activity was reduced by SBTI from 40% to 15% from 2 to 4 hr of incubation, which is the average time of residence of feed in the shrimp digestive system. During the bioassays, experimental groups were fed with increasing concentration of supplemental SBTI (1 g kg−1 and 2 g kg−1) and digestive gland and faeces of individual specimens were collected daily. At the end of the bioassay, peptidase activity of digestive gland and faeces was shown, revealing differential inhibition after feeding for 5 days. Several serine peptidases were observed in zymograms, showing a compensation effect on the digestive gland through the activation of peptidases from different catalytic type. These results provide evidence that the shrimp digestive gland can overcome the effect of SBTI by two adaptive mechanisms: synthesis of additional peptidases of the serine class and other unidentified peptidases. [ABSTRACT FROM AUTHOR]

Examination of spatial patterns of organisms in the rocky subtidal zone is logistically challenging, particularly over large geographic distances. In the present study, we describe patterns of richness and abundance of decapod crustaceans and small demersal fishes colonizing cobble-filled bio-collectors in 2008 and 2009 at nearshore sites across an important oceanographic and biogeographic gradient in the North-west Atlantic from Rhode Island, USA to Newfoundland, Canada. At least 17 decapod and 24 fish genera were caught, including cryptic fish taxa not readily sampled with other gear. Species richness and abundance of decapods and fishes in collectors at shallow sites (5–10 m) was similar among nearby sites and was greatest in the southernmost region, but did not follow a simple latitudinal cline. The lack of clear latitudinal patterns is likely to be a result of the complex geography of summer temperatures along this coast, with the lowest temperatures at the mouth of the Bay of Fundy, the centre of the study domain. In 2008, the abundance of crabs was positively related to temperature while that of shrimp was negatively related. There was also a significant interaction between depth and study area, with greater similarity among areas at greater depths (up to 76 m), and greater similarity among depths in areas with little temperature stratification. Our results indicate that bio-collectors are a powerful tool for sampling decapod crustaceans and small demersal fishes in nearshore rocky habitats. Given the anthropogenic impacts in coastal habitats, this information is likely to prove useful for detecting changes in rocky subtidal habitats. [ABSTRACT FROM AUTHOR]

Benthic microbial communities can play an important role in the induction of larval metamorphosis in marine invertebrates. The role of biofilms in recognizing the parental habitat is unknown for the ecologically and economically important mangrove crab Ucides cordatus , a species suffering from environmental pressures such as habitat degradation and disease. In the laboratory, we experimentally tested the influence of biofilms grown in offshore and estuarine waters on the moulting rates and developmental time to metamorphosis (TTM) of the last larval stage (megalopa) of U. cordatus . Here, we specifically studied whether: (i) megalopae of this larval-exporting species respond differently to marine (MB) and estuarine biofilms (EB), (ii) biofilms previously immersed (24 h) in adult crab-conditioned seawater (ACSW; i.e. conspecific chemical cues) exhibit a greater effectiveness (i.e. by inducing higher moulting rates and shorter TTM) on larval metamorphosis than non-immersed ones and (iii) biofilms pre-immersed (24 h) in ACSW decrease their effectiveness when incubated (24 h) in pure filtered seawater (FSW) before offering them to megalopae. U. cordatus megalopae metamorphosed to the first juvenile crab stage (JI) in response to both MB and EB, however the moulting rates were significantly higher and development TTM shorter in the presence of EB compared to MB. The metamorphosis-inducing effects were significantly enhanced when both types of biofilms were pre-immersed in ACSW, suggesting that conspecific cues can be absorbed and stored by microbial matrix. The higher inductiveness of EB compared to MB persisted after previous contact with ACSW. Furthermore, EB exhibited a significantly greater biomass production (measured as dry weight) than MB, and when immersed in ACSW, both groups of biofilms significantly increased in biomass (maintaining the hierarchy EB > MB), suggesting that water-soluble chemical substances emitted by the adult crabs may have been absorbed and metabolized by the biofilms. The metamorphic inductiveness and biomass production decreased when both groups of biofilms that were previously kept (24 h) in ACSW were thereafter immersed (24 h) in FSW. All megalopae successfully moulted to JI after accelerated TTM when reared in ACSW, regardless of presence or absence of biofilms, corroborating that conspecific stimuli are the most effective metamorphosis-stimulating cues tested so far in U. cordatus . The fact that EB improved the moulting rates and shortened the development TTM indicates that megalopae can recognize and respond to microbial assemblages typical for specific environments. This should be ecologically important during larval recruitment by facilitating settlement in appropriate habitats for the post-metamorphic development of early benthic recruits. In addition, the influence of EB could encourage colonization of new estuarine areas and aid natural recovery of U. cordatus in mangrove habitats where crab populations have suffered significant reduction due to deforestation, fishing pressure or diseases. [ABSTRACT FROM AUTHOR]

The presence of an Oxygen Minimum Zone (OMZ) is one of the major characteristics of the eastern Pacific. The OMZ changes strongly adjacent to Mexico in its thickness and intensity. The ecological impacts of those changes were studied by examining the community structures of bathyal benthic and bentho-pelagic decapod crustaceans, and their oceanographic contexts, on the Mexican Pacific slope along a wide latitudinal range (16–32°N). Decapod crustaceans were collected with a benthic sledge from 48 stations between 865 and 2165 m in three main areas: offshore of northern Baja California (NBC), off southern Baja California (SBC) and in the southern Mexican Pacific (SMP). Physical–chemical parameters were measured in the water column, and sediment composition was analyzed for each station. The narrowing and weakening of the OMZ north of ca. 26°N was confirmed. Water with dissolved oxygen <0.5 ml l −1 occupied a stratum of 1231 m in the SMP vs. only 664 m off NBC. The strongest changes coincided with a region of surface, subsurface and intermediate water mass transitions, where less saline waters from the north extended to depths of ca. 1000 m. Sand proportions were higher in sediments to the south, whereas silt dominated offshore of NBC. A strong latitudinal shift in decapod community composition and bathymetric distribution occurred from off SBC to off NBC, coinciding with changes in oceanographic conditions. The dominant genera of decapod crustaceans at slope depths were cognate to those dominating slope areas in other tropical and subtropical regions of the world. In the SMP and off SBC, large aggregations of organisms were observed at 900–1300 m, with a sharp decrease in abundance at greater depth. Off NBC, the density of organisms was intermediate at all depths. The combined effects of dissolved oxygen concentration and characteristics of water masses affected the distribution of organisms. The faunal patterns were also related with sediment grain size. [ABSTRACT FROM AUTHOR]

Although iono-regulatory processes are critical for survival of crustaceans during the molt cycle, the mechanisms involved are still not clear. The Na + /K + /2Cl − cotransporter (NKCC), a SLC12A family protein that transports Na + , K + and 2Cl − into cells, is essential for cell ionic and osmotic regulation. To better understand the role of NKCC in the molt osmoregulation, we cloned and characterized a NKCC gene from the mud crab, Scylla paramamosain (designated as SpNKCC ). The predicted Sp NKCC protein is well conserved, and phylogenetic analysis revealed that this protein was clustered with crustacean NKCC. Expression of SpNKCC was detected in all the tissues examined but was highest in the posterior gills. Transmission electron microscopy revealed that posterior gills had a thick type of epithelium for ion regulation while the anterior gills possessed a thin phenotype related to gas exchange. During the molting cycle, hemolymph osmolality and ion concentrations (Na + and Cl − ) increased significantly over the postmolt period, remained stable in the intermolt and premolt stages and then decreased at ecdysis. Meanwhile, the expression of SpNKCC mRNA was significantly elevated (26.7 to 338.8-fold) at the ion re-establishing stages (postmolt) as compared with baseline molt level. This pattern was consistent with the coordinated regulation of Na + /K + -ATPase α-subunit ( NKA α ), carbonic anhydrase cytoplasmic ( CAc ) isoform and Na + /H + exchanger ( NHE ) genes in the posterior gills. These data suggest that SpNKCC may be important in mediating branchial ion uptake during the molt cycle, especially at the postmolt stages. [ABSTRACT FROM AUTHOR]

Four new species of freshwater shrimp of the Palaemonidae family are recorded for Colombia: Macrobrachium dierytrhum Pereira, 1986; Macrobrachium manningi Pereira and Lasso, 2007, Pseudopalaemon gouldingi Kensley and Walker, 1982 and Pseudopalaemon nigramnis Kensley and Walker, 1982, collected in the Bita River drainage, Orinoco River Basin. [ABSTRACT FROM AUTHOR]

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