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In the American Museum of Natural History, New York, there is an old specimen labelled as "Holodromia harrisonwilliamsi Boone, MS name" that was collected from Cocos Island in 1925. This name has never been published. An examination of the specimen shows that it is a juvenile specimen of Homolodromia robertsi Garth, 1973, a species described from Peru, which has since been reported from Chile and off the coast of Ecuador. This paper reports on the specimen Homolodromia robertsi Garth found in Costa Rica for the first time, a discovery that extends the known range of this species northwards. [ABSTRACT FROM AUTHOR]

Simple Summary: Artemia is an important crustacean group, especially for aquaculture live food and as a model organism for toxicity assessment. The present study aimed to identify the current trends, research gaps, and literature development in the study of Artemia around the world. This primitive Arthropod has undergone significant evolution in terms of its application in various industries as well as relevant literature patterns in terms of scientometric analyses. An increasing number of scientists since 1970 has examined Artemia as an important species in aquaculture-related fields. However, a global scientometric review of Artemia literature is still lacking, which is the objective of this research. Using a CiteSpace analysis, the distribution of core authors and institutions, highly cited keywords and papers, author and journal contributions, and hot topics in the literature, as well as a co-citation analysis, particularly regarding authors, journals, documents, and clusters, were determined. Hence, 8741 relevant publications were generated from the Web of Science Core Collection database. The results revealed that the most significant contributions in Artemia research primarily originated from the USA, Brazil, Spain, India, China, and Belgium. Moreover, Artemia research focused mainly on top keywords such as brine shrimp and antimicrobial activity. Emerging trends related to Artemia research were Atlantic halibut, elongation factor, Artemia salina, lean protein, inert diet, alpha-crystallin protein, and Artemia embryo. At the same time, the study generated a vast total of 45 co-citation clusters. The present study provides the existing body of knowledge on Artemia research by sharing a visual knowledge map. This study offers a valuable perspective and profound understanding for researchers, farmers, and consortia interested in promoting Artemia as a sustainable live food in the global aquaculture industry. [ABSTRACT FROM AUTHOR]

A new species of gall crab collected from elegance coral, Catalaphyllia jardinei, is described in this paper. The male holotype was collected from a reef tank in Germany in 2016, and it is described here using integrative taxonomy. This species, named Lithoscaptus aquarius sp. nov., is the thirteenth assigned to the genus. It is morphologically and phylogenetically closest to Lithoscaptus semperi, a cryptochirid associated with Trachyphyllia geoffroyi. Like L. semperi, it has a large, broad W-shaped depression on the anterior half of the carapace, but the carapace surface of L. aquarius sp. nov. is smooth overall, lacking spines or tubercles. This new species is so named because it was found in a reef tank after searching in vain for material during fieldwork campaigns over the course of several years. [ABSTRACT FROM AUTHOR]

Simple Summary: Each year, approximately 167 billion Penaeus vannamei (white-leg shrimp) are farmed worldwide from an estimated total of more than 400 billion marines and freshwater shrimp farmed. In this context, the welfare of decapod crustaceans, the group with the most farmed animals on the planet, is becoming an increasingly important issue for researchers and society, and this debate will soon reach shrimp labs and farms. This article presents protocols specifically designed to measure the welfare of P. vannamei at all stages of their production cycle, from reproduction through larval rearing and postlarval transport to juvenile rearing in earthen ponds. These protocols were developed using four domains of welfare: nutrition, environment, health, and behaviour. Together, they help assess the fifth domain: psychology. The assessment protocols also include reference values for each indicator and three possible values for animal welfare on a continuum from positive (score 1) to very negative (score 3). Our assessment protocols can identify the critical points in the shrimp aquaculture process and are an essential step towards improving the welfare of farmed shrimp worldwide. Gradually, concern for the welfare of aquatic invertebrates produced on a commercial/industrial scale is crossing the boundaries of science and becoming a demand of other societal actors. The objective of this paper is to propose protocols for assessing the Penaeus vannamei welfare during the stages of reproduction, larval rearing, transport, and growing-out in earthen ponds and to discuss, based on a literature review, the processes and perspectives associated with the development and application of on-farm shrimp welfare protocols. Protocols were developed based on four of the five domains of animal welfare: nutrition, environment, health, and behaviour. The indicators related to the psychology domain were not considered a separate category, and the other proposed indicators indirectly assessed this domain. For each indicator, the corresponding reference values were defined based on literature and field experience, apart from the three possible scores related to animal experience on a continuum from positive (score 1) to very negative (score 3). It is very likely that non-invasive methods for measuring the farmed shrimp welfare, such as those proposed here, will become a standard tool for farms and laboratories and that it will become increasingly challenging to produce shrimp without considering their welfare throughout the production cycle. [ABSTRACT FROM AUTHOR]

The aim of this paper is to study the species composition, structure and seasonal dynamics of the cladoceran fauna and species associations in inland water bodies of Jeju Island (Republic of Korea). Only 47 taxa were found in 199 samples. Such faunal paucity could be explained by the existence of only a few types of aquatic environments on Jeju Island as compared to continental China and the Far East of Russia, with their great diversity of water types. We have demonstrated a high significance of the tropical species on Jeju. Our data confirm seasonal faunistic changes in the continental waters of Jeju Island. The rate of tropical taxa is highest in September, after the monsoon season, while the Far Eastern endemic taxa are more common in winter. At the same time, the contribution of Boreal taxa to the fauna of the island is low even in winter. Species associations have been revealed based on binominal distribution; they change significantly from summer to winter. However, a contribution of Boreal taxa to the species associations also is minimal (even in winter), whereas tropical taxa contribute to them greatly (including in winter). We can propose a rough scheme of faunal formation exploring the whole set of obtained information. Initially, at the earlier stages of the island formation, its fauna was consisted of some pre-Pleistocene taxa. Then, during the Pleistocene time, Jeju Island was secondarily interconnected with more southern territories, and tropical species have colonized it. Recent Boreal cladoceran invaders arrived at the island water bodies later when they were already inhabited by formed associations, and for this reason only few of them were able to settle down there. Such a scheme is a hypothesis which needs to be checked by the future phylogeographic studies. [ABSTRACT FROM AUTHOR]

Serranus scriba is a common member of the coastal fish community in the Adriatic Sea, but knowledge about its feeding ecology is scarce. The aim of this paper is to present new evidence about its food preferences and feeding habits. An innovative non-destructive method of fecal pellet analysis was used for this study. This method does not require sacrificing specimens and the fish can be released back into the sea alive after the laboratory work. The results demonstrated that S. scriba mainly preys on decapods, followed by polychaetes, isopods, fish, mollusks and swarming shrimps. The calculated index of trophic diversity (ITD) value of 0.89 indicates that it is an opportunistic feeder that feeds on a wide range of different prey. According to the calculated trophic level of 3.43, which is higher than that of other members of the community, S. scriba is also an important piscivorous predator. With age, S. scriba undergoes an ontogenetic shift. The proportion of crustaceans, gastropods and polychaetes decreases with age and body size, while the proportion of fish increases. [ABSTRACT FROM AUTHOR]

In the framework of the PNRA (Italian National Antarctic Research Program) project CARBONANT focusing on biogenic carbonates and held in January–February 2002, several Ross Sea banks were sampled to obtain samples of biogenic carbonates. In the Mawson Bank, species belonging to the isopod genus Chaetarcturus Brandt, 1990 were recorded, including a specimen that did not match any described species. In this paper we describe Chaetarcturus cervicornis sp. n., which is characterized by supraocular spines and two pairs of tubercle-like protrusions on the cephalothorax. The new species is very similar to C. bovinus (Brandt & Wägele, 1988) and C. adareanus (Hodgson, 1902), but has a clearly different spine pattern. The study of the species of the genus Chaetarcturus in the Ross Sea contributes to increase our knowledge on the diversity of the Antarcturidae in the Southern Ocean. Ross Sea banks seem to hold an interesting and not-well-known fauna, deserving attention in future research. [ABSTRACT FROM AUTHOR]

Various biological traits support the invasive success of different organisms. The osmoregulatory capacity and food preferences of the signal crayfish Pacifastacus leniusculus were experimentally tested to determine if they contribute to its invasive success. The osmotic concentrations of haemolymph were determined after acclimation of the crustaceans to seven salinities from 0 to 20 PSU. Food preferences were tested using Canadian pondweed Elodea canadensis, and rainbow trout Oncorhynchus mykiss. The results showed that the signal crayfish exhibits a hyper-hypoosmotic regulation pattern in the salinity range from 0 to 20 PSU, enabling them to inhabit both freshwater and brackish environments. Furthermore, the study found signal crayfish to have non-specific food preferences, although fish muscle tissue is more beneficial as a source of energy. Both features, osmoregulatory ability and food preferences, can increase the invasive success of this species as it expands into new areas. The ability to survive in higher salinities compared to the coastal waters of the Baltic Sea along the Polish coastline should be considered in targeted management strategies to control the spread of this invasive species. [ABSTRACT FROM AUTHOR]

Simple Summary: This research investigated microplastic ingestion in two marine crustacean species of high commercial importance, namely the Giant Red Shrimp Aristaeomorpha foliacea and the Deep-Water Rose Shrimp Parapenaeus longirostris. The primary purpose of this study was to better understand how these species are affected by microplastic pollution, a growing concern in the marine environment worldwide. Based on stable isotope analysis of muscle tissue and on the examination of their gastrointestinal tracts, it was found that the trophic niche of the two species is similar, but the type of particles ingested differed significantly in terms of shape, colour, size class, and polymer. These outcomes shed light on the pervasive impact of microplastic contamination on marine wildlife, emphasising potential threats to consumers at higher levels of the food web. A better knowledge of pathways that microplastics follow through marine food webs is crucial for understanding the ecological implications posed by this emerging contaminant. Increasing plastic contamination poses a serious threat to marine organisms. Microplastics (MPs) ingestion can represent a risk for the organism itself and for the ultimate consumer. Through the analysis of the gastrointestinal tract, coupled with stable isotope analysis on the muscle tissue, this study provides insights into the relationship between MPs pollution and ecology in two commercial marine species caught in the Central Tyrrhenian Sea: Aristaeomorpha foliacea and Parapenaeus longirostris. Stable isotope analysis was conducted to determine the trophic position and the trophic niche width. The gastrointestinal tracts were processed, and the resultant MPs were analysed under FT-IR spectroscopy to estimate the occurrence, abundance, and typology of the ingested MPs. The trophic level of the species was similar (P. longirostris TP = 3 ± 0.10 and A. foliacea TP = 3.1 ± 0.08), with an important trophic niche overlap, where 38% and 52% of P. longirostris and A. foliacea has ingested MPs, respectively. Though species-level differences may not be evident regarding MP's abundance per individual, a high degree of dissimilarity was noted in the typologies of ingested particles. This research provides valuable insights into how MPs enter marine trophic webs, stressing that isotopic niche analysis should be combined with other methods to explain in detail the differences in MPs ingestion. [ABSTRACT FROM AUTHOR]

The alien Red Sea goatfish, Parupeneus forsskali (Fourmanoir & Guézé, 1976), is a Lessepsian migrant, entering the Mediterranean through the Suez Canal. This study explores its seasonal diet and biological traits in Cyprus, its non-native habitat. From August 2019 to July 2021, a total of 249 specimens were collected, ranging in total length (TL) from 5.8 to 27.7 cm, with a mean TL of 15.1 ± 4.54 cm (SD). These specimens were examined with respect to sex and season. Through various methods (F%, N%, W%, and IRI), the feeding habits of the species were analysed, revealing a diet dominated by Crustacea (mainly Decapoda) and Polychaeta, with the secondary consumption of Mollusca, Echinodermata, and others. Significant differences were found between males and juveniles and females and juveniles, with adults preferring Decapoda and juveniles Copepoda, while seasonal variations were mainly influenced by prey availability. The Red Sea goatfish exhibited ontogenetic niche shifts in its depth and habitat distribution, influenced by size and age. The trophic level (TROPH) of P. forsskali ranged from 3.22 to 3.46, corresponding to an omnivorous diet with a preference for animals. These findings suggest that P. forsskali is an opportunistic predator with a diverse diet, thriving in its new habitat and potentially impacting the local marine food webs by competing with economically important native species for resources. [ABSTRACT FROM AUTHOR]

Four new species of freshwater crab are described from material collected in northern and southwestern Cameroon and assigned to Sudanonautes Bott, 1955. Sudanonautes cameroonensis sp. n., S. eyimba sp. n., S. ngaoundere sp. n. and S. nkam sp. n., are distinguished by characters of the carapace, thoracic sternum, chelipeds, mandibles, adult male gonopods, and in addition by genetic analyses using the mitochondrial CO1 and 16S rRNA genes. Diagnoses, illustrations, and a phylogenetic tree based on mtDNA sequences are provided, as well as a discussion of the threats and conservation of all species. [ABSTRACT FROM AUTHOR]

Ocypode Weber, 1795 (Brachyura: Ocypodidae) is popularly known as ghost crab, and encompasses 21 valid species, including Ocypode quadrata (Fabricius, 1787). This species has wide distribution along the Atlantic coast of America, from the USA (Massachusetts) to Brazil (Rio Grande do Sul), Central America, and Antilles. Such distribution, along with some biological characteristics of its life cycle and the presence of geographic barriers, could lead to genetic structuring. Herein, we evaluate the hypothesis of the presence of geographic barriers using COI and 16S partial gene fragments. The Maximum Likelihood tree suggests the monophyly of O. quadrata, while the values of intraspecific genetic distance along with the star-shaped haplotype network suggested a lack of genetic structure in Brazilian, Panama, and French Guiana populations, probably caused by larval dispersion. USA and Mexico populations may be a new lineage, but we cannot say it with few sequences and with no morphological characters. [ABSTRACT FROM AUTHOR]

Axiidea housed in the collection of the Museu de Oceanografia Prof. Petrônio Alves Coelho, Universidade Federal de Pernambuco (MOUFPE) were studied. This collection contains 66% of the total diversity of axiideans recorded from the continental shelf of the Brazilian coast. The species are listed by family and genus as follows: Axiidea: Axiidae (Axiopsis, Axiorygma, Calaxius, Coralaxius, Manaxius, Paraxiopsis), Callianassidae (Cheramoides), Callichiridae (Callichirus, Corallianassa, Lepidophthalmus, Neocallichirus), Ctenochelidae (Ctenocheles, Ctenocheloides, Dawsonius, Gourretia), Micheleidae (Marcusiaxius, Meticonaxius). Details on the biology and taxonomy of some of these species are given. In addition, certain poorly documented species are now better understood. [ABSTRACT FROM AUTHOR]

Twelve species of atyid shrimps are reported from three Micronesian islands (Babeldaob, Pohnpei, and Guam) and studied using a combined morphological and molecular approach. Among them, three are new records for the area (Caridina appendiculata, Caridina lobocensis, and Caridina rubella), while three new species are here described: Atyoida chacei sp. nov., Caridina ponapensis sp. nov., and Caridina rintelenorum sp. nov. Descriptions for these new species, diagnoses for poorly known species, and taxonomic notes are provided herein and their biogeography is discussed. [ABSTRACT FROM AUTHOR]

Three new species of the genus Caridina are described from the northernmost part of Australia. Caridina darwin n. sp. resembles Caridina temasek Choy and Ng, 1991 but differs in the armature of the rostrum, the development of epipods on the pereiopods and the absence of an appendix interna on the male first pleopods. Caridina magnovis n. sp. resembles Caridina serratirostris de Man, 1892 but differs in the armature of the ventral margin of the rostrum, a shorter stylocerite, a stouter carpus of the first pereiopod, the number and size of spiniform setae on the third and fifth pereiopods, the shape of the preanal carina and the size of the embryos (referred to as "eggs" in most previous publications). Caridina wilsoni n. sp. resembles Caridina gracilirostris de Man, 1892 but differs in the size of the embryos and in some length to width ratios of the segments of the pereiopods. Detailed morphological descriptions of all three new species are given. A molecular phylogeny (mt DNA 16S) supports the morphospecies hypothesis and illustrates the phylogenetic relationship with morphologically similar species from outside Australia. [ABSTRACT FROM AUTHOR]

Coral-dwelling gall crabs (Cryptochiridae) are common inhabitants of scleractinian corals. Several species have been described as new in recent years, including Lithoscaptus doughnut, which was described from Hong Kong based on a single female retrieved from the coral Plesiastrea peroni. Here we extend the distribution range of L. doughnut with nine additional localities throughout the Indo-West Pacific, from the Red Sea to the Coral Triangle and Japan. We describe a male specimen of L. doughnut for the first time, based on a specimen from Malaysia, and provide photographs of life and preserved material. Haplotype networks based on COI mtDNA (n = 12) and 16 rRNA sequences (n = 12) were created. We retrieved eleven COI haplotypes and six 16S haplotypes, however no clear geographic distribution pattern was discerned. Intraspecific variation in L. doughnut was 1.4% for COI and 0.2% for 16S. Lastly, the first colour photos and records of associated parasites of this species are provided. [ABSTRACT FROM AUTHOR]

Simple Summary: The possibility of pain occurring in animals is often accepted if various criteria are fulfilled. These criteria include prolonged grooming or rubbing at the site of a wound or tissue damage, or other behaviour involving the site of damage. We also expect to see a reduction in such activities if a local anaesthetic is applied. Here, we report on an experiment that applied caustic soda, a known irritant in humans, to one eyestalk of the glass prawn. This caused immediate escape responses and then nipping and picking at the treated eyestalk rather than at the untreated eyestalk. Prior application of a local anaesthetic reduced the amount of directed behaviour. However, the local anaesthetic also appeared to be an irritant as it too caused immediate escape responses and directed behaviour to the eyestalk. The results provide further support to the idea that these animals can experience pain. Acceptance of the possibility of pain in animals usually requires that various criteria are fulfilled. One such criterion is that a noxious stimulus or wound would elicit directed rubbing or grooming at the site of the stimulus. There is also an expectation that local anaesthetics would reduce these responses to damage. These expectations have been fulfilled in decapod crustaceans but there has been criticism of a lack of replication. Here, we report an experiment on the effects of a noxious chemical, sodium hydroxide, applied to one eyestalk of the glass prawn. This caused an immediate escape tail-flick response. It then caused nipping and picking with the chelipeds at the treated eyestalk but much less so at the alternative eyestalk. Prior treatment with benzocaine also caused an immediate tail-flick and directed behaviour, suggesting that this agent is aversive. Subsequently, however, it reduced the directed behaviour caused by caustic soda. We thus demonstrated responses that are consistent with the idea of pain in decapod crustaceans. [ABSTRACT FROM AUTHOR]

Continental rifting of the Tisza microplate started during the Late Jurassic and resulted in phreatic eruptions, peperite, and the construction of a volcanic edifice in the Early Cretaceous in the Mecsek Mountains (South Hungary). In the SE direction from the volcanic edifice at Zengővárkony, a shallow marine (depth 100–200 m) carbonate sediment hosted a vent environment, and iron ore deposition occurred at the end of the Valanginian to early Hauterivian, hosting a diverse, endemic fauna of approximately 60 species. The detailed mineralogical analysis of the transport conduits included Fe oxides (ferrihydrite, goethite, hematite, and magnetite), quartz, mixed carbonate, pyrite, feldspar, Fe-bearing clay minerals, apatite, sulfates (barite, gypsum, and jarosite), and native sulfur. Filamentous, microbially mediated microtextures with inner sequented, necklace-like spheric forms (diameter of 1 μm) and bacterial laminae are also observed inside decapod crustacean coprolites (Palaxius tetraochetarius) and in the rock matrix. This complex ecological and mineralogical analysis provided direct evidence for the presence of bacteria in fossil sediment-hosted vent (SHV) environments on the one hand and for the intimate connection between bacteria and decapod crustaceans in hydrothermal environments 135 Ma before. This observation completes the fossil food chain of chemosynthesis-based ecosystems, from primary producers to the top carnivores reported for the first time from this locality. [ABSTRACT FROM AUTHOR]

Rhodolith seabeds function as 'ecosystems engineers', which globally provide a range of 'ecosystem services'. However, knowledge on the structure, composition and distribution of rhodolith seabeds is still lacking. This Special Issue comprises six articles, addressing specific questions of rhodolith seabeds, and covering a wide range of topics. Two papers provide new large-scale information on the presence, structure and distribution of rhodolith beds at two southern hemisphere areas, in particular continental shelfs off South Africa and Brazil. Another two studies contributed to the discovery on new algal species from rhodolith beds, including Sporolithon franciscanum, a new rhodolith-forming species from Brazil, and the small benthic alga Schizocladia ischiensis. In terms of associated fauna, the taxonomic composition and patterns of abundance of decapod crustaceans are described in another article, including the description of a depth-partitioning in the abundance of juveniles and adults of the crab Nanocassiope melanodactylus. Rhodoliths are often present in fossilized deposits, so we can track changes in their presence with climate fluctuations. High temperatures during the Eocene and widespread oligotrophic conditions are finally connected with low abundances of rhodolith beds at mid and high latitudes, despite a larger presence at equatorial regions. [ABSTRACT FROM AUTHOR]

Decapod crustaceans are important components of the fauna of soft-bottom habitats. In this work, the records of decapod crustaceans are provided through the analysis of a large soft-bottom benthic macroinvertebrates dataset of the Central Mediterranean Sea. Decapod crustacean assemblages were collected in the last twenty years by a Van Veen grab in 42 study sites located along the Italian coasts at depths ranging from 1 up to 120 m. The spatial distribution of the crustaceans examined, which include 120 species belonging to 40 families, was investigated according to the biogeographical zones identified in the Italian seas. The spatial distribution of 36 species was updated, comparing the ISPRA decapod crustacean dataset with the most recent Italian checklists. For the species updated, the number of specimens, the year and season of sampling, and environmental data, such as the bathymetric range and habitat details, are provided for each site investigated. Data are discussed and compared with the existing literature, also referring to what is reported in the World Register of Marine Species (WoRMS), with the aim of contributing to the knowledge of the biodiversity of the marine species and supporting the updating of checklists and registers in the Mediterranean Basin. [ABSTRACT FROM AUTHOR]

The population parameters of the ecologically important mud shrimp Upogebia major (De Haan, 1841) were analyzed from 2012 to 2015 in tidal flats in Seonjaedo and Jugyo on the west coast of Korea. The shrimp density averaged 265/m2 in Seonjaedo and 118/m2 in Jugyo. The sex ratio varied monthly, often male-biased, and, by size, males were significantly dominant, with a carapace length (CL) over 30 mm. Although the shrimp settled almost annually, only a single size-group was observed from 2012 to 2014. The recruitment in Jugyo in 2014 was notably successful, resulting in two cohorts persisting until 2015. Many shrimp were parasitized at varying local rates: 6.0% in Seonjaedo and 37.1% in Jugyo. The growth curves revealed that the shrimp grew annually after settlement, reaching CLs of 11.90, 18.24, and 23.02 mm in Seonjaedo and 13.73, 20.86, and 25.82 mm in Jugyo. Annual mortality was 77.2% in Seonjaedo and 67.4% in Jugyo. The estimated lifespan (tmax) was 10 years in Seonjaedo and 8 years in Jugyo, whereas the 2010 cohort in Jugyo largely disappeared in 5 years. Ovigerous females appeared from November to June and benthic juveniles between June and September. The shrimps' growth was slower relative to other East Asian populations, likely due to colder sea water temperatures and altered food conditions from a higher shrimp density. [ABSTRACT FROM AUTHOR]

Decapod crustaceans have tooth-like white denticles that are present only on the pinching side of the claws. In the mud crab, Scylla serrata, a huge denticle exists on the movable finger of the dominant claw. This is mainly used to crush the shells of the crab's staple food. The local mechanical properties, hardness (HIT) and elastic modulus (Er), of the peak and valley areas of the largest denticle were examined via a nanoindentation test. The microstructure and elemental composition were characterized using a scanning electron microscope and energy-dispersive X-ray spectroscopy. The striation patterns originating from a twisted plywood structure parallel to the surface were visible over the entire denticle. Most of the largest denticle was occupied by a hard area without phosphorus, and there was a soft layer corresponding to the endocuticle with phosphorus in the innermost part. The HIT of the denticle valley was about 40% lower than that of the denticle peak, and the thickness of the soft endocuticle of the denticle valley was five times thicker than that of the denticle peak. The HIT–Er map showed that the abrasion resistance of the denticle surface was vastly superior and was in the top class among organisms. The claw denticles were designed with the necessary characteristics in the necessary places, as related to the ecology of the mud crab. [ABSTRACT FROM AUTHOR]

Plankton communities often consist of cosmopolitan species with an extensive gene flow between populations. Nevertheless, populations of some plankton species are genetically structured, owing to various barriers such as ocean currents, hydrological fronts, and continents. Drivers that could explain the genetic structures of most mesopelagic species remain unknown on an ocean-basin scale, and our study aims to analyze the genetic and morphological differences between populations of a cosmopolitan mesopelagic shrimp, Systellaspis debilis, from the Southern and Northern Atlantic Ocean, and the Southwest Indian Ocean. We analyzed the ITS-1 and COI markers of 75 specimens and assessed the genetic integrity and within-species variability of these genes. We also coded 32 morphological characteristics in 73 specimens, analyzed their variability, and assessed the correlation between morphological and genetic characteristics using a Redundancy analysis and Mantel test. Systellaspis debilis was genetically cohesive across the whole Atlantic and Southwest Indian Oceans, which is possibly a result of an intensive gene flow through ecological barriers, the resistance of species to hydrological gradients, a purifying selection of mitochondrial genes, etc. In contrast, we found significant morphological differences between populations from different regions, which mirrors morphological diversification and calls for further genomic approaches in order to understand the basis of these variations and uncover potential local adaptations. [ABSTRACT FROM AUTHOR]

To further understand the origin and evolution of Palaemonidae (Decapoda: Caridea), we determined the mitochondrial genome sequence of Palaemon macrodactylus and Palaemon tenuidactylus. The entire mitochondrial genome sequences of these two Palaemon species encompassed 37 typical genes, including 13 protein-coding genes (PCGs), 2 ribosomal RNA genes (rRNAs), and 22 transfer RNA genes (tRNAs), and a control region (CR). The lengths of their mitochondrial genomes were 15,744 bp (P. macrodactylus) and 15,735 bp (P. tenuidactylus), respectively. We analyzed their genomic features and structural functions. In comparison with the ancestral Decapoda, these two newly sequenced Palaemon species exhibited a translocation event, where the gene order was trnK-trnD instead of trnD-trnK. Based on phylogenetic analysis constructed from 13 PCGs, the 12 families from Caridea can be divided into four major clades. Furthermore, it was revealed that Alpheidae and Palaemonidae formed sister groups, supporting the monophyly of various families within Caridea. These findings highlight the significant gene rearrangements within Palaemonidae and provide valuable evidence for the phylogenetic relationships within Caridea. [ABSTRACT FROM AUTHOR]

Decapod crustaceans have tooth-like denticles on their claw fingers, which come into direct contact with predators and prey. Since the denticles are subject to more frequent and intense stress than other parts of the exoskeleton, they must be especially resistant to wear and abrasion. We clarified the mechanical resistance and tissue structure of the denticles arranged in a line on the fixed finger of the mud crab, which has huge claws. The denticles of the mud crab are small at the fingertip and become larger closer to the palm. The denticles have a twisted-plywood-pattern structure stacked parallel to the surface regardless of size, but the abrasion resistance strongly depends on the size of the denticles. Due to the dense tissue structure and calcification, the abrasion resistance increases as the denticle size increases, reaching its maximum at the denticle surface. The denticles of the mud crab have a tissue structure that prevents them from breaking when pinched. The high abrasion resistance of the large denticle surface is an essential feature for the frequent crushing of shellfish, which is the mud crab's staple food. The characteristics and tissue structure of the claw denticles on the mud crab may provide ideas for developing stronger, tougher materials. [ABSTRACT FROM AUTHOR]

Simple Summary: The shrimp Penaeus aztecus, native to the western Atlantic, was first reported in the Mediterranean Sea (Bay of Antalya, Southern Turkey) in 2010. In the following years, it proved its invasiveness with multiple records from all over the Mediterranean except the westernmost sector and the North Adriatic Sea. Several pieces of evidence suggest that the unintentional transport of larvae in the ballast waters of transoceanic vessels departing from the U.S. West Coast, instead of the escape of adults from unreported experimental shrimp farming, is the more likely pathway of the introduction of P. aztecus in the Mediterranean Sea. The accurate scrutiny of scientific literature on non-indigenous species brought to light an earlier (2005) arrival in the Black Sea, which passed unnoticed as the shrimps were misidentified as Penaeus semisulcatus, also a non-indigenous species, which is established and exploited in the Levant Sea since 90 years. But it is native to the Indo-Pacific region, other misidentifications were also found, therefore morphological characters allowing correct identification of the two species and of the autochthonous Penaeus kerathurus are illustrated. Non-indigenous species are among the descriptors adopted in the Marine Strategy Framework Directive for determining the good environmental status of marine waters in the European States, hence the importance of their correct identification. The shrimp Penaeus aztecus, native to the western Atlantic, was first reported in the eastern Mediterranean Sea in 2010. New records, from different Mediterranean localities, multiplied in the following years. The accurate search of the literature on non-indigenous species discovered it was misidentified more than once as another alien shrimp, P. semisulcatus, native to the Indo-Pacific region, with the result that its earlier presence in the Black Sea went unnoticed. Morphological characteristics allowing the identification of these two species, the autochthonous P. kerathurus and two other alien Penaeus species present in the Mediterranean, are reprised. The present distribution of P. aztecus based on literature records and surveys carried out in the northern and central Adriatic between 2016 and 2021 is mapped. The unintentional transport of larvae carried in ballast water by transoceanic vessels departing from the U.S. East Coast is suggested as the most probable introduction pathway. The significance of the correct identification of non-indigenous species, a "Descriptor" adopted in the Marine Strategy Framework Directive for determining the good environmental status of marine waters in the European States, is emphasized. [ABSTRACT FROM AUTHOR]

Complete mitochondrial genome (mitogenome) sequences can provide useful and varied information for evolutionary and phylogenetic studies. We report the first complete mitogenome sequence of the bumblebee shrimp (Gnathophyllum americanum). The mitogenome is 15,842 bp in length and contains 13 protein-encoding genes, 2 ribosomal RNA genes, and 22 transfer RNA genes. The nucleotide composition of the mitogenome was as follows: A,36.72%; T,29.62%; C,21.0%; and G,12.66%. The most common start and stop codons are ATG and TAA, respectively. The MGO (mitochondrial gene order) of G. americanum and Hymenocera picta is unique in Decapoda. Both the phylogeny based on mitochondrial genomic DNA data and the unique MGO pattern indicate that the genus Gnathophyllum might be a sister genus to the genus Hymenocera. The mitogenomic sequence data obtained in this study will provide more information on G. americanum for species identification, population genetics, and biogeography. [ABSTRACT FROM AUTHOR]

Simple Summary: Current European legislation that protects animals used for scientific purposes excludes decapod crustaceans (for example, lobster, crab and crayfish) on the grounds that they are non-sentient and, therefore, incapable of suffering. However, recent work suggests that this view requires substantial revision. Our current understanding of the nervous systems and behavior of decapods suggests an urgent need to amend and update all relevant legislation. This paper examines recent experiments that suggest sentience and how that work has changed current opinion. It reflects on the use of decapods as models in biomedical research and in ecotoxicology, and it recommends that these animals should be included in the European protection legislation. Decapod crustaceans are widely used as experimental models, due to their biology, their sensitivity to pollutants and/or their convenience of collection and use. Decapods have been viewed as being non-sentient, and are not covered by current legislation from the European Parliament. However, recent studies suggest it is likely that they experience pain and may have the capacity to suffer. Accordingly, there is ethical concern regarding their continued use in research in the absence of protective measures. We argue that their welfare should be taken into account and included in ethical review processes that include the assessment of welfare and the minimization or alleviation of potential pain. We review the current use of these animals in research and the recent experiments that suggest sentience in this group. We also review recent changes in the views of scientists, veterinary scientists and animal charity groups, and their conclusion that these animals are likely to be sentient, and that changes in legislation are needed to protect them. A precautionary approach should be adopted to safeguard these animals from possible pain and suffering. Finally, we recommend that decapods be included in the European legislation concerning the welfare of animals used in experimentation. [ABSTRACT FROM AUTHOR]

Simple Summary: Animals that are capable of suffering from pain and distress should be protected when they are being submitted to circumstances that could provoke suffering, such as experimental surgery or killing for human consumption. In terrestrial animals used for scientific purposes and food production, evidence of their capacity to experience pain has led to their legal protection. Recent studies have suggested a pain-like experience in decapod crustaceans. As a consequence, the UK Government has recently recognized decapods as sentient beings. Similarly, some countries have imposed recommendations for the handling, transport, and stunning prior to killing of decapods (Australia, New Zealand, Norway, and Switzerland), acknowledging that suffering during slaughter has a high risk for their welfare. Drugs and methods that may act as anesthetics rendering crustaceans unconscious as well as analgesics or pain-relievers are reviewed here, and other non-decapod crustaceans such as amphipods, brachiurids, branchiopods, copepods, ostracods, and isopods are also included. We developed a detailed on-line tool available publicly that scientists and other stakeholders can employ to search for the most effective methods that effectively anesthetize different crustacean species. This novel tool will also help to identify gaps in existing knowledge so that new drugs or species can be explored in future studies. Methods to induce analgesia and anesthesia for research purposes, handling, transport, or stunning have been used in 71 species of crustaceans. A non-systematic literature search was conducted on crustacean anesthetic methods. This review presents a comprehensive evaluation of drugs and non-chemical methods used to provide analgesia and anesthesia in many crustacean species rather than just decapod crustaceans. This information allows users to select an appropriate method or agent for their species of interest. We prepared an on-line tool based on datasette, a no-code open-source solution for simple web-based database frontends that allows exploration and downloading data by method, analgesic/anesthetic, species, life stage, or sex, as well as other data including environmental conditions (temperature, salinity, light), route of administration, dosage, and induction and recovery times. These values can be selected to filter the dataset and export it to CSV or JSON formats. Currently, several techniques and chemicals are, in our opinion, unsuitable for use as anesthetics in crustaceans, and the basis for these opinions are presented. Given the evidence of a pain-like experience in crustaceans, we propose that researchers should treat crustaceans humanely, applying the principles of good handling, care, and the management of stress and pain to safeguard their welfare. [ABSTRACT FROM AUTHOR]

Decapod crustaceans are ecologically and commercially important members of marine communities. Faunal surveys constitute essential tools for the understanding of local diversity, especially in areas subjected to significant alterations of community composition due to climate changes, anthropogenic impacts, and biological invasions. Following a literature review and the study of new samples, we hereby update on the Crustacea Decapoda from the Rhodes Island area (Greece), situated in a key position in the eastern Mediterranean Sea. Published data yielded records of 120 species, whereas 28 taxa are recorded here for the first time from the study area. Among them, the collection of Liocarcinus bolivari widens its distribution to the eastern Mediterranean. Details on material examined and distributional/faunal remarks are provided for the species newly recorded and for some other native and alien species rarely reported from Rhodes. The present paper raises the local decapod biodiversity to 148 species, accounting for ~50% of the Hellenic Aegean decapod fauna and provides a useful baseline for analysing the long-term changes in the local fauna and the westward spreading of Lessepsian species. Despite present advances, the lack of records of many common Mediterranean species may be still due to limited fieldwork in some habitats rather than a true absence. [ABSTRACT FROM AUTHOR]

Crustaceans are a key component of the fauna living in rhodoliths, but patterns in their distribution and abundance remain largely unknown. This paper assessed spatio-temporal variability of Brachyura associated with rhodoliths. A seasonal study was conducted at three depth layers (18, 25, and 40 m), throughout two years (December 2015 to October 2017) at Gran Canaria Island (eastern Atlantic Ocean). A total of 765 crabs belonging to 10 species were collected. A larger abundance and richness of crabs at 25 m correlated with a larger biomass of epiphytic algae attached to rhodoliths. A seasonal pattern was also observed, where a higher richness of crabs occurred in the summer. The Xanthid crab, Nanocassiope melanodactylus, dominated the assemblage (83%); juveniles of this species were more abundant in deeper waters (40 m), while adults were more abundant on the shallower depth layers (18 m and 25 m). The species Pilmunushirtellus was restricted to 25 m. Nevertheless, Pisa carinimana and Achaeuscranchii did not show any spatio-temporal pattern. In summary, this study demonstrated that two conspicuous crabs, N. melanodactylus and P. hirtellus, associated with rhodolith beds are bathymetrically segregated. [ABSTRACT FROM AUTHOR]

We describe and diagnose a new species of Acanthephyra (Acanthephyridae: Caridea: Decapoda) and provide an amended key to all species of the genus. In order to assess the taxonomic position of the new species, we examined and coded 55 characters in available specimens of Acanthephyra and ran morphological phylogenetic analyses. We also used a COI gene marker for molecular analyses of the new species and other available specimens of Acanthephyra. Both analyses retrieved an unexpected grouping of species that contradicted a recently accepted morphological grouping. We tested a new, quantitative, set of characters and found that three of them may explain the molecular grouping of the genus. These characters are linked to: (1) proportions of the 6th pleonic somite, (2) length of the same against carapace length, and (3) length of the same against length of two preceding somites. We suggest that these characters mirror evolutionary traits in Acanthephyra and discuss their possible adaptive sense. [ABSTRACT FROM AUTHOR]

Simple Summary: Plastic litter is ubiquitous in the marine environment due to its rapid dispersion and great durability. Furthermore, several environmental processes can modify the characteristics of plastics, altering their density and, consequently, their likelihood of sinking. In fact, deep-sea environments are highly threatened by plastic waste, with a greater risk for benthic species. The Ionian Sea is heavily impacted by man-made floating debris, accumulated on beaches or on the seabed. The aim of this work was to evaluate the presence of anthropogenic debris in the gastrointestinal tracts of three decapods (Parapenaeus longirostris, Aristeus antennatus, Aristaeomorpha foliacea) from the southwestern Ionian Sea. A total of 230 anthropogenic debris were isolated from 136 specimens, with a high frequency of occurrence in all analyzed species (76% in P. longirostris, 70% in A. antennatus and 83% in A. foliacea) mainly represented by fibers (92.6%) with a size between 0.10 and 0.49 mm, and with a predominance of blue color. The results of this study, highlight the importance of expanding knowledge on these Decapoda species of high commercial and ecological value, in a heavily impacted basin, such as the Sea Mediterranean, helping to monitor possible risks to human health. Deep Sea environments represent the final collector of anthropogenic debris mainly represented by both plastic and non-plastic materials with different size. This led to potential contamination of deep marine fauna due to direct and indirect ingestion, representing a potential hazard for the species itself and for the final consumer. In this framework, the present study explored the occurrence of anthropogenic debris in the gastrointestinal tract of three Decapoda species of high commercial and ecological value (Parapenaeus longirostris, Aristeus antennatus, and Aristaeomorpha foliacea) from south-western Ionian Sea. After morphometrical measurements and sex determination, the gastrointestinal tract of 136 specimens were extracted and then chemically digested. A total of 230 low density microparticles were isolated, with a high frequency of occurrence in all the analyzed species (76% in P. longirostris, 70% in A. antennatus, and 83% in A. foliacea) mainly represented by fibers (92.6%) with a size between 0.10 and 0.49 mm, and with a dominance of the blue color. The results of the present study report for the first time the anthropogenic debris presence in the studied Decapoda from south-western Ionian Sea, highlighting the necessity to broaden the knowledge about anthropogenic debris pollution status in Mediterranean deep-sea species. [ABSTRACT FROM AUTHOR]

Silicified ostracods from the Tin Mountain Limestone provide new information regarding the Carboniferous paleontology of the Death Valley Region, California, USA. Acid maceration of marine limestones yielded the following ostracods: Acratia spp., Bairdia quasilecta, Bairdia sp. cf. B. orientalis, Ceratobairdia sp., Kirkbya panamintensis sp. nov., Rectobairdia sp. cf. R. legumen, and Silenites sp. This is the first report of Ceratobairdia and Silenites from the Tin Mountain Limestone. These ostracods occupied a carbonate ramp environment that formed during a major Paleozoic transgression. The ostracods played an important paleoecological role, likely as benthic marine scavengers in a shallow marine biotope along the northern shores of Pangea. [ABSTRACT FROM AUTHOR]

Carnivorous sponges (family Cladorhizidae) use small invertebrates as their main source of nutrients. We discovered a novel iridovirus (carnivorous sponge-associated iridovirus, CaSpA-IV) in Chondrocladia grandis and Cladorhiza oxeata specimens collected in the Arctic and Atlantic oceans at depths of 537–852 m. The sequenced viral genome (~190,000 bp) comprised 185 predicted ORFs, including those encoding 26 iridoviral core proteins, and phylogenetic analyses showed that CaSpA-IV is a close relative to members of the genus Decapodiridovirus and highly identical to a partially sequenced virus pathogenic to decapod shrimps. CaSpA-IV was found in various anatomical regions of six C. grandis (sphere, stem, root) from the Gulf of Maine and Baffin Bay and of two C. oxeata (sphere, secondary axis) from Baffin Bay. Partial MCP sequencing revealed a divergent virus (CaSpA-IV-2) in one C. oxeata. The analysis of a 10 nt long tandem repeat showed a number of repeats consistent across sub-sections of the same sponges but different between animals, suggesting the presence of different strains. As the genetic material of crustaceans, particularly from the zooplanktonic copepod order Calanoida, was identified in the investigated samples, further studies are required to elucidate whether CaSpA-IV infects the carnivorous sponges, their crustacean prey, or both. [ABSTRACT FROM AUTHOR]

Simple Summary: The use of decapods (such as lobsters and crabs) and cephalopods (such as octopuses and cuttlefish) by humans for food, experimentation and education (e.g., in zoos and aquariums) is on the increase. Growing evidence that these species have feelings and can experience emotions has highlighted the need for a tool to monitor the welfare of these species in captivity. This study adapted a welfare monitoring tool, the Animal Welfare Assessment Grid, that has been successfully used with a variety of mammal and bird species, for use with decapods and cephalopods. This tool was then trialed at a zoological institution (Marwell Zoo, UK) and, for the first time, a public aquarium (National Marine Aquarium, UK), with the intention of showing how data collected on invertebrates in a zoological environment can be both efficiently and easily applied to implement positive welfare. This study highlights how evaluating the welfare impact of management processes using animal-based indicators can lead to improved welfare outcomes. Consumer demand for invertebrates is on the rise as their numbers in the wild dwindle. However, with the growing conservation efforts of modern zoos and aquariums, and evidence from over 300 studies showing that invertebrates are capable of sentience, public interest, and moral concern for welfare of invertebrates have increased. The challenge for zoos and aquariums is in developing an objective and repeatable method for evaluating welfare that can be applied to invertebrates in zoological collections. Recently introduced into zoological collection management is the Animal Welfare Assessment Grid (AWAG). The AWAG helps to identify negative and positive welfare states, through assessing animal- and environmental-based indicators to make changes that lead to a better quality of life. Originally developed for the assessment of laboratory primates, the system has been successfully adapted to assess a variety of taxa across different environments, facilitated by the development of cloud-based software. In this study, the AWAG has been adapted to assess the cumulative lifetime experience of captive decapods and cephalopods at two different institutions, Marwell Zoo and National Marine Aquarium. This study has provided further evidence that the AWAG is adaptable and demonstrates the first time any objective scoring system has been successfully adapted for use in invertebrates. Through graphical representation, the results show that the AWAG identifies changes in welfare scores that can be attributed to specific events and can be used to predict the future vulnerability of species to welfare changes and suggest alternative management methods. This monitoring tool provides a versatile method of implementing practical welfare monitoring in zoos and aquariums. [ABSTRACT FROM AUTHOR]

This is the first report on the use of a taste sensing system to quantitatively evaluate the taste attributes of two groups of native "June hairy crab" juveniles (commonly referred to as "Liu-Yue-Huang") of the Chinese mitten crab (Eriocheir Sinensis H. Milne Edwards, 1853) from a net enclosure culture area in Yangcheng Lake (lake culture) and aquaculture ponds near the lake (pond culture). We showed that umami was the predominant basic taste of steamed June hairy crabs, followed by bitterness and astringency. The intensity value of saltiness was aberrant and could not be determined using this system. The average values of aftertaste-U reached 8.7 and 10.7 in the male June hairy crabs from the lake and pond cultures, respectively, which was significantly higher than their respective aftertaste-B and aftertaste-A values (p < 0.01). Female crabs did not have aftertaste-B, while their aftertaste-U was significantly higher than aftertaste-A (p < 0.01). Although principal component analysis and linear discriminant analysis were not able to completely distinguish among crabs from different cultures, they could robustly distinguish between male and female crabs. [ABSTRACT FROM AUTHOR]

Finally, a Zeiss laser scanning confocal microscope (LSM880, Carl Zeiss, Oberkochen, Germany) was used to observe the distribution of Mr-KIFC1 and Mr-Acrosin and the colocalization status of Mr-KIFC1 and AFS. At the same time, during the entire process of spermatogenesis in I M. rosenbergii i , Mr-KIFC1 localization was closely linked to nucleus reshaping (Figure 10a3-f3), which may explain the function of Mr-KIFC1 as a motor protein involved in sperm nucleus deformation. The above results indicate that Mr-Acrosin and Mr-KIFC1 are both involved in spermatogenesis and that Mr-Acrosin is transported by Mr-KIFC1, which leads us to speculate that Mr-KIFC1 may transport Mr-Acrosin along the AFS structure to the acrosome to exert protease-like effects and participate in the sperm-egg union in I M. rosenbergii i . 5. We also discovered that microtubules formed an umbrella-shaped AFS structure, and Mr-KIFC1 signals overlapped with tubulin, which may suggest that AFS act as scaffolds for Mr-KIFC1 to transport cargoes that are later organized into functional acrosomes. Multiple Sequence Alignment, Phylogenetic Evolutionary Tree Analysis and Protein Structu... The putative protein sequences of Mr-KIFC1 and Mr-Acrosin were obtained by the online sequence processing toolkit SMS (http://www.bio-soft.net/sms/, accessed on 10 March 2021). [Extracted from the article]

The current knowledge of Sicilian inland water decapod malacostracans is scarce and an updated synopsis on species distribution is lacking. Therefore, we reviewed the checklist and recent distribution of Sicilian inland water decapods based on published and unpublished records and novel observations with the aim of providing an exhaustive repository, also to be used as a sound baseline for future surveys. Overall, five native decapod species occur in the study area, i.e., the atyid shrimp Atyaephyra desmarestii, the palaemonid shrimps Palaemon adspersus, P. antennarius, and P. elegans, and the freshwater crab Potamon fluviatile, and their current local distributions are described. In addition, three alien species were recorded: the common yabby Cherax destructor and the red swamp crayfish Procambarus clarkii, strictly linked to inland waters, and the Atlantic blue crab Callinectes sapidus, a mainly marine species that can also colonise the lower stretches of rivers and coastal brackish waters. The collected data suggest the existence of a partial segregation of native versus non-native species, with the latter currently confined to coastal water bodies and the lower stretches of rivers. Moreover, the exclusively freshwater caridean A. desmarestii and P. antennarius show a parapatric distribution in the study area, which may suggest the existence of mutual exclusion phenomena. The results obtained raise some concerns about the effects of alien species on the native biota, and dedicated monitoring and management strategies should be implemented in order to better understand and mitigate their impact. [ABSTRACT FROM AUTHOR]

Decapod crustaceans are important components of the fauna of marine caves worldwide, yet information on their ecology is still scarce. Mediterranean marine caves are perhaps the best known of the world and may offer paradigms to the students of marine cave decapods from other geographic regions. This review summarizes and updates the existing knowledge about the decapod fauna of Mediterranean marine caves on the basis of a dataset of 76 species from 133 caves in 13 Mediterranean countries. Most species were found occasionally, while 15 species were comparatively frequent (found in at least seven caves). They comprise cryptobiotic and bathyphilic species that only secondarily colonize caves (secondary stygobiosis). Little is known about the population biology of cave decapods, and quantitative data are virtually lacking. The knowledge on Mediterranean marine cave decapods is far from being complete. Future research should focus on filling regional gaps and on the decapod ecological role: getting out at night to feed and resting in caves during daytime, decapods may import organic matter to the cave ecosystem. Some decapod species occurring in caves are protected by law. Ecological interest and the need for conservation initiatives combine to claim for intensifying research on the decapod fauna of the Mediterranean Sea caves. [ABSTRACT FROM AUTHOR]

Biotic introductions are an ongoing disruption for many ecosystems. For passively dispersed freshwater zooplankton, transcontinental introductions have been common but are poorly studied in the southern hemisphere. Here we assess the hypothesis of recent introduction for populations of the Chydorus sphaericus group (Crustacea: Cladocera) in Australia. We analyzed 254 sequences (63 original sequences) from the cytochrome oxidase I region of mitochondrial DNA of Chydorus sp., which included global representation. Three Australian populations were connected with separate clades in the northern hemisphere, suggesting multiple colonization events for Australia. The timescale of the divergences was consistent with recent (Quaternary) dispersal. As Australian populations are exposed to migrating birds from the northern hemisphere, both avian and anthropogenic sources are candidates for dispersal vectors. We concluded that recent cross-hemisphere dispersal in the Chydorus sphaericus group is more common than previously believed. [ABSTRACT FROM AUTHOR]

Some decapod crustaceans have tooth-like white denticles that exist only on the pinching side of claws. We revealed the denticle microstructure in the coconut crab, Birgus latro, using optical and scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and a focused ion beam (FIB)-SEM. Three-dimensional analysis and fracture surface observation were performed in order to clarify the microstructural differences in two mineralized layers—the exocuticle and the endocuticle. The denticles consist of a columnar structure normal to the surface and are covered with a very thin epicuticle and an exocuticle with a twisted plywood pattern structure. Due to abrasion, the exocuticle layer was lost in the wide area above the large denticles; conversely, these layers remained on the surface of the relatively small denticles and on the base of the denticle. The results showed that the mineralized exoskeleton of the crab's claw is classified into three structures: a twisted plywood pattern structure stacked parallel to the surface for the exocuticle, a porous structure with many regularly arranged pores vertical to the surface for the endocuticle, and a columnar structure vertical to the surface for the denticle. [ABSTRACT FROM AUTHOR]

The southern king crab, Lithodes santolla, is a well-known predator/scavenger species during its adult phase but its feeding strategy in early stages is less studied. This information is important to understand their role in ecosystems and to improve fishery management (i.e., stock enhancement). Based on stomach contents and stable isotope analysis, we determined variation in the composition of diet and niche overlap in vagile and cryptic phase collected within and outside a kelp forest, Macrocystis pyrifera, of Aguila Bay at the Magellan Strait in Patagonia, Chile. Results of juvenile stomach content analysis showed 60% dissimilarity between cryptic and vagile juvenile phases. Algae dominated the volumetric contribution in cryptic juveniles while crustacean dominated the diet in vagile phase. Exoskeleton of other king crabs occurred in 43% of juveniles with crustaceans in their stomach. This fact confirms cannibalistic behavior in the wild in this species, which is consistent with findings in massive laboratory cultures. There was no evidence of isotopic niche shift between cryptic and vagile juvenile phases. Overlapping isotopic niches of different-sized juveniles suggest that they exploit similar food resources. However, vagile individuals occupy a higher trophic position than cryptic individuals, which could suggest a switch in dietary preference, from detritivorous/herbivory within kelp forests to omnivory outside of kelp forests, and an increase in the level of cannibalism in vagile juveniles. [ABSTRACT FROM AUTHOR]

The deep sea is the largest biome on Earth and hosts the majority of as yet undescribed species; description of these may trigger a new mindset about evolution and function of characters. We describe and diagnose a new genus and species Sclerodora crosnieri sp. nov. belonging to the superfamily Oplophoroidea. We examined and coded 81 characters for morphological analyses and used four gene markers for molecular analyses involving the new taxon and representatives of all other genera of Oplophoroidea. Retrieved morphological and molecular trees were similar and suggested that the new genus is a sister group to Hymenodora and both form a clade sister to the rest of Acanthephyridae. We provide an amended key to all genera of Oplophoroidea. We found an unusual chelate structure on the dactyl of the fifth pereopod, tested and confirmed a hypothesis that this structure is common for the whole family Acanthephyridae. We suggest that this derived structure is linked to an active cleaning of branchia—a function associated with chelipeds in some other carid shrimps. Convergent chelate structures are likely efficient for cleaning branchia, whichever appendage is adapted for these functions. In Oplophoridae (sister to Acanthephyridae), cleaning function is carried out by well-developed epipods. [ABSTRACT FROM AUTHOR]

Achelata (Palinuridae and Scyllaridae) have a flat, transparent, long-lived planktonic larva called phyllosoma, which comprises multiple stages and has a duration from a few weeks (some scyllarids) to >20 months (some palinurids). The larval development of many Achelata occurs in oceanic waters, where conventional plankton nets usually collect the early- to mid-stages but not the later stages, which remain poorly known. We examined the diversity and distribution of mid- and late-stage phyllosomata in the oceanic waters of the Mexican Caribbean, where the swift Yucatan Current is the dominant feature. The plankton samples were collected at night with a large mid-water trawl in autumn 2012 (55 stations) and spring 2013 (34 stations). In total, we obtained 2599 mid- and late-stage phyllosomata (1742 in autumn, 857 in spring) of five palinurids (Panulirus argus, Panulirus guttatus, Panulirus laevicauda, Palinurellus gundlachi, Justitia longimana) and three scyllarids (Parribacus antarcticus, Scyllarides aequinoctialis, Scyllarus chacei). Overall, the mid-stages were ~2.5 times as abundant as the late stages. The palinurids far outnumbered the scyllarids, and P. argus dominated over all the other species, followed at a distance by P. guttatus. The densities of all the species were generally low, with no clear spatial pattern, and the phyllosomata assemblage composition greatly overlapped between seasons. These results suggest the extensive mixing of the organisms entrained in the strong Yucatan Current, which clearly favors the advection of the phyllosomata in this region despite the presence of some local sub-mesoscale features that may favor short-term retention. [ABSTRACT FROM AUTHOR]

The identification of deep-sea (>200 m) pelagic larvae is extremely challenging due to the morphological diversity across ontogeny and duration of larval phases. Within Decapoda, developmental stages often differ conspicuously from their adult form, representing a bizarre and mysterious world still left to be discovered. The difficulties with sampling and rearing deep-sea larvae, combined with the lack of taxonomic expertise, argues for the use of molecular methods to aid in identification. Here, we use DNA barcoding combined with morphological methods, to match larval stages with their adult counterpart from the northern Gulf of Mexico and adjacent waters. For DNA barcoding, we targeted the mitochondrial ribosomal large subunit 16S (16S) and the protein coding cytochrome oxidase subunit 1 (COI). These data were combined with previous sequences to generate phylogenetic trees that were used to identify 12 unknown larval and two juvenile species from the infraorder Caridea and the suborder Dendrobranchiata. Once identified, we provide taxonomic descriptions and illustrations alongside the current state of knowledge for all families. For many groups, larval descriptions are missing or non-existent, so this study represents a first step of many to advance deep-sea larval diversity. [ABSTRACT FROM AUTHOR]

This study records the number of Peracarida (Cumacea, Isopoda, Mysida, Lophogastrida and Tanaidacea) from Algerian coastal waters. A total of 170 species are reported with the highest richness observed in the Isopoda (71 species), then the Cumacea with 43 species, the Mysida and Tanaidacea with 27 species each and the Lophogastrida with only two species. The diversity of Peracarida in Algeria is high, corresponding to 60% of the species recorded for the Mediterranean Sea. A geographical analysis of the distribution of the species shows that the Algerian fauna has a close similarity with taxa reported from both the European and African coasts of the Atlantic Ocean. This reflects the influence of Atlantic waters along the North African coasts extending from Morocco to Tunisia in the south of the Mediterranean Sea, which is related to the connection via the Strait of Gibraltar. For the Algerian coasts only five Peracarida species may be considered as Non-Indigenous Species. [ABSTRACT FROM AUTHOR]

Simple Summary: Examination of preferences of an aquarium "Red Cherry" shrimp for differently coloured backgrounds revealed common traits, irrespective of shrimp body colouration. The shrimp selected dark backgrounds and coarse patterns over light and fine patterned substrata. Thus, the use of materials with dark and uniform colouration can contribute to designing proper monitoring tools to detect biological invasions after releasing this pet into the wild, as well as to provide shrimp with comfortable conditions in captivity. An ornamental freshwater shrimp, Neocaridina davidi, is popular as an aquarium hobby and, therefore, a potentially invasive species. There is a growing need for proper management of this species to determine not only their optimum breeding conditions, but also their ability to colonise novel environments. We tested habitat preferences of colour morphs (brown, red, white) of N. davidi for substratum colour (black, white, grey shades, red) and fine or coarse chess-board patterns to recognise their suitable captivity conditions and predict their distribution after potential release into nature. We conducted laboratory choice experiments (n = 8) with three individuals of the same morph exposed for two hours to a range of backgrounds. Shrimp preferred dark backgrounds over light ones irrespective of their own colouration and its match with the background colour. Moreover, the brown and red morphs, in contrast to the white morph, preferred the coarse background pattern over the finer pattern. This suggests that the presence of dark, uniform substrata (e.g., rocks, macrophytes) will favour N. davidi. Nevertheless, the polymorphism of the species has little effect on its total niche breadth, and thus its invasive potential. [ABSTRACT FROM AUTHOR]

The Yucatán Peninsula is a karstic region, rich in subterranean environments with a diverse crustacean stygobiont fauna. In order to gain insights into the biological evolution of the subterranean environments of this region, we evaluated the ostracode species composition of caves and cenotes in five independent sampling campaigns (2008, 2013, 2017–2019). Using morphometric analyses, we evaluated inter-population morphological variability; using molecular analysis based on mitochondrial COI and nuclear 18S rDNA, we evaluated genetic differentiation in selected species. The observed fauna is composed of 20 (epigean) species, presenting a lack of strict stygobionts. Morphometric analyses discriminated up to three morphotypes in each of the three most abundant species: Cytheridella ilosvayi, Alicenula sp. and Cypridopsis vidua. High intraspecific morphological variability was found either in shape or size. Phylogenetic analysis based on COI demonstrated the existence of three lineages on C. ilosvayi, with high support (>0.9). The 18S rDNA sequences were identical among individuals of different populations. A lack of congruence between the genetic markers precluded us from postulating speciation in subterranean environments. It is likely that Late Pleistocene—Early Holocene climate variation related to sea level and precipitation was forcing agent for epigean ostracode dominance in subterranean environments of the Peninsula. [ABSTRACT FROM AUTHOR]

Hemocyanins are copper-binding proteins that play a crucial role in the physiological processes in crustaceans. In this study, the cDNA encoding hemocyanin subunit 5 from the Black sea crab Eriphia verrucosa (EvHc5) was cloned using EST analysis, RT-PCR and rapid amplification of the cDNA ends (RACE) approach. The full-length cDNA of EvHc5 was 2254 bp, consisting of a 5′ and 3′ untranslated regions and an open reading frame of 2022 bp, encoding a protein consisting of 674 amino acid residues. The protein has an N-terminal signal peptide of 14 amino acids as is expected for proteins synthesized in hepatopancreas tubule cells and secreted into the hemolymph. The 3D model showed the presence of three functional domains and six conserved histidine residues that participate in the formation of the copper active site in Domain 2. The EvHc5 is O-glycosylated and the glycan is exposed on the surface of the subunit similar to Panulirus interruptus. The phylogenetic analysis has shown its close grouping with γ-type of hemocyanins of other crustacean species belonging to order Decapoda, infraorder Brachyura. [ABSTRACT FROM AUTHOR]