Identification of Phyllosoma Larvae of the Lobsters Acantharctus and Biarctus (Crustacea: Scyllaridae) from the SW Indian Ocean.

The accurate assignment of cryptic larvae to species-level is a key aspect of marine ecological research and can be achieved through integrated molecular and morphological studies. A combination of two mitochondrial markers (COI and 16S) and a detailed morphological analysis was used to identify phyllosoma larvae of slipper lobster (Scyllaridae) species collected during a survey in the SW Indian Ocean. Two morphotypes were tentatively assigned to Acantharctus ornatus and Biarctus pumilus, both genera for which the larval morphology was unknown. Morphological revision of an adult specimen used to generate the putative A. ornatus sequences in GenBank revealed that it was misidentified and corresponds to B. dubius. The final phyllosoma stage of B. pumilus and subfinal and final stages of A. ornatus were described, clarifying prior misidentifications in the literature. Scyllarid biodiversity in the SW Indian Ocean is underestimated and sampling of deeper water layers is recommended to complete current knowledge of species and larval stages present in the region.

Macrolitter and mesolitter in the Thames Estuary: A temporal litter assessment and brand audit of submerged and riverbed debris.

Macroplastic is a growing concern for marine environments with estuaries providing a major pathway for pollution from land-based sources to the sea. In the Thames Estuary, plastic was abundant floating below the surface and on the riverbed, with an average catch per unit effort of 0.57 ± 0.42 and 2.75 ± 2.44 item per minute respectively. Whilst the abundance of litter differed between midwater and benthic zones, the types of products recovered did not. These were identified through visual examination and use of a unique citizen science engagement protocol, allowing for the item age, brand and countries of origin to be established. The majority of litter from the present study (n = 1335) was packaging (40%), some of which was over 30-years old and may have originated from landfill run off. Also abundant was sewage-related debris, the inputs of which was related to heavy or prolonged rainfall. Peaks in this material were recorded in September 2020 following the greatest volume of rain recorded in a single day and in June 2019 after the longest period of continuous rainfall. The Covid-19 pandemic did not influence the abundance or diversity of plastic recovered between December 2018 and September 2020. The durability of plastic ensures it has high potential for harm through entanglement, deoxygenation of sediment and ingestion. The retention in the environment also increases opportunities to fragment into micro- or nanoplastics and, therefore, it is important to monitor plastics at both a macro- and micro-scale.

A checklist and key to the Ivorian freshwater crabs, with the description of a new species of Liberonautes Bott, 1955 (Brachyura: Potamoidea: Potamonautidae).

A new freshwater crab species of Liberonautes Bott, 1955 from Mt. Tonkori in the Upper Guinea rainforest in Côte d'Ivoire, West Africa is described. Liberonautes constantini n. sp. is morphologically distinct from other species of this genus found in Côte d'Ivoire and the neighboring countries. The new species is recognised by a unique combination of morphological characters of the carapace, thoracic sternum, major cheliped, and adult male first gonopod. Illustrations of L. constantini n. sp. are provided and differences from congeners found elsewhere in West Africa are discussed. The addition of L. constantini n. sp. raises the number of species of freshwater crabs known to occur in Côte d'Ivoire to seven. An updated checklist and key are provided to the Ivorian species of freshwater crabs, and their conservation status is discussed.

Discovery of Buea bangem Mvogo Ndongo, von Rintelen, Tomedi-Eyango & Cumberlidge, 2020 (Crustacea: Potamoidea: Potamonautidae: Liberonautinae) from Mt. Nlonako Wildlife Reserve, Cameroon.

N/A.

Redescription of Arcotheres tivelae (Gordon, 1936), a pea crab endemic to the Persian Gulf and Gulf of Oman (Crustacea: Decapoda: Brachyura: Pinnotheridae).

The taxonomy of the pinnotherid crab, Pinnotheres tivelae (Gordon, 1936), now assigned to Arcotheres Manning, 1993, is revised. Type specimens from Muscat, Gulf of Oman, are compared with extensive material from the type locality and Persian Gulf. Arcotheres tivelae is shown to be a valid species, is redescribed, figured to modern standards and males are reported for the first time. This species had been confused with A. placunae (Hornell Southwell, 1909) from Pakistan and western India, but the two species can be distinguished by the morphology of the carapace, third maxilliped, ambulatory leg features and characters of the male first gonopod. Arcotheres tivelae is morphologically closest to three other species also found in venerid clams, A. exiguus (Brger, 1895), A. rayi Ahyong Ng, 2007, and A. obesus (Dana, 1852), but the distal morphology of its male first gonopod is distinct from its congeners. Furthermore, A. tivelae is recorded from Kuwait for the first time.

A comprehensive molecular phylogeny of the brachyuran crab superfamily Xanthoidea provides novel insights into its systematics and evolutionary history.

Maximum likelihood and Bayesian phylogenies for the brachyuran crab superfamily Xanthoidea were estimated based on three mitochondrial and four nuclear genes to infer phylogenetic relationships and inform taxonomy. Habitat data was then used in conjunction with several diversification rates analyses (BAMM, BiSSE, HiSSE, and FiSSE) to test evolutionary hypotheses regarding the diversification of xanthoid crabs. The phylogenies presented are the most comprehensive to date in terms of global diversity as they include all four constituent families (Xanthidae, Panopeidae, Pseudorhombilidae, and Linnaeoxanthidae) spanning all oceans in which xanthoid crabs occur. Six Xanthoidea families are recognised. Panopeidae and Xanthidae sensu stricto are the two largest family-level clades, which are reciprocally monophyletic. Pseudorhombilidae is nested within and is here treated as a subfamily of Panopeidae. Former subfamilies or tribes of Xanthidae sensu lato are basally positioned clades in Xanthoidea and are here assigned family-level ranks: Garthiellidae, Linnaeoxanthidae, Antrocarcinidae, and Nanocassiopidae. The genera Linnaeoxantho and Melybia were recovered in separate clades with Linnaeoxantho being sister to the family Antrocarcinidae, while Melybia was recovered within the family Panopeidae. The existing subfamily classification of Xanthidae and Panopeidae is drastically restructured with 20 xanthid and four panopeid subfamilies provisionally recognised. Diversification-time analyses inferred the origin of Xanthoidea and Garthiellidae in the Eocene, while the other families originated during the Oligocene. The majority of genus- and species-level diversification took place during the Miocene. Ancestral state reconstruction based on depth of occurrence (shallow vs. deep water) shows some ambiguity for the most recent common ancestor of Xanthoidea and Nanocassiopidae. The most recent common ancestors of Antrocarcinidae and Panopeidae were likely deep-water species, while those of Garthiellidae and Xanthidae were probably shallow-water species. Several shifts in net diversification rates were detected but they were not associated with depth-related habitat transitions.

The Identity of Homoioplax haswelli (Miers, 1884) (Crustacea: Decapoda: Brachyura).

The brachyuran crab Pseudorhombila haswelli Miers, 1884, described on the basis of two juveniles from the Arafura Sea, is a poorly known species of uncertain systematic position. It was made the type and only species of Homoioplax Rathbun, 1914, and assigned to the Prionoplacinae (Goneplacidae). Subsequent revisions of the goneplacids showed Prionoplacinae to be a junior synonym of Eucratopsinae Stimpson, 1871, as a member of the Panopeidae Ortmann, 1893, but no one has re-evaluated the position of Homoioplax. As a result, Homoioplax has remained in the Panopeidae as the only Indo-West Pacific representative of the family. This study assesses the systematic status of Homoioplax haswelli based on a re-examination of the type and other material of the species. Homoioplax haswelli is here attributed to Carcinoplax H. Milne Edwards, 1852 (Goneplacidae), justifying the recognition of the species described by Miers as C. haswelli. Moreover, Carcinoplax haswelli is shown to be a senior synonym of C. sinica Chen, 1984, described from the South China Sea. Therefore, C. haswelli is now known to range from southern Taiwan and the Philippines, through the South China Sea, northern Vietnam, the eastern waters of Singapore to the Madura Straits in eastern Java and Arafura Sea, northern Australia, at 25-187 m, but usually less than 100 m depth.

Phylogenetic relationships among the species of the Cameroonian endemic freshwater crab genus Louisea Cumberlidge, 1994 (Crustacea, Brachyura, Potamonautidae), with notes on intraspecific morphological variation within two threatened species.

Louisea Cumberlidge, 1994 (Crustacea, Brachyura, Potamonautidae) currently includes four endemic Cameroonian freshwater crab species whose phylogenetic relationships were previously unresolved. In the present study, phylogenetic analyses are carried out involving three mtDNA loci (COI, 12S rRNA, and 16S rRNA). The COI locus revealed divergence times of 5.6 million years ago (myr) for when L.balssi (Bott, 1959) diverged from L.edeaensis (Bott, 1969); 4.1 myr for when L.edeaensis diverged from L.yabassi Mvogo Ndongo, von Rintelen & Cumberlidge, 2019; and 2.48 myr for when the later species diverged from L.nkongsamba Mvogo Ndongo, von Rintelen & Cumberlidge, 2019. Three genetic lineages were found within L.nkongsamba that are supported by uncorrected p-distances and the haplotype network. Morphological variation in some taxonomically important characters was found within both L.nkongsamba and L.yabassi. No correlation, however, was found between the morphotypes within these species and the uncovered genetic lineages. Recognition of species boundaries and of subpopulations of species will prove valuable when making informed conservation decisions as part of the development of species action plans for these rare and threatened freshwater crabs.

Distinguishing ten sympatric species of fiddler crab (Decapoda: Ocypodidae) using a suite of phenotypic characteristics.

Ten species of fiddler crab are reported inhabiting the intertidal zone of a shore on Kaledupa Island, Indonesia. This is one of the highest recorded numbers of fiddler crab species living in sympatry, equating to over two-thirds of those known from the Wallacea biogeographic region and more than half of all those recorded from Indonesia. The descriptions to identify and distinguish these ten species are provided using a suite of characters e.g., carapace, major cheliped, male gonopods, gastric mills, life colouration in males and females, and notes on their ecology and distribution. Specimens were observed and collected in the Wakatobi National Park, near the village of Ambeua on Kaledupa island, Sulawesi Tenggara, Indonesia. Gastric mills are described for the first time for Gelasimus jocelynae, Paraleptuca crassipes, Tubuca coarctata, T. demani and T. dussumieri. A tabulation of anatomical features and colouration for all species in this study is provided as a support for field studies. It identifies features that support the recently proposed taxonomic revision of fiddler crabs by Shih et al. (2016).

The megalopal stage of the hydrothermal vent crab Austinograea rodriguezensis Tsuchida amp; Hashimoto, 2002 (Decapoda: Bythograeidae): a morphological description based on CLSM images.

The Bythograeidae is unique amongst brachyuran crab taxa as it is the only family where all 6 genera and 16 species are endemic to hydrothermal vents. During the research conducted by German Federal Institute for Geosciences and Natural Resources to identify inactive polymetallic sulphide deposits along Central and Southeast Indian Ridges, the INDEX project collected from hydrothermal vent fields 6 Bythograeidae megalopae. Entire specimens and dissected appendages were stained, mounted on slides and examined using Light Microscopy and Confocal Laser Scanning Microscopy. Additional molecular analysis using mtCOI confirmed the identification of the specimens as Austinograea rodriguezensis Tsuchida Hashimoto, 2002. The megalopal stage of A. rodriguezensis shows similarities and distinctions between the characters of two other bythograeid megalopae, Bythograea thermydron Williams, 1980, and B. microps Saint Laurent, 1984. Unlike other brachyuran megalopae, B. thermydron and A. rodriguezensis lack long serrate setae and stout serrate spines on the dactylus of the fifth pereiopod. In both species no coxal spines on the pereiopods were observed. The elliptical carapace of B. thermydron is broader than long vs longitudinally rectangular in A. rodriguezensis. This carapace shape resembles B. microps more than B. thermydron, however, the dorsal surface of B. microps carapace is densely covered in short setae vs only covered with short setae on the anterior 1/4 and the posterior 1/6 length of carapace in A. rodriguezensis. Furthermore, the amount of plumose natatory setae on the pleopods in B. microps is in total larger and more variable, than in A. rodriguezensis. Bythograeid megalopae seem quite generalized and miss specific features that reveal them distinctively as endemic vent crab. A distinction from other species is possible by observing the unique combinations of certain characters. This is the first megalopal stage description of Austinograea and the fourth within the Bythograeidae.

Pseudolitochira integra (Miers, 1884) (Crustacea: Brachyura: Pilumnidae): redescribed and illustrated from micro-ct scanning the type female.

The taxonomy of the poorly known pilumnid crab, Pseudolitochira integra (Miers, 1884), has been confused because the original description and figures of the type female have inaccuracies, and the specimen has not been examined in detail since the original publication. Consequently, numerous specimens from the Indo-West Pacific have been incorrectly assigned to P. integra, suggesting that this species is widely distributed. The type female was micro-CT scanned in order to provide video and accurate figures of this rare pilumnid. The female possesses a suite of carapace and pereopodal characters that distinctly distinguish it from other pilumnoid taxa. The species is redescribed, refigured and formally designated as the type species of Pseudolitochira Ward, 1942. The identities of the numerous specimens assigned to P. integra are discussed and the distribution of the species is restricted to the western Indian Ocean for the time being.

Disentangling the Sudanonautes granulatus (Balss, 1929) species complex (Potamoidea: Potamonautidae), with the description of two new freshwater crabs from Nigeria and Côte d'Ivoire, West Africa.

The taxonomic status of the widely distributed West and Central African freshwater crab Sudanonautes granulatus (Balss, 1929) sensu lato is revised in the light of improved morphological evidence which indicates that this taxon is a complex comprising at least 4 species: Sudanonautes granulatus (Balss, 1929) sensu stricto from Togo, S. koudougou n. sp. from Côte d'Ivoire, S. umaji n. sp. from Nigeria, and S. tiko from Cameroon, Nigeria, and Bioko. Diagnoses, illustrations and distribution maps are provided for these species and they are compared with congeners from West and Central Africa.

Endemicity of Paragonimus and paragonimiasis in Sub-Saharan Africa: A systematic review and mapping reveals stability of transmission in endemic foci for a multi-host parasite system.

Paragonimiasis is caused by zoonotic trematodes of Paragonimus spp., found in Asia, the Americas and Africa, particularly in tropical regions. These parasites have a complex, multi-host life cycle, with mammalian definitive hosts and larval stages cycling through two intermediate hosts (snails and freshwater decapod crustaceans). In Africa, paragonimiasis is particularly neglected, and remains the only human parasitic disease without a fully characterised life cycle. However paragonimiasis has potentially significant impacts on public health in Africa, and prevalence has likely been underestimated through under-reporting and misdiagnosis as tuberculosis due to a similar clinical presentation. We identified the need to synthesise current knowledge and map endemic foci for African Paragonimus spp. together with Poikilorchis congolensis, a rare, taxonomically distant trematode with a similar distribution and morphology. We present the first systematic review of the literature relating to African paragonimiasis, combined with mapping of all reported occurrences of Paragonimus spp. throughout Africa, from the 1910s to the present. In human surveys, numerous reports of significant recent transmission in Southeast Nigeria were uncovered, with high prevalence and intensity of infection. Overall prevalence was significantly higher for P. uterobilateralis compared to P. africanus across studies. The potential endemicity of P. africanus in Côte d'Ivoire is also reported. In freshwater crab intermediate hosts, differences in prevalence and intensity of either P. uterobilateralis or P. africanus were evident across genera and species, suggesting differences in susceptibility. Mapping showed temporal stability of endemic foci, with the majority of known occurrences of Paragonimus found in the rainforest zone of West and Central Africa, but with several outliers elsewhere on the continent. This suggests substantial under sampling and localised infection where potential host distributions overlap. Our review highlights the urgent need for increased sampling in active disease foci in Africa, particularly using molecular analysis to fully characterise Paragonimus species and their hosts.

Malacostraca Podophthalmata Britanni 18151875 by William Elford Leach and the history of its fragmented publication (Crustacea: Decapoda).

The present study documents the fragmented publication history of Malacostraca Podophthalmata Britanni by William Elford Leach, illustrated with coloured figures of all the species by James Sowerby. This work was originally proposed to consist of 12 or 14 numbers. One number was to be published every two months between the years 1815 and 1818. Although this was increased to 19 numbers its publication by James Sowerby halted at number 17 in 1820. In that year Leach had a complete nervous breakdown and, although he eventually recovered, he was retired from his post at the British Museum in 1822. Although Leach was optimistic and set out plans to complete Malacostraca, he died from cholera in 1836 near Genoa, Italy, with the work unfinished. During the early 1870s fortuitous events occurred that would lead to the publication of numbers 18 and 19 and the completion of the work. At that time William Sowerby began negotiating with Bernard Quaritch, a London publisher, for disposal of old stock from the Sowerby publishing house including Malacostraca. George Brettingham Sowerby the younger, an established naturalist and highly skilled illustrator, proposed that the Malacostraca should be updated and he prepared Nos. 18 and 19 for publication. These last two volumes of Malacostraca were finally made available by Quaritch in November 1875. The authorship of Nos. 117 has never been in doubt and this is the work of Leach with illustrations by James Sowerby. Among the taxa illustrated in Nos. 18 19 however, are species which were not known to occur in British waters when Leach was working and as such the choice of Malacostraca illustrated in 1875 differed significantly from the original proposals. Consequently the 1875 supplement should therefore correctly be credited entirely to G.B. Sowerby II and cited as Sowerby, G.B. II in Leach, W.E. (1875). Finally, because copies of the Malacostraca are not generally available, all the magnificent plates illustrated by James Sowerby and George Sowerby II are reproduced here in full colour.

Additional notes on the publication of the Narrative, Zoology and Notes from a Journal of Research into the Natural History of the Voyage of H.M.S. Samarang and its consequences for the nomenclature of decapod crustaceans and other taxa.

Captain Edward Belcher was instructed by the Lords of the Admiralty to conduct a Surveying Expedition of the various coasts and islands in the Eastern Seas using H.M.S. Samarang. During this voyage from 1843-1846, Assistant-Surgeon Arthur Adams, made a significant contribution to the collection of natural history specimens, and together with fellow officers J. Richards and W. Browne, he prepared numerous drawings used by Belcher to illustrate the Narrative of the voyage. Later, Adams collaborated with Adam White (an Assistant in the Zoological Branch of the British Museum) to describe the Samarang Crustacea, published jointly with Lovell Reeve on the Samarang Mollusca, edited the Zoology of the voyage of H.M.S. Samarang and was the author of Notes from a Journal of the Natural History which was published in the Narrative of the voyage by Belcher. In his Natural History, Adams provided detailed accounts on some of the crustaceans collected with formal descriptions of species new to science thereby making these names available. The history, nomenclature and validity of the crustacean species cited in this work is discussed and a list of the available names is tabulated.

High prevalence of plastic ingestion by Eriocheir sinensis and Carcinus maenas (Crustacea: Decapoda: Brachyura) in the Thames Estuary.

This study presents evidence for microplastic contamination in two resident species of brachyuran crab from the Thames Estuary: the native shore crab, Carcinus maenas (Linneaus, 1758) and the invasive Chinese mitten crab, Eriocheir sinensis (H. Milne Edwards, 1853). The gills, gastric mill and intestine of 94 C. maenas and 41 E. sinensis were examined. Crabs were sampled periodically (ca. every three months) between December 2018 and October 2019. A total of 874 plastics were recovered, ranging 34 µm-34 mm in length. Overall, 71.3% and 100% of C. maenas and E. sinensis, respectively, contained at least one item (fibre, film, fragment or tangle of fibres) in the gill chamber, gastric mill or gastrointestinal tract. The most common items were fibres (78.5%) but in some cases, particularly in the gastric mill, these were aggregated into tangles (7.8%). Almost all E. sinensis contained tangles of fibres (95.1%), whereas, relatively few C. maenas contained similar tangles (10.6%).

London's river of plastic: High levels of microplastics in the Thames water column.

This opportunistic study focussed on the quantification of microplastics in the River Thames water column, the catchment responsible for draining Greater London. Two sites on the tidal Thames were sampled; one upstream of the City of London at Putney, and the other downstream at Greenwich. Water column samples were collected from June through to October 2017, being taken on the ebb and flood tides, at the surface and a depth of 2 m. Microplastics (excluding microfibres) were identified to test whether the load varied between the two sites in relation to tide, depth and season. Secondary microplastics, films and fragments, contributed 93.5% of all those found at Putney and Greenwich. Site, tide, depth and month affected density, with the combined interaction of month and site found to have the greatest influence on microplastics. Fourier Transform Infrared Spectroscopy analysis showed that polyethylene and polypropylene were the most common polymers collected from the River, suggesting broken down packaging was the primary source of microplastics in these samples. Excluding microfibres, the estimate of microplastics in the water column was 24.8 per m3 at Putney and 14.2 per m3 at Greenwich. These levels are comparable to some of the highest recorded in the world.

Lobithelphusa mexicana Rodriguez, 1982 (Decapoda: Pseudothelphusidae): a reassessment of key characters and systematics.

Lobithelphusa Rodriguez, 1982 is endemic to southern Mexico. Assigned to this monotypic genus is the freshwater pseudothelphusid crab, L. mexicana Rodriguez, 1982. The original description based on an old, dry, male specimen in the collections of the Natural History Museum, London, is brief and the crab was only partially figured. Lobithelphusa mexicana has subsequently never been recorded from Mexico and, consequently, the conservation status of this species is unknown. The type specimen has a complete, but detached left chela; is devoid of the left ambulatory pereiopods 1-3, with the fourth missing the carpus, propodus and dactylus; and its left first gonopod detached but retained in a glass tube kept adjacent to the crab. In spite of this damage the crab is still in remarkably good condition for a specimen registered in 1860. The purpose of this study is to apply computed tomography (CT) scanning techniques on the extant type, including its first gonopod, in order to provide detailed illustrations of the crab. These, in turn, shall be used to re-describe the species in order to help establish the current distribution status of L. mexicana in Mexico, and clarify its systematic position within the Pseudothelphusidae Ortmann, 1893.

Ingestion of plastic by fish: A comparison of Thames Estuary and Firth of Clyde populations.

This study compared plastic ingestion between pelagic and benthic fish populations from two UK watersheds: the Thames Estuary and the Firth of Clyde. The alimentary canals of 876 individuals were examined. Of twenty-one estuarine species investigated, fourteen ingested plastics, including predator (fish) and prey (shrimp) species. Overall, 32% of organisms ingested plastic, mostly fibres (88% of total plastics). More flatfish (38%) ingested plastics than other benthic species (17%). In the Thames, more plastic was ingested by pelagic species (average number of plastic pieces ingested: 3.2) and flatfish (average number of plastic pieces ingested: 2.9) than by shrimp (average number of plastic pieces ingested: 1). More fish from the Clyde ingested plastic than similar Thames species (39% compared to 28% respectively); however, the average amount of plastic ingested did not differ between the sites.

Re-description of Chinese mitten crab Eriocheir sinensis H. Milne Edwards, 1853 (Crustacea: Brachyura: Grapsoidea: Varunidae) zoeal development using confocal laser scanning microscopy.

A number of authors have described the zoeal development of the Chinese mitten crab, Eriocheir sinensis H. Milne Edwards, 1853, while some of these studies only recognised 5 zoeal stages, two of them described six. The present study re-examined the zoeal stages of E. sinensis from laboratory-reared material using confocal laser scanning microscopy and visualised the images using the open-source software programmes ImageJ and Drishti. From these images 6 zoeal stages were re-described and compared with all previous larval descriptions of the Chinese mitten crab. Comments on the variation of some setal characters are also described in zoeal stages IV-VI.