Abstract in English:Abstract Morphological identification of planktic crustacean larvae is required in many scientific contexts, such as ecology or taxonomy. Due to a still low availability of genetic sequences for many ingroups of Eumalacostraca, this task is still more feasible by morphological methods. Our understanding of eumalacostracan larval morphology is challenged by phenotypic variability. We investigated four eumalacostracan ingroups: Galatheidae, Hippoidea, Raninidae and Stomatopoda. Representatives of all four groups develop through spine-bearing planktic larval stages. Incorporating dorsal and lateral shield outlines into three-dimensional shape analysis of the shields, we compare specimens from the wild with laboratory-reared specimens. Using graphical and statistical analysis methods, we find that at least the lateral morphology of the shields of Hippoidea and Raninidae seems to be too strongly dependent on phylogeny to show phenotypic variability with our current sample size, but Hippoidea do show phenotypic variability in their dorsal shield morphology. In Galatheidae and Stomatopoda, a clear difference in shield morphology can be found between wild-caught and laboratory-reared specimens. This difference likely represents phenotypic variability. The exact environmental signals causing this phenotypic variability are still unknown, but some candidates are discussed.
Abstract in English:Abstract A collection of various developmental stages of Aegidae is presented and described, with the first description and photographs of eggs and embryos of this group. Intra-specific variation among specimens and developmental stages is described, as well as inter-specific, ontogenetic variation between immature stages and their better-known adult stages. Developmental stage differentiation of these opportunistic feeders is compared to that of the closely related parasitic representatives of Cymothoidae. This study is the first to attempt to provide the life cycle of these animals, which include well-documented and described immature stages.
Abstract in English:Abstract Two new species of Diploexochus are described. Diploexochus spinatus sp. nov. from Lapa do Honorato cave, located in the municipality of Iuiu, and Diploexochus obscurus sp. nov. from Água Escura I cave, located in the municipality of Carinhanha, both in the southwest of Bahia State, northeastern Brazil. Both species are likely to occur in caves due to anthropogenic impacts in the surrounding area (such as deforestation) and/or looking for the stable microclimatic conditions found in the subterranean realm. Additionally, D. echinatus is recorded in a cave in the municipality of Rurópolis, Pará State, northern Brazil. These represent the first records of the genus for subterranean environments.
Abstract in English:Abstract A new podocerid amphipod, Leipsuropus seisuiae sp. nov., from 338-340 m depth in the Kumano Sea, Japan, Northwestern Pacific, is described. This is the deepest record of any Leipsuropus species. Leipsuropus seisuiae sp. nov. is distinguished from four other congeneric species in having: i) pereonites 2-5 each with five narrow spiniform projections on tergal plate, ii) one dorsal tubercle on the telson, and iii) one small, proximal, denticulate projection on gnathopod-2 palmar margin. A key to males of the species of Leipsuropus is provided.
Abstract in English:Abstract A body entirely covered with long and sharp-pointed spines makes Acanthoniscus spiniger Gosse, 1851, one of the rarest and most ornamented terrestrial isopods in the world. The original description of this species was based on a single specimen collected by the British naturalist Philip Henry Gosse in Jamaica in 1845 and deposited in the British Museum (currently The Natural History Museum, London). A second specimen, presumably of this species, was collected by the American entomologist Henry Guernsey Hubbard in 1877 and deposited in the United States National Museum, Smithsonian Institution, which served as the basis for a further description by Richardson (1909). After Gosse and Hubbard specimens, no additional material appears to have reached any museum collection. Due to the scarce available information on this genus, it has been indistinctly placed in at least four different families through history, without a consensus on its definitive placement to date. Herein, we describe a new species of Acanthoniscus Gosse, 1851, based on a population discovered in the Blue Mountains, Jamaica, above 1,200 m elevation and more than 150 km eastward of A. spiniger’s type locality. We also emend the authorship and diagnoses of the genus Acanthoniscus and its type species. Finally, we discuss the possible relationships of Acanthoniscus at the family level, concluding that, despite some putative autapomorphies, it belongs to Armadillidae, as its present-day status.
Abstract in English:Abstract The natural history and conservation status of the West Indian endemic freshwater crabs of the genus Epilobocera are poorly known. Several species have restricted distributions and apparently specific ecological requirements, which make them particularly vulnerable to anthropogenic threats. Epilobocera capolongoi is known to occur exclusively in mountain streams and rivers above 300 m elevation in the Guamuhaya Massif, central Cuba. In addition to the publication with the original description, there is only one paper exclusively on this species, which reported it as being preyed upon by a heron and recorded it from some additional localities in the vicinity of Topes de Collantes, provinces of Cienfuegos and Sancti Spíritus. Epilobocera capolongoi is herein reported from Pico San Juan Ecological Reserve and Lomas de Banao Ecological Reserve, which expands its geographic range to about 60 km and its elevation to 1,000 m. The species was found living sympatric with the congeneric Epilobocera cubensis poliorcetes in Lomas de Banao Ecological Reserve, but apparently there exists some habitat segregation between them. Some phenotypic characters important to distinguish both species are described, some basic data on their natural history are provided, and an assessment of the conservation status of E. capolongoi following current IUCN criteria is made.
Abstract in English:Abstract Alpheus christofferseni Anker, Hurt and Knowlton, 2007 was described based on four specimens from Atol das Rocas, northeastern Brazil, and one specimen from Bocas del Toro, the Caribbean coast of Panama. Here, we report the collection of two specimens from Pernambuco, Brazil (~ 8°41’S), thus increasing the knowledge on species distribution along the Brazilian coast by approximately five latitudinal degrees south of its type locality (Atol das Rocas, Rio Grande do Norte, ~ 3°51'S). We also report a substantial increase in the known bathymetric distribution from shallow intertidal to approximately 51 m. Notes on morphological variation are provided based on the new material, and the first sequence of the 16S ribosomal subunit gene for the Brazilian coast is provided and compared with congeners.
Abstract in English:Abstract The present work aims to describe the first troglobitic terrestrial isopod (Oniscidea) from Peru. Caecopactes chullachaqui sp. nov. is described from Cueva de Palestina, Department of San Martín. The new species constitutes the third troglobitic taxon known for the country and extends the knowledge of the distribution of the genus.
Abstract in English:Abstract The status of the obscure Pagurus bouvieri (Faxon, 1895), a replacement name proposed for the preoccupied Eupagurus smithii A. Milne-Edwards and Bouvier, 1893, was evaluated. Based on types and numerous unreported museum materials, P. bouvieri is found to be synonymous with Pagurus politus (Smith, 1882) a commonly encountered but infrequently discussed northwestern Atlantic species. The taxonomy and geographic distribution of P. politus is updated with a complete synonymy, redescription, and illustrations. The taxonomy of the northeastern Pacific species Pagurus smithi (Benedict, 1892) is also updated, including a redescription with illustrations.
Abstract in English:Abstract The study investigated the population parameters of the shrimp Xiphopenaeus spp. (commonly known as seabob shrimp) in Anchieta, south coast of the state of Espírito Santo, Brazil, focusing on reducing the sampling effort. Shrimp were collected between February 2013 and February 2015. Individuals were measured, analyzed for sex and stage of reproductive development. In total, 1,564 individuals were analyzed in Anchieta, 534 males (74 juveniles and 460 adults) and 663 females (88 juveniles and 575 adults), and 367 individuals were not identified to sex or maturity. Significant differences were observed in shrimp abundance, with higher catches at the shallowest sampling point and associated with the type of substrate (silt+clay), while in the rainy season (September to March) and dry season (April to August) there were no significant differences. Despite this, greater abundances were found in the rainy season. The sex ratio was 0.80♂: 1♀. Carapace length ranged from 5.7 to 28.9 mm, with larger sizes recorded for females, as well as a larger size at first maturation than males, 12.86 and 11.60 mm respectively. All stages of development of the seabob shrimp were observed at the sampling points and periods, which represents a pattern of continuous reproduction and recruitment of the species in the area. Considering the sample size used, which is comparatively smaller than other studies, all estimates confirm current knowledge about the biology of the species and provide robust data on the seabob shrimp off the Anchieta coast, which are necessary for management and conservation.
Abstract in English:Abstract Two new species of Hyalella S.I. Smith, 1874 are described from state of Jalisco, Mexico. Hyalella marysolae sp. nov. can be identified by the presence of small projections or carinae on pleonites 1−2, with the first antenna being composed of 12 articles and the second antenna being composed of 15 articles. The first maxilla bearing 2−3 distal pappose setae, and the propodus in male first gnathopod is hammer-shaped. Conversely, in H. morronei sp. nov., dorsal projections or carinae are absent on pleonites 1−2, with the first antenna being composed of 10 articles and the second antenna of 14 articles. The first maxilla always bears two distal pappose setae, and the propodus in male first gnathopod is hatchet-shaped. Both species are distinguishable from other Hyalella species found in Mexico by the second antenna. In these two species, the second antenna is approximately half as long as the total body length, and the peduncle comprises 14 −15 articles; whereas, in other Mexican species, it is shorter and composed of maximum 12 articles. Here, we add two species to the four previously described in Mexico as it is necessary to increase the knowledge of the alpha taxonomy of this group of crustaceans and compensate for the biodiversity of the genus being underestimated.
Abstract in English:Abstract A new epigean asellid isopod, Caecidotea contrerasbalderasi sp. nov. is described from Nayarit, northwestern Mexico. This new species has morphological characters belonging to two different types of environments, both depigmentation and anophthalmia, indicators of organisms adapted to live in constant darkness as cavernicolous species. Despite showing characteristics of hypogean species, the new taxon does not show elongation of appendages, such as pereiopods, antennae or uropods. Its pleopod IV exopod lacks false sutures. This is a new pattern type “C”, and differs from that observed in types A and B. The description of this new species brings a new total of 101 species and three subspecies, for the genus Caecidotea in North America all morphologically poorly differentiated and with a restricted distribution.
Abstract in English:Abstract The poorly known pilumnid, Vellumnus penicillatus (Gordon, 1930), is redescribed by examining the Hong Kong types. A new species, Vellumnus tki n. sp., is described from Macclesfield Bank, South China Sea, and it is distinguished from its closest congener, Vellumnus minabensis (Sakai, 1969) from Japan, by the setal pattern on the carapace and pereiopods, carapace proportions, structure of the front and anterolateral teeth, armature on the chelipeds and relatively shorter ambulatory legs.
Abstract in English:Abstract Five anomuran and one brachyuran species collected from continental shelf and slope off southern Brazil have their geographic ranges considerably extended southward: Neolithodes agassizii (Smith), Paguristes spectabilis McLaughlin and Provenzano, Pagurus heblingi Nucci and Melo, Phimochirus occlusus (Henderson), Mixtopagurus paradoxus A. Milne-Edwards, and the brachyuran Euchirograpsus antillensis Türkay. Pagurus heblingi was previously known only from its type locality (off Cabo Frio, Rio de Janeiro) and from off Espírito Santo. Paguristes spectabilis was known only from the holotype (off Trinidad, Caribbean Sea) and two additional females from off Rio de Janeiro. One female was found of the brachyuran Robertsella meridionalis Tavares and Gouvêa, a species previously known only from two males. Additionally, the occurrence of the hermit crabs Dardanus venosus (H. Milne Edwards) and Oncopagurus gracilis (Henderson), and the brachyuran Hexapanopeus paulensis Rathbun are confirmed for Santa Catarina. The record of the brachyuran Neopilumnoplax americana (Rathbun) from Santa Catarina (27°S) probably actually refers to Neopilumnoplax lipkeholthuisi Tavares and Melo, a species described from Rio Grande do Sul (33°S) and Mar del Plata (37°S).
Abstract in English:Abstract The genus Trichoniscoides Sars, 1899 is composed mostly of cave-dwelling species. In the Iberian Peninsula, 32 species, and three additional species of uncertain status (partially described but not named), are currently known to occur. We were able to study one of these unnamed species, clarify its status, and name it. Most of the Iberian species of this genus are troglobiotic (22) and the ten remaining are epigean or troglophilic. The description of the new species from the surface can help in understanding the variability observed in the troglobitic species. The new, formally described, species has morphological characteristics that fit in several currently proposed groups for the genus, therefore, it is not possible to attribute Trichoniscoides gallaecus n. sp. to any of them.
Abstract in English:Abstract Revised diagnoses are given for the mysid genus Parapseudomma Nouvel and Lagardère, 1976, and its type species Parapseudomma calloplura (Holt and Tattersall, 1905) from the Northeast-Atlantic, Mediterranean and waters off Japan, depth range 94-1200 m. Parapseudomma stenurum n. sp. from the sea floor off Cape Verde Islands and the Angola Basin, depth range 3825-5460 m, is described as the second species of its genus. It differs from the type species mainly by an unsegmented antennal scale, the carpus of thoracic endopods 3-8 separated from the propodus by a transverse articulation, the digitus mobilis of the right mandible reduced to a slender spine, and by a more slender telson. Reduction of the right digitus is also found in Abyssomysis and Xenomysis, the latter with potential genetic affinity to Parapseudomma. The three genera also share reduced eyes as in many other deep-sea Erythropinae. Both species of Parapseudomma share recently detected, probably sensorial structures: a pit-like depression here named 'antennular bursa', dorsally on the basal segment of the antennula, and a median 'eye-cyst' inside the fused 'eye-bar', the cyst opening to the surface by a duct. The evidence in Parapseudomma raises expectations that these sensorial organs are potentially present in a great variety of Erythropinae taxa.
Abstract in English:Abstract Evidence is provided to support the synonymy of two species of sand crabs (Anomura: Albuneidae). Zygopa lalanai Ortiz, 2015 is a synonym of Zygopa michaelis Holthuis, 1961 and Lepidopa boykoi Ortiz, Tello-Musi and Morales-Moreno, 2018 is a synonym of Lepidopa benedicti Schmitt, 1935. Each of the recently described species was based on a single specimen collected well within the range of their respective senior synonyms.
Abstract in English:Abstract Neocaridina davidi (Bouvier, 1904) is a shrimp commonly used in aquaculture throughout the world. It is an exotic species in several places. We investigated the preference of N. davidi for four types of shelter (rock, Vesicularia sp., Egeria sp., and wood) and its nictemeral activity variation. Individuals were divided into three experimental groups: males, non-ovigerous females, and ovigerous females. They were placed in tanks with the four shelter types and observed every 3 hours for 72 hours. Neocaridina davidi presented cryptic behavior with 82.1 ± 8.69% of individuals sheltering per observation. Sheltering was higher during the daytime (88.8 ±5.54%) than at nighttime (75.4 ± 5.53%). Vesicularia sp. was the most used shelter followed by wood. The least used shelter type was a rock. Swimming and walking were more frequently observed at nighttime, especially for ovigerous females. We have demonstrated the importance of providing shelter for the maintenance of N. davidi in tanks as well as its higher activity at nighttime.
Abstract in English:Abstract The present study provides some parameters of the population biology of Charybdis (Charybdis) hellerii (A. Milne-Edwards, 1867), an invasive swimming crab inhabiting the estuarine portion of the Sergipe River, northeastern Brazilian coast. Samplings were carried out monthly from July 2015 to June 2016 with baited traps. The species was the second most abundant caught organism and its relative abundance ranged over the time from 11 to 59%. Sex ratio was 1:1 and all individuals were morphologically mature. Males were bigger than females. Ovigerous females were observed year-round and the smallest one was 31.35 mm carapace width. These findings show that the population is well established on the Sergipe coast. The entire distribution, and possible impacts, of C. (C.) hellerii on local environments need to be evaluated in further studies.
Abstract in English:Abstract Specimens of lophogastrids were collected off Chile, including four first records: Ceratolepis hamata G.O. Sars, 1883 in the vicinity of Easter Island, Eucopia unguiculata (Willemoës-Suhm, 1875) the Juan Fernández Archipelago, Gnathophausia zoea Willemoës-Suhm, 1873 off Concepción, and Neognathophausia ingens (Dohrn, 1870) off Valparaíso. Additional records were also obtained for Chile for four species: Eucopia australis Dana, 1852, Eucopia grimaldii Nouvel, 1942, Fagegnathophausia gracilis (Willemoës-Suhm, 1875), and Paralophogaster sp. Based on these records, lophogastrids are now represented off Chile, in the southeastern Pacific, by nine species.
Abstract in English:Abstract The presence of a long-wavelength sensitive (LWS) opsin gene was demonstrated in the stygobitic crustacean Creaseria morleyi (Creaser, 1936) by PCR readings from genomic DNA. In order to find the expression of this gene in extraocular tissue, shrimps were collected and placed in a tank to expose them to light/dark conditions for a period of 72 hours, and immediately after, sacrificed and sampled for RNA in the eyes, cephalothorax, abdomen, and sixth abdominal segment plus uropods. The transcripts of the LWS opsin gene were found in the eyes and abdomen of individuals exposed to light. The expression of these opsins could be involved in extravisual functions such as synchronization of their biological processes with environmental cycles related to diurnal vertical migration.
Abstract in English:Abstract We provide morphological and genetic evidence to establish the presence/occurrence of Alpheus angulosus, Alpheus buckupi, and Axianassa australis on the coast of Maranhão, Brazil. The specimens were collected in December 2019 by actively searching the estuaries and rocky shores of São Luís Island, northeast of Brazil. In addition to morphological analyses, two mitochondrial genes were obtained (Cytochrome C Oxidase I and 16S), and a phylogenetic analysis was conducted to verify the specimens’ identity. Accurate identification is an essential tool to obtain reliable information about the occurrence of the species and thus help assess biodiversity in a highly diverse region. These finding also serve to stimulate future studies in poorly studied areas as well as set a baseline for biodiversity conservation and preservation strategies.
Abstract in English:Abstract The Parapaguridae comprises hermit crabs that inhabit deep-water environments. In these environments, shell availability can be limited, mostly consisting of small and fragile-shelled gastropods. Thus, different strategies have evolved to mitigate this limited shell supply. Sympagurus dimorphus (Studer, 1883) lives in association with a zoanthid cnidarian that creates a pseudo-shell that grows with the hermit crab. In contrast, Oncopagurus gracilis (Henderson, 1888) inhabits small, calcified gastropod shells. Therefore, we selected these two species as models to test sexual dimorphism and shape patterns of their chelipeds and cephalothoracic shield, due to their different shelter acquisition methods. We photographed the animals and digitized the images to employ comparative geometric morphometric techniques. We tested the differences in shape between the sexes within each species, and also tested sexual size dimorphism based on centroid size. For O. gracilis, we found shape differences for the chelipeds and cephalothoracic shield, however, we only observed sexual size dimorphism for the chelipeds. For S. dimorphus, an inverse pattern was found, in which females presented more robust chelipeds, and sexual size dimorphism was present in which males were larger. These differences can be reasonably explained by their shelter acquisition methods, in which O. gracilis depends on small shells that limit growth, while S. dimorphus grows with its cnidarian pseudo-shell. The robustness found in the shape patterns may also be related to their behaviors, e.g., in addition to competition for shells, they also fight during mating. However, we emphasize that future studies with other populations of these species are needed for comparative purposes.
Abstract in English:Abstract The Gulf of California is known for its high productivity, diversity, and unique oceanography. Based on old and recent contributions, we estimate a richness of 160 copepod species in this province. This work seeks to identify latitudinal and seasonal patterns of the copepod composition, abundance, and diversity in the Gulf of California during 1985. Differences between four zones of the gulf (NGC, CGC, SGC, EGC) and between the cold and warm seasons were hypothesized, based on taxonomic and ecological data. Samples were collected during the CORTES cruises (1985), which also measured salinity, temperature, and dissolved oxygen at each station. We analyzed the latitudinal and seasonal variation of the copepod community with multivariate analyses (NMDS-PCA) and correlated these with the environmental data (CCA). Seventy-nine copepod species were identified, averaging 265,649 and 98,885 ind/10 m3 in the cold and warm seasons, respectively. Only 53 of these occurred in both seasons, indicating seasonal change in species composition. Composition and diversity varied latitudinally in the cold season (P < 0.05 in all comparisons but CGC vs. SGC), but not in the warm season (except NGC vs. the rest of the gulf). There was seasonal change in the composition and the abundance (P < 0.005 cold vs. warm season). Richness and diversity were negatively correlated with salinity (decreasing from the north of the gulf); the abundance and composition were mainly affected by the shift in temperature. These patterns also match the phytoplankton abundance and size structure in the gulf, probably the main factors affecting copepod distribution.
Abstract in English:Abstract The mysid Rhopalophthalmus hastatus Hanamura, Murano and Man, 2011 was collected from the shallow zone of the Thale Sap Songkhla, Songkhla Lagoon, southern Thailand on 18 November 2018. Specimens are described and illustrated using material collected by hand with a Riley push net. Rhopalophthalmus hastatus is characterized by the presence of one large spine, one mesial, two small spines on the antennal sympod, antennal scale slightly overreaching the end of the antennular peduncle, carpopropodus of the fourth to seventh thoracic endopods composed of six articles, two red chromatophores on the telson and lateral margin of the apical spine forming sharp spine-like process. This species was found in the shallow zone of the Songkhla Lagoon with brackish water and muddy substratum.
Abstract in English:Abstract Freshwater crabs of the family Potamidae Ortmann, 1896, have so far not been recorded in the state of Odisha in India. We report for the first time a potamid crab, Acanthopotamon martensi (Wood-Mason, 1875), from Odisha. With this record, in addition to the ‘Ganges Delta and Plain’ and the ‘Lower and Middle Indus’ freshwater ecoregions, A. martensi is now known to occur also in the ‘Northern Deccan Plateau’ ecoregion. The present record of A. martensi from Odisha represents the southernmost record of the family Potamidae in the Indian subcontinent. In fact, A. martensi is one of two potamid species that is known from south of the Ganges. Five species of freshwater crabs, including A. martensi, are now known from Odisha.
Abstract in English:Abstract In this study, we report six records of the non-native giant river prawn Macrobrachium rosenbergii (De Man, 1879) in the Furnas mega reservoir, state of Minas Gerais (Southeast Brazil), during continuous monitoring conducted from 2006 to 2023. All recorded specimens were males of the blue claw (BC) morphotype and possibly entered interior areas of the reservoir via accidental escapes. There was no occurrence of established populations in the region, nor any evidence of disease in the specimens obtained. However, continuous monitoring is recommended to record new escapes and determine the possibility of establishment of giant river prawn populations in the aquatic environment of the Furnas mega reservoir.