Abstract in English:Abstract The brackish-water crabs of the genus Ptychognathus Stimpson, 1858, the most diverse genus in the family Varunidae, inhabit the estuaries or seashores influenced by freshwater. Ptychognathus sakaii, a new species from Kenting, southern Taiwan, is described in this study, with a comprehensive key to the ten species of this genus from Taiwan. This new species is similar to its congeners, but can be distinguished mainly by the features of the carapace, ambulatory legs, and male first gonopods.
Abstract in English:Abstract Detailed morphology of the first three postembryonic developmental stages (Stages I-III juvenile) in representatives from all four crayfish families, Austropotamobius torrentium (von Paula Schrank, 1803) (Astacidae), Procambarus virginalis Lyko, 2017 (Cambaridae), Cambaroides japonicus (De Haan, 1841 [in De Haan, 1833-1850]) (Cambaroididae) and Cherax destructor Clark, 1936 (Parastacidae) are described and the diagnostic characters for each family are indicated. A phylogenetic tree of freshwater Astacidea, based on these new diagnostic juvenile characters is constructed to suborder, superfamily and family levels, and compared with a molecular phylogenetic tree. The evolutionary history of maternal care in freshwater crayfish is discussed based on particular features of the postembryonic stages of each family. Using comparisons between the phylogenetic tree and global geo-history, the location and timing of the early evolution of maternal care in postembryonic development and the extension of this care are estimated.
Abstract in English:Abstract This work aims to list all known species of terrestrial isopods from Peru until September, 2020. Also, Circoniscus ornatus (Verhoeff, 1941) (Scleropactidae) and Ethelum americanum (Dollfus, 1896) (Eubelidae) are recorded for the first time from Nueva Alianza and Nuevo Sucre, Contamana, Loreto department, Peruvian Amazon rainforest.
Abstract in English:Abstract Macrobrachium candango Mantelatto, Pileggi, Pantaleão, Magalhães, Villalobos and Álvarez, 2021 is an endemic shrimp species to the Brazilian Central-West region (Brasília, Federal District). The present study aims to analyze the relative growth, morphometry, morphological sexual maturity, and fecundity of this species. Specimens were collected from tributaries of the Paranoá Lake hydrographic basin, Brasília, during sporadic periods between 1983 and 2012. Relative growth was analyzed for different structures (carapace, abdomen, second abdominal pleura, merus, carpus, and propodus). The laterality and heterochely patterns were evaluated based on the dimensions of the propodus length. Fecundity was calculated as the average total number of eggs per female and egg size was measured to obtain the volume. There were differences in relative growth (p < 0.05) of the structures analyzed between juveniles and adults, and distinct allometric patterns were observed between the life stages, which could reflect the habit of these animals at each developmental stage. No pattern of laterality and heterochely was observed between the chelipeds of the animals analyzed (p > 0.05). The lack of laterality may indicate that this species directs energy to the smallest propodus when the largest propodus is injured. Egg volume ranged from 4.41 to 7.71 mm3, and fecundity ranged from 38 to 61 eggs, indicating a life cycle with abbreviated larval development. The characteristics presented herein are unprecedented for M. candango and present relevant information needed to assess the conservation status of this species, which is currently threatened.
Abstract in English:Abstract Farfantepenaeus brasiliensis (Latreille, 1817) and Farfantepenaeus paulensis (Pérez Farfante, 1967), commonly known as pink shrimps, are two commercially important penaeid species caught by artisanal and industrial fisheries in the Southwestern Atlantic Ocean. The currently known southern distribution for F. brasiliensis extends to Rio Grande do Sul (Brazil), while F. paulensis reaches the coastal waters of Buenos Aires (Argentina), although Uruguay represents the southern limit of commercial captures for the latter. In the shrimp season of 2019 (February-May) the presence of F. brasiliensis was recorded together with F. paulensis in the brackish coastal lagoons of Uruguay (34º30’ to 34º50’S). A total of 143 specimens of F. brasiliensis and 152 of F. paulensis were analyzed evaluating morphological, morphometric and genetic differences. The presence of both species was validated based on morphological differences and sequencing the Cytochrome Oxidase I (COI) mitochondrial gene. Significant morphometric differences were found between both species, particularly, the larger rostral length in relation to the carapace and cephalothorax length in F. paulensis compared to F. brasiliensis. To our knowledge, this is the first confirmed record and commercial catch of F. brasiliensis in Uruguayan waters. This southwards expansion could be explained by extending climatic variability events associated with prolonged periods of positive sea surface temperature anomalies in the region. Given the potential commercial relevance of the species, a better understanding of the southward expansion of F. brasiliensis into Uruguayan waters would be helpful in developing efficient management and conservation strategies under a scenario of increasing water temperatures.
Abstract in English:Abstract In this study, the effect of methyl farnesoate (MF) injection on haemolymph MF levels, spermatozoa production and the reproductive indices of gonadosomatic index (GSI), testicular index (TI) and vasosomatic index (VSI) were investigated in males of Pontastacus leptodactylus (Escholtz, 1823). Sixty male P. leptodactylus were used for the study. They were housed in a total of twelve tanks in their normal reproductive season in 2018 and were fed ad libitum with a pelleted food. Animals were injected once a week for five consecutive weeks, at doses of 250 (G2), 500 (G3) and 1000 (G4) ng MF g-1 of body weight. The doses of the injections, the durations used, and the frequency of administration were determined according to the literature. An increase was observed in gonadosomatic index and spermatozoal number of crayfish injected with 1000 ng of MF g-1 of body weight when compared to control (G1, no MF injection applied) and other experimental groups. In addition, the present study indicated that G4 crayfish had a higher GSI, TI and VSI than control crayfish. There was no difference in the level of hemolymph MF between control and MF injected crayfish. In conclusion, MF injection is effective for inducing increased gonadasomatic index and spermatozoal number in P. leptodactylus.
Abstract in English:Abstract The relationship of body weight and length with sperm load and spermatophore weight was evaluated in wild males of Macrobrachium tenellum (Smith, 1871). In addition, the influence of a commercial and natural feed on the load and viability of sperm was determined in wild males. In 28 wild males spermatophore extraction was performed by electrostimulation 24 h after capture to analyze the relationship between body length/weight and sperm load and viability, respectively. Spermatophore weight (SW), total number (TS), dead (DS) and abnormal sperm cells (AS) were used as indicators of sperm viability. The results obtained show that there is a positive correlation between TS per spermatophore compared to body length and weight of the male. To study the effect of different diets on sperm load, three diets were employed: Diet A, commercial shrimp feed; Diet B, natural feed (mixture of squid, sardine and clam); and Diet C, combination of natural and commercial diet. To assess the initial reproductive status of the males at the beginning of the experiment, sperm viability was determined in a subsample of specimens after capture. Broodstock were fed ad libitum once a day during 70 days. TS, DS, AS and SW were evaluated. The results of the bioassay did not show differences between treatments in the parameters analyzed, except DS, which was higher in the initial group. In conclusion, the present work suggests that it is feasible to substitute fresh feed for an artificial diet for the maintenance in captivity of male M. tenellum broodstock shrimp.
Abstract in English:Abstract A new species, Actinimenes koyas sp. nov. (Decapoda: Palaemonidae) was collected at a depth of 1.0-2.0 m from the coral atoll of Agatti Island, Lakshadweep, Arabian Sea. The species was associated with the sea anemone, Heteractis magnifica (Quoy and Gaimard, 1833). It is the second representative of the genus Actinimenes Ďuriš and Horká, 2017 described from the Arabian Sea. Actinimenes koyas sp. nov. is closely related to A. ornatellus in terms of morphological traits. Actinimenes koyas sp. nov. is distinguished from Actinimenes ornatellus (Bruce, 1979) by the presence of a biramous outer antennular flagellum with three proximal segments fused, a shorter free ramus consisting of 7 to 8 segments with 12-14 groups of aesthetascs, a fourth thoracic sternite with V-shaped median incision and features of the telson and third maxilliped. The present new species is easily distinguished from the other three described species in the genus Actinimenes by the structural variation in the fourth sternal plate with a median notch. Additionally, a phylogenetic analysis inferred by Maximum Likelihood using the mitochondrial genes COI and 16S rRNA shows a close relationship of Actinimenes koyas sp. nov. with Actinimenes inornatus (Kemp, 1922). Pairwise genetic distances estimated using the COI and 16S data provided divergences between A. koyas sp. nov. and other congeneric species.
Abstract in English:Abstract Sphaeromopsis jayaraji sp. nov. is described from intertidal habitats on the coast of South Andaman, Andaman Islands, the second record of the genus from India. Sphaeromopsis jayaraji sp. nov. is characterized by the following: epistome being widest anteriorly, with a broadly rounded anterior margin and sub-parallel lateral margins, anterior margin with widely spaced plumose setae; pleotelson posterior margin produced to narrowly rounded apex with five setae; uropodal exopod dorsal surface with two deep longitudinal mesial grooves; endopod lateral margin weakly sinuate with long setae, apex with deep mesial groove with plumose setae.
Abstract in English:Abstract We propose a new species of the troglobitic genus Spelaeogammarus da Silva Brum, 1975, with data on its distribution, ecology, aspects of behavior, and conservation status. Spelaeogammarus ginae sp. nov. occurs in a single cave in the Serra do Ramalho karst area, of the northeastern Brazilian semi-arid region. We also provide new data on the distribution and conservation status of its congener, Spelaeogammarus spinilacertus Koenemann and Holsinger, 2000 that occurs in the upper phreatic aquifer inside caves from Chapada Diamantina domain. Both species occur in caves in the state of Bahia, northeastern Brazil.
Abstract in English:Abstract The porcellanid crab Polyonyx gibbesi Haig, 1956, an obligate symbiont of Chaetopterus cf. variopedatus (Renier, 1804) in the western Atlantic, is parasitized by a rare entoniscid isopod. Crabs from coastal North Carolina and Florida, U.S.A., were dissected and examined for this internal parasite in 1966 and 1967. Two of 83 crabs (2.4 %) and 3 of 100 (3.0 %) crabs from North Carolina and Florida, respectively, were parasitized. Only female parasites were found, including five immature and three mature specimens; one host was parasitized by three immature entonicisds simultaneously. One of the mature parasites was liberating epicaridium larvae and the others had developing eggs or larvae. Parasitized female crabs were all ovigerous; the parasites did not castrate the hosts. The parasite is identified as Entoniscus creplinii Giard and Bonnier, 1887, previously known only from Brazil, and the female is redescribed.
Abstract in English:Abstract Ethnobiology helps to better understand research processes involving humans and nature. It produces important information for the management of ecosystems and their natural resources. The mangrove crab (Ucides cordatus) is an endemic mangrove crustacean that lives in close association with arboreal vegetation and whose distribution extends throughout this ecosystem along the Brazilian coast. It plays an important role in ecosystem processes, actively participating in sediment bioturbation and the flow of organic matter and energy, affecting the entire trophic chain of coastal environments. This study compiles ethnobiological data from catchers in the Itanhaém River Estuary (SP) on the biology of the mangrove crab according to morphotype (male and female), biological cycle (growth and reproductive period), fishing season, and its participation in the trophic chain of mangroves. Thus, this study serves as a basis for education and environmental management actions. The authors conducted interviews using the snowball technique and applied a semi-structured questionnaire with open and closed questions for catchers. We submitted the data to qualitative and quantitative analysis and compared it with data from the available literature. We interviewed the entire sample universe of catchers in the study area. Ethnobiological data referring to the periods of growth and reproduction coincided with literature data in the following proportions: 66.8 % for Brazil and 82.5 % for the southeast-south region. The results reinforce the relevance and accuracy of local ecological knowledge in the interpretation of data from nature. Moreover, the results show gaps in compliance with the norms for the protection of this species.
Abstract in English:Abstract Spelunconiscus Campos-Filho, Araujo and Taiti, 2014 is a monotypic genus of the family Styloniscidae represented by a troglobitic species, Spelunconiscus castroi Campos-Filho, Araujo and Taiti, 2014, from the cave MOC-32, in the state of Minas Gerais, southeastern Brazil. New representatives of this family were found in three additional caves, which revealed a new species, Spelunconiscus septemlacuum sp. nov., from Taboa and Tatuzinhos caves and a new occurrence for the type-species in Retiro cave. The original diagnosis of Spelunconiscus is emended due to the discovery of a spur-like structure in the male pereopod VII ischium, as well as some supplementary traits that have not been previously considered. Spelunconiscus septemlacuum sp. nov. differs from S. castroi in the number of articles of the antennal flagellum, in the proportion between this flagellum and 5th article of peduncle of antenna, in the size of maxilliped endite, in the morphology of male pleopod II and in body size. A discussion is provided for both taxonomic and ecological concerns.
Abstract in English:Abstract Members of the fish parasitic isopod family Cymothoidae usually parasitize a host fish by a single species infestation. For the first time from Indian waters two species of cymothoids, the body surface infesting Anilocra grandmaae Aneesh, Hadfield, Smit and Kumar, 2021 and the branchial infesting Agarna malayi Tiwari, 1952, were reported simultaneously parasitizing the same individual toli shad, Tenualosa toli (Valenciennes, 1847). Each double-infested T. toli harboured an ovigerous female of A. grandmaae and an ovigerous female and male of A. malayi. Out of 814 host fishes collected from seven different localities, along the Kerala coast, southwest coast and Bay of Bengal coast, 113 fishes were infested with only A. malayi and 71 individuals were infested with only A. grandmaae. Interestingly, nine individuals of T. toli harboured both A. malayi and A. grandmaae simultaneously. Cymothoid co-occurrence is rarely reported, and this is the first report of two cymothoid species infesting a single fish host from India. Globally, it is the third record of simultaneous occurrence of two cymothoids and the first record of body surface and branchial cymothoids parasitising the same individual fish.
Abstract in English:Abstract A new hermit crab of the genus Calcinus Dana, 1851 is described from a specimen collected at a depth of 100 m near Rapa Island, Austral Islands, French Polynesia. In a previous report, we had reported this specimen provisionally as Calcinus aff. sirius, pending availability of live color data for Calcinus sirius Morgan, 1991. Recently obtained color photographs of live C. sirius from the Solitary Islands, Eastern Australia, has shown that the specimen from Rapa Island is distinct from Morgan’s taxon and represents a new species which is fully illustrated and described herein as Calcinus shawi sp. nov. The morphology and coloration of this new species are compared with the closely allied C. sirius and Calcinus dapsiles Morgan, 1989.
Abstract in English:Abstract This study was conducted to estimate the key population parameters to understand both the current status and the yield of Penaeus indicus H. Milne Edwards, 1837 in the Andharmanik River, southern Bangladesh, using monthly samples collected from July 2019 to June 2020. We found that the size at first sexual maturity of P. indicus is 15.5 mm CL. The spawning season was August - December with a peak in September. Recruitment occurred at ~8.4 mm CL for an extended period of the year with two pulses: one in November (minor recruitment pulse) and another in February (major recruitment pulse). The von Bertalanffy growth equation gave the following results: CL∞ = 31.9 mm and K = 1.14 year-1. The overall growth performance index was 3.37 and the longevity was 2.6 years. The estimated total, natural, and fishing mortalities were 3.53, 2.15, and 1.38 year-1, respectively. Therefore, the exploitation rate was 0.39 and the maximum sustainable yield was 0.42, indicating that the stock is almost optimally exploited. Hence our work should help improve decisions to (i) conserve the stock, (ii) maximize economic returns from the stock, and (iii) continue ensuring that the stock is exploited in an ecologically sustainable way.
Abstract in English:Abstract Temperature affects ectotherm's biological processes and plays a fundamental role in determining their geographical distribution. We elucidated the temperature adaptation of juveniles of two mud crab species in the genus Scylla De Haan, 1833 (in De Haan, 1833-1850): Scylla paramamosain Estampador, 1949 and Scylla serrata (Forskål, 1775), which occur mainly in temperate and subtropical/tropical areas in Japan, respectively. The first instar crabs (C1) were raised from three broods for each species and were individually cultured to molt to C2-C5 at different temperatures (15.2-30.5 °C℃). In S. paramamosain, C1 juveniles could molt to C2 at 15.4 °C and the survival rate was reduced at 29.8 °C through C4-C5. In S. serrata, C1 juveniles could not molt to C2 at 15.2 °C and the survival rate was not affected by temperature thereafter. The intermolt period was shortened at higher temperatures in both species. The carapace width of juveniles increased with increasing temperature but became smaller at 27.6-30.2 °C in S. paramamosain, whereas it appeared to reach a plateau at > 24 °C in S. serrata. The lower threshold temperature (95 % confidence interval) for the development of C1 juveniles was estimated as 13.65 °C (13.51-13.77 °C) for S. paramamosain, and 15.44 °C (15.12-15.72 °C) for S. serrata. Thus, juveniles of S. paramamosain and S. serrata adapted to lower and higher temperature conditions, respectively, reflecting their biogeographical distribution.
Abstract in English:Abstract A new planktonic copepod assigned to the subgenus Tortanus (Atortus) Ohtsuka, 1992 is described from Great Nicobar Island, Andaman and Nicobar archipelago. The new species Tortanus (Atortus) dhritiae sp. nov. belongs to the tropicus-group. The new species can be distinguished from all other species of the tropicus-group by the presence of a notch on the left lateral joining of fourth and fifth pedigerous somites, asymmetrical caudal rami with a rounded process originating from the anterior portion of the left ramus produced over to the right, and an elliptical shaped exopodal lobe of leg 5 with distolateral curved seta in female. In male, serrated ridge on the anterior one-third surface of segment XX of the right antennule, obtuse trapezoid-shaped right leg 5 coxa with triangle-shaped medial process, semi-circular basis with slight curve near base and crocodilian head-shaped medial process with small process distally and bearing one distal and one medial setae.
Abstract in English:Abstract Interstitial harpacticoids along the mediolittoral zones of Sarımsaklı Beach, Turkey, were sampled monthly between April 2016 and March 2017 in order to reveal the effects of pH, water temperature, salinity, electrical conductivity, dissolved oxygen, and grain size on the occurrence and composition of the harpacticoids. Examination of the samples from nine stations revealed a total of 66 species. In terms of harpacticoid species abundance, Ectinosoma soyeri Apostolov, 1975 was ranked first followed by Sarsamphiascus angustipes (Gurney, 1927) and Leptomesochra eulitoralis Noodt, 1952. The variations in harpacticoid community were estimated by using some ecological indices (Species richness, Shannon’s diversity and Pielou’s evenness). Principal component analysis (PCA) based on the abiotic factors was applied for ordination of the stations. Relationships between environmental and temporal parameters as well as harpacticoid community structure were analyzed using distance-based Linear Models (DistLM). Relationships between environmental variables and most abundant species were determined with the Redundancy analysis (RDA). The abundance of S. angustipes and Klieonychocamptus ponticus (Serban and Plesa, 1957) were positively correlated with all tested variables except water temperature. The abundance of Klieonychocamptus kliei (Monard, 1935) was positively correlated with water temperature, grain size and salinity, while it was negatively correlated with dissolved oxygen and pH. The abundance of Ameira sp. and Microsetella norvegica (Boeck, 1865) were negatively correlated with all tested variables except water temperature. The abundance of E. soyeri and Ameira parvula (Claus, 1866) were negatively correlated with all tested variables except pH. The abundance of Leptomesochra eulitoralis was positively correlated with water temperature and salinity, while it was negatively correlated with grain size, dissolved oxygen and pH.
Abstract in English:Abstract We describe Kupellonura tamago sp. nov., collected from the North Pacific off the southern coast of the Boso Peninsula, Japan, at a depth of 445-407 m. This is the first record of Hyssuridae not only for Japan but also for the Temperate Northern Pacific ecoregion. Female K. tamago closely resembles Kupellonura gidgee Poore and Lew Ton, 1988 and Kupellonura indonesica Annisaqois and Wägele, 2021 in the shape of the uropodal exopod but differs from them in having a broader uropodal exopod (length/width ratio 1.47), a broader uropodal endopod (length/width ratio 1.64), and the telson margins smooth. We transfer Kupellonura flexibilis (Pasternak, 1982), originally described in Ananthura Barnard, 1925 but provisionally transferred to Kupellonura Barnard, 1925, to Anthelura Norman and Stebbing, 1886 in Antheluridae, as Anthelura flexibilis (Pasternak, 1982) comb. nov.
Abstract in English:Abstract A new species of the freshwater crab genus Ghatiana Pati and Sharma, 2014, is recognized herein from the Karnataka State, India. Ghatiana dvivarna sp. nov. usually inhabits holes in the laterite rocks on the elevated mountains of the Central Western Ghats (south of Goa-Nilgiris). The predominantly white color in life and the characteristic smaller eyes relative to the orbits of the new species easily distinguish it from congeners. Ghatiana dvivarna sp. nov. most resembles Ghatiana pulchra Pati and Thackeray, 2018, but can be differentiated mainly by its relatively more slender terminal segment of the male first gonopod. Ghatiana currently comprises 11 species, now including Ghatiana dvivarna sp. nov.
Abstract in English:Abstract Aeglids are endemic crustaceans from the Neotropical region of South America, with great importance in the freshwater food chain. We investigated the trophic relationships in different streams containing Aegla castro Schmitt, 1942 through the use of stable isotopes, testing the hypothesis that these animals occupy a lower position and that the environments are different and will modulate the isotopic ratios of carbon and nitrogen. Aegla castro showed a low trophic level in all locations, being an important link between producers and other trophic levels. They present differences in their isotopic signature for the sampling areas, indicating that environment can be a factor that modulates the trophic webs. We did not find intraspecific differences in isotopic signatures, probably due to the similar food items consumed by both juveniles and adults foraging in the same locations. Studies like this are becoming increasingly important due to the rapid degradation of freshwater environments and the lack of trophic knowledge about these endemic animals. It is increasingly important to understand how environmental changes (such as through anthropogenic action) is interfering in freshwater trophic relationships, and how this can affect the permanence of aeglids.
Abstract in English:Abstract In 2015, a serious environmental disaster occurred at ULTRACARGO - Aratu S/A Terminal (Cubatão, SP) causing a long-lasting, large-scale, fire that resulted in the release of various chemical pollutants, including those used to contain the fire. These pollutants affected adjacent regions and the innermost area of the Santos-São Vicente Estuarine System, requiring the assessment of environmental quality in two mangrove areas post-disaster (2016). This assessment considered biomarkers for the species including population density, structure, and cytogenotoxicity. The population structure and cytotoxicity of Ucides cordatus (Linnaeus, 1763) only changed slightly from pre-disaster (2013) to post-disaster (2016), as a consequence of the greater resilience and biological flexibility of this crab to environmental stress caused by pollutants. We recommend continuous monitoring be conducted using this species endemic to the mangroves of the study site, as this will make it possible to assess the magnitude of the chronic environmental impacts of the accident. In addition, it could guide environmental agencies in damage mitigation or in the quantification of possible future impacts.
Abstract in English:Abstract The blue swimming crab (Portunus pelagicus (Linnaeus, 1758)) is an economically and ecologically important species in Vietnam, and a potential subject for aquaculture as well. More than 400 individual crabs were collected along the Vietnamese coastline and examined for ectosymbiotic crustaceans. Two molecular markers (28S rRNA and COI mtDNA) were applied for species delineation. Seven species were reported and described, of which six are cirripede barnacles (Thecostraca, Thoracia); and one parasitic copepod Choniosphaera indica Gnanamuthu, 1954 (Copepoda, Podoplea). Four species (Chelonibia testudinaria (Linnaeus, 1758), Semibalanus sp., Octolasmis neptuni (MacDonald, 1869), and Dianajonesia tridens (Aurivillius, 1894)) were the first records for both host and location. The symbiotic crustaceans occupy specific niches on the crab body, and vary in their infestation status. Molecular taxonomy of symbiotic crustaceans was classified and confirmed based on sequence similarity and phylogenetic analyses.
Abstract in English:Abstract The identity of Philyra sexangula Alcock, 1896 (Leucosiidae), an inhabitant of mangrove habitats, is clarified. The redescription of the lectotype male and examination of fresh material collected from Pichavaram mangrove forest located in Tamil Nadu State of India revealed that P. sexangula shows significant morphological differences from the generic characters of Philyra sensu stricto. Therefore, a new genus Bellayra gen. nov., is established herewith for the species. In addition, one new species, Bellayra persicum gen. nov., sp. nov., is described based on a syntype male of P. sexangula collected from the Persian Gulf. Furthermore, Philyra taekoae Takeda, 1972 and Philyra nishihirai Takeda and Nakasone, 1991, described from Japan are also transferred to Bellayra gen. nov.
Abstract in English:Abstract Marine shrimps of the genus Thor Kingsley, 1878 are distributed in the eastern and western Atlantic, eastern Pacific, and Indo-West Pacific. Thor manningi Chace, 1972 was originally described from Antigua and since then has been recorded from other Atlantic localities, including the Caribbean Sea, Bermuda, USA, Brazil, and Ascension Island. Specimens previously identified as T. manningi from Panama and Brazil were analyzed using a combination of morphological and molecular approaches. The analyses yielded a new species from the Atlantic coast of Panama, herein described as Thor paulae sp. nov. Moreover, we provide additional morphological observations on T. manningi, mainly regarding mouthparts and pereopods. The new species is morphologically similar to the Pacific Thor cocoensis Wicksten and Vargas, 2001 and Thor marguitae Bruce, 1978. However, it can be separated from them by the carpus of the second pereopod, rostral dorsal dentition, and chela of the first pereopod, respectively. The two species studied here can be easily distinguished by the supraorbital prominence in T. manningi (versus absent in the new species), and the pterygostomial margin rounded and unarmed in T. manningi (versus angular, with tooth in the new species). Thor manningi is morphologically closer to the western Atlantic Thor dobkini Chace, 1972 and Thor floridanus Kingsley, 1878, but can be separated from both by the merus of the first pereopod (T. dobkini) and dactylus of fourth and fifth pereopods (T. floridanus, but with the possibility of overlap). We provide a comparative table with morphological characters of all 17 valid species of Thor, as well as a worldwide identification key to the genus.
Abstract in English:Abstract Thoe Bell, 1836 is amphi-American in distribution and includes small spider crabs with cryptic habits and rare records in the literature and carcinological collections. The taxonomy of the three recent and two fossil species currently known in the genus has been revised. A phylogenetic reconstruction conducted here based on the mitochondrial markers COI and 16S rRNA supports the monophyletic status of Thoe. The resulting phylogeny suggests a western Atlantic to eastern Pacific radiation of the genus.
Abstract in English:Abstract Four species of sesarmid crabs of the genus Nanosesarma Tweedie, 1950, have been reported from India: Nanosesarma andersoni (De Man, 1888), Nanosesarma batavicum (Moreira, 1903), Nanosesarma jousseaumei (Nobili, 1906), and Nanosesarma minutum (De Man, 1887). In the present study, one more species, Nanosesarma sarii Naderloo and Türkay, 2009 is reported for the first time from India along with the diagnosis and illustrations of the five Indian Nanosesarma species.
Abstract in English:Abstract Cheliped dimorphism is common in decapod crustaceans, and many decapods have a pair of different-sized chelipeds, i.e., one side being larger (major) than the other (minor), a phenomenon known as heterochely. Anomuran crabs from the family Porcellanidae exhibit a true crab-like body shape, with relatively large chelipeds for their body size, and they show a sexual size dimorphism of chelipeds (i.e., males with larger chelipeds). However, very little is known about heterochely in porcellanid crabs. Therefore, we aim to elucidate heterochely and cheliped dimorphism in the porcellanid crab Petrolisthes japonicus (De Haan, 1849). We examined the laterality of the chelipeds and performed allometric growth analyses of the cheliped dimensions. Heterochely was observed in most of the specimens, and major chelipeds occurred randomly on either the right or left sides of the body, regardless of the crab size. Major and minor cheliped size of males surpassed female cheliped size, and males increased the growth of both major and minor chelipeds to the same degree during the breeding season, thereby inducing the distinct intersexual size dimorphism of the cheliped. This is probably attributable to sexual selection (i.e., male-male competition). Intersexual dimorphism as an energy allocation strategy was also evident with females allocating their energy evenly to both major and minor cheliped growth without changing the chela shape; regardless of the body size, whereas males were investing more energy in major cheliped growth, resulting in wider chelae with increasing body size. Consequently, the major cheliped may have a greater role in male-male competition in P. japonicus.
Abstract in English:Abstract Specimens of the harpacticoid copepod Eudactylopus fasciatus Sewell, 1940 were found in plankton samples taken from Lakshadweep, India. In this study, E. fasciatus is redescribed on several additional distinct morphological characters along with the original description dating back to 1940 (Sewell, 1940). The most important features of E. fasciatus from Bangaram Island are the external coloration pattern with eight longitudinal bands, additional numbers of setae on the 1st, 2nd, 3rd, and 7th segments of the A1, and the modified saber-shaped sexually dimorphic second endopod segment of the male P2 with a bud-like structure. The illustrated redescription and a taxonomic key for the identification of all the species of the genus Eudactylopus are also provided.
Abstract in English:Abstract Our knowledge of cladoceran species composition and distribution of Neotropical taxa is incomplete, therefore misleading the basic understanding of biodiversity processes and biogeographical patterns of this ecologically relevant group. We present new records and an updated checklist of the cladocerans of Rio de Janeiro State (Brazil) based on a critical review of their known distribution throughout the different freshwater ecoregions. Nine marine species were recorded, and 80 non-marine cladocerans were counted from two of the four ecoregions of Rio de Janeiro State. We estimate species richness applying the interpolation and extrapolation method, using iNEXT function. With this approach we compute diversity estimates for rarefied and extrapolated samples up to double the reference sample size (number of studies). Four new records of rare species were included from surveys in the Paraiba do Sul ecoregion. The Fluminense ecoregion shows a higher richness with a more asymptotic curve and thus a lower expected richness in comparison to the Paraiba do Sul ecoregion. Ceriodaphnia cornuta Sars, 1886 was the most frequently found species whilst Moina macrocopa Straus, 1820 was the only non-native species encountered. Our study can contribute to developing a biogeographical understanding of this diverse group in a heterogeneous territory in terms of inland waters. Future studies are suggested to prioritize novel ecoregions and unexplored habitats e.g. littoral zones with high macrophyte and periphyton coverage, brackish waters, saline and high-altitude lakes, as more diverse and heterogeneous habitats will undoubtedly reveal additional records.
Abstract in English:Abstract From January to June 2021, mark-recapture and biometric data were collected from a population of blue crab, Cardisoma crassum Smith, 1870, from Ponuga, in Veraguas, Panama. Recapture histories of 163 crabs indicate strong burrow fidelity. During the dry season (January-March) burrow fidelity was 73.2 %, while in the rainy season (April-June) it was 50.7 %. Population was estimated at 2,569 crabs in 10.93-ha with a density of 0.024 ind. m-2. Cephalothorax width averaged 63.62 ± 6.37 mm for males (50.95-78.01 mm, N = 83) and 61.90 ± 5.47 mm for females (53.21-77.78 mm, N = 80). Blue crab reproductive season was traditionally known to take place just during the rainy season. Here, we report ovigerous females in February and March (dry season), suggesting reproduction may occur throughout the year in Panama. This is the first report of burrow fidelity and continuous biometry measurements in natural conditions for C. crassum. Burrow fidelity seems to be closely related to abiotic factors and is different between dry and rainy seasons.
Abstract in English:Abstract Limited studies have been conducted on the use of anesthetic agents during handling, cooking, and transportation of crayfish species. This study was carried out to evaluate the anesthetic effects of clove (Syzygium aromaticum), spearmint (Mentha spicata) and chamomile (Matricaria chamomilla) essential oils on red swamp crayfish (Procambarus clarkii (Girard, 1852)) at temperatures of 17 and 23 °C. The study was performed in 10 L plastic containers filled with 3 L of dechlorinated freshwater to determine induction and recovery times and stages under laboratory conditions. Five concentrations (200, 350, 500, 750, and 1000 µL/L) of essential oils were used. This study found that the induction time at 1000 µL/L was significantly lower than 200 and 350 µL/L at 17 °C (p < 0.05) and there was no statistical difference between the five concentrations at 23 °C (p < 0.05). Recovery at 1000 µL/L was markedly higher than 200, 350, and 500 µL/L at 23 °C (p < 0.05). Red swamp crayfish exposed to clove oil reached Stage 6, which is identified as a total loss of equilibrium, using 1000 µL/L at both temperatures. For spearmint oil, induction time at 1000 µL/L was significantly lower than 200, 350, and 500 µL/L at 17 °C, induction time at 200 µL/L was the highest at 23 °C (p < 0.05), and Stage 5 (partial loss of equilibrium) was recorded as the maximum stage reached. Recovery time at 1000 µL/L was the highest at 17 °C, and recovery at 200 and 300 µL/L were lower than 750 and 1000 µL/L at 23 °C (p < 0.05). No significant differences were recorded in the induction and recovery times of chamomile oil for all the concentrations at both 17 and 23 °C (p > 0.05) and the crayfish reached a maximum of Stage 3 (deep sedation) at 1000 µL/L at 23 °C. Overall, clove and spearmint essential oils were proven to be the most successful at providing effective anesthesia to the red swamp crayfish. However, the length of induction and recovery times may be a disadvantage for some procedures. In addition, it has been revealed that chamomile oil may have only a sedative effect and is therefore unsuitable to be used as an anesthetic.
Abstract in English:Abstract In the Atlantic Ocean, the shrimp Cuapetes americanus (Kingsley, 1878) is well distributed. This species has been studied regarding its taxonomic status, distribution records, and some biological and reproductive traits. However, its fecundity and reproductive aspects have never been evaluated in Brazilian waters before. SCUBA (Self Contained Underwater Breathing Apparatus) diving and Artificial Refuge Substrate were used to sample C. americanus specimens quarterly in a sheltered location in the Marine State Parks of Laje de Santos and Vitória Island for a year (2015-2016). A total of 45 animals (carapace length 1.35-4.54 mm) were sampled: 6 females; 18 ovigerous females; 3 juveniles; and 17 males. The major axis references were employed to analyze the relationship between the second pleura (SPL) and the carapace length (CL). The fecundity was 87.05 ± 80.50 eggs and it was similar to other populations connected to it, and it was exclusively associated favorably with CL. Despite being a small and inconspicuous species, C. americanus is a caridean shrimp species that has evolved to thrive and breed on continental islands. The importance of the creation and revision of management plans for no-take marine areas on the Brazilian coast is supported when many kinds of information about the ecology and biology of the species are available, such as caridean shrimps, which can be present as a link between trophic levels of the aquatic food web.
Abstract in English:Abstract After a study of the type specimens, as well as supplementary materials of the eastern Pacific hermit crab Pagurus gladius (Benedict, 1892), this taxon is transferred to the genus Spathapagurus Lemaitre and Felder, 2011, and a full redescription and illustrations are presented. Morphological similarities of Benedict’s taxon with three other eastern Pacific species (Pagurus albus (Benedict, 1892), Pagurus perlatus H. Milne Edwards, 1848, and Pagurus pseudoalbus Ayón-Parente and Wehrtmann, 2019) are summarized. While examining museum specimens during this study, one female specimen representing a new species of Pagurus Fabricius, 1775, was discovered. This new species, named Pagurus marysolae sp. nov., is fully described and illustrated, and is assigned to Group II (“exilis”) of Pagurus.
Abstract in English:Abstract Carapace width-carapace length (CW/CLRs), carapace width-weight (CW/WRs), and carapace length-weight (CL/WR) relationships are presented for the portunid species Callinectes bocourti A. Milne Edwards, 1879, Callinectes danae Smith, 1869, and Callinectes ornatus Ordway, 1863 from the northern coast of Brazil. A total of 85 crabs were collected between May and October 2015 in intertidal zones of the Caeté, Pirabas and Salinas estuaries. All species had strong relationships between measurements with a coefficient of determination (r 2) ranging between 0.97 and 0.99. The variable most strongly related to CW was CL with 99 % of the variability provided by C. ornatus. These relationships are a useful tool for field ecologists to estimate length and/or mass of portunid species, and it is not necessary to euthanize the organism to collect body measurements. Additionally, this study describes the first reference of CW/CLRs and CL/WRs for these portunid species in the region. The Callinectes species in Amazon estuaries are still poorly studied, and there is a need for monitoring their stocks due to its importance for artisanal fishery. The present data are important for supplying biological information required for an adequate management of this fishery.
Abstract in English:Abstract Coral-associated fauna contributes greatly to coral reef biodiversity. Many species are obligately associated with their hosts on which they depend for food and/or refuge from predators. Their close relationship with their hosts makes them vulnerable to coral mortality. Here I report a coral-dwelling gall crab (Cryptochiridae) inhabiting a partially dead Echinopora Lamarck, 1816 coral, at Magoodhoo Island, Faafu Atoll, Maldives. Cryptochirids are thought to feed off the mucus provided by their coral host, although some questions about their feeding biology remain. This observation highlights that these crabs remain associated with a dead host, even if it can no longer provide nutrients. The strong host association makes gall crabs vulnerable to widespread habitat degradation.