Abstract in English:Abstract The present study was conducted to examine the occurrence and distribution of early juvenile land hermit crabs of the genus Coenobita on a small beach on the Boso Peninsula, Japan as a basis for understanding the important habitats that land hermit crabs use during the sea-to-land transition. The survey sites were supratidal zones at six points with heterogeneous topography, and visual surveys for early juveniles were conducted from middle July to late October in 2015 and 2016. The number of empty gastropod shells in four quadrats along the intertidal zone at each point was also counted in the 2016 survey. The occurrence of early juveniles varied among survey points and was spatially stable for two successive years. The first appearance and abundance of early juveniles varied among survey years. Early juveniles were abundant at points with a gravel bottom throughout the intertidal zone, and empty gastropod shells were also abundant at these points. The abundance of early juveniles was highly correlated with the amount of empty gastropod shells. Thus, our surveys suggested the importance of the sediment types and abundance of empty gastropod shells in the intertidal zones for settlement and landing by land hermit crabs.
Abstract in English:Abstract We present a documentation of the morphological details of two larval stages of mantis shrimps. Documentation was done using the autofluorescence capacities of the cuticle. This is the first time that morphological details of late mantis shrimp larvae are documented in great detail via photography, including all parts of the body up to the proximal elements of the appendages, and not presented as line drawings; it is the second time for mantis shrimp larvae in general. The description is presented as a standardized descriptive matrix. Documentation and description style are adjusted to facilitate comparison with fossil representatives of mantis shrimps, but also their extant counterparts, as well as specimens in the wider framework of Malacostraca and Eucrustacea. Through an exemplary comparison with fossil mantis shrimps, we provide indications about the early evolutionary history of the group. Through an out-group comparison, we identify several possible evolutionary changes of developmental timing, i.e., heterochrony, which could explain some morphological specialisations of mantis shrimps.
Abstract in English:Abstract We estimated the growth parameters of the spider crab, Libinia ferreirae (age, asymptotic size and growth rate) using the von Bertalanffy growth equation model. We obtained nine cohorts for female carapace asymptotic width (CW∞) = 64.32 mm, growth coefficient (day-1) (k) = 0.0027 e t0= 0.77 days) and seven for males (CW∞ = 81.93 mm, k= 0.0021 e t0= 0.49 days). The longevity for males was higher than that for females, estimated 2,156 days (5.91 years) and 1,706 days (4.68 years), respectively. The growth curves for males and females differed (F = 34.67 e p < 0.001). Males reached gonadal maturity before morphometric maturity and occurred at 8.8 and 16.6 months of life, respectively. Females reach gonad and morphometric maturity synchronously and this was estimated to occur at about 11.42 months of life. These crabs invest a great amount of energy in growth during a brief period of their development until reaching the terminal moult. This growth strategy would bring less wear to the organism and consequently a greater longevity.
Abstract in English:Abstract Seaweed aggregates form secondary substrates on rocky shores, providing habitats for phytal organisms such as the spider crab Epialtus brasiliensis Dana, 1852. This species is one of the most abundant macroinvertebrate component from seaweed communities. Although the literature suggests that E. brasiliensis lives in many species of seaweed, their density has only been reported in communities of Sargassum spp. This study assessed the density of the spider crab E. brasiliensis associated with the seaweed Sargassum cymosum Agardh, 1820, Hypnea musciformis (Wulfen) Lamouroux and Acanthophora spicifera (Vahl) Borgesen. We expected to observe a higher density of E. brasiliensis in S. cymosum, which shows greater morphological complexity, followed by H. musciformis, with intermediate complexity, and then by A. spicifera, with low complexity. We found that the density of these crabs can be as abundant in H. musciformis as has been previously reported for S. cymosum, but in both species, the density was higher than in A. spicifera. Overall, our findings improve the knowledge of the phytal habitats used by E. brasiliensis in rocky shore environments.
Abstract in English:Abstract Two species of Oniscidea are recorded for the state of Paraíba for the first time. Cubaris murina Brandt, 1833 from Campina Grande and Cabaceiras and Porcellionides pruinosus (Brandt, 1833) from Campina Grande. Moreover, Alloniscus buckupi Campos-Filho & Cardoso, 2018 and Atlantoscia floridana (Van Name, 1940) have their distribution extended, and a short discussion about the record of A. buckupi in a semiarid area is provided.
Abstract in English:Abstract Novorostrum decorocrus Osawa, 1998, so far only known from its type locality, Iriomote Island, Ryukyu Islands, southern Japan, is herein recorded from much farther south, Ambon Island, Indonesia. Males and females of N. decorocrus differ from each other in some morphological traits and their morphological differences are also discussed and illustrated. The female of N. decorocrus is illustrated for the first time. The present record of N. decorocrus from Indonesia lends empirical support to a previous proposition, based on the duration of 12-14 days of the planktonic period of the zoeal phase, that the distribution range of N. decorocrus could possibly be wider than known at that time.
Abstract in English:ABSTRACT This study investigated the population dynamics of Persephona punctata with emphasis on population structure, sex-ratio, spatial distribution, maturity and reproductive period. Crabs and environmental factors (i.e., water temperature and salinity, and sediment texture and organic matter content) were collected monthly, from July 2012 to June 2014 in four sites within the Federal Environmental Protection Area of Cananéia-Iguape-Peruíbe: located in the oceanic area adjacent to the Cananéia region. The population had a female-biased sex-ratio. Persephona punctata had a seasonal reproduction and the higher percentage of ovigerous females (OF) occurred in spring and summer. There was a positive correlation (“lag 0”) between temperature and number of OF (cross-correlation, p < 0.05) and a negative correlation between salinity and OF (“lag-2”), suggesting that periods of higher salinity may be favorable to larval hatching. The estimated size (carapace width - CW50) at the onset of gonadal maturity of males (35.0 mm) was larger than that of females (30.1 mm), which is a common feature of Brachyura. Our results extend the knowledge on the life history of P. punctata and may be useful for the development of future mitigation measures aimed at its conservation.
Abstract in English:ABSTRACT Shrimp trawling is an important socioeconomic activity but catches a large number of non-target species, including Hepatus pudibundus. This study aimed at assessing the population structure of H. pudibundus, analyzing its sex ratio, length distribution, size at first morphological maturity and biometric relationships, and identifying latitudinal patterns. Four samples of 6 kg (shrimps plus by-catch) were monthly collected in March/2015-May/2016 in Pirambu, Sergipe. Carapace width (CW) and length (LC), and total weight (TW, g) were measured. Sex and stage of morphological maturity were defined. A total of 240 individuals wes collected from all samples and the sex ratio did not differ from 1:1. This was observed in low latitudes, but females dominated in higher latitudes. The carapace width was 20.8-60.1 mm for females and 19.1-60.8 mm CW for males. Larger sizes were observed in higher latitudes. The estimated carapace width-length relationships for females and males were not significantly different (CL=0.6764+0.7390∙CW; sex grouped). The estimated weight-length relationship was TW=0.0004∙CW2.8568 for females and TW=0.0001∙CW3.1225 for males. When compared with previous studies carried out throughout the Brazilian coast, slope values (b) for weight-length relationships were higher for males. The length at first morphological maturity for females and males was 28.9 and 29.6 mm, respectively, the lowest ever recorded for this species, reflecting the occurrence of smaller sizes in lower latitudes. These results are the first obtained for northeastern Brazil.
Abstract in English:Abstract The monotypic xanthid crab genus Pulcratis Ng and Huang, 1997, previously known only from the South China Sea, is recorded for the first time in the Indian Ocean. The new material was collected by commercial trawlers fishing off the coast of Tamil Nadu state, in southeastern India, and represents a new species, herein described. Pulcratis amabilis n. sp. is similar to the only other congener and type species, P. reticulatus Ng and Huang, 1997, in the general form and fresh coloration, but differs mainly in the outline of the carapace, and morphology of the chelipeds, and the male pleon and gonopods. The subfamilial classification of Pulcratis within Xanthidae is also discussed.
Abstract in English:Abstract We estimated the growth patterns, age at the onset of sexual maturity, longevity, and natural mortality of the snapping shrimp Alpheus brasileiro Anker, 2012. The sampling occurred monthly from April 2015 to March 2016 in the estuarine intertidal zone of Cananéia, São Paulo, Brazil. To estimate the growth parameters, all cohorts were adjusted to the Bertalanffy growth model. Longevity was estimated by the inverse growth equation. Natural mortality was calculated following the decrease in abundance over time of each cohort. We obtained the following estimates: CL∞ = 9.49 mm, k = 0.0077 day-1 (1.64 year-1), t0 = - 0.7628 for males, and CL∞ = 9.31 mm, k = 0.0095 day-1 (1.32 year-1), t0 = 0.0374 for females. The estimated age at the onset of morphological sexual maturity was 94 and 74 days for males and females, respectively. Females take 89 days to reach functional maturity, and have a higher mortality (4.35 year-1) than males (3.67 year-1). We rejected the hypothesis that males and females of A. brasileiro have the same growth patterns, longevity, mortality and, reaches sexual maturity at the same age. Our results suggest that physiological aspects and energy allocation strategies modulate the growth, longevity, and mortality of these snapping shrimps.
Abstract in English:Abstract In this study we evaluated the effects of changes in salinity, temperature, pH and dissolved oxygen on the spatiotemporal variation of zooplankton. Samples were collected in January−March, May; October−December 2010; and January−March 2011 in the Araruama lagoon, state of Rio de Janeiro, Brazil. There were eight fixed stations sampled using a WP2 net equipped with a flow meter. The zooplankton diversity of the Araruama lagoon was low and dominated by Cirripedia larvae and by the copepod Acartia tonsa, which is an indicator species of eutrophication. In general, a few species from the Cabo Frio region were able to adapt to the conditions of this hypersaline lagoon. In addition, a specimen of Monstrilla bahiana (Monstrilloidae) was found at a salinity of 46‰. This is the first record of the order Monstrilloida in the region of Cabo Frio. Temperature, salinity and pH were shown to be limiting factors for the species present in the lagoon since Cirripedia seemed to avoid releasing their larvae under unfavorable environmental conditions. The abundance of A. tonsa was always associated with that of Cirripedia larvae, and it was higher at cooler temperatures.
Abstract in English:Abstract A new species of smooth clam shrimp (Branchiopoda: Laevicaudata) from Mongolia and China is described here based on both morphological and genetic differences. The new species, Lynceus grossipedia n. sp., has unique features, including asymmetrically modified male thoracopods (left side thoracopods III-VI), male claspers “movable finger” (=endopod) with delicate setation, and broad, bicarinate male and female rostrum. Lynceus grossipedia n. sp. is compared with the genera Paralimnetis Gurney, 1931 and Lynceiopsis Daday, 1912 and a recently described Lynceus Müller, 1776 from China, also showing modified male thoracopods. Lynceus mandsuricus Daday, 1927 is declared nomen inquirendum. DNA barcoding has not previously been applied on smooth clam shrimp taxonomy, so we generated new cytochrome c oxidase (COX1) data for 10 Lynceus species in order to explore its usefulness for Laevicaudata. Previous Laevicaudata sequences in GenBank were scarce (~50) and biased, with 62% (n=31) being assigned to a single taxon (i.e., Lynceus macleayanus) and 28% (n=14) not assigned to species. Based on the addition of new barcoding data and the comparison with GenBank data for other clam shrimps, we conclude that distance thresholds between species (=barcoding gap) are similar for all three suborders (Spinicaudata, Cyclestherida, and Laevicaudata).
Abstract in English:Abstract This paper describes two new species of parasitic copepods of the family Chondracanthidae H. Milne Edwards, 1840. Acanthochondria krishnai sp. n. is described from Dollfus' stargrazer, Uranoscopus guttatus Cuvier, collected from Muttom and Colachel, Tamil Nadu, and Chondracanthus kabatai sp. n. from Silvery john dory, Zenopsis conchifer Lowe, collected from Neendakara, Quilon, Kerala, both along the southwest coast of India. Both the species are described and illustrated based on the fresh female and male specimens collected from India. Both the species are the first Indian representative of the respective genera. The checklist of Indian species of the family Chondracanthidae is also presented.
Abstract in English:Abstract Mursia spiridonovi Karasawa, 2018 known only from the western Indian Ocean, is the smallest species of the genus, measuring only 18 mm in carapace length. The species is redescribed from fresh material collected in Tamil Nadu in southern India. It is compared with similarly sized specimens of M. bicristimana Alcock and Anderson, 1894, all of which are immature. Mursia spiridonovi is characterised not only by its occurrence in shallow waters (less than 300 m depth) and small adult size but also by the prominently granular carapace and structure of the cheliped merus, male pleonal somites and gonopods.
Abstract in English:Abstract Freshwater crayfish were previously absent in the territory stretching from the Caspian Sea basin to the Amur basin. That gap is now being filled, mainly due to the eastward invasion of the narrow-clawed crayfish Astacus leptodactylus, which has currently approached Lake Baikal. This invasion is the result of unauthorized releases. Further spread of the narrow-clawed crayfish or other crayfish species in Siberia may be expected.
Abstract in English:Abstract In this study we investigated the distribution of Macrobrachium olfersii (Wiegmann, 1836) along ~150 km of the Ribeira de Iguape river, São Paulo, Brazil. We compared the abundance and spatio-temporal distribution, and checked for differences in size and proportion of each sex in the collections, using two sampling methods. Shrimps were collected monthly at four sites (Eldorado, Sete Barros, Registro, and Iguape), from January to December 2007, using traps and sieves. We obtained a total of 23,818 individuals. The abundance was significantly higher at the Iguape-site, which was the closest to the estuary. There was a positive cross-correlation between abundance and rainfall, indicating an increase in abundance with a decrease in rainfall. The body size increased significantly upstream, suggesting a juvenile upstream migration, controlled by the rainfall regime and the amphidromous behavior of M. olfersii. More than 95% of the individuals were captured by sieving through the marginal vegetation of the river. The average size and sex ratio of each sample varied depending on the capture method: traps captured more and larger males than the sieve. Therefore, we recommend the combined use of these methods to obtain a better coverage of the population biology of freshwater shrimps.
Abstract in English:Abstract Previous reports of Gilvossius setimanus (De Kay, 1844) from the Gulf of Mexico have been based on a population of small specimens from deep offshore continental shelf waters off Texas and larger specimens from shorelines and shallow embayments of western Florida. The offshore population, herein designated Gilvossius fredericqae n. sp., reaches sexual maturity at much smaller size than does Gilvossius setimanus s.s. from the U.S. Atlantic seaboard, a species from which it differs in a number of morphological characters. While maturing at a similar size to G. setimanus s.s., a western Florida population, herein designated Gilvossius howellorum n. sp., differs from it in the 16S mt gene sequence, and from both it and the offshore species in morphology. An updated synonymy and rediagnosis of G. setimanus s.s. herein accompany descriptions of the two new species.
Abstract in English:Abstract Freshwater crabs are macroconsumers that are commonly found in Neotropical headwater streams that may play a key role in energy flow and nutrient cycling in detrital food webs. Although studies have examined the feeding habits of trichodactylid crabs, little is known of this behavior in pseudothelphusid species, and specifically whether they actually consume leaf material. We conducted three nine-day laboratory trials with pseudothelphusid crabs (Ptychophallus tumimanus (Rathbun, 1898)) and leaves (Koanophyllon pittieri) to investigate whether crabs shred leaves. We hypothesized that leaf mass loss would be faster with crabs present relative to control tanks with only leaves. Leaf mass loss was significantly higher (p < 0.001) in tanks with crabs (0.49 ± 0.07 g, mean ± 1 SD) compared to control tanks (0.31 ± 0.05 g). We observed crabs manipulating, shredding, and consuming leaves, with leaf fragments and egesta present in tanks with crabs but not in control tanks. Their consumption and egestion activity may affect nutrient availability and transformation by stimulating microbial activity during leaf breakdown and converting coarse particulate organic matter (CPOM) to fine particulate organic matter (FPOM). Therefore, freshwater crabs need to be considered when studying energy flow and nutrient cycling in detrital food webs of Neotropical headwater streams.
Abstract in English:Abstract A new species of freshwater crab, Kingsleya parnaiba n. sp., collected in a tributary stream of the Parnaíba River Basin in Brazil, is described and illustrated. Kingsleya parnaiba n. sp. morphologically resembles Kingsleya attenboroughi Pinheiro and Santana, 2016 and Kingsleya gustavoi Magalhães, 2005, from which it can be separated by a set of characters of the first gonopod, chelipeds, and female abdomen.
Abstract in English:Abstract Two species of the palaemonid genus Periclimenaeus Borradaile, 1915, P. ascidiarum Holthuis, 1951 and P. maxillulidens (Schmitt, 1936), are reported from the offshore Escalvada Island, Espírito Santo, Brazil. The location represents a new southernmost record for these species in the western Atlantic. Both species were found inside an undescribed tunicate species of Diplosoma, dwelling inside the circulatory channels, among the zooid clusters. Although P. ascidiarum is known to occur in tunicates, the finding of the rare P. maxillulidens inside an ascidian host represents the first record of this association. Illustrations for both species and a taxonomic key for the southwestern Atlantic Periclimenaeus are provided based on the present material and literature records.
Abstract in English:Abstract Here, we report the first occurrence of Trizocarcinus Rathbun, 1914 (Brachyura: Euryplacidae) from the South Atlantic (Brazil). Trizocarcinus tacitus Chace, 1940 was collected in the upper continental slope of the Potiguar Basin, northeastern Brazil. The new record expands by 3000 km the southern distribution of the species in the Western Atlantic.
Abstract in English:Abstract The aim of this study was to investigate the spatial and temporal distribution of Exhippolysmata oplophoroides and relate its abundance to various environmental variables (bottom water temperature and salinity, texture of sediment and percentage of dissolved organic matter). The sampling of shrimp and abiotic factors was carried out monthly from July 2012 to June 2014, in seven trawling stations (S1-S7), four of them in the marine area and three in the estuary (southern coast of the state of São Paulo, Brazil). The distribution of individuals showed significant differences between stations and between the two years of study (ANOVA, p < 0.05), but not among seasons (p > 0.05). A total of 2005 shrimp were collected, with the highest abundance being found in S4 (n= 937). Bottom salinity and sediment texture were the environmental factors with significant influence on the distribution of the species in the studied region. The low salinity values at S6 and S7, and the low capacity for osmoregulation of E. oplophoroides limit its distribution in the marine environment. High concentrations of silt+clay found at S4 contributed to the accumulation of organic matter, which influenced the high abundance of shrimp there. The information gathered in our study provides valuable results for the knowledge of this species in its area of distribution and contributes to a better understanding of the life history.
Abstract in English:Abstract The purpose of this study was to describe the structure of the midgut (hepatopancreas and intestine) in the endemic species, Macrobrachium carcinus. Thirty specimens were collected, and the midgut was fixed in Bouin's solution for histological and histochemical analyzes by light microscopy. The hepatopancreas consists of two lobes that connect to the end of the stomach by primary ducts, which originate secondary tubules or hepatopancreatic ducts, that branch into hepatopancreatic tubules. The hepatopancreatic duct presents a columnar epithelium composed of R- and F- cells with evident brush borders for absorption and storage. The hepatopancreatic tubule is lined by epithelium with five cell types (E, F, R, B, and M). The distal region presents all cell types, with a predominance of E-cells that correspond to epithelial renewal. The middle region presents F- and B- cells, characteristic of extracellular and intracellular digestion. The proximal region, with B- and R- cells, performs the final digestion, storage, and extrusion of the cells with waste material. The intestine is lined by a single cell type with an evident brush border, suggesting luminal absorption. This cellular arrangement along the length of the midgut proposes distinct morpho-functional characteristics of digestion, absorption, and storage in this species.
Abstract in English:Abstract Alpheus platycheirus Boone, 1927 (Decapoda, Alpheidae) is a snapping shrimp widely distributed in the western Atlantic, from the Gulf of Mexico to eastern Brazil. This shrimp usually inhabits muddy marine bottoms; however, here we record for the first time A. platycheirus in association with Thalassia testudinum and Halodule wrightii meadows at an unusually shallow depth in northwest Venezuela. This record extends the known habitat and distribution of A. platycheirus in the Caribbean. Moreover, it represents an additional alpheid species for Venezuela, bringing the known total to 34 species.
Abstract in English:ABSTRACT The relationship between color and size supports the hypothesis that color is an important signal for some crab species during mating rituals or agonistic interactions. Thus, the objective of this study was to describe the color variation of D. pagei and its relationship with sex and sexual maturity. The crabs were placed on a surface for photographic recording of the body parts: cephalothorax, chelipeds, abdomen and pereiopods using a digital camera installed on a photographic table. Images were converted to the spectrum of red, green, blue and also of them combined (RGB). The values of each spectrum revealed that the color variation of the cephalothorax and chelipeds were different between adults and juveniles. The abdomen and pereiopods showed color variation in both sexes and at developmental stages. The pattern of color variation observed in juveniles ranged from light to dark brown and adults are from orange to intense red. The change in color of the cephalothorax and chelipeds could be used as a character to determine the onset of sexual maturity. The high color variation of the abdomen and pereiopods in both sexes and at developmental stages, though, indicates individual variation which probably is associated with other factors, such as molt stage or even the quality of food available.
Abstract in English:Abstract A new behavior related to shell care was recently reported for the intertidal hermit crab Clibanarius erythropus (Latreille, 1818) in the Gulf of Cádiz (southwestern Europe). It also has been observed in other species of the diogenid genera Clibanarius Dana, 1952, and Calcinus Dana, 1951, however, it has not been described as an active behavior. In the present study, intertidal hermit crabs from different species and localities were sampled to assess if air-exposure is a shell cleaning behavior restricted to some species of intertidal hermit crabs or if it is a more generalized behavior among species inhabiting intertidal habitats. The results revealed that air-exposure is an active behavior in species of Clibanarius and Calcinus, since we observed it also in Clibanarius albidigitus Nobili, 1901, and Calcinus obscurus Stimpson, 1859, from the Pacific coast of Costa Rica, although not in other intertidal species studied by us. We found interspecific differences in tolerance to physical stress of emerged hermit crabs. This air-exposure tolerance can be interpreted as a physiological adaptation to desiccation stress and is also related to the shell type they inhabit. Also, we provide additional features and details of the air-exposure behavior, combining observations of the first description in 2015 with our new field observations.
Abstract in English:Abstract The influence of salinity on the survival of the larvae of Leptuca leptodactyla (Rathbun, in Rankin, 1898) from zoea (Z) to megalopa (M) stage was analyzed in order to deduce the larval dispersal strategy of the species. Larvae were obtained from 10 ovigerous females captured in the mangrove of Guaratuba Bay, southern Brazil. Five salinity treatments were conducted from 0 to 35 PSU (S0, S5, S15, S25 and S35). The larvae were individually raised in plastic cell culture plates, totaling 120 experimental units per treatment, kept under natural photoperiod (12:12 h) and water constant temperature (26.3 ± 0.82°C), and fed with microalgae, rotifers and Artemia nauplii. While all larvae died at S0, S5 and S15, complete larval development until the M stage was only observed at S25 and S35. The highest survival rate was recorded at S35 (18 M from 120 newly-hatched Z, survivorship 15%) and the lowest at S25 (2 M, 1.66%). No significant difference in the total duration was observed between S25 (28.5 ± 0.70 days) and S35 (23.61 ± 3.05 days). The life cycle of L. leptodactyla is based on a larval exportation strategy as they need to perform ontogenetic migrations to the coastal area.
Abstract in English:Abstract A new genus and new species of caprellid, Parapseudaeginella n. gen., and Parapseudaeginella australiensis n. sp., is described from shallow water of Ningaloo Reef, south of Tantabiddy, reef front, Western Australia. The new genus is very similar to Pseudaeginella Mayer, 1890, but can be easily distinguished by the pereonites 6 and 7 being clearly fused (separated in Pseudaeginella) and by the absence of a pair of proximal grasping spines on the propodus of pereopods 5-7 (present in Pseudaeginella). The new species is characterised by acute dorsal projections on head, pereonite 1 and 2, and acute lateral projections near the coxa of gnathopod 2 in males. The new taxon has probably been overlooked in the past due to its tiny size. Further efforts to sample and describe the smaller caprellids is needed to fully understand the global diversity and relationships of caprellids.
Abstract in English:Abstract Relative growth can help to identify dimorphism between individuals, and it is also used to determine changes in ontogeny related to sexual maturity. The morphometric variables recorded were width, length and height in carapace and chelae. The abdomen width was taken only in females. Data analysis was made separating males and females. Exploratory analysis used maximum, minimum and mean values and compared these values between sexes using MANOVA, ANOVA and LSD-Fisher methods. A weight-size relationship was also determined. Relative growth was estimated using a multi-model approach. Six models were applied, and the best was selected using Akaike and Bayesian information criteria. Residual versus predicted graphics were also produced based on the selected models. The mean sizes were similar between sexes, but the maximum values were observed in males. The weight-size relationships showed a negative allometry. The best model varied by morphometric variables and sex, but the type of relative growth was principally isometric and negative allometry. Biometric characteristics in Menippe frontalis A. Milne-Edwards, 1879 did not show abrupt changes in the relative growth. The threshold was not assumed as an indicator of morphometric sexual maturity however, they may be used for establishing legal minimum size in M. frontalis.
Abstract in English:Abstract While previous studies on Alpheus formosus Gibbes, 1850 focused on taxonomic and phylogenetic issues, the present study provides information on the biology and ecology of this snapping shrimp, a representative coral reef species widely distributed in the Atlantic Ocean. We studied A. formosus between 2015 and 2016 on two islands in São Paulo state, Brazil: Laje de Santos and Vitoria Island. We analyzed 47 specimens from Laje de Santos and 44 from Vitoria Island. Individuals ranged in size from 2.0 mm to 13.99 mm CL. The mean number of embryos attached to the pleopods of females was 211.28 ± 312.8 in Laje de Santos and 125.2 ± 177.8 in Vitoria Island. This species should be included in monitoring programs of coral ecosystems they inhabit as A. formosus represents a key element in trophic dynamics of these ecosystems.
Abstract in English:Abstract In this study, the larval development of Libinia rhomboidea Streets, 1870 under laboratory conditions is described and compared with the description of Libinia spinosa H. Milne Edwards in Guérin, 1832, Libinia dubia H. Milne Edwards, 1834, and Libinia emarginata Leach, 1815 published by other authors. The ovigerous females collected released larvae asynchronously. Two zoeas and one megalopa stage were obtained. Larval development required 13 to 14 days at 20.5 - 22.0°C and 32 - 35 psu of salinity. The differences in L. rhomboidea with respect to the other three species are the following: in the first zoea, the total length and carapace length were greater and the number of setae on the basial endite of the maxillula was different; in the second zoea the size of the endopod and the number of setae on the scaphognathite of the maxilla were greater; in the megalopa, the total length and carapace length were both greater, while the number of setae on the scaphognathite of the maxilla was less. A great similarity between L. rhomboidea and L. dubia was found; however, it is possible to distinguish the larval morphology of L. rhomboidea from the three species compared.
Abstract in English:Abstract Increasing global concern with respect to the levels of bioavailable microplastic (<5 mm) contamination in marine environments has led to many studies examining the physiological impacts of microplastic consumption on a range of species. The copepod, Temora longicornis (Müller, 1785), is a common inhabitant of the upper epipelagic zone of gulf and estuarine waters of the North Atlantic which we hypothesised would be regularly exposed to microplastic contaminated marine environments. They are therefore at risk of consumption of microplastic pollutants, which could have wider trophic impacts. Microplastic was recorded in all water samples with an average concentration of 8.2 particles/m3. However, there was no significant difference in abundance or size of microplastics sampled from three localities within Chichester Harbour, UK. Individual digestion of ninety copepods found no evidence of consumption of any microplastic contaminants above our observable size range of 23 μm. Whilst microplastic pollution remains of wider ecological concern, our results suggest limited support for the potential for this copepod species to transfer these pollutants to higher trophic levels.
Abstract in English:Abstract The loggerhead marine turtle is an ideal substrate for epibionts and presents the highest diversity of associated fauna among marine turtles. Here we report the occurrence of two amphipod species, Caprella andreae Mayer, 1890 and Podocerus chelonophilus (Chevreux and Guerne, 1888) from the carapace of one stranded Caretta caretta (Linnaeus , 1758) in Ubatuba, São Paulo state, Brazil. This is the first record of P. cheloniphilus for Brazil and for the South Atlantic Ocean.
Abstract in English:Abstract Freshwater crabs exhibit complex behavioral patterns, including those related to mating, which is generally characterized by the approach of the male towards the female. Kingsleya attenboroughi Pinheiro and Santana, 2016 is a pseudothelphusid freshwater crab endemic to Brazil. As with other species from this family, K. attenboroughi is nocturnal. The main objective of the present study is to describe the mating behavior of K. attenboroughi and to evaluate if the molt cycle stage influences mating. The crabs were allocated to pairs and filmed for 24 hr. The mating behavior of the species was characterized by the physical positioning of the male under the female, with an elaborate courtship occurring prior to copulation. The molt cycle appears to influence mating since mating occurred predominantly between pairs in which males were in the inter-molt stage and females were in the post-molt stage.
Abstract in English:Abstract The study of Colombian freshwater crabs has advanced significantly, but species records are scattered across different museums and research institutions. Assuming that museum collections incorporate valuable information in estimating species diversity, a database was organized on the 94 known species of family Pseudothelphusidae, which includes 568 records from 1853 to 2019 in continental Colombia and Gorgona Island. The natural regions of Colombia (Amazonian, Andean, Caribbean, Orinoquian, Pacific) were further subdivided into 75 natural sub-regions according to habitat types used by freshwater crabs. Sub-regions were (i) ranked in terms of species richness, with respective species reported in each sub-region listed accordingly, and (ii) classified into a scale of five categories on the basis of a geometric biodiversity index combining species richness and Simpson index. Species accumulation curves are presented to estimate the current status of knowledge about the diversity of the Colombian pseudothelphusids. Although the available data are not standardized for an adequate assessment of relative abundance, since they are influenced by sampling efforts and natural sub-regions are of different sizes and characteristics, the present study may be useful in future ecological and biogeographic research, as well as for conservation purposes.
Abstract in English:Abstract We investigated the abundance and spatial distribution of Callinectes danae Smith, 1869 during the day/night periods and tidal cycles in a coastal area of Brazil. Sex ratio, size class distribution, and mean sizes of males and females were also analyzed. The sampling occurred between February and March 2011 in the estuary-bay complex of São Vicente. Collections occurred in six sampling stations during both daytime and nighttime. A total of 1997 specimens were collected in the bay and 963 specimens in the estuary. The abundance of males and females differed between the bay and estuary, with males more abundant in the estuary and adult females in the bay. Crabs in all demographic categories were more abundant at night. The species distribution was intrinsically related to the interaction between environmental factors. In addition to the higher capture during nocturnal collections, a positive correlation was found between the abundance of reproductive females and salinity, while juveniles were more abundant in shallower stations and at lower salinities. Our results contribute to a better understanding of the influence of day/night periods and tidal cycles on the abundance and distribution of the swimming crab C. danae.
Abstract in English:Abstract The genus Pectenoniscus Andersson, 1960 currently presents two described species, one epigean, Pectenoniscus angulatus Andersson, 1960, from Nova Teutônia municipality, Santa Catarina state (Southern Brazil) and the hypogean Pectenoniscus liliae Campo-Filho, Bichuette and Taiti, 2019, found in two caves in the Serra do Ramalho karst area (Carinhanha municipality), Bahia state (northeastern Brazil). Recent surveys in karstic areas of Minas Gerais and Bahia revealed six new cave species from this genus, which are herein described. Two species occur in Minas Gerais state in the transition between the biomes Cerrado (Brazilian savannah) and Caatinga (mesophytic and xeromorphic forests): Pectenoniscus montalvaniensis n. sp. from Abrigo da Ema cave (Montalvânia municipality) and Pectenoniscus juveniliensis n. sp. from Gruta do Tabuleirinho cave (Juvenilia municipality). The other four species were found in Bahia state, in Caatinga biome: Pectenoniscus iuiuensis n. sp. from Baixa da Fortuna cave (Iuiu municipality); Pectenoniscus carinhanhensis n. sp. from three caves in Serra do Ramalho (Carinhanha municipality); Pectenoniscus santanensis n. sp. from Gruta do Padre cave (Santana municipality); and Pectenoniscus morrensis n. sp. from Gruta dos Brejões cave (Morro do Chapéu municipality). Aside from the taxonomic descriptions, we provide ecological notes for each described species, as well as an identification key for Pectenoniscus.
Abstract in English:Abstract Terrestrial isopods are a successful group of terrestrial crustaceans. Their exoskeletal cuticle has been studied in several species. However, it is not known whether the cuticle of these animals becomes thicker or how its structure changes as the animals grow. We aimed to determine the principles of upscaling of the exoskeletal cuticle during growth in the terrestrial isopods Armadillidium vulgare (Latreille, 1804) and Porcellio scaber Latreille, 1804 with scanning electron microscopy. The tergal cuticle becomes thicker with increasing body length. In A. vulgare, which rolls into a ball in defense against predators, the rate of increase of tergite thickness was greater than in P. scaber, which clings to the substrate when threatened. As the cuticles of both species become thicker, the proportion of the endocuticle in the cuticle increases. There is a strong correlation between cuticle thickness and the thickness of endocuticular lamellae. This indicates that in thicker cuticles, chitin-protein fibers in sequential layers change their orientation by a smaller angle. We found no significant differences in morphometric parameters between the cuticles of A. vulgare and P. scaber when controlling for cuticle thickness. This suggests that known differences in cuticle structure and composition between these two species may result from differences in cuticle thickness.
Abstract in English:Abstract In this study we analyze both seasonal and inter-annual variations in the community parameters of Brachyura zoea I in the Parque Nacional Sistema Arrecifal Veracruzano. Planktonic samples from four transects were collected during three weather conditions: cold fronts; rainy and dry conditions in 2011 and 2012; and cold fronts and dry conditions in 2013. We measured temperature, salinity, and dissolved oxygen, in situ, to determine whether these parameters could explain the observed variations in the community patterns of brachyuran zoea I. We collected zoeae I of 18 species of brachyurans. The dominant species were Libinia dubia H. Milne Edwards, 1834; Menippe nodifrons Stimpson, 1859; and Callinectes sapidus Rathbun, 1896. The temperature and dissolved oxygen were the highest during the rainy conditions and the salinity during the dry conditions in the southern transects. The highest species richness (14) and diversity (2.97 bits individual-1) were found in central transects during cold front conditions. However, we found the highest species richness and diversity during the dry conditions, in the southern transects. Libinia dubia presented the highest density during cold fronts with 1592 ± 127 zoeae 100 m−3 in the northern transect, followed by C. sapidus in the north-central transect, this was observed for both species in the offshore zone. In conclusion, the parameters of the community of zoea I were influenced by the physical parameters measured in each sampling zone.
Abstract in English:Abstract The offshore mysid Neobirsteiniamysis inermis (Willemoes-Suhm, 1874) is reported for the first time in western Mexico. A large series of specimens (168 specimens: 44 males, 124 females) was obtained from samples taken with a large benthic sled in as many as 28 localities distributed off the west coast of the Baja California Peninsula (15), in the Gulf of California (11), and off SW Mexico (2). Only one ovigerous female was collected. A complete description of the material, based on a mature specimen, is provided, including SEM images of the mandibles, which are described in detail, and of the eyes.
Abstract in English:Abstract Zoological collections are fundamental repositories of biodiversity and have an important role in scientific dissemination. The National Institute of Mata Atlântica (INMA, previously called Professor Mello Leitão Biology Museum) founded by Augusto Ruschi is situated in Santa Teresa, Espírito Santo, Brazil, within the Atlantic Forest Biome, being a relevant source for the development of research in this habitat. The aim herein is to inventory the crustacean collection of INMA with a complete list of the species and their habitat. This collection is not yet digitized or available online. The collection totals 52 species in 41 genera, belonging to 26 families and comprises major crustacean groups, with a particular focus on Decapoda. All holdings are from Brazil. It consists of 443 specimens included in 131 records, representing mostly the Espírito Santo carcinofauna. Without online publication of the specimen data, the visibility and use of the collection would likely remain limited. Sourcing specimens through online databases will facilitate the production of guides and taxonomic training, and also more information can be passed on to the community as a whole. Thus, a proposal for future management of the Crustacea collection of INMA is to digitize the data through photos of the specimens and associated labels.
Abstract in English:Abstract An adult female of the Jewel-Box clam crab Gemmotheres chamae (Roberts, 1975) was collected from a shrimp trawl during a biological exploration off Campeche coast, Mexico. This finding represents its first record in the Gulf of Mexico and the second locality for this species along the Atlantic coast of America, the first being from off North Carolina, U.S.A. As an adult, G. chamae has a soft, thin carapace, and a subconical protuberance on article 1 of the antennae (with the nephridiopore of the antennal gland), so it is considered to belong to the Pinnotherinae sensu stricto. G. chamae and Nannotheres moorei Manning and Felder, 1996 (Atlantic) are the only members of the American Pinnotherinae sensu stricto that have the maxilliped 3 with a 2-segmented palp. The asymmetry of pereiopod 3 is confirmed, as well as that of the pereiopod 4, but the right legs are the longest. All these features are diagnostic for G. chamae.
Abstract in English:Abstract A new genus of Mysidae, Neobirsteiniamysis, was proposed in early 2020 for the nomen nudum Birsteiniamysis Tchindonova. This new genus, however, was not available for being published online only. The new genus is hereby officially registered in Zoobank and validated.
Abstract in English:Abstract The crayfish Procambarus clarkii (Girard, 1852) is a native species from the south-central region of the USA and northeastern Mexico that has been introduced to all continents except Antarctica and Oceania. In Brazil, P. clarkii has 17 established populations, all found in the southeastern region. The studied specimens were obtained at Ribeirão Claro municipality (23°11’38”S 49°45’28”W) in Paraná State, southern Brazil, in fish ponds from a private property near the Paranapanema River reservoir. Sampling was performed in September 2013 and March 2015, yielding a total of 13 crayfish specimens. Interviews with residents and workers at the sampling sites revealed that the aquarium trade could be an important introductory pathway, since the first crayfish observed had been released into nature shortly after being purchased at a pet shop in the neighboring state of São Paulo; even though current legislation forbids their importation, transportation, and commercialization.
Abstract in English:Abstract Freshwater shrimp can reach high biomasses, affecting ecosystem processes. It is important to define the most accurate methodology to estimate their densities and biomass. We studied two species of different sizes, Potimirim brasiliana Villalobos F., 1960 and Macrobrachium olfersii (Wiegmann, 1836), in three sites of a coastal stream in Ilha Grande, Rio de Janeiro, Brazil. We evaluated the efficiency of two infrequently used sampling methods: a depletion method using electrofishing, and a substrate method using benthic samplers. The methodologies provided different estimates, especially for M. olfersii, of density (electrofishing 1.27 ± 6.3 ind/m²; substrate sampling 0.1 ± 5.05 ind/m²) and biomass (electrofishing 1.66 ± 8.5 g/m²; substrate sampling 0.11 ± 1.16 g/m²). The median size of M. olfersii was higher for electrofishing, while the median size of P. brasiliana was higher for substrate sampling. Electrofishing is good at collecting bigger individuals that are not possible to catch with the substrate method and it samples a bigger area that includes many different microhabitats. The substrate method is cost-effective, especially for P. brasiliana, but by sampling a small area, its estimates can be highly affected by local heterogeneity. The substrate method is not recommended for M. olfersii, as it underestimated both its density and biomass.
Abstract in English:Abstract The aim of this study was to evaluate the gonadosomatic index (GSI) and the weight/length ratio in important shrimp populations (Xiphopenaeus kroyeri (Heller, 1862), Litopenaeus schmitti (Burkenroad, 1936), Rimapenaeus constrictus (Stimpson, 1874)) from the northern littoral of São Paulo State. The samples were collected between 2015 and 2016, with 212 females that were identified, classified according to their gonadal development stage, and measured (CL). The gonads were macroscopically classified into immature, spent and developed, and were then removed. Both body (BodW) and gonad (GonW) dry weights were obtained in order to calculate the gonadosomatic index. Weight/length relationship and weight gain rate were assessed. The weight gain presented negative allometry, indicating that the animals grow faster than they gain weight. The weight/length relationship showed a pattern of continuous reproduction, as previously determined for tropical species. From the GSI values, it was possible to separate the three predetermined gonadal stages, proving that macroscopic evaluation is reliable for evaluating the reproductive period of these shrimps. These results can be used as a guide for fishery stocks management and monitoring.