RCAAP Repository

Abstract A new species of the freshwater crab genus Sundathelphusa Bott, 1969 is described from the Indonesian island of Lombok. Sundathelphusa tuerkayi, new species, appears to be most closely related to Sundathelphusa aruana (Roux, 1911), which is known for certain only from the Aru Islands, but differs from it and all other congeners by a unique combination of morphological characters. The new crab hosts a small ectosymbiotic temnocephalid flatworm, possibly belonging to the genus Temnosewellia Damborenea and Cannon, 2001 (Platyhelminthes: Temnocephalida).

Abstract This study aimed to characterize the population dynamics of Hyalella bonariensis Bond-Buckup, Araujo & Santos, 2008 from headwater spring in a rural area of state of Rio Grande do Sul, Brazil. Four samples were collected in August (winter) and October (spring) of 2012 and January (summer) and April (autumn) of 2013. Ovigerous females and precopula pairs were separated from other individual in the field. A total of 5,266 specimens were sampled, being 1,878 males, 2,073 females (including 240 ovigerous females) and 1,315 juveniles. The frequency distribution of size classes (measured as cephalothorax length, CL) was polymodal and bimodal in males and females, respectively. Males reach larger size than females. Sexual maturity of males and females was estimated at 0.40 and 0.38 mm for CL, respectively. Total sex ratio favored females, and these were more frequent in intermediate size classes, while males were more frequent in larger size classes. Ovigerous females and couples were found in four seasons, but both were more abundant in winter. Juveniles were also found in all seasons, being more frequent in winter and spring. These results showed that this H. bonariensis population has similar dynamics to other species of Hyalella Smith, 1874 from Brazil, but present variations when compared to other freshwater amphipods.

Abstract A new species of the freshwater crab genus Potamonautes MacLeay, 1838, is described from Gorongosa National Park in Sofala Province, Mozambique, southern Africa. Potamonautes gorongosa, new species, is morphologically and phylogenetically distinct from the other species of Potamonautes found in Mozambique and nearby countries, and is most closely related to Potamonautes mutareensis Phiri and Daniels, 2013, from eastern Zimbabwe. The new species differs from this species and its other congeners by a unique combination of morphological characters of the first gonopod, the anterior sternum, third maxilliped, and the major cheliped. Illustrations of P. gorongosa new species are provided, and differences with other species found in Mozambique and southeastern Africa are discussed.

Abstract The caridean family Glyphocrangonidae Smith, 1884 is monotypic, including only the genus Glyphocrangon A. Milne-Edwards, 1881. The species of this genus are exclusively inhabitants of deep sea. The current contribution aims to enrich the knowledge of Glyphocrangon in the southwestern Atlantic, by reporting its occurrence and bathymetric distribution in the Potiguar Basin, northeastern Brazil. The samples were collected by R/V Luke Thomas and R/V Seward Johnson, with bottom trawling at isobaths of 400, 1,000 and 2,000 m, using an otter trawl semi-balloon. The specimens were identified and stored in the carcinological collection of the Museu de Oceanografia Prof. Petrônio Alves Coelho, in Recife, Brazil. A total of 810 specimens were examined from five species: Glyphocrangon aculeata A. Milne-Edwards, 1881, G. alispina Chace, 1939, G. longirostris (Smith, 1882), G. sculpta (Smith, 1882) and G. spinicauda A. Milne-Edwards, 1881. Glyphocrangon spinicauda was the most abundant with 334 individuals, and G. sculpta was the rarest, with only one individual. All species were recorded in the study area for the first time.

Abstract The goal of this study was to evaluate the reproductive investment (RI) and the fecundity of the shrimp Nematopalaemon schmitti (Holthuis, 1950), caught by trawling in the southeastern Brazilian coast in 2008, 2009 and 2011. The carapace length (CL) of ovigerous females was measured and the development stage of their ovaries and embryos were analyzed. A significant relationship was observed between the female body and embryo weights (Linear regression: r² = 0.26, F = 20.77, P < 0.0001, Ln BDW = 0.92. Ln FBDW - 2.24) and between number of embryos and CL (Linear regression; stage I: r² = 0.38, F = 36.15, P < 0.0001; stage II: r² = 0.34, F = 14.10, P < 0.001), but not between the RI and CL (ANOVA: F = 0.47, df = 7, P = 0.85). Association of the changes in embryo development and ovarian maturation of ovigerous females was tested. Females with rudimentary ovaries predominantly showed embryos in stage I (early development) and females with developed ovaries only showed embryos in stage II (final development), showing synchrony between the development of both, thus supporting the hypothesis of a continuous reproductive cycle for N. schmitti in the region. Such information is fundamental for understanding the reproductive biology of these crustaceans, as well as other caridean shrimps, in order to promote the maintenance and preservation of natural stocks.

Abstract This study investigated the temporal abundance, periods of reproduction and recruitment, gonad sexual maturity, and population structure of the swimming crab Achelous spinimanus (Latreille, 1819) in Macaé, a region of the Brazilian coast affected by upwelling events. The samples were collected monthly during one year. The crabs were counted, sexed and measured for maximum carapace width (MCW). Four developmental stages were described in males and females. Environmental variables as temperature, salinity, organic matter and Phi were measured. A Principal Components Analysis indicated that environmental variables were strongly correlated with seasons, affecting the abundance of this species, which was high during summer and autumn. The periods of reproduction and recruitment were also seasonal, with a peak of females with developed gonads and ovigerous females during autumn and immatures during summer and autumn. Males and females did not differ in size at gonad sexual maturity, estimated at 39.9 and 42.9 mm MCW, respectively. The environmental conditions in this upwelling region may have induced this population of A. spinimanus to show different characteristics and behaviors from other populations on the Brazilian coast, since alterations linked to the periods of reproduction and recruitment, as well as the population structure and distribution, may reveal different survival strategies of the species.

Abstract The subfamily Portuninae includes about 130 species organized in 11 genera. The genera Portunus (Weber, 1795) and Achelous (De Haan, 1833) include about 80 species altogether. In Brazilian waters there are five known species of Achelous and four of Portunus. In the present contribution, a catalogue and illustrated key are provided for all Brazilian Achelous and Portunus species known to date.

Abstract In this contribution we describe a new species of burrowing crayfish of the genus Parastacus Huxley, 1879 from a swamp forest in southern Brazil and determine its conservation status. The distinction of the new species is based on morphology and the mitochondrial DNA marker 16S rRNA. The extinction risk was assessed according to the sub-criterion B1 of IUCN that estimates the Extent of Occurrence (EOO). Parastacus tuerkayi sp. nov. is morphologically distinguishable from all species of Parastacus by having three lines of verrucous tubercles on the dorsomesial margin of the cheliped propodus and a suborbital angle exceeding 90°. The EOO comprises 647,674 km², and the species is classified as “endangered”. Phylogenetic relationships indicate the distinct position of this new species in relation to the already described species.

Abstract The taxonomy of the genus Neopseudothelphusa Pretzmann, 1965 is revised based on the morphology of the male first gonopod. A new genus, Culterthelphusa, is here proposed to receive Neopseudothelphusa simoni (Rathbun, 1905), while the genus Neopseudothelphusa is restricted to its type species, Neopseudothelphusa fossor (Rathbun, 1898). Illustrations of the first gonopod of both genera are provided.

ABSTRACT We analyzed the spatio-temporal variations of the abundance, distribution and the population structure of Hexapanopeus paulensis Rathbun, 1930 from the southeastern Brazilian coast. Monthly samples were taken from January 1998 to December 1999 at Ubatumirim, Ubatuba and Mar Virado bays. A total of 1084 individuals were obtained, 76 specimens at Mar Virado, 322 at Ubatuba and 686 at Ubatumirim. It was possible to verify an association between the abundance of H. paulensis and bottom temperature (positive correlation), grain size of sediment and organic matter content (both negatively). This explains the higher number of individuals in the stations nearest to the continent (with higher temperature values and heterogeneous substrate). Juveniles were recorded throughout the study period, constituting 39.5% of the sampled population, which highlights the importance of the region (especially Ubatumirim Bay, due the highest abundance) for the establishment of the species. Only females occupied the largest size classes, which could mean differential mortality between the sexes or growth rate. Nevertheless, further studies should be accomplished to a better comprehension of such difference.

Abstract The speciose genus Aegla Leach, 1820 is the only valid extant genus of the anomuran family Aeglidae, bearing 83 known species. This diversity may be even greater since there is some evidence for cryptic speciation. The genus is endemic to southern South America, occurring in freshwater habitats. We assessed the conservation status of 82 species of Aegla and found almost 70% of them under some level of threat, which represents a concerning proportion. Major threats to the group include freshwater pollution with urban, agricultural and industrial effluents, habitat modification and fragmentation, riparian forest removal, among others. Conservation measures are required to mitigate the major threats to freshwater ecosystems along rivers where the group occurs.

Abstract The variation in reproductive investment (RI) and the hypothesis of multiple spawning were evaluated in the redfinger rubble crab Eriphia gonagra (Fabricius, 1781). The gonads and embryos showed synchronous development, and fecundity and RI varied widely among females of the same size class. The mean RI value recorded was 11.31%, with no significant differences among the means for different size classes. The allometric analysis of fecundity indicated RI decrease while body size increase, but we suggested that this occurs due to size overestimation where the largest width of carapace was used as body size reference in these analyzes. In addition, we found an isometric relationship for “female weight vs. egg number”, and also for “female weight vs. egg weight”, indicating that RI ​​increased proportionally with size of females. Relatively high frequencies both of smaller females with rudimentary gonads, and of larger females with developed gonads were observed. This indicates that larger females take place more frequently in the population reproductive output over time. This difference could not be observed by means of RI analyses of captured and fixed crabs, for which only one stage of gonad development and/or one spawning is usually recorded.

Abstract Squillidae is the largest family in the Stomatopoda, with 47 genera to date. Phylogenetic analyses have shown Squilla Fabricius, 1787 and Oratosquilla Manning, 1968 to be para- or polyphyletic. Two poorly documented species within these genera, Squilla parva Bigelow, 1891 (eastern Pacific) and Oratosquilla kempi (Schmitt, 1931) (western Pacific) are not closely related to the respective type species of the genera in which they are currently placed. We herein redescribe S. parva and O. kempi based on type and other material, and propose two new genera for their reception, increasing the number of squillid genera to 49.

Abstract A new palaemonid shrimp genus, Michaelimenes n. gen., is established for three Indo-West Pacific species, Periclimenes latipollex Kemp, 1922, Periclimenes perlucidus Bruce, 1969 (type species) and Periclimenes platydactylus Li, 2008. The present new genus can be immediately distinguished from other related genera by the combination of the second pereiopod with the dorsal flange on the dactylus, the proximal excavation on the fixed finger and the smooth propodus, and the unarmed, non-subspatulate fingers of the first pereiopod. The type species, Michaelimenes perlucidus, is recorded from Japan for the first time on the basis of 34 specimens associated with the alcyonacean genus Chironephthya Studer, 1887. The intraspecific morphological variation and host specificity of M. perlucidus are commented upon. Periclimenes involens Bruce, 1996 is regarded as a junior synonym of M. perlucidus.

Abstract A new species of Pulmoniscus Leistikow, 2001 from Department of Bolívar, Colombia, is described. It constitutes the first record of the genus for the country and for the continental portion of the Neotropics. Pulmoniscus turbanaensis n. sp. is distinguished by the male pereopod 7 ischium with concave sternal margin and the shape of the male pleopod 1. In addition, ecological remarks and a distribution map are provided.

Abstract A checklist of caridean and stenopodidean shrimps of the Caribbean coast of Panama is presented, based on material collected during two local workshops (2005, 2008) as well as extensive sampling during 2006-2010. This material is augmented by an annotated list of previously recorded species, amounting to a total of 157 species, including 20 new records. Doubtful records are discussed. The current checklist is however considered relatively incomplete as older records could not always be verified and more taxa remain to be described. Despite the deficiencies of the present list, the Caribbean coastline of Panama is clearly one of the most species rich areas in the entire Atlantic Ocean for caridean shrimps.

Abstract This study analyzes ontogenetic allometry in Aegla marginata Bond-Buckup & Buckup, 1994, a freshwater crustacean, in order to evaluate the growth pattern and the presence of sexual dimorphism, using a multivariate approach. The specimens were sampled from streams in Intervales State Park, São Paulo State, Brazil. For each specimen, we measured the following structures: carapace length and width, chelae height and length, and abdomen length. Allometry was evaluated using Jolicoeur’s multivariate allometric coefficient. Our results showed that for females, ABL (abdomen length) and LCH (left chelae heigh) presented positive allometry; LCL (left chelae length) and RCH (right chelae heigh) isometry; and CL (carapace length), CW (carapace width), and RCL (right chelae length) negative allometry. For males, RCH, LCH, and LCL presented positive allometry; RCL (right chelae length) isometry; and CL, CW, and ABL negative allometry. In addition, sexual dimorphism was amplified with body size.

Abstract Mussel farms are one of the most important modalities of aquaculture and constitute almost 80% of the total bivalve production in Brazil, representing about 5% of the national production. Brachyuran crabs are common inhabitants of these environments and represent an important link in coastal marine food chains. The aim of this investigation is to describe the population structure of Panopeus austrobesus Williams, 1983 in a Perna perna (Linnaeus, 1758) farm located at the southeastern Brazilian coast. The samplings were carried out in the northeastern coast of São Paulo State. From May 2002 to April 2003, one mussel net was recovered monthly, and all individuals of P. austrobesus were collected. Population size-frequency analysis indicated a unimodal and non-normal distribution. Males were significantly larger than females, and the overall sex ratio significantly skewed from 1:1, female-biased. Recruitment occurred during the entire period, and ovigerous females were found in 11 months. The onset of sexual maturity was estimated around 5 mm cephalothorax width. Mussel farms represent an anthropogenic intervention in the sea landscape, causing environmental changes. However, these structures must allow species introduction, increasing their ecological and geographical distribution, and provide available space and food to establish new populations. This is particularly important for species with small populations, such as P. austrobesus. The results of this study attest the environmental counterpart role of the mussel farms. Once they can support populations, they may also help to reintroduce them into the area and could therefore be used in a consortium generating economic profits and acting as bioremediation tool, assuring the maintenance of the genetic patrimony.

Abstract A new species of the Clausidium Kossmann, 1874 copepods is described, illustrated and provided by Confocal Laser Scanning Microscope photo on the basis of specimens from the gill chamber of Callianidea typa H. Milne Edwards, 1837 from the Iranian coast of the Persian Gulf. Clausidium persiaensis sp. nov is unique in the possession of a fine spine on endopod-1 of the antennae, large blade-like setae with an acute tip on P1, and the shape of P5 and the anal somite. The new species extends the group distribution into the northwest Indian Ocean and represents the first records of the genus in Iran.

Abstract A new parasitic copepod species, Ergasilus turkayi n. sp., found on the gills of the Holland’s piranha, Serrasalmus hollandi Jégu, 2003, in the Paragua River, Bolivia, is described based on 10 adult females. The new species presents a triangular-shaped cephalothorax, spinules on interpodal plates and aesthetascs on antennule - two aesthetascs on the sixth, and one aesthetasc plus two setae on the fifth segment. Additionally, the second abdominal somite of E. turkayi n. sp. bears an anal pseudoperculum, a dorsal and elongate projection which is usually absent or vestigial in poecilostome families within the Cyclopoida but that was never reported in species of Ergasilidae.