A new species of pseudothelphusid crab the tribe Kingsleyini Ortmann, 1897, from southern Amazon region in state Rondônia, Brazil, is described and illustrated. Fredius avilai n. sp. can be readily distinguished its congeners by following characters male first gonopod: mesial lobe elongated, convoluted, proximal portion directed laterally, distal sharply recurved abdominal direction; marginal process rounded, not projected over opening spermatic channel, merging with surface after a shallow...

Abstract The evolutionary success of the Alpheus snapping shrimps is linked to their claws, which were considered key innovation in evolution these shrimps. However, many aspects claws remain unknown. We evaluate degree intra‐ and interspecific variation shape claw different shrimp species. For this, we used a geometric morphometric tool. investigated from two perspectives — sexual dimorphism three species: angulosus , A. carlae, estuariensis locations along southern coast Bahia state...

Freshwater crabs are important components of aquatic ecosystems; however, their distributions restricted because characteristics life history, which hinder conservation strategies. Fredius reflexifrons is a widely distributed freshwater crab the Amazon basin with relictual occurrences in small wetlands on Planalto da Ibiapaba Northeastern Brazil. Habitat degradation, destruction forest patches, channeling water bodies, and use land for legume cropping can seriously impact species by leading...

Freshwater crabs present cryptic habits and generally live in burrows, rocks leaves among the vegetation, streams or rivers. The behavior of Kingsleya attenboroughi, a recently discovered freshwater crab already at considerable risk extinction, was investigated under laboratory conditions for 12 hr light/dark cycle. Nine K. attenboroughi behavioral acts were described six distinct categories: emersion, immersion, environment exploration, feeding, stance self-cleaning. results show...

Rensch's rule attempts to explain the evolutionary processes that have resulted in current patterns of sexual size dimorphism several taxa. This predicts increases according average body size, when males are larger, decreasing females largest sex. In decapod crustaceans, general pattern is with hypertrophied structures used agonistic disputes, and a greater expansion abdominal chamber. We analyzed freshwater shrimp Macrobrachium jelskii its relationship rule, as well relative growth between...

The objective of this study was to evaluate if seasonal abiotic factor variations (pluviosity, depth, temperature, dissolved oxygen, hydrogen potential, ammonia and electrical conductivity) in a northeastern semiarid reservoir influence abundance population structure Palaemonidae Macrobrachium amazonicum M. jelskii shrimp. Data were collected bimonthly from 30 sampling sites October 2016 September 2017 during the dry rainy seasons. A principal component analysis determined factors that...

The body colour variation in response to different background colours is associated with camouflage, increasing efficiency against predation. In our study, we investigated the of freshwater shrimp Macrobrachium jelskii colours. For this, collected specimens M. Thomás Osterne Reservoir, Municipality Crato, State Ceará, Brazil. experiment, used six aquariums divided into three treatment groups: white background; black red two replicates for each group. Before photographed 30 dorsal view. Then,...

We investigate the onset of morphological sexual maturity, dimorphism and relative growth freshwater crab Fredius ibiapaba. collected specimens bimonthly between August 2017 June 2018. measured crabs to obtain following morphometric variables: carapace width (CW); pleon (PLW); propodus length (PL); height (PH) (PW). A total 175 F. ibiapaba were analysed. The maturity was estimated at 31.7 mm for males, 35.2 females. observed size in CL PLW, with females larger than males. Positive allometry...

TThe occurrence of the alpheid mangrove shrimp Potamalpheops tyrymembe Soledade, Santos and Almeida, 2014, is here e extended from 8°41’S (Rio Ariquindá, state Pernambuco) to 7°01’S Paraíba do Norte, Paraíba) in northeastern Brazil, enlarging northern known range this shrimp. Moreover, we provide additional locality records for tiny poorly which has been observed burrows crab Ucides cordatus (Linnaeus, 1763). Keywords: Caridea, estuarine fauna, new records, western Atlantic.

The aim of this study was to investigate whether Fredius ibiapaba presents heterochely and laterality the larger chela, highlighting its implications for biology ecology species. We carried out with specimens deposited in carcinological collection Laboratório de Crustáceos do Semiárido Universidade Regional Cariri. results show that adult juvenile males females exhibit heterochely, a more pronounced asymmetry males. Handedness exhibited, strong righthanded tendency females. hypertrophy one...

Reservoirs are ecologically important ecosystems. In the Brazilian semiarid region, these ecosystems impacted by environmental changes resulting from rainfall regime. Furthermore, reservoirs boast a rich planktonic biodiversity, which is directly influenced ecological dynamics of each reservoir. Our aim was to analyse impact rapid between dry and rainy seasons on limnological variables in we analysed this phenomenon microcrustacean community We observed that reservoir significantly region's...

The humid forest zones of northeastern Brazil are recognized as endemic hotspots for pseudothelphusid crabs. In this study, we report new occurrence records the pseudothelphusids, Fredius ibiapaba and Kingsleya attenboroughi, in soil streams within forests semi-arid region Brazil. These expand geographical distribution these crabs, highlighting their potential to inhabit throughout region. Furthermore, information indicates that especially K. not confined slopes patches highland swamps but...

Our study investigated the size at onset of morphological sexual maturity, dimorphism, and relative growth in green porcelain crab Petrolisthes armatus from a population Northeastern Brazil. Specimens were collected monthly between February 2011 January 2012 Baía do Pontal, Ilhéus, Bahia. We analysed 576 specimens, with females reaching maturity carapace width 4.7 mm males 5.83 mm. Sexual dimorphism was confirmed, exhibiting broader pleon wider larger chelipeds. Positive allometry observed...

Freshwater crabs exhibit complex behavioral patterns, including those related to mating, which is generally characterized by the approach of male towards female. Kingsleya attenboroughi Pinheiro and Santana, 2016 a pseudothelphusid freshwater crab endemic Brazil. As with other species from this family, K. nocturnal. The main objective present study describe mating behavior evaluate if molt cycle stage influences mating. were allocated pairs filmed for 24 hr. was physical positioning under...

The current paper had as objective to record the occurrence of H. littorale in Salgado River basin, Juazeiro do Norte municipality, southern region Ceara, based on collection 12 specimens, made with use appropriate tools a thickness 0.5 cm, fishes were captured Caras and Sao Jose River, effluents River. With larger sizes weights, collected seem have adapted pollution, since river receives sanitary sewage from surrounding neighborhoods dry season is its only source water. does not sewage, but...

We observed the occurrence of pseudothelphusid freshwater crab Kingsleya attenboroughi Pinheiro & Santana, 2016 in an unexplored stream on northern slopes Chapada do Araripe, Ceará state, northeastern Brazil. A female specimen K. was found a small pool Gameleira stream, district Missão Nova, municipality Velha, southern part state. The new record extends geographic distribution by 7 km beyond Sítio Cocos, its easternmost previously known occurrence;...

The freshwater prawn Macrobrachium jelskii (Miers, 1877) is a species with wide geographical distribution. However, the biological and ecological aspects of this are poorly studied. Thus, present study was carried out in Batateiras River, at municipality Juazeiro do Norte, located south Ceará, semiarid region northeastern Brazil. Samples were monthly between January December 2013, along river margins. A total 628 M. specimens collected, 347 males 281 females. overall sex ratio 1:0.81 (M:F)....