Comparative reproductive biology of two southwestern Atlantic populations of the hermit crab Pagurus exilis (Crustacea: Anomura: Paguridae)

Pagurus exilis (Benedict, 1892) is an endemic South Atlantic hermit crab with a distribution ranging from Rio de Janeiro State, Brazil, to Buenos Aires Province, Argentina. The present study analyzed the reproduction of two populations at the extremes of this geographical distribution, and compared their reproductive period, fecundity, and changes in egg size and egg volume during the incubation period in order to assess the variability over this latitudinal range. Hermit crabs were collected monthly over a 2-year period. In total, 108 females were analyzed for Brazil (44 non-ovigerous and 64 ovigerous), and 141 for Argentina (87 non-ovigerous and 54 ovigerous). Reproduction in Brazil occurs year-round, with peaks in the fall and winter seasons; in Argentina reproduction occurs only in spring and summer. The Brazilian ovigerous females were significantly larger than the Argentina ones (Brazil: SL = 5.33 +/- 1.45 mm; Argentina: SL = 4.15 +/- 0.52 mm; P < 0.001). The fecundity was 1447 +/- 831 eggs (317 to 2885) in Brazil and 987 +/- 711 eggs (114 to 2665) in Argentina, with a trend towards higher fecundity in Brazil. Eggs in the Argentina population were larger than those in Brazil for all the three stages investigated, and no changes in egg volume were found during egg development for both populations. The reproductive traits of the two populations showed some important differences, which may reflect adaptations to local environmental conditions, demonstrating a high plasticity of reproductive features of the species in Brazilian and Argentine waters. The strategy adopted by the Argentina population involves a lower production of larger eggs compared to the population in Brazil; this lower production is associated with reproduction in cold-water regions.

Temporal dynamic of the relationship between the parasitic isopod Aporobopyrus curtatus (Crustacea: Isopoda: Bopyridae) and the anomuran crab Petrolisthes armatus (Crustacea: Decapoda: Porcellanidae) in southern Brazil

The prevalence of the parasite Aporobopyrus curtatus in Petrolisthes armatus from southern Brazil was determined, and the effect the parasite had on host reproduction was evaluated. Of all 775 crabs sampled in Araca region from March 2005 to July 2006, 3.2% presented bopyrid parasites. All the parasitized individuals had one branchial chamber occupied by two mature parasites, with no preference for the right or left chamber. Male and female hosts were infested in equal proportions. Parasitized juveniles, large individuals and ovigerous females were not found in our study. The absence of parasitized ovigerous females seems to be insufficient evidence to support the hypothesis of parasitic castration and would require a histological study to confirm their reproductive death. The percentage of infestation observed in our study (3.1%) is lower than the one found in other studies and it could indicate the existence of factor(s) regulating the density of A. curtatus in the Araca region. At least in this population, the low but constant presence of the bopyrid A. curtatus population did not appear to have a negative effect on the porcellanid population, and parasitized individuals did not play a significant role in the natural history of P. armatus.

Mitochondrial genome data alone are not enough to unambiguously resolve the relationships of Entognatha, Insecta and Crustacea sensu lato (Arthropoda)

An analysis of the relationships of the major arthropod groups Was undertaken using mitochondrial genome data to examine the hypotheses that Hexapoda is polyphyletic and that Collembola is more closely related to branchiopod crustaceans than insects. We sought to examine the sensitivity of this relationship to outgroup choice, data treatment. gene choice and optimality criteria used in the phylogenetic analysis of mitochondrial genome data. Additionally we sequenced the mitochondrial genome of ail archaeognathan, Nesomachilis australica. to improve taxon selection in the apterygote insects, a group poorly represented in previous mitochondrial phylogenies. The sister group of the Collembola was rarely resolved in our analyses with a significant level of support. The use of different outgroups (myriapods, nematodes, or annelids + mollusks) resulted in many different placements of Collembola. The way in which the dataset was coded for analysis (DNA, DNA with the exclusion of third codon position and as amino acids) also had marked affects on tree topology. We found that nodal Support was spread evenly throughout the 13 mitochondrial genes and the exclusion of genes resulted in significantly less resolution in the inferred trees. Optimality criteria had a much lesser effect on topology than the preceding factors; parsimony and Bayesian trees for a given data set and treatment were quite similar. We therefore conclude that the relationships of the extant arthropod groups as inferred by mitochondrial genomes are highly vulnerable to outgroup choice, data treatment and gene choice, and no consistent alternative hypothesis of Collembola's relationships is supported. Pending the resolution of these identified problems with the application of mitogenomic data to basal arthropod relationships, it is difficult to justify the rejection of hexapod monophyly, which is well supported on morphological grounds. (c) The Willi Hennig Society 2004.

Reproductive Biology of the Freshwater Shrimp Atya scabra (Leach, 1815) (Crustacea: Atyidae) in Ilheus, Bahia, Brazil

Alexandre Oliveira Almeida, Emerson Contreira Mossolin, and Joaldo Rocha Luz (2010) Reproductive biology of the freshwater shrimp Atya scabra (Leach, 1815) (Crustacea: Atyidae) in Ilheus, Bahia, Brazil. Zoological Studies 49(2): 243-252. Reproduction and population aspects of the freshwater shrimp Atya scabra in the Santana River, city of Ilheus, state of Bahia, Brazil, were studied from Apr. 2004 to May 2005. During these 14 mo, 3752 individuals were captured, with a sex ratio of 1.01 males for each female. The total number of individuals caught per month ranged 80-532. Males were generally larger than females. The smallest female found (5.40 mm in carapace length and 29.03 mm in total length) was ovigerous, which indicates that only adult individuals were caught. Ovigerous females were found every month, which indicates continuous reproduction and a high index of reproductive activity during the year. The highest reproduction indices were observed in May (94.3%) and Oct. (98.6%) 2004, and Mar. (93.7%) 2005. Fecundity ranged 870-8907 eggs, with a mean of 3811 (+/- 1992.87) eggs per female. The size of the females and their fecundity were positively correlated. The distribution of individuals in length classes by month showed that representatives of smaller classes occurred throughout almost the entire study period. This indicates a constant input of individuals into the population, which corroborates the characterization of the reproductive period as being continuous, and explains the large numbers of ovigerous females found each month. The 2nd abdominal segment is proportionally larger in females than in males, in width, height, and pleural length: these female secondary characteristics are related to an increased incubation area for eggs. http://zoolstud.sinica.edu.tw/Journals/49.2/243.pdf

Spermatozoal morphology of the freshwater anomuran Aegla longirostri Bond-Buckup & Buckup, 1994 (Crustacea : Decapoda : Aeglidae) from South America

Unique sperm morphology is described for Aegla longirostri Bond-Buckup & Buckup, 1994. a representative of the freshwater anomuran family Aeglidae from South America. Comparisons of the spermatozoal ultrastructure of this species with that described for other anomurans indicate that A. longirostri has a distinct suite of spermatozoal characters. Within the Anomura, the aeglids share more spermatozoal characters with the superfamily Lomoidea. represented by the monotypic Australian endemic genus, Lomis, than to any previously described representative from the Galatheoidea, Hippoidea. or Paguroidea. A more basal ancestry, with an independent evolutionary lineage. within the Anomura is Postulated for the Aeglidae. A Superficial resemblance of the spermatozoal ultrastructure of A. longirostri to that described for a palinurid lobster, Jasus, and a thalassinidean mud shrimp, Neaxius, is also noted.

Independent and conjugate eye movements during optokinesis in teleost fish

In response to movements involving a large part of the visual field, the eyes of vertebrates typically show an optokinetic nystagmus, a response in which both eyes are tightly yoked. Using a comparative approach, this study sets out to establish whether fish with independent spontaneous eye movements show independent optokinetic nystagmus in each eye. Two fish with independent spontaneous eye movements, the pipefish Corythoichthyes intestinalis and the sandlance Limnichthyes fasciatus were compared with the butterflyfish Chaetodon rainfordi, which exhibits tightly yoked eye movements. In the butterflyfish a single whole-field stimulus elicits conjugate optokinesis, whereas the sandlance and pipefish show asynchronous optokinetic movements. In a split drum experiment, when both eyes were stimulated in opposite directions with different speeds, both the sandlance and the pipefish compensated independently with each eye. The optokinetic response in the butterflyfish showed some disconjugacy but was generally confused. When one eye was occluded, the seeing eye was capable of driving the occluded eye in both the butterflyfish and the pipefish but not in the sandlance. Monocular occlusion therefore unmasks a link between the two eyes in the pipefish, which is overridden when both eyes receive visual input. The sandlance never showed any correlation between the eyes during optokinesis in all stimulus conditions. This suggests that there are different levels of linkage between the two eyes in the oculomotor system of teleosts, depending on the visual input.

Survey of cyclopids (Crustacea, Copepoda) in Brazil and preliminary screening of their potential as dengue vector predators

INTRODUCTION: Cyclopid copepods are known to be good mosquito controllers, specially as regards the larvae of the dengue vectors Aedes aegypti and Ae. albopictus. MATERIAL AND METHOD: The objective of the study was to survey the local copepod fauna and search for new strains of M. longisetus var. longisetus, comparing the potential of the samples found with the current strain ML-01 against Ae. albopictus larvae, under laboratory conditions. Eleven bodies of water in Campinas, SP, Brazil, were screened for copepods by collecting 1.5 l of water from each of then. The predatory potential of adults copepods was evaluated over 24 h, in the laboratory, for groups of 5 individuals preying upon 30 first instar Ae. albopictus larvae. RESULTS AND CONCLUSION: The following cyclopid species were found: Metacyclops mendocinus, Tropocyclops prasinus, Eucyclops sp, Eucyclops serrulatus, Eucyclops solitarius, Eucyclops ensifer, Macrocyclops albidus var. albidus and Mesocyclops longisetus var. longisetus. The predatory potential of these copepods ranged from nil to 97.3%. A sample collected in the field containing only M. longisetus var. longisetus showed the best control efficiency with no significant difference from a three-year old laboratory culture (ML-01) of the same species evaluated for comparison. The sample with few M. albidus var. albidus was ranked in second place showing an average 25.9% efficiency. The use of copepods in trap tires as dengue vector controllers is discussed.

Marine palaeo-ecological and depositional processes on the shallow-waters of the Azores archipelago: the mobile Ostracoda (Crustacea) and the sessile Bryozoa as case-studies

Tese de Doutoramento, Biologia (Taxonomia Zoológica), 11 de Outubro de 2013, Universidade dos Açores.

Infeccion natural de Ptychophallus tristani (Crustacea: decapoda) con metacercarias de Paragonimus mexicanus (Trematoda) en Tabarcia de Mora, Costa Rica

Se determinó el grado de infección de los crustáceos Ptychophallus tristani presentes en una área endémica de Paragonimus mexicanus, encontrándose que de un total de 182 cangrejos, 161 resultaron positivos (88,5%) por metacercarias. Al comparar la infección entre machos y hembras no se encontró diferencias estadísticamente significativas y en relación a su tamaño se observó una relación directa entre tamaño y porcentaje y grado de infección. Se estableció que no existen diferencias significativas en relación a la época del año en que los cangrejos fueron capturados lo que epidemiológicamente es importante pues indica que las fuentes de infección permanecen potencialmente activas durante todo el año.

Lectotype designation for Amazonian Diaptomidae and Bosminidae (Crustacea: Copepoda Cladocera).

Lectotipos (e paralectotipos) são designados para Aspinus acicularisBrandorff 1973, "Diaptomus" linus Brandorff 1973, "D". negrensisAndrade & Brandorff 1975, "D". ohlei Brandorff 1978, Notodiaptomus kieferi Brandorff 1973, Rhacodiaotomus calatus Brandorff 1974, R. retroflexus Brandorff 1973 (DIAPTOMIDAE) e Bosminopsis negrensisBrandorff 1976 (BOSMINIDAE) depositados nas Coleções de Entomologia Sistemática do INPA, Manaus/Brasil.

The larval development of palaemonid shrimps from the amazon region reared in the laboratory. V. The abbreviated development of Pseudopalaemon chryseus Kensley & Walker, 1982 (CRUSTACEA : DECAPODA: PALAEMONIDAE)

Larval development of the freshwater palaemonid shrip Pseudopalaemon chryseus Kensley & Walker, 1982 was studied in the laboratory from the offspring oof females collected in a lake of the lower Negro River system. Females carry few (14 to 43), large (1.86 + 0.13 x 1.29 + 0.06 mm), yolk-rich eggs. The species goes throught three larval stages without feeding and the main feature of its larval development is the presence of functional walking legs on hatching. Descriptions and illustrations of the three larval and first juvenile stages are presented.

O DESENVOLVIMENTO OVOCITÁRIO EM Macrobrachium amazonicum(Heller, 1862)(CRUSTACEA: DECAPODA: PALAEMONIDAE), CAMARÃO DULCÍCOLA DA REGIÃO AMAZÔNICA

É descrito o desenvolvimento ovocitário em Macrobrachium amazonicum(Heller, 1862), um camarão dulcícola da família Palaemonidae da Amazônia Central. O seu desenvolvimento é semelhante ao de Macrobrachium acanthurus(Wiegmann, 1836). As fases iniciais do desenvolvimento ocupam a região intema do ovario, enquanto que as fases vitelogênica e madura situam-se perifericamente. São descritas ainda a morfologia dos folículos pós-ovulatórios e das células foliculares.

A NEW SPECIES OF Rhacodiaptomus Kiefer, 1936, FROM THE BRAZILIAN AMAZON (CRUSTACEA:COPEPODA: CALANOIDA)

A new species of Calanoid copepod, Rhacodiaptomus besti,is described from material collected in the Igarapé São Pedro, Rio Jamari, State of Rondônia, and Lago Amanã, Rio Japurá, State of Amazonas, in Western Amazonia. A detailed morphological analysis of the species was undertaken in order to provide a basis for future studies on inter and intrageneric relationships.

Vanamea GEN. NOV. FOR Livoneca symmetricaVAN NAME,1925, (CRUSTACEA, ISOPODA, CYMOTHOIDAE) AND A REDESCRIPTION OF THE SPECIES BASED ON SPECIMENS FROM BRAZILIAN PIRANHAS

Studies of the cymothoid isopod Livoneca symmetricaVan Name, 1925, showed that this species has characters that preclude its inclusion in LivonecaLeach, 1818, or in any other known genus. The species is redescribed on the basis of male and female specimens from the mouth cavities of Amazonian piranhas (Serrasalmus spilopleura(Kner) and S. elongatusKner) and Vanameagen. nov. is proposed for it. The new genus is defined as having: a cephalon that is not immersed in pereonite 1; mandibles that are "foot-shaped" and without incisors, pereopods that are long and unequal in size and shape; a pleon that is not immersed in the pereon; and a pleotelson that is inflated anteriorly and medially.