Multi-gene phylogeny of the primary freshwater crab genus Ptychophallus Smalley, 1964 (Pseudothelphusidae: Ptychophallinae) from the Neotropical region.

The diversity of primary freshwater crabs of Central America is underestimated and poorly known, specially when considering both Atlantic and Pacific drainages distribution. Among the family Pseudothelphusidae Ortmann, 1893, the genus Ptychophallus Smalley, 1964 was recently revised using morphological data and encompassing 14 valid species, which are distributed exclusively in Costa Rica and Panama. Despite the informative scenario constructed with this previous study, some uncertainties remained such as those related to the populations distributed along different drainages and the lack of complete information regarding the phylogenetic relationships among the species that belong to this genus. Our phylogenetic reconstruction based on multigenes revealed four lineages. Ptychophallus costaricensis, P. colombianus, P. lavallensis, P. montanus, and P. tumimanus are well-established species, while P. paraxanthusi, P. exilipes and P. tristani were recovered as non-monophyletic in some relationships. Ptychophallus tristani and P. paraxanthusi were determined to be close relatives one with other, but with some representatives showing no clear correspondence and positioning in the molecular phylogeny, which raised doubts about the validity as separate species and/or the accuracy of identifications for some GenBank sequences. Ptychophallus tumimanus and P. montanus are morphologically very similar, but they are positioned in distinct clades. The genetic results confirmed a previous proposal that P. barbillaensis is a junior synonym of P. uncinatus, and P. bilobatus is closely related to P. uncinatus. The findings revealed the presence of one peculiar lineage with one species from Costa Rica compound by the resurrected P. campylus and another species from Costa Rica, originally identified as "P. cf. exilipes"; its morphology, however, did not match with any other analyzed species, which requires further analysis. Finally, possible misidentification in some sequences deposited in the GenBank were detected and should be reviewed. The reconstructed molecular phylogeny for the genus that inhabits both Atlantic and Pacific drainages of Central America provides a better understanding of the knowledge on the evolution of freshwater crabs and represents key information that will serve as baseline for further taxonomic studies on the cryptic biodiversity of this group.

Multigene phylogeny and taxonomic revision of American shrimps of the genus Cryphiops Dana, 1852 (Decapoda, Palaemonidae) implies a proposal for reversal of precedence with Macrobrachium Spence Bate, 1868.

The freshwater shrimp genus Cryphiops Dana, 1852 has a disjunct distribution in North (Mexico) and South (Brazil, Chile) America, and is composed of only six species. The current classification of genera in the Palaemonidae is controversial, based on variable morphological characters, and still far from a clear definition. Cryphiops differs from the speciose genus Macrobrachium Spence Bate, 1868 only by the absence of the hepatic spines on the carapace. Previous studies with a limited dataset suggested the necessity to link morphology and phylogeny to create an internal rearrangement in the genus to resolve the paraphyletic status. Through a molecular phylogenetic approach, the evolutionary relationships are inferred based on four (mitochondrial and nuclear) genes, among all recognized species of Cryphiops and, in combination with a taxonomic revision, a rearrangement in the systematics of the genus is suggested. The absence of hepatic spines on the carapace, the only character used to separate the genus Cryphiops, is subjective and should be considered as a homoplasy. This implies that Cryphiops and Macrobrachium are subjective synonyms and, because the latter genus is much more diverse and widely known, with several economically important species, to avoid confusion and disturbance in nomenclatural stability and keep universality, a proposal for the priority of the older synonym (Cryphiops) to be partially suppressed in favor of maintaining the prevailing use of the younger synonym (Macrobrachium) is presented. As the species of Cryphiops should be accommodated in the genus Macrobrachium, new names to replace three preoccupied specific names that, by this action, resulted to be secondary homonyms are offered.

A new species of the genus Fredius Pretzmann, 1967 (Decapoda: Brachyura: Pseudothelphusidae) from Brazil, with comments on the southerly distribution of the family.

A new species of pseudothelphusid crab of the tribe Kingsleyini Ortmann, 1897, from the southern Amazon region in the state of Rondônia, Brazil, is described and illustrated. Fredius avilai n. sp. can be readily distinguished from its congeners by the following characters of the male first gonopod: mesial lobe elongated, convoluted, proximal portion directed laterally, distal portion sharply recurved in abdominal direction; marginal process rounded, not projected over distal opening of spermatic channel, merging with distal portion of abdominal surface after a shallow depression; lateral suture well demarcated along mesoabdominal surface of stem, distal portion directed inwards. The assignment of the new species to the genus Fredius Pretzmann, 1967 and its affinities with another closed related species are discussed.

Uncovering a hidden diversity: a new species of freshwater shrimp Macrobrachium (Decapoda: Caridea: Palaemonidae) from Neotropical region (Brazil) revealed by morphological review and mitochondrial genes analyses.

A freshwater palaemonid shrimp from the São Francisco river basin in Brazil has been found to be a new species and is herein nominated as Macrobrachium veredensis sp. nov. It is morphologically similar to M. brasiliense (Heller, 1862), which is found in many rivers of South America. However, M. veredensis sp. nov. has a smooth carapace and few spinules on the second pereopods, while M. brasiliense has the anterolateral surface of the carapace with small spinules and the palm of the second pereopods with spines, spinules and setae. Despite their similar morphology with these subtle differences, the remarkable genetic different evidenced in DNA analysis. Molecular analyses were based on 43 sequences with 528 base pairs (bp) for 16S rDNA, and 16 new sequences with 581bp, without pseudogenes, for COI mtDNA. The nucleotide divergence between M. veredensis sp. nov. and M. brasiliense (7.0-8.5% for 16S and 11.8-12.5% for COI.), the phylogenetic topology and the haplotype network configuration and it is endemism to a region of the São Francisco river basin support the recognition of a new taxon.

A comparative study of the gastric ossicles of Trichodactylidae crabs (Brachyura: Decapoda) with comments on the role of diet and phylogeny in shaping morphological traits.

The gastric armature of decapod foregut is a feeding structure that sparks controversial debates about the role dietary and historical components have in shaping its morphological traits. Having previous information about the natural diet is an interesting way to gather evidence on this issue. For the present study, we analyzed the morphological traits of gastric ossicles involved directly in the maceration of food in nine species of freshwater crabs of the family Trichodactylidae (Brachyura: Decapoda) representing five genera, three tribes and two subfamilies. The analyzed gastric ossicles were quite consistent among closely related species, suggesting that the observed traits had a clear phylogenetic component. However, it was also noted that the morphological traits of the gastric teeth of trichodactylid crabs match well with the natural diet and presented likeness with general features of other species with a similar trophic habit. We discuss the influence of phylogeny and function on the design of morphological traits and propose to quantify the role of phylogeny and function in shaping morphological traits through the analysis of phylogenetic signals.

A new genus of freshwater crab of the tribe Kingsleyini Bott, 1970 (Crustacea: Decapoda: Brachyura: Pseudothelphusidae) with description of a new species from Mato Grosso, Brazil.

A new genus and species of freshwater crab, Melothelphusa apiaka n. gen., n. sp., from Mato Grosso, Central Brazil is described and illustrated. Brasiliothelphusa dardanelosensis Magalhães & Türkay, 2010, is assigned to the new genus Melothelphusa. Therefore, the genus Brasiliothelphusa Magalhães & Türkay, 1986, is restricted to its type species B. tapajoense Magalhães & Türkay, 1986. The new taxa can be easily separated from their close relatives by a suite of morphological characters from the first gonopod.

Taxonomy of the freshwater crabs of Costa Rica, with a revision of the genus Ptychophallus Smalley, 1964 (Crustacea: Decapoda: Pseudothelphusidae).

The taxonomy and geographic distribution of the freshwater crabs of the family Pseudothelphusidae Ortmann, 1893, of Costa Rica, Central America, particularly of the genus Ptychophallus Smalley, 1964, are revised. Historical materials deposited in major collections of several institutions were examined, as well as valuable collections in the Zoological Museum of the University of Costa Rica that include abundant specimens obtained recently (2007-2010) in the southern region of the country. The pseudothelphusids of Costa Rica consists of 15 currently valid species belonging to Achlidon Smalley, 1964 (two species), Allacanthos Smalley, 1964 (two species), Potamocarcinus H. Milne Edwards, 1853 (three species), and Ptychophallus (eight species). Two species seem to be restricted to the Atlantic drainage, while seven are known only from the Pacific drainage; six species occur in both drainages. Ptychophallus comprises 13 valid species; four new synonymies are proposed: P. osaensis Rodríguez, 2001, P. campylus Pretzmann, 1968, P. tumimanus ingae            Pretzmann, 1978, and P. barbillaensis Rodríguez & Hedström, 2001, as junior synonyms of P. paraxantusi (Bott, 1968), P. tristani (Rathbum 1896), P. tumimanus (Rathbun, 1898), and P. uncinatus Campos & Lemaitre, 1999, respectively. Two species, P. colombianus (Rathbun, 1896) and P. exilipes (Rathbun, 1898), are considered species inquerendae. Lectotype designations are made for P. montanus and P. colombianus. Three species of Ptychophallus are known exclusively from Costa Rica, five exclusively from Panama, and five species occur in both countries; one species appears to be exclusive of the Atlantic drainage, whereas five are known only from the Pacific drainage and seven occur in both drainages. The gonopod morphology of all species is redescribed and illustrated, and maps of their geographic distribution are furnished. A key to the species of Pseudothelphusidae from Costa Rica and to all species of Ptychophallus is provided. 

Colombiathelphusa, a new genus of freshwater crab from Colombia, and the first location record of Eidocamptophallus chacei (Pretzmann, 1967) (Crustacea: Decapoda: Pseudothelphusidae).

A new genus of pseudothelphusid crab, Colombiathelphusa gen. nov., is established to include Colombiathelphusa culmarcuata n. sp., from the Chocó Department, western Colombia. The new genus is characterized by the morphology of the male first gonopod, which has a prominent lateral process, a cephalic surface with two spine-like cephalic processes subdistally, and the outline of the apex strongly recurved, resembling a bow's arch. The new species is described and illustrated. The first location record of Eidocamptophallus chacei (Pretzmann, 1967), is made and its male first gonopod is redescribed and illustrated. Possible affinities of both taxa are discussed.

Molecular and morphological differentiation between two Miocene-divergent lineages of Amazonian shrimps, with the description of a new species (Decapoda, Palaemonidae, Palaemon).

Palaemoncarteri (Gordon, 1935) and Palaemonivonicus (Holthuis, 1950) are morphologically similar species of South American freshwater shrimps. Past studies have questioned the taxonomic status of both species, which are supposed to have partially sympatric geographic distributions in the Amazon basin. We analyzed a 550 bp fragment of the mitochondrial 16S rRNA gene from these Amazonian Palaemon species as well as from 11 palaemonids as the outgroup. Additionally, we checked diagnostic characters of the genus and family as well as other morphological characters that have been little explored before. Palaemoncarteri and Palaemonivonicus are allocated in two sister lineages, with wide genetic divergence and little morphological differentiation. The divergence time between these lineages was estimated as approximately 10 million years ago. Both molecular and morphological data support the taxonomic validity of both Palaemoncarteri and Palaemonivonicus, refuting the hypothesis of synonymy. In addition, a new species, Palaemonyuna sp. n., closely related to Palaemonivonicus, is described. Our findings indicate that these species can be differentiated using the projection of the anterolateral margin and anterolateral spine of the first antennular segment, shape of the rostrum, and relative size of the appendix masculina.

Freshwater crabs from eastern Panamá: a new species of Potamocarcinus H. Milne Edwards, 1853, and new records of two little-known species (Crustacea: Decapoda: Pseudothelphusidae, Trichodactylidae).

A small collection of freshwater crabs from eastern Panamá revealed a new species of pseudothelphusid crab, Potamocarcinus darienensis n. sp., which is described and illustrated. The new species is characterized by an unusual arrangement of distal processes in the male first gonopod, in which the mesial lobe is folded in a latero-cephalic direction over the apex and the apex is broadened by a rounded protuberance in its caudo-lateral surface, the cephalic surface having a small, conical median cephalic process, and a large, prominent, subtriangular proximal cephalic process. New records of two little-known species described from eastern Panamá, Spirocarcinus garthi (Pretzmann, 1971) (Pseudothelphusidae) and Melocarcinus meekei (Pretzmann, 1968) (Trichodactylidae), are listed and the first gonopod of S. garthi is redescribed.

Catalogue of type specimens of the Collection of Invertebrates of Instituto Nacional de Pesquisas da Amazônia, Manaus, Brazil. III. Hexapoda: Isoptera, Mantodea, Mecoptera, Orthoptera, Plecoptera, Trichoptera and Zoraptera / Catálogo dos espécimes-tipo de invertebrados da coleção do Instituto Nacional de Pesquisas da Amazônia, Manaus, Brasil. III. Hexapoda: Isoptera, Mantodea, Mecoptera, Orthoptera, Plecoptera, Trichoptera e Zoraptera

A catalogue of the type specimens of Isoptera, Mantodea, Mecoptera, Orthoptera, Plecoptera, Trichoptera, and Zoraptera deposited in the Invertebrate Collection of the Instituto Nacional de Pesquisas da Amazônia (INPA), Manaus, Brazil, is presented and updated to December, 2007. A total of eight holotypes and seven lots of paratypes of nine species of Isoptera; three holotypes and one paratype of three species of Mantodea; five holotypes and five lots of paratypes of five species of Mecoptera; eight holotypes and five lots of paratypes of eleven species of Orthoptera; three holotypes, three neotypes and two lots of paratypes of seven species of Plecoptera; six holotypes and seven lots of paratypes of ten species of Trichoptera; and two holotypes and three lots of paratypes of three species of Zoraptera, are listed. Specific names are listed alphabetically within the family, followed by bibliographic citation, original genus name, status of type, collection number, locality data and remarks when appropriate.

É apresentado o catálogo dos espécimes-tipo de Isoptera, Mantodea, Orthoptera, Plecoptera, Trichoptera e Zoraptera depositados na Coleção de Invertebrados do Instituto Nacional de Pesquisas da Amazônia (INPA), Manaus, Brasil, atualizado até dezembro de 2007. É relacionado um total de sete holótipos e sete lotes de parátipos de nove espécies de Isoptera; três holótipos e um parátipo de três espécies de Mantodea; cinco holótipos e cinco lotes de parátipos de cinco espécies de Mecoptera; oito holótipos e cinco lotes de parátipos de 11 espécies de Orthoptera; três holótipos, três neótipos e dois lotes de parátipos de sete espécies de Plecoptera; seis holótipos e sete lotes de parátipos de dez espécies de Trichoptera; e dois holótipos e três lotes de parátipos de três espécies de Zoraptera. São listados alfabeticamente em cada família os nomes das espécies, seguidos da citação bibliográfica, nome original do gênero, categoria do tipo, número de registro na coleção, dados de localidade e comentários quando pertinentes.

Catalogue of type specimens of invertebrates in the collection of the Instituto Nacional de Pesquisas da Amazônia, Manaus, Brazil. II. Hexapoda: Collembola, Diplura, Archaeognatha, Ephemeroptera and Blattaria / Catálogo dos espécimes-tipo da Coleção de Invertebrados do Instituto Nacional de Pesquisas da Amazônia, Manaus, Brasil. II. Hexapoda: Collembola, Diplura, Archaeognatha, Ephemeroptera e Blattaria

A catalogue of type specimens of Collembola, Diplura, Archaeognatha, Ephemeroptera, and Blattaria deposited in the Invertebrate Collection of the Instituto Nacional de Pesquisas da Amazônia (INPA), Manaus, Brazil, is presented and updated to June, 2007. It contains a total of 22 holotypes and 18 lots of paratypes of 22 species of Collembola; one holotype and one paratype of one species of Diplura; four holotypes and four paratypes of four species of Archaeognatha; 10 holotypes and thirteen lots of paratypes of 11 species of Ephemeroptera; and one holotype and two lots of paratypes of one species of Blattaria. Specific names are listed alphabetically within family, followed by bibliographical citation, original genus name, status of type, collection number and locality data.

É apresentado um catálogo dos espécimes-tipo de Collembola, Diplura, Archaeognatha, Ephemeroptera e Blattaria depositados na Coleção de Invertebrados do Instituto Nacional de Pesquisas da Amazônia (INPA), Manaus, Brasil, atualizado até junho de 2007. É relacionado um total de 22 holótipos e 18 lotes de parátipos de 22 espécies de Collembola; um holótipo e um lote de parátipos de uma espécie de Diplura; quatro holótipos e quatro parátipos de quatro espécies de Archaeognatha; dez holótipos e sete lotes de parátipos de 11 espécies de Ephemeroptera e um holótipo e dois lotes de parátipos de uma espécie de Blattaria. São listados alfabeticamente em cada família os nomes das espécies, seguidos da citação bibliográfica, nome original do gênero, categoria do tipo, número de registro na coleção e dados de localidade.

Assessment of the decapod crustacean diversity in the Guayana Shield region aiming at conservation decisions / Avaliação da diversidade de crustáceos decápodos na região do escudo das Guianas como subsídio a decisões de conservação

The current state of knowledge of freshwater decapod crustacean diversity of the Guayana Shield Region is briefly assessed, based upon information gathered from the scientific literature as well as unpublished data from academic theses, technical reports, and carcinological collections. The decapod fauna of the region is presently known to include 64 species and subspecies within six families and 17 genera. Diversity by countries, basins, and rivers is listed, comments on endemic, rare or threatened species are made, and information about relevant taxonomic literature is presented. Seven priority areas for conservation actions concerning crustacean decapods are suggested and related to the 25 priority areas defined by the Fishes and Freshwater Working Group at the Guayana Shield Conservation Priority Setting Workshop, held at Paramaribo (Suriname) in April 2002.

Avalia-se resumidamente a situação atual do conhecimento sobre a diversidade dos crustáceos decápodos de água doce da região do Escudo das Guianas com base em informações obtidas da literatura científica e dados inéditos de trabalhos acadêmicos, relatórios técnicos e coleções carcinológicas. A fauna de decápodos da região está atualmente constituída por 64 espécies e subespécies em seis famílias e 17 gêneros. Relaciona-se a diversidade por país, bacias e rios, faz-se comentários sobre espécies endêmicas, raras ou ameaçadas, e apresenta-se informações sobre a literatura taxonômica relevante de cada grupo. Em relação aos crustáceos decápodos, sugere-se sete áreas prioritárias para ações conservacionistas e relaciona-se essas áreas com as 25 áreas prioritárias definidas pelo Grupo de Trabalho em Peixes e Organismos Dulcícolas no "Guayana Shield Conservation Priority Setting Workshop", realizado em Paramaribo (Suriname), em abril de 2002.

Decapod crustaceans used as food by the Yanomami Indians of the Balawa-ú village, State of Amazonas, Brazil

The Yanomami are a group of South American Indians that live in the rainforest along the borderlands of Brazil and Venezuela. They depend on hunting, gardening and wild food for survival; crustaceans are a highly prized food item in their diet. Taxonomical and ethnozoological aspects of the Yanomami Indians of the Balawa-ú village, state of Amazonas, Brazil, related to the crustaceans are described. Information and specimens were obtained from August to December, 2003. Interviews were conducted with residents of the village and focused on questions about species exploited, indigenous names, modes of capture and use of the species. One shrimp species of the family Palaemonidae (Macrobrachium brasiliense) and two crab species of Trichodactylidae (Sylviocarcinus pictus, Valdivia serrata) as well as two of Pseudothelphusidae (Fredius fittkaui, F. platyacanthus) were recorded. The indigenous names applied to these species are: shuhu, for shrimp, oko and peimatherimi for each of the two pseudothelphusid crabs, and hesiki tôtôrema for both trichodactylid crabs.

Os Yanomami são um grupo de índios que habitam a floresta tropical úmida ao longo da fronteira entre Brasil e Venezuela. Eles dependem da caça, da agricultura e da coleta de produtos da floresta para a sua sobrevivência, sendo os crustáceos um dos itens alimentares mais apreciados. São descritos aspectos taxonômicos e etnozoológicos dos índios Yanomami da aldeia de Balawa-ú, no estado do Amazonas, Brasil, relacionados aos crustáceos. Informações e espécimes foram coletados de agosto a dezembro de 2003. Foram realizadas entrevistas com habitantes da aldeia com enfoque nas espécies exploradas, nomes indígenas, modos de captura e utilização. Foram registradas uma espécie de camarão da família Palaemonidae (Macrobrachium brasiliense), duas espécies de caranguejos da família Trichodactylidae (Sylviocarcinus pictus, Valdivia serrata) e duas da família Pseudothelphusidae (Fredius fittkaui, F. platyacanthus). Os nomes indígenas usados para elas são: shuhu, para o camarão, oko e peimatherimi para cada um dos caranguejos pseudotelfusídeos, e hesiki tôtôrema para ambas as espécies de caranguejos tricodactilídeos.

New records of Fredius denticulatus (H. Milne-Edwards, 1853) and F. reflexifrons (Ortmann, 1897), and the eastern limits of the distribution of pseudothelphusid crabs (Crustacea: Decapoda) in Brazil

É registrada pela primeira vez a ocorrência de Fredius reflexifrons (Ortmann, 1897), um caranguejo da família Pseudothelphusidae de ampla distribuição na Amazônia e nas Guianas, no estado do Ceará, Nordeste do Brazil. São feitos registros adicionais de dessa espécie e de Fredius denticulatus (H. Milne-Edwards, 1853) para a região amazônica. É feita uma discussão sobre os limites orientais da distribuição da família Pseudothelphusidae no Brasil.

Distributional congruence among aquatic plants: invertebrates and fishes withim the Río Paraguay Basin, Paraguay

Hipótesis nulas concernientes a distribuciones de especies al azar con respecto a subregiones y macrohábitats dentro del Río Paraguay son examinadas con datos provenientes de 131 especies de macrocrustáceos e invertebrados bénticos y 186 especies de plantas acuáticas. Los patrones son comparados con el resultado de distrubuciones de peces presentedos por Chernoff et al. (2004). Los datos provenientes de invertebrados mostraron un patrón identico entre subregiones, como es evidente en las distribuciones de peces. Los resulatdos apoyan el reconocimiento de dos zonas:i) la zona del Río Paraguay incluyendo las regiones superiores e inferiores del Río Negro, ii) la zona del Río Apa incluyendo el Río Apa y el Riacho La Paz. Para todos los grupos de datos, la zona del Río Paraguay posee una mayor riqueza de especies que la zona del Río Apa. La frontera entre las zonas es abrupta, lo cual es tamién apoyado por los datos provenientes de las plantas. Solo 11 de 186 especies de plantas fueron encontradas en ambas zonas. No existen patrones de congruencia entre macrohábotats. Datos de plantas e invertebrados contienen muchos valores que no son diferentes de las medias de similaridades al azar. Los datos provenientes de las plantas demuestra una relación entre hábitats de orilla y arena, los cuales están más sometidos a grandes corrientes que los otros hábitats. Las plantas encontradas en hábitats de aguas negras poseen poca similaridad con otros macrohábitats. Basado en estas observaciones, se concluye que habitats significantes dentro de cada zona deben ser preservados para mantener una gran porción de la biodiversidad

Revisão taxonômica dos camarões de água doce (Crustacea: Decapoda: Palaemonidae, Sergestidae) da Amazônia Peruana / Taxonomic revision of the freshwater shrimps (Crustacea: Decapoda: Palaemonidae, Sergestidae) from the Peruvian Amazonia

Foi realizada uma revisão taxonômica das espécies de camarões de água doce da Amazônia peruana que abrangeu oito espécies da família Palaemonidae e uma espécie da família Sergestidae. São descritas duas novas espécies do gênero Pseudopalaemon e feitos os primeiros registros de Euryrhynchus amazoniensis Tiefenbacher, 1978, Macrobrachium jelskii Miers, 1877 e Palaemonetes ivonicus Holthuis, 1950 para o Peru. São fornecidos chave de identificação, dados distribucionais e ilustrações para as espécies estudadas.

A taxonomic revision of eight species of freshwater shrimps of the family Palaemonidae and one of the family Sergestidae from the Peruvian Amazonia was made. Two new species of the genus Pseudopalaemon are described, and Euryrhynchus amazoniensis Tiefenbacher, 1978, Macrobrachium jelskii Miers, 1877 e Palaemonetes ivonicus Holthuis, 1950 are recorded from Peru for the first time. Key, distributional data and ilustrations for the species are presented.

Revisão taxonômica dos camarões de água doce (Crustacea: Decapoda: Palaemonidae, Sergestidae) da Amazônia Peruana

A taxonomic revision of eight species of freshwater shrimps of the family Palaemonidae and one of the family Sergestidae from the Peruvian Amazonia was made. Two new species of the genus Pseudopalaemon are described, and Euryrhynchus amazoniensis Tiefenbacher, 1978, Macrobrachium jelskii Miers, 1877 e Palaemonetes ivonicus Holthuis, 1950 are recorded from Peru for the first time. Key, distributional data and ilustrations for the species are presented

Foi realizada uma revisão taxonômica das espécies de camarões de água doce da Amazônia peruana que abrangeu oito espécies da família Palaemonidae e uma espécie da família Sergestidae. São descritas duas novas espécies do gênero Pseudopalaemon e feitos os primeiros registros de Euryrhynchus amazoniensis Tiefenbacher, 1978, Macrobrachium jelskii Miers, 1877 e Palaemonetes ivonicus Holthuis, 1950 para o Peru. São fornecidos chave de identificação, dados distribucionais e ilustrações para as espécies estudadas.

The systematic and biogeographical status of Fredius reflexifrons (Ortmann, 1897) and Fredius fittkaui (Bott, 1967) (Crustacea: Brachyura: Pseudothelphusidae) from the Amazon and Atlantic Guianas River basins

There is considerable confusion in the literature regarding the systematic position and distribution of two pseudothelphusid crabs originally described as Potamocarcinus reflexifrons Ortmann, 1897 and Potamocarcinus reflexifrons fittkaui Bott, 1967, and now included in the genus Fredius Pretzman, 1965, as F. reflexifrons and F. fittkaui. Study of numerous specimens from recent collections, together with a critical analysis of the data published in the literature, shows that both taxa could be easily separated by gonopodal characters. The two species occupy discrete areas of distribution along the main axis of the Amazon River and in the upper Rio Negro Basin, respectively, with an overlap in the Atlantic Guianas. It is postulated that they originated from a common ancestor, through a process of vicariance, in the two areas observed at present. Permeability of barriers allowed their further occupancy of the Atlantic Guianas after the marine regressions in this area.

Há uma considerável confusão na literatura a respeito da posição sistemática e distribuição de duas espécies de caranguejos pseudotelfusídeos originalmente descritos como Potamocarcinus reflexifrons Ortmann, 1897 e Potamocarcinus reflexifrons fittkaui Bott, 1967, atualmente incluídos no gênero Fredius Pretzmann, 1965 como F. reflexifrons e F. fittkaui. O estudo de numerosos espécimes obtidos em coletas recentes, complementado por uma análise crítica dos dados publicados na literatura, mostra que ambos os taxa podem ser facilmente separados por caracteres do gonópodo. As duas espécies ocupam áreas de distribuição distintas ao longo do eixo principal do rio Amazonas e no alto rio Negro, respectivamente, com uma sobreposição na região das Guianas. Postula-se que essas espécies se originaram de um ancestral comum, por meio de um processo de vicariância, nas duas áreas observadas atualmente. A permeabilidade das barreiras permitiu uma posterior distribuição na região das Guianas após as regressões marinhas ocorridas naquela área.