RESUMO
The Neotropical region is the most diverse on the planet, largely owing to its mosaic of tropical rainforests. Multiple tectonic and climatic processes have been hypothesized to contribute to generating this diversity, including Andean orogeny, the closure of the Isthmus of Panama, the GAARlandia land bridge and historical connections among currently isolated forests. Micrathena spiders are diverse and widespread in the region, and thus a complete phylogeny of this genus allows the testing of hypotheses at multiple scales. We estimated a complete, dated phylogeny using morphological data for 117 Micrathena species and molecular data of up to five genes for a subset of 79 species. Employing eventc-based approaches and biogeographic stochastic mapping while considering phylogenetic uncertainty, we estimated ancestral distributions, the timing and direction of dispersal events and diversification rates among areas. The phylogeny is generally robust, with uncertainty in the position of some of the species lacking sequences. Micrathena started diversifying around 25 Ma. Andean cloud forests show the highest in-situ speciation, while the Amazon is the major dispersal source for adjacent areas. The Dry Diagonal generated few species and is a sink of diversity. Species exchange between Central and South America involved approximately 23 dispersal events and started ~20 Ma, which is consistent with a Miocene age for the Isthmus of Panama closure. We inferred four dispersal events from Central America to the Antilles in the last 20 Myr, indicating the spiders did not reach the islands through the GAARlandia land bridge. We identified important species exchange routes among the Amazon, Andean cloud forests and Atlantic forests during the Plio-Pleistocene. Sampling all species of the genus was fundamental to the conclusions above, especially in identifying the Andean forests as the area that generated the majority of species. This highlights the importance of complete taxonomic sampling in biogeographic studies.
RESUMO
The South American palpimanid genus Fernandezina Birabn currently comprises 15 described species, all known from epigean environments. Representatives of Fernandezina are easily recognized by the unexpanded femora I in both sexes and by the dorsally extended opisthosomal scutum in males. Herein, F. fernandoi sp. nov. is described based on males and females from hypogean environments and F. angeloi sp. nov. is described based on a single male from a nearby epigean environment, both in Brazil. Additionally, we provide an identification key for the species of the genus.
Assuntos
Aranhas , Feminino , Masculino , Animais , Brasil , Distribuição Animal , Cavernas , EcossistemaRESUMO
A new scorpion species, Microtityus adriki n. sp., is described based on adult specimens collected in Cantá, state of Roraima (RR), northern Brazil. Microtityus adriki n. sp. is the second species of Microtityus Kjellesvig-Waering, 1966 known from Brazil and is one of the smallest scorpion species (12.39-19.47 mm) in the Amazonian region. In this study, we propose an amended generic diagnosis and a specific diagnosis, describe the male hemispermatophore of Microtityus, give the sequence of COI barcode, and present a potential distribution analysis for the genus. The morphology of the male hemispermatophore of Microtityus differs from that of other Neotropical buthid genera, except for the number of lobes (three lobes), which is a character state shared with several genera. The potential distribution model generated by MaxEnt suggests high environmental suitability for the genus in the Antilles and northern South America, with scattered high suitability in several regions of Central America. However, the model did not indicate high suitability in areas where Brazilian species occur (i.e., Microtityus adriki n. sp. and Microtityus vanzolinii Lourenço & Eickstedt, 1983), and this could be explained by a sampling bias. Therefore, future studies, including extensive sampling, are required to better understand the biogeographic processes behind the distribution of this genus.
RESUMO
The widely distributed species, Stenochrus portoricensis Chamberlin, 1922, is recorded for the first time from Costa Rica and Venezuela, and new occurrences from Brazil and Colombia are presented. Morphology of spermathecae from 14 localities is compared and illustrated. The need for studies to evaluate the potential status as an invasive species of S. portoricensis is commented on and a distribution map of the species in southern Central America and South America is given.(AU)
La especie exótica Stenochrus portoricensis Chamberlin, 1922 (Schizomida: Hubbardiidae): disminución del déficit de Wallace en el Nuevo Mundo. La especie de amplia distribución Stenochrus portoricensis Chamberlin, 1922 se registra por primera vez en Costa Rica y Venezuela, y se presentan nuevas ocurrencias en Brasil y Colombia. Se compara e ilustra la morfología de las espermatecas de especímenes provenientes de 14 localidades. Se comenta la necesidad de realizar estudios para evaluar el estatus potencial de S. portoricensis como especie invasora y se presenta un mapa de distribución de la especie en el sur de Centroamérica y Sudamérica.(AU)
Assuntos
Animais , Aracnídeos/anatomia & histologia , Aracnídeos/classificação , Especificidade da Espécie , Animais ExóticosRESUMO
A new sun-spider species of the ibirapemussu species-group of the genus Gaucha is described based on males and a female collected in Southeastern Brazil. The newly described species can be readily distinguished from its congeners by the reduction of the cheliceral fixed finger, distal tooth (FD), closely positioned and smaller than the medial tooth (FM); the presence of cheliceral fixed finger profondal subproximal (PFSP) and retrofondal submedial (RFSM) teeth; and by the cheliceral movable finger, medial tooth (MM) well developed, larger than submedial tooth (MSM) and smaller than proximal tooth (MP). This is the thirteenth described species in the genus Gaucha, all known from South America.
Assuntos
Aracnídeos , Aranhas , Animais , Brasil , Feminino , MasculinoRESUMO
A new solifuge species in the genus Gaucha Mello-Leitão, 1924 and the ibirapemussu species-group is herein described based on males and females collected at Itacuruba, State of Pernambuco, and Jaicós, State of Piauí, both in Northeastern Brazil. Males of the new species can be readily recognized by having the movable finger MM and MSM teeth reduced and of similar size. The present finding raises to twelve the number of described species in the genus, five of which belong to the ibirapemussu species-group. Besides, a new locality record for the species Gaucha ibirapemussu (Carvalho et al., 2010) is here presented, along with an updated identification key for all Gaucha species.
Assuntos
Aranhas , Distribuição Animal , Animais , Feminino , MasculinoRESUMO
In this paper it is provided a checklist of Scorpiones species in the state of Mato Grosso do Sul, Brazil. There are 16 species and one non-nominotypical subspecies recorded for the state, although it is discussed the presence and/or the taxonomic status of three of these species. This, it is considered that the scorpiofauna of the Mato Grosso do Sul is actually composed of 13 species, which represents more than 50% of all known species from Central-western Brazil. Two bothriurid species are known only for this state and are considered endemics: Bothriurus pora Mattoni & Acosta, 2005 and Brazilobothriurus pantanalensis Lourenço & Monod, 2000. The distribution of the scorpion registries in the Mato Grosso do Sul is heterogeneous, being the areas dominated by Atlantic Forest and Pantanal is sampled worse than those covered by the Cerrado domains.(AU)
Nesse artigo é fornecida uma lista de espécies de Scorpiones do estado do Mato Grosso do Sul, Brasil. Até o momento 16 espécies e uma subespécie não-nominotípica estão registradas para o estado, porém é discutida a presença e/ou o status taxonômico de três destas espécies. Assim, considera-se que a escorpiofauna do Mato Grosso do Sul é composta, até o momento, por 13 espécies, o que representa mais de 50% de todas as espécies de escorpiões conhecidas para o Centro-Oeste brasileiro. Duas espécies de bothriurídeos são conhecidas apenas para este estado e consideradas endêmicas Bothriurus pora Mattoni & Acosta, 2005 e Brazilobothriurus pantanalensis Lourenço & Monod, 2000. A distribuição dos registros de escorpiões no Mato Grosso do Sul é heterogênea, uma vez que as áreas dominadas por Mata Atlântica e pelo Pantanal são menos amostradas em relação àquelas de domínios do Cerrado.(AU)
Assuntos
Animais , Escorpiões , Grupos de População Animal , BrasilRESUMO
ABSTRACT In this paper it is provided a checklist of Scorpiones species in the state of Mato Grosso do Sul, Brazil. There are 16 species and one non-nominotypical subspecies recorded for the state, although it is discussed the presence and/or the taxonomic status of three of these species. This, it is considered that the scorpiofauna of the Mato Grosso do Sul is actually composed of 13 species, which represents more than 50% of all known species from Central-western Brazil. Two bothriurid species are known only for this state and are considered endemics: Bothriurus pora Mattoni & Acosta, 2005 and Brazilobothriurus pantanalensis Lourenço & Monod, 2000. The distribution of the scorpion registries in the Mato Grosso do Sul is heterogeneous, being the areas dominated by Atlantic Forest and Pantanal is sampled worse than those covered by the Cerrado domains.
RESUMO Nesse artigo é fornecida uma lista de espécies de Scorpiones do estado do Mato Grosso do Sul, Brasil. Até o momento 16 espécies e uma subespécie não-nominotípica estão registradas para o estado, porém é discutida a presença e/ou o status taxonômico de três destas espécies. Assim, considera-se que a escorpiofauna do Mato Grosso do Sul é composta, até o momento, por 13 espécies, o que representa mais de 50% de todas as espécies de escorpiões conhecidas para o Centro-Oeste brasileiro. Duas espécies de bothriurídeos são conhecidas apenas para este estado e consideradas endêmicas Bothriurus pora Mattoni & Acosta, 2005 e Brazilobothriurus pantanalensis Lourenço & Monod, 2000. A distribuição dos registros de escorpiões no Mato Grosso do Sul é heterogênea, uma vez que as áreas dominadas por Mata Atlântica e pelo Pantanal são menos amostradas em relação àquelas de domínios do Cerrado.
RESUMO
In this paper it is provided a checklist of Scorpiones species in the state of Mato Grosso do Sul, Brazil. There are 16 species and one non-nominotypical subspecies recorded for the state, although it is discussed the presence and/or the taxonomic status of three of these species. This, it is considered that the scorpiofauna of the Mato Grosso do Sul is actually composed of 13 species, which represents more than 50% of all known species from Central-western Brazil. Two bothriurid species are known only for this state and are considered endemics: Bothriurus pora Mattoni & Acosta, 2005 and Brazilobothriurus pantanalensis Lourenço & Monod, 2000. The distribution of the scorpion registries in the Mato Grosso do Sul is heterogeneous, being the areas dominated by Atlantic Forest and Pantanal is sampled worse than those covered by the Cerrado domains.
Nesse artigo é fornecida uma lista de espécies de Scorpiones do estado do Mato Grosso do Sul, Brasil. Até o momento 16 espécies e uma subespécie não-nominotípica estão registradas para o estado, porém é discutida a presença e/ou o status taxonômico de três destas espécies. Assim, considera-se que a escorpiofauna do Mato Grosso do Sul é composta, até o momento, por 13 espécies, o que representa mais de 50% de todas as espécies de escorpiões conhecidas para o Centro-Oeste brasileiro. Duas espécies de bothriurídeos são conhecidas apenas para este estado e consideradas endêmicas Bothriurus pora Mattoni & Acosta, 2005 e Brazilobothriurus pantanalensis Lourenço & Monod, 2000. A distribuição dos registros de escorpiões no Mato Grosso do Sul é heterogênea, uma vez que as áreas dominadas por Mata Atlântica e pelo Pantanal são menos amostradas em relação àquelas de domínios do Cerrado.
Assuntos
Animais , Brasil , Escorpiões , Grupos de População AnimalRESUMO
Seven new species of the spider genus Xeropigo O. P.-Cambridge are described from Brazil, increasing the genus member list up to 16 species. X. piripiri n. sp., X. aitatu n. sp., and X. cajuina n. sp. are described from the state of Piauí. X. crispim n. sp. is described from the states of Ceará, Piauí, and Maranhão. X. oxente n. sp. is described from the state of Rio Grande do Norte. X. canga n. sp. is described from the state of Minas Gerais. X. ufo n. sp. is described from the state of Mato Grosso. The geographical distribution of X. tridentiger, X. camilae, X. pachitea, and X. perene is updated. A key to all species of Xeropigo is presented and possible relationships among all species of the genus are discussed.
Assuntos
Aranhas/classificação , Distribuição Animal , Estruturas Animais/anatomia & histologia , Estruturas Animais/crescimento & desenvolvimento , Animais , Tamanho Corporal , Brasil , Ecossistema , Feminino , Masculino , Tamanho do Órgão , Aranhas/anatomia & histologia , Aranhas/crescimento & desenvolvimentoRESUMO
Spiders are abundant in tropical ecosystems and exert predatory pressure on a wide variety of invertebrate populations and also serve as prey for many others organisms, being part of complex interrelationships influenced directly and indirectly by a myriad of factors. We examined the influence of biotic (i.e., prey availability) and abiotic (i.e., temperature, precipitation, relative humidity, real evapotranspiration) factors on species richness and abundance during a two-year period in the semiarid Caatinga vegetation in northeastern Brazil. Data were analyzed through partial autocorrelation functions, cross correlations, and a path analysis. A total of 2522 spiders were collected with beating tray, pit-fall traps, and malaise traps, comprising 91 species and 34 families. Spider abundance peaked in the rainy season. Our results suggest that total invertebrate abundance has a direct influence on spider richness and abundance, whereas the effects of precipitation were mainly indirectly related to most spider assemblage parameters. The increase in vegetation cover with the rainy season in the Caatinga provides more breeding and foraging sites for spiders and stimulates their activities. Additionally, rainfall in arid and semiarid ecosystems stimulated the activity and reproduction of many herbivore and detritivore invertebrates dependent on plant biomass and necromass consumption, leading to an increase in spider prey availability.
Assuntos
Biodiversidade , Clima , Chuva , Aranhas/fisiologia , Animais , Biomassa , Brasil , Cadeia Alimentar , Invertebrados , Densidade Demográfica , Estações do AnoRESUMO
Testicular cells of 4 buthid scorpions, Rhopalurus agamemnon (2n = 28), R. rochai (2n = 28), Tityus bahiensis (2n = 6), and T. fasciolatus (2n = 14), which show different types of chromosomal configurations in meiosis I, were subjected to cellular microspreading in order to (1) obtain knowledge about the organization and behavior of the synaptonemal complex (SC), and (2) acquire data about the mechanisms responsible for inter- and intraindividual chromosomal variation within Buthidae. Ultrastructural analysis of microspread nuclei revealed SCs with a well-preserved structure until late substages of prophase I, but did not detect kinetochore plates and recombination nodules. Pachytene cells of R. agamemnon, R. rochai and T. bahiensis exhibited single and unsynapsed axes continuous with totally synapsed SCs, indicating the occurrence of heterozygous chromosomal rearrangements. Although chromosome chains were not observed in T. fasciolatus, the presence of gaps and interlocks points out that this species also carries heterozygous rearrangements, involving a small chromosome segment. Especially in R. rochai, the cellular microspreading analysis was useful to clarify the origin of inter- and intraindividual variation in the number of bivalent-like elements and in the number of chromosomes involved in multivalent associations. It was found that more chromosomes were involved in rearrangements than previously established through investigations using light microscopy alone.