Leonardo S. Carvalho

Location of 45S Ribosomal Genes in Mitotic and Meiotic Chromosomes of Buthid Scorpions

Buthid scorpions exhibit a high variability in diploid number within genera and even within species. Cytogenetically, Buthidae differs from other families of Scorpiones based on its low diploid numbers, holocentric chromosomes, and complex chromosomal chains, which form during meiosis. In this study, we analyzed the distribution of the 45S ribosomal DNA (rDNA) genes in the mitotic and meiotic chromosomes of seven buthid species belonging to the genera Rhopalurus and Tityus with the ultimate goal of elucidating the chromosome organization in these scorpions. The chromosome number ranged from 2n = 6 to 2n = 28. Despite the high variance in diploid number, all species examined carried their 45S rDNA sites in the terminal region of exactly two chromosomes. Analyses of meiotic cells revealed 45S rDNA clusters in the chromosomal chains of Rhopalurus agamemnon, Tityus bahiensis, Tityus confluens, and Tityus martinpaechi, or in bivalent-like configuration in Rhopalurus rochai, Tityus bahiensis, Tityus confluens, Tityus fasciolatus, and Tityus paraguayensis. In the species examined, the 45S rDNA sites colocalized with constitutive heterochromatin regions. In light of the high chromosome variability and maintenance of number and terminal position of 45S rDNA sites in buthids, the heterochromatin may act to conserve the integrity of the ribosomal genes.

Microhabitat use and intraspecific associations in the whip spider Heterophrynus longicornis (Arachnida: Amblypygi) in forest fragments formed by the Tucuruí Dam lake, Pará, Brazil

The effect of forest fragmentation on the abundance of the whip spiders Heterophrynus longicornis (Butler 1973) in land-bridge island fragments created by the lake formed by Tucuruí Dam, Pará, Brazil, was investigated. These fragments have been isolated for at least 23 years, on small islands that range in size from 12.9 to 91.3 ha. The abundance of whip spiders was calculated in 100 m transects on eight islands, both in the edge and in the interior of the islands. There were no differences in whip spider abundance between the edge or interior of islands, but the whip spiders strongly preferred areas with greater numbers of trees, trees with a DBH between 10 to 50 cm, and trees with termite nests. Over 31% of the whip spiders were found in association with other individuals on the same tree. Individuals were found in mother–offspring associations, mating pairs, and in mixed-age sex groups.

Scorpionism in the rural zone of Teresina, State of Piauí: relate of envenomation cases

1. Laboratório de Aracnologia, Museu Paraense Emílio Goeldi, Laboratório de Aracnologia, Belém, PA. 2. Laboratório de Zoologia, Departamento de Zoologia, Universidade Federal do Piauí, Teresina, PI. Endereço para corrrespondência: Sr. Leonardo Sousa Carvalho. Laboratório de Aracnologia/Museu Paraense Emílio Goeldi. Campus de Pesquisa. Av. Perimetral 1901, Caixa Postal 399, 66017-970 Belém, PA. e-mail: leosc_fla@yahoo.com.br Recebido em:16/01/2007 Aceito em: 23/05/2007 No Brasil, o acidente escorpiônico constitui um problema atual de saúde pública, não só pela alta incidência em determinadas regiões, como pela sua potencialidade em ocasionar quadros graves, às vezes fatais, principalmente em crianças . No Estado do Piauí, nenhum caso de escorpionismo havia sido relatado até o momento. Realizamos uma entrevista com dois moradores da zona rural de Teresina que sofreram acidentes com escorpiões a fim de sabermos a espécie causadora e as manifestações do envenenamento. A identificação dos escorpiões foi feita comparando-se as descrições fornecidas pelos moradores com chaves de identificação propostas 3 . O primeiro acidente ocorreu com uma mulher de 54 anos no dia 14 de fevereiro de 2004. A paciente foi encaminhada ao hospital com dor local de forte intensidade, agitação, sialorréia, taquicardia, visão embaçada, lacrimejando, espasmos musculares e hipotensão arterial. Ficou em observação no hospital, onde não havia soro anti-escorpiônico, por dois dias. Uma coleta na área da ocorrência do acidente levou à captura de sete espécimes, todos Rhopalurus agamemnon (C.L. Koch, 1839). O segundo acidente ocorreu com um jovem de 18 anos no dia três de outubro de 2004. O paciente, atingido no 2o quirodáctilo, foi socorrido precocemente e apresentava-se com dor local intensa, sialorréia, sonolência e dor irradiada no ombro direito. Ficou em observação no hospital por 24 horas após receber soro anti-escorpiônico. Não levou o escorpião para identificação, mas o descreveu com características similares a Rhopalurus agamemnon. Os dois pacientes foram atendidos precocemente, lavaram o local da picada, não fizeram incisões ou torniquetes e não tomaram medicamento sem prescrição médica. Rhopalurus agamemnon, é um animal que se distribui pelos Estados do Piauí, Goiás, Bahia, Ceará, Mato Grosso e Pernambuco . É caracterizado pelo grande tamanho, podendo chegar a 110mm de comprimento total, e possui coloração de modo geral marrom, pernas amareladas, pedipalpos com tons marrons/amarelados, segmentos metassomais I a III amarelos/marrons, IV e V mais escuros ou quase negros. São, geralmente, encontrados em vegetações abertas 3 . Há espécimes registrados para Piracuruca, Castelo do Piauí, União, Teresina, José de Freitas e São Raimundo Nonato, no Estado do Piauí.

Impact of different land management on soil spiders (Arachnida: Araneae) in two Amazonian areas of Brazil and Colombia

Abstract The global demand for different land-use practice commodities in the Amazonia is growing, and this region is increasingly affected by the impacts of land management. The aim of this study was to evaluate the influence of land-use intensification on soil spider assemblages from six different land-use systems in Colombia and Brazil. The systems were fallows after crops and pastures, forest, crops, pastures and plantations. Spider species richness and density decreased with increasing farming management intensity. A principal component analysis (PCA) showed forests and fallows were separated from systems with stronger anthropogenic soil disturbance. The relationships of ten spider guilds differed significantly between land-uses, suggesting that they can be a reliable parameter for studies of ecological indicators.

Organization and Behavior of the Synaptonemal Complex during Achiasmatic Meiosis of Four Buthid Scorpions

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.

A new species of Sickesia (Laniatores: Stygnidae: Opiliones) and new records for the State of Piauí, Brazil

Sickesia tremembe sp. nov. is described from Piaui, Northeast Brazil (type-locality: Sete Cidades National Park, Brasileira and Piracuruca municipalities). It differs from S. usta and S. helmuti by the clavate male femur IV and chelicerae segment I with a pair of large tubercles on retrolateral surface. The Stygnidae Stygnus polyacanthus (Mello-Leitao, 1923); the Cosmetidae, Gryne pluriarcuata Mello-Leitao, 1936 and undetermined species of Paecilaema and Gryne and also repre- sentatives of Escadabiidae and Sclerosomatidae (Gagrellinae) are recorded from this state, for the first time.

Arachnida, Amblypygi, Heterophrynus longicornis (Butler, 1873): distribution extension for the state of Piauí northeastern Brazil

In this paper, we report the first records of Heterophrynus longicornis (Butler, 1873) for the state of Piaui, northeastern Brazil. We collected 58 individuals in thirteen municipalities throughout the state: Altos, Brasileira, Caracol, Castelo do Piaui, Guaribas, Jose de Freitas, Lagoa Alegre, Oeiras, Pedro II, Piracuruca, Teresina, Uniao and Urucui.

. Primeiro registro da família Cithaeronidae (Araneae, Gnaphosoidea) no Novo Mundo

Tres femeas de Cithaeron praedonius O.P.-Cambridge, 1872 (Araneae, Gnaphosoidea, Cithaeronidae), a especie com distribuicao mais ampla da familia, foram encontradas em areas urbanas em Teresina, capital do estado do Piaui, nordeste do Brasil. Este primeiro registro da familia Cithaeronidae para o novo mundo e explicado por introducao acidental.

Cytogenetical characterization of six orb-weaver species and review of cytogenetical data for Araneidae

Abstract The family Araneidae is the third largest among spiders and the third most studied from a cytogenetical point of view. In spite of this, only 2% of all araneids have been karyotyped. The majority of araneids analyzed possess 2n  =  24 chromosomes in males; however, the study of additional species could reveal unusual karyotype characteristics. Thus, the aim of this work is to analyze chromosomally, for the first time, six species belonging to three araneid genera from Brazil. The specimens of Alpaida leucogramma (White 1841), Alpaida truncata (Keyserling 1865), Alpaida veniliae (Keyserling 1865), Parawixia kochi (Taczanowski 1873), Parawixia velutina (Taczanowski 1878) and Wagneriana sp. were collected in Parque Nacional de Ilha Grande and in the municipality of Rio Claro. The gonads were treated with colchicine and hypotonic solution before fixation with Carnoy I solution. The results were 2n♂  =  24 (11II+X1X2) in A. leucogramma and P. velutina, and 2n♂  =  22 (10II+X1X2) in A. truncata, A. veniliae, P. kochi and Wagneriana sp. When the chromosomal morphologies were established, we observed telocentric chromosomes in all specimens save one female specimen of P. velutina. The univalent sex chromosomes were easily recognized on diplotenes. The unpaired metacentric element found in one female specimen of P. velutina with 2n  =  25 probably arises by centric fusion/fission. Araneidae is a megadiverse family composed of ∼3000 species distributed mainly in the tropics; thus the analysis of more species may provide new insights about orb-weaver chromosome evolution.

On the female of Metagonia taruma (Araneae: Pholcidae), ecology of the pholcid spiders in the Urucu River Basin, Amazonas, Brazil and new records from Brazilian Amazonia

In this study we describe the unknown female of Metagonia taruma Huber, 2000, which was discovered after sampling in two forest gap types at Porto Urucu (Urucu River Basin, Coari, Amazonas, Brazil), and also provide information on the community ecology and natural history of the sampled species. The female of M. taruma is similar to that of M. samiria (Huber, 2000) by having an epigynum with a slightly projecting broad scape with a distal pocket; it differs by the larger pore plates. We collected twelve Pholcidae species at Porto Urucu and M. taruma was the most frequent and abundant. The populations of Carapoia ocaina Huber, 2000 and Mesabolivar aurantiacus (Mello-Leitao, 1930) present homogeneous sex ratios, while M. taruma and Mesabolivar sp. were female biased. Only two species (M. taruma and Mesabolivar sp. ) exhibited differences in abundance in each forest gap type, being higher at the poorly regenerated gaps. Thus, the use of Pholcidae species as ecological indicators is promising. We also present new records, throughout the Amazon Basin, for the Pholcidae species collected at Porto Urucu.