Abstract In this work, we analyzed cytogenetically eight Chactidae and Buthidae, including the localization of repetitive DNA sequences. The chactids possess monocentric chromosomes and the highest diploid numbers (2n=50 in Brotheas amazonicus, 2n=36 in Chactopsis amazonica, 2n=30 in Neochactas sp.) when compared with buthids (2n=10 in Tityus bahiensis, 2n=14 in Tityus apiacas and Tityus metuendus, 2n=18 in Tityus aba, 2n=26 in Ischnotelson peruassu). The localization of rDNA genes and (TTAGG)n sequences exhibited a conserved pattern of two terminal/subterminal ribosomal cistrons and terminal telomere signals. However, the comparison between the data of C-banding, DAPI after FISH and Cot-DNA fraction indicated a variable quantity and distribution of these regions, as follow: (i) positive heterochromatin and Cot-DNA signals (B. amazonicus and I. peruassu), (ii) small blocks of heterochromatin with large Cot-DNA signals (T. metuendus), (iii) positive heterochromatic regions and absence of Cot-DNA signals (T. aba and T. apiacas), and (iv) negative heterochromatin and Cot-DNA signals (T. bahiensis). Therefore, our results revealed that there still is not a clear relation between quantity of heterochromatin and presence of monocentric or holocentric chromosomes and occurrence of chromosomal rearrangements, indicating that repetitive regions in scorpions must be analyzed using different cytogenetic approaches.

ABSTRACT Although Brazil has one of the highest scorpion diversities worldwide, the scorpion fauna of the Amazon region remains relatively poorly described. In this study, we updated the list of scorpion species from the state of Acre, in the southwestern Brazilian Amazon, based on a revision of records contained in Brazilian arachnid collections and a survey of the relevant literature. We recorded the occurrence of seven scorpion species belonging to two families (Buthidae and Chactidae) among which we report three new records (Ananteris sp., Tityus (Tityus) gasci, and Chactopsis cf. insignis) for Acre. The results presented herein make an important contribution to the knowledge on scorpion diversity in the Amazonian forests of Acre.

RESUMEN Aunque Brasil tiene una de las diversidades de escorpiones más altas del mundo, la fauna de escorpiones de la región amazónica sigue siendo relativamente poco descrita. En este estudio, actualizamos la lista de especies de escorpiones para el estado de Acre, en el suroeste de la Amazonía brasileña, en base a una revisión de los registros contenidos en colecciones de arácnidos brasileños y un estudio de la literatura relevante. Registramos la ocurrencia de siete especies de escorpiones pertenecientes a dos familias (Buthidae y Chactidae), entre las cuales informamos tres nuevos registros (Ananteris sp., Tityus (Tityus) gasci y Chactopsis cf. insignis) para Acre. Los resultados presentados aquí hacen una contribución importante al conocimiento acerca de la diversidad de escorpiones en los bosques amazónicos de Acre.

Quatro fitofisionomias do Bioma Cerrado (mata dos cocais, mata seca semi-decídua primária, mata seca semi-decídua secundária e cerrado típico) na Fazenda Nazareth (Município de José de Freitas, Piauí) foram amostradas utilizando-se guarda-chuva entomológico e armadilhas de queda. Os indivíduos coletados a partir do protocolo estruturado e aqueles coletados previamente na área de estudo (amostragens ocasionais com armadilhas de interceptação e queda) foram identificados unificadamente. Um total de 1215 aranhas, 40 famílias e 114 espécies foram amostradas. Somente 38 espécies foram amostradas no durante o inventário padronizado. As curvas de riqueza de espécies estimadas variaram entre 47 (Bootstrap) e 124 (Chao2) espécies. A mata seca semi-decídua secundária exibiu maior abundância de aranhas (221 indivíduos) e riqueza em espécies (19 spp.). Este é o primeiro estudo comparando estas fitofisionomias, comuns no Norte do Piauí, e indubitavelmente ameaçadas pelo avanço da agricultura no estado. A riqueza em espécies de aranhas encontrada na Fazenda Nazareth é a segunda maior registrada para o Estado do Piauí.

Four Cerrado Biome phytophysiognomies (palm tree woodlands, primary semi-deciduous dry forest, secondary semi-deciduous dry forest and Cerrado stricto sensu), at Nazareth Farm (Municipality of José de Freitas, State of Piauí) were sampled using beating tray and pitfall traps. All the collected individuals during the structured protocol and those previously collected in the study area (occasional sampling with pit-fall traps with drift fences) were identified together. A total of 1215 spiders, 40 families and 114 species were sampled. Only 38 species were sampled during the structured inventory. The estimate species richness curves reached from 47 (Bootstrap) to 124 (Chao2) species. The secondary semi-deciduous dry forest harbored the highest spider abundance (n = 221) and species richness (19 spp.). This is the first study to compare these vegetation types, too characteristic in the North of Piauí, and assuredly threatened by the agricultural advance in this state. The spider species richness found at Nazareth Farm is the second higher recorded from Piauí.