A comparison of adhesive performance among six cursorial spider species

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  A comparison of adhesive performance among six cursorial spider species Abstract The ability to adhere to surfaces is particularly relevant for cursorial predatory arthropods like hunting spiders, which often traverse relatively complex environments characterized by large variation in substrate properties. Here, we evaluated the adhesive performance of six hunting spider species that are common in eastern temperate North America and lack specialized tarsi for climbing smooth or inclined surfaces [Lycosidae: Pardosa lapidicina Emerton, 1885 and Rabidosa rabida (Walckenaer, 1837); Oxyopidae: Oxyopes salticus Hentz, 1845; Pisauridae: Pisaurina mira (Walckenaer, 1837); Dolomedidae: Dolomedes triton (Walckenaer, 1837), and Dolomedes scriptus Hentz, 1845]. We tested adhesion performance as shear load resistance (g) on a glass plate, and as the angle of failure (°) when the plate was gradually inclined relative to horizontal. Average angle of failure and shear resistance differed among ...

Two new species of Vitalius (Araneae: Theraphosidae) from the restingas of the states of Rio de Janeiro, Bahia and Sergipe, Brazil

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Two new species of Vitalius (Araneae: Theraphosidae) from the restingas of the states of Rio de Janeiro, Bahia and Sergipe, Brazil

ABSTRACT

Brazil is the country with the most diverse tarantula (Theraphosidae) fauna, having 215 described species. Vitalius Lucas, Silva Júnior & Bertani, 1993 is one of the most diverse and common genera in Southern, Southeastern and Central-West regions of Brazil with ten described species. Individuals of Vitalius species are large and widespread in areas of the Brazilian Atlantic Forest. A single species is known to occur in areas of Cerrado vegetation. Herein, two new species are described from areas of restinga, coastal areas typically with low vegetation and sandy soil, in the coast of the states of Rio de Janeiro (Vitalius restinga sp. nov.), Bahia and Sergipe (Vitalius sapiranga sp. nov.). Males and females of these two new species have a much longer than wide sternum. Males have a short apical keel in the male palpal bulb. The two species can be distinguished by embolus width, slender in V. restinga sp. nov. and thicker in V. sapiranga sp. nov. Females can be distinguished by the spermathecae shape, slender in V. restinga sp. nov. and broader in V. sapiranga sp. nov. These are the first known theraphosids endemic to Brazilian Atlantic Coast restingas. Biological data indicate V. sapiranga sp. nov. and maybe V. restinga sp. nov. commonly use bromeliads as retreats. It is herein hypothesized they are sister species occupying similar habitats in Brazilian coast, but separated by ca. 1,000 kilometers.

Bertani, R.. (2023). Two new species of Vitalius (Araneae: Theraphosidae) from the restingas of the states of Rio de Janeiro, Bahia and Sergipe, Brazil. Zoologia (curitiba), 40, e23001. https://doi.org/10.1590/S1984-4689.v40.e23001