Body temperature can strongly influence fitness. Some Sun-exposed ectotherms thermoregulate by adjusting body posture according to the Sun's position. In these species, body elongation should reduce the risk of heat stress by allowing the exposure of a smaller body area to sunlight. Therefore, selection should favour more elongated bodies in Sun-exposed than in Sun-protected species. Diurnal orb-web spider species that sit on their webs are more likely to be Sun-exposed, on average, than nocturnal or diurnal shelter-building species. We measured the body elongation of orb-web spiders (Araneae, Araneidae) across 1024 species and classified them as Sun-protected or exposed based on the literature. We found that Sun-exposed species evolved more elongate bodies than Sun-protected ones. Further, we built a model combining traditional heat transfer models with models of thermoregulatory postures in orb-web spiders and meteorological data. The model indicates that body elongation in large orb-web spiders decreases the risk of high body temperatures. Overall, our results suggest that Sun exposure influenced the evolution of body shapes of orb-web spiders.

Three new species of the araneid spider genera Carepalxis L. Koch, 1872 and Ocrepeira Marx, 1883 from Central Brazil are described and illustrated: Carepalxis topazio new species, based on a single female from Cristalina; C. quasimodo new species, from Brasília and Jaborandi based on females and a male, this being the first male of Carepalxis described in the American continent; and Ocrepeira planalto new species, based on males and females from Cavalcante, Cristalina, Jaborandi and Alto Paraíso. A key to Carepalxis females in the New World is provided. Furthermore, the similarity between American Carepalxis and Ocrepeira is discussed, with diagnostic considerations.

The area known as Parque Ermida Dom Bosco on the shores of the Paranoá Lake, 7.8 km from the centre of Brasília (Rodoviária do Plano Piloto), Distrito Federal, Brazil, is a preservation area of Monumento Natural category (since 2019), and one of the few protected areas of the Distrito Federal without a floristic list. Collecting focused on the vascular flora and was undertaken as monthly, 1-day events from August of 2017 to August of 2018. Our study identified 293 species, of which half (50%) were distributed among just seven botanical families: Fabaceae (42 species), Asteraceae (31 spp.), Malpighiaceae (19 spp.), Myrtaceae (19 spp.), Lamiaceae (14 spp.), Poaceae (12 spp.), and Euphorbiaceae (8 spp.), a result that is congruent with the known Cerrado flora. Anemopaegma goyazense (Bignoniaceae) was recorded from a protected area in the Distrito Federal for the first time; other regional species with narrow geographic distributions recorded were Mimosa gatesiae (Fabaceae), Myrcia capitata and Myrcia federalis (Myrtaceae).