Sociable widow spiders? Evidence of subsociality in Latrodectus Walckenaer, 1805 (Araneae, Theridiidae)

A first case of subsociality is reported for the genus Latrodectus. Individuals were found sharing the same web and feeding together. In captivity they showed mutual tolerance and communal feeding. This finding is remarkable for two reasons. First, widow spiders, even compared with other spiders, are famously aggressive and cannibalistic so that social behavior in the genus was unexpected. Second, the genus nests outside the ""Anelosimus + lost colulus"" clade where all the other social theridiids are found.

Mating behavior of Sickius longibulbi (Araneae, Theraphosidae, Ischnocolinae), a spider that lacks spermathecae

We describe the mating behavior in the spermatheca-lacking theraphosid species Sickius longibulbi Soares & Camargo 1948. The behavior in captivity of nine pairs of S. longibulbi was videotaped and analyzed. The matting of this species presented an uncommon theraphosid pattern. There is little in the way of overt courtship by the male, the primary behavior seen being the male`s use of legs I and II to touch the female`s first pairs of legs and her chelicerae. Sometimes the male clasped one of the female`s first pairs of legs, bringing her close to him. While the female raised her body, the male clasped her fangs and held her tightly with his legs III wrapped around her prosoma. The male seemed to try to knock the female down, pushing her entire body until she lay on her dorsum. In this phase we observed the male biting the female on the sternum or on the leg joints. When the female fell, the male attempted to position himself at an angle of 90 degrees from the female. These movements appear to demand a lot of energy, particularly because the female is not passive during the mating. Our findings suggest that copulating in this position is, for the male, more successful than adopting other positions because it allows his extremely long palpal bulbs to deposit more sperm in the female oviduct where - since she lacks spermathecae - she retains the sperm. We suggest that the further he reaches into the oviduct, the greater the chance that he will fertilize the female`s eggs.

The identity of Mygale brunnipes CL Koch 1842 (Araneae, Theraphosidae), with a redescription of the species and the description of a new genus

We describe Kochiana new genus to accommodate a small Brazilian theraphosine species described originally as Mygale brunnipes by Koch (1842), resulting in Kochiana brunnipes new combination. Recently, specimens were rediscovered in northeastern Brazilian Atlantic rainforest. A preliminary cladistic analysis using equal weights parsimony and implied weights, was carried out to examine its phylogenetic placement. Kochiana new genus was monophyletic in all trees regardless of weighting scheme or concavity used. There is preliminary evidence for Kochiana new genus monophyly and weak evidence for its placement as sister group of Plesiopelma. Kochiana new genus can be characterized by the presence of a hornshaped spermatheca in females and males with a palpal bulb having prolateral accessory keels and a well developed medial crest on the embolus apex.

Revalidation of Pterinopelma Pocock 1901 with description of a new species and the female of Pterinopelma vitiosum (Keyserling 1891) (Araneae: Theraphosidae: Theraphosinae)

We revalidate the theraphosid genus Pterinopelma Pocock 1901, describe the female of P. vitiosum for first time and Pterinopelma sazimai sp. nov. from Brazil. These two species were included in a matrix with 35 characters and 32 taxa and were analyzed both with all characters having same weight and with implied weights. Searches considering all characters non-additive or some additive were also carried out. The preferred tree, obtained with implied weights, concavity 6 and all characters non-additive shows that Pterinopelma is a monophyletic genus sister to the clade Lasiodora (Vitalius + Nhandu). The presence of denticles on the prolateral inferior male palpal bulb keel is a synapomorphy of the genus.

Loxosceles chapadensis (Araneae: Sicariidae): a new recluse spider species of the gaucho group from Brazil

A new species of the medically important recluse spider genus Loxosceles Heinecken & Lowe 1832 is described from the State of Bahia, Brazil. The species occurs between rocks and crevices, as well as in and around man-made structures. The new species belongs to the gaucho group, as evidenced by the spermathecal shape and color pattern. The presence of a long male palpal tibia is unusual in the gaucho group; thus, the inclusion of the new species in this group is discussed.

Description of two new species of Avicularia Lamarck 1818 and redescription of Avicularia diversipes (C. L. Koch 1842) (Araneae, Theraphosidae, Aviculariinae)-three possibly threatened Brazilian species

Avicularia diversipes (C. L. Koch 1842) known previously only from its original description is redescribed along with Avicularia sooretama sp. nov. and Avicularia gamba sp. nov. The three species are endemic to Brazilian Atlantic rainforest. With other Avicularia species, they share a procurved anterior eye row, slender embolus and medially folded spermathecae, whereas they have unusual characters, such as a very long and spiraled embolus (A. diversipes) and spermathecae with multilobular apex (A. sooretama sp. nov.). Furthermore, the three species lack a tibial apophysis in males and share a distinctive color pattern ontogeny that is not known in any other Avicularia species. The conservation status of the three species is discussed, especially with respect to endemism, illegal trafficking and habitat destruction. The creation of protected areas in southern State of Bahia, Brazil, is recommended, as well as the inclusion of these species in IUCN and CITES lists. Appendices with figures and species information are presented to facilitate correct specimen identification by custom officers, in order to limit illegal traffic.