Abstract Velvet worms are ancient predators with Cambrian origins that occasionally prey on Ctenid spiders. Here we report the opposite case: wolf spiders (Ctenus spp.) feeding on Epiperipatus spp. in Colombia and Costa Rica. Apparently the worms could not expel their defensive adhesive, and the efficacy of the spider venom suggests that onychophoran nerves and muscles are biochemically equivalent to those of insects.

Resumen Los gusanos de terciopelo (Onychophora) son antiguos depredadores de origen cámbrico que ocasionalmente consumen arañas cténidas. Aquí informamos el caso contrario: arañas (Ctenus spp.) alimentándose de gusanos onicóforos (Epiperipatus spp.) en Colombia y Costa Rica. Aparentemente las presas no lograron expulsar su red defensiva y la eficacia del veneno de araña sugiere que los nervios y músculos de los onicóforos son bioquímicamente equivalentes a los de los insectos.

The wolf spider Lycosa singoriensis is a large and venomous spider distributed throughout northwestern China. Like other spider venoms, the wolf spider venom is a chemical cocktail. Its protein content is 0.659 mg protein/mg crude venom as determined by the Lowry method. MALDI-TOF analysis revealed that the venom peptides are highly diverse and may be divided into three groups characterized by three independent molecular ranges: 2,000 to 2,500 Da, 4,800 to 5,500 Da and 7,000 to 8,000 Da, respectively. This molecular distribution differs substantially from those of most spider venoms studied so far. This wolf spider venom has low neurotoxic action on mice, but it can induce hemolysis of human erythrocytes. Furthermore, the venom shows antimicrobial activity against prokaryotic and eukaryotic cells.

The wolf spider Lycosa singoriensis (Laxmann, 1770) (Lycosidae: Araneae) is distributed throughout central and eastern Europe, including Russia, Kazakhistan and Turkey. This study describes the venom apparatus morphology of L. singoriensis through scanning electron microscopy (SEM). Its structure follows the general architecture observed in other spiders. Generally, a venom apparatus is composed by a pair of venom glands and chelicerae. L. singoriensis chelicerae are robust and consist of a stout basis and a movable apical segment (fang). The fang rests in a groove on the basal segment that is covered by different types of hair. L. singoriensis venom glands present equal size and measure about 4 mm in length. Each gland is enclosed by irregular muscular layers.

A new species of the wolf spider genus Arctosa C. L. Koch, 1847 is described and illustrated, based on material collected in Sapiranga, Southern Brazil. Members of Arctosa are known to build burrows in sandy lake shores, but this new species is found under the rocks on the margins of small streams. Females with eggsacs and males can be found all year, being more abundant in the summer period.

Se describe e ilustra una nueva especie del género Arctosa C. L. a Koch, 1848, en base a material procedente de Sapiranga, sur del Brasil. Los miembros de este género por lo general excavan refugios pequeños en los bordes arenosos de los lagos, sin embargo, esta nueva especie se encuentra debajo de rocas en los bordes de rios pequeños. Se puede encontrar hembras con ootecas y machos durante todo el año, aunque son más abundantes en el período del verano.