Two new tiny Nemesiidae species from Reserva Biológica do Tinguá, Rio de Janeiro, Brazil (Araneae: Mygalomorphae)

Two new Nemesiidae species from Reserva Biológica do Tinguá, Rio de Janeiro, Brazil are described. Acanthogonatus minimussp. nov. differs from the remaining species of the genus by the male palpal bulb, which has very long and twisted embolus, ca. 2/3 the length of the palpal tibia, long and twisted spermathecae, anterior eye row recurved and fovea T-shaped. Chaco tinguasp. nov. differs from the remaining species of the genus by the retrolateral megaspine on tibia I, palpal embolus tip hook-shaped, inferior tarsal claw on all legs, absence of pubescence on the carapace and legs. Both species were collected with Winkler extractors in leaf litter. They are the smallest specimens in their respective genera and also among the world Nemesiidae described to date. The smallest male of A. minimussp. nov. measures 4.22 mm and of C. tinguasp. nov. measures 3.85 mm. Data on the phenology of C. tinguasp. nov. is presented.

本文记述采自巴西里约热内卢州廷瓜生物保护区（Reserva Biológica do Tinguá）的2个线蛛科（Nemesiidae）新种。迷你刺蛛新种（Acanthogonatus minimus sp. nov.）与该属其余物种的区别在于：雄性触肢器（male palpal bulb）具极长且卷曲的插入器（embolus），其长度约为触肢胫节（palpal tibia）的2/3；受精囊（spermathecae）长且卷曲；前眼列后曲；头胸窝呈T形。廷瓜查科蛛新种（Chaco tingua sp. nov.）与该属其余物种的区别在于：第一胫节具后侧巨棘；触肢器插入器端部呈钩状；所有步足均具跗节下爪（inferior tarsal claw）；头胸部及步足无柔毛（pubescence）。两种新种均通过温克勒提取器（Winkler extractors）从枯落物层中采集获得，它们分别是各自所属属中体型最小的物种，同时也是截至目前全球已正式记述的线蛛科物种中体型最小的类群之一。迷你刺蛛新种的最小雄性个体体长为4.22 mm，廷瓜查科蛛新种的最小雄性个体体长为3.85 mm。本文还提供了廷瓜查科蛛新种的物候学相关数据。