The first Symphytognathidae ( Arachnida : Araneae ) from Argentina , with the description of a new species of Anapistula from the Yungas mountain rainforest La primera Symphytognathidae ( Arachnida : Araneae ) para Argentina , con la descripción de una nueva especie de Anapistula para la selva de mo

The spider family Symphytognathidae is reported from Argentina for the first time. Anapistula yungas, a new species of this family is described and illustrated. The specimen was collected during an ecological study of biodiversity in different sites from northwestern Argentina. Dichotomous key to Neotropical female species of genus Anapistula is provided.


INTRODUCTION
The family Symphytognatidae was established by Hickman (1931) for the Australian species Symphytognatha globosa Hickman, extraordinary for its tiny size (Forster & Platnick 1977).This spider family is diagnosed by the following combination of characters: the female pedipalp is either reduced to a unisegmented lobe or absent, the chelicerae are more or less fused, the labium is much wider than long, and the sternum is broadly truncate posteriorly (Forster & Platnick 1977) Brescovit 2003, Platnick 2009).These spiders are rarely collected in large numbers owing to their minute size and occurrence in leaf litter habitats (Miller et al. 2009), and are usually captured only when specifically searched for or when Berlese funnels, Winkler extractors or pitfail traps are used (Rheims & Brescovit 2003).This is the first record of a spider of the family Symphytognathidae from Argentina and, according to the morphology of the female genitalia, the specimen is here postulated to represent a new species of the genus Anapistula.For comparative purposes, a dichotomous key to Neotropical female species of the genus is also given here.

METHODS
The material was collected during an ecological study of biodiversity in different sites in northwestern Argentina, using a G-Vac method to collect spiders from vegetation.This method consist of a vacuum cleaner Sthil® with tube of 110 cm of longitude and 12 cm of diameter (flow 710 m3 h'1), and each sample is the suction of the vegetation in an area of a square meter during one minute.The vegetation in this place is rainforest, and corresponds to the Yungas eco-region (Brown et al. 2002).
The description and terminology follow mainly Tong & Li (2006).Female genitalia was observed and illustrated without dissect the epigynum from the specimen and after cleared in clove oil.The photos and illustrations were prepared from digital photographs captured using a Sony DSC-W290 camera attached to a Leica MS5 stereomicroscope.All measurements were taken with a micrometer ocular and are in millimeters.
The specimen examined is deposited in the Museo de La Plata, Argentina (MLP, curator L. Pereira).

Etymology
The specific name, yungas, is a noun in apposition after the eco-region to which the type locality belongs.

Diagnosis
The female genitalia closely resembles that of A. secreta Gerstch by having the median epigynal duct reaching to the anterior tip of spermathecae (see Gertsch 1941, figs. 14-17), but it differs from that species because their length is the same as that of the spermathecae diameter, and it lacks the small vesicular projections on the spermathecae (Fig. IE and IF).Other important characters include the proportionally bigger globular spermathecae than the rest members of genus Anapistula.

Description female (Holotype)
Total length, not including chelicerae, 0.57.Carapace 0.25 long, 0.25 wide, 0.10 high.Opisthosoma 0.35 long, 0.35 wide, 0.17 high.Body without markings, color entirely pale yellow except for a black ring surrounding the eyes, and sclerotised internal genitalia.Carapace relatively low, with a setae at level of eyes, at middle (Figs.1A and IB).Anterior margin of clypeus with a row of setae.Cephalic part only slightly lower than thoracic part; part cephalic only slightly lower than part thoracic; lateral margins evenly rounded.Four eyes present in two diads, surrounded by darker rings, distance between diads 0.07 wide; anterior eyes larger than posteriors (Figs. 1A and IB).Clypeus wide.Chelicerae slightly fused near their base, each with two sharp teeth near the base of the fang (Figs.1H and II).Labium wider than long distinctly.Sternum posteriorly truncate, slightly longer than wide (Fig. 1C).Palp completely absent.Legs pale yellow, clothed with setae and bristles, each patella with a long distally-dorsal spine; joint inflexible between tarsus and metatarsus (Fig. ID).Three tarsal claws, all of which appear smooth (Fig. 1G).Femur I 0.25 long, tibia I 0.15 long, metatarsus + tarsus I 0.32 long; femur II 0.22 long, tibia II 0.17 long, metatarsus + tarsus II 0.25 long; femur III 0.20 long, tibia III 0.13 long, metatarsus + tarsus III 0.28 long; femur IV 0.21 long, tibia IV 0.16 long, metatarsus + tarsus IV 0.30 long.Leg formula: I-IV-II-III.Opisthosoma without scute, covered with long smooth setae, globular, as long as wide (Figs.1A-D).Book lungs not visible.Anterior spinnerets slightly larger than posteriors; median spinnerets not visible; colulus absent (Fig. 1C).Epigynum not sclerotized, two large globular spermathecae sclerotized, of which connected by relatively short lateral branches to median duct; bases of copulatory duct with a small anterior swelling (Fig. IE).Distance between spermathecae 0.04 long. Male.Unknown.

Remarks Natural history
This species is currently represented only by the holotype which was captured with more than 3,300 spiders obtained in winter and autumn expeditions.
The specimen was collected by a G-Vac method from low vegetation less than one meter from the forest floor, in rainforest at 1,700 m altitude.