Neodrassex , a new genus of the Leptodrassex group (Araneae, Gnaphosidae) from South America

. The new genus Neodrassex is proposed to include two new species of Gnaphosidae from Brazil. Neodrassex aureus sp. nov. is described from Amazonas, Paraná and Rio Grande do Sul states, and N. iguatemi sp. nov. is described from Paraná state. Neodrassex gen. nov. is characterized by small size, pale coloration, large anterior median eyes surrounded by black pigmentation, absence of a dorsal abdominal scutum in males and by the cheliceral dentition with 2-3 teeth on the promargin and 2-4 on the retromargin. The new genus is tentatively placed at the Leptodrassex group.

The gnaphosid Leptodrassex group was proposed by Murphy (2007) to include the simultaneously proposed genus Leptodrassex Murphy, 2007.This genus currently includes four species from the Mediterranean, Canary Islands and Asia, all formerly placed in Leptodrassus Simon, 1878 (Murphy, 2007;platnick, 2012).
According to Murphy (2007), Leptodrassex species were separated from Leptodrassus primarily because of their unusual dentition, with 2-4 "discrete small" teeth on the promargin of the chelicerae and 2-3 teeth on the retromargin.Other diagnostic characters cited for Leptodrassex are: small size (2-4 mm), pale coloration, lack of dorsal abdominal scutum in males, anterior median eyes surrounded with black pigment and larger than the other eyes when viewed from the front.
While revising the unidentified Gnaphosidae vials in the arachnological collection of the Museu de Ciências Naturais da Fundação Zoobotânica do Rio Grande do Sul, several specimens were found presenting similar somatic characteristics to Leptodrassex.By a closer examination I was able to identify two distinct female morphospecies and one male.The cheliceral tooth formula of the examined specimens, with 2-3 teeth on the promargin and 2-4 on the retromargin doesn't agree exactly with the Lexptodrassex genus dentition presented by Murphy (2007).The herein examined specimens also don't match any known Leptodrassex species in the shape of the external female genitalia (which presents a large, divided atrium) or male palp morphology (with small, hooked, slightly sclerotized and translucent median apophysis).Based on the provided evidence (tooth formula and the regular appearance of female genitalia) the new genus is proposed and tentatively placed in the Leptodrassex group sensu Murphy (2007).

MATERIAL AND METHODS
The specimens examined are deposited in the arachnological collection of the Museu de Ciências Naturais, Fundação Zoobotânica do Rio Grande do Sul (MCN, E. H. Buckup and R. Ott), Porto Alegre, Brazil.The description format follows Ott et al. (2012) with inclusion of descriptions of male and female palp spination.Only leg articles with spines are indicated.All femoral dorsal spines are considered erect and bristle-like; all remaining article spines are considered surface bearing.The female epigynum was dissected and immersed in clove oil for clearing in order to facilitate the study and imaging of its structures.
Incident light images were taken through a stereomicroscope with attached camera and processed with Helicon Focus multi-range program.Drawings were made using a stereomicroscope with attached camera lucida.Transmitted light images of cleared female epigyna were taken with a compound microscope using a digital camera and also processed with Helicon Focus.Electron scanning microscope (SEM) images were taken using a Jeol-JSM-5200 with attached SLR digital camera.All measurements are in millimeters.Ott Neodrassex gen.nov.Type-species.Neodrassex aureus sp.nov.Etimology.Neodrassex is a contraction between Neotropical and Leptodrassex.Gender is masculine.
Diagnosis.Neodrassex resembles Leptodrassex in the small size, pale coloration, larger AME surrounded with black pigment, absence of a dorsal abdominal scutum in males, presence of lateral epigynal processes (Figs 39, 45;see also kOvblyuk & nadOlny, 2010:194, figs 28-30) and posteriorly directed fertilization ducts in the internal female genitalia (Figs 1,40,46; see also Murphy, 2007:519-520); Neodrassex species can be distinguished from Leptodrassex by the cheliceral dentition with 2-3 teeth on the PM and 2-4 teeth on the RM 47); males can be distinguished by the shape of the palp bulb with a flat, hooked, slightly sclerotized and translucent MA rising from a deep depression on the apical portion of the tegulum (Figs 5-7, 9-16); females can be identified by the shape of the external female genitalia, which present a large atrium with a narrow median septum (Figs 37,39,43,45).
Note.The presence of a larger number of independent teeth on the promargin of the chelicera seems to be the more common pattern in Gnaphosidae.
Note.There are a large number of gnaphosoids which are introduced or have wide distributions ranges (platnick, 2012).Due to the large distribution range of at least one of the herein described species, along with the proximity of some of the collection areas to highly impacted anthropic environments, there is for now a considerable doubt about the biogeographic origin of Neodrassex species.However other Neotropical species of spiders from other families (e.g.Linyphiidae) have the same distribution pattern and similar collection sites from Amazonas (Fazenda Esteio, Manaus) to state of Rio Grande do Sul (Everton N. L. Rodrigues, pers.comm.).Etymology.The specific name is a latin adjective in honor of the golden wedding anniversary  of my father and my mother, Germano Rudolfo Ott and Elke Elisabeth Ott.

Neodrassex aureus sp. nov.
Diagnosis.Males and females of Neodrassex aureus sp.nov.can be recognized by the presence of three teeth on the PM and four on the RM.The species can be also recognized by the shape of the male palp (Figs 5-19) and by the shape of the female genitalia .