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Four new species of recluse spiders from Brazilian caves are described with both males and females. Loxoscelesericsoni Bertani, von Schimonsky & Gallão, sp. n. and L.karstica Bertani, von Schimonsky & Gallão, sp. n. both occur in caves in the Peruaçu region, located in the northern area of the state of Minas Gerais; L.karsticasp. n. is additionally found in the Serra do Ramalho karst area, located in the southwestern region of the state of Bahia. These two species belong to the gaucho group. Loxoscelescarinhanha Bertani, von Schimonsky & Gallão, sp. n. and L.cardosoi Bertani, von Schimonsky & Gallão, sp. n. occur exclusively in caves of the Serra do Ramalho karst area and belong to the rufescens/amazonica species group. The discovery of two additional and highly distinct species in the rufescens/amazonica group (L.carinhanhasp. n. and L.cardosoisp. n.) increases the debate on the origin, evolution, and geographical distribution of this widely distributed group of recluse spiders in the New and Old World. The presence of three species (L.ericsonisp. n., L.carinhanhasp. n., and L.cardosoisp. n.) with marked differences in morphological characters in a relatively small area indicates that the region seems to be an important center for Loxosceles diversity, which remains poorly studied.

A new species of the spider genusLoxoscelesHeineken & Lowe, 1832,Loxoscelesmalintzisp. n., is described from the states of Puebla, Morelos and Guerrero, in the central region of Mexico. The description is based on adult males and females with morphological and ultra-morphological images. Updated distribution maps are provided for the 39 species recorded from the Mexican territory (including the new species). The states with the greatest diversity are Baja California Sur, Baja California and Sonora, with five species each. A total of 441 records for the 39 species, based on arachnological collections, data bases and literature, were used to update the distribution maps.LoxoscelesbonetiGertsch, 1958 is the species with the highest number of records in Mexico, with a total of 58 records from different localities. The states with the most records so far are Guerrero, with 55 records, Morelos, with 35 records, and Baja California Sur, with 30 records.Loxoscelesrufescens(Dufour, 1820), an introduced species, is recorded for the second time in Mexico, from the state of Chihuahua, being the first well-documented record for the country. Mexico has the greatest diversity of species ofLoxoscelesworldwide, with 39 (two introduced species) of the 134 described species. Additionally, biogeographical comments for the species from Mexico are provided.

Psilodercidae contains some 200 known extant species of small spiders that live in tropical rainforests and caves and is mainly restricted to the Oriental biogeographic realm. Interestingly, at least ten different fossil species have been described from inclusions in Upper Cretaceous Burmese amber. This suggests the family has been diversifying in the region for at least ~100 million years. In this paper, we revise the taxonomy of fossil species of this family and the closely related Ochyroceratidae, based on the re-examination of type specimens of described species. We find that ten Cretaceous species described in the psilodercid genera Priscaleclercera and Aculeatosoma are valid, and present new illustrations of their type material. The genus Propterpsiloderces apparently does not belong to Psilodercidae, but rather to a family representing a stem lineage within Scytodoidea. Ochyroceratidae is represented in the fossil record by a single ochyroceratine genus from Miocene Dominican amber, Arachnolithulus. The original combination of the extant species Leclercera spinata Deeleman-Reinhold, 1995 is reinstated by transferring it from Priscaleclercera, leaving this latter genus as a strictly fossil taxon. Finally, we present the description of a hitherto unknown species of Priscaleclercera from mid-Cretaceous Burmese amber, Priscaleclercera christae sp. nov., bringing the total number of congeners to ten. By studying its morphological features, we argue that Priscaleclercera is a crown-group Psilodercidae, closely related to the Althepus–Leclercera lineage. The high species diversity of Priscaleclercera indicates that Psilodercidae was already a diverse component of the Oriental tropical forests during the Cretaceous.

Background The IUCN Red List of Threatened Species is the most widely used information source on the extinction risk of species. One of the uses of the Red List is to evaluate and monitor the state of biodiversity and a possible approach for this purpose is the Red List Index (RLI). For many taxa, mainly hyperdiverse groups, it is not possible within available resources to assess all known species. In such cases, a random sample of species might be selected for assessment and the results derived from it extrapolated for the entire group - the Sampled Red List Index (SRLI). The current contribution is the final in four papers that will constitute the baseline of a future spider SRLI encompassing 200 species distributed across the world. New information A sample of 200 species of spiders were randomly selected from the World Spider Catalogue, an updated global database containing all recognised species names for the group. The selected species were classified taxonomically at the family level and the familes were ordered alphabetically. In this publication, we present the conservation profiles of 50 species belonging to the families alphabetically arranged between Scytodidae and Zoropsidae, which encompassed Scytodidae, Selenopidae, Sicariidae, Sparassidae, Tetrablemmidae, Tetragnathidae, Theraphosidae, Theridiidae, Theridiosomatidae, Thomisidae, Trochanteriidae, Zodariidae and Zoropsidae.

The family Drymusidae includes 16 cryptic spiders that build irregular websin dark places. The family is distributed in South Africa, the Neotropical,and Andean regions. Here, we use a molecular approach to infer therelationships of Drymusidae using three mitochondrial (COI, 16S, 12S) andthree nuclear (H3, 28S, 18S) markers. Our preferred analyses supportDrymusidae and its American and African clades, which emerge as sistergroups. Our analyses suggest a Gondwanan distribution of Drymusidae anda Westward radiation of Izithunzi gen. nov. within South Africa, but bothhypotheses remain to be thoroughly tested. We describe Izithunzi gen.nov. for the African species. All previous African species are redescribedand new combinations proposed: Izithunzi capense (Simon) comb. nov.,Izithunzi productum (Purcell) comb. nov. and Izithunzi silvicola (Purcell)comb. nov.. Two new species are described: Izithunzi lina sp. nov. (knownfrom both sexes) and Izithunzi zondii sp. nov. (known only from females).The male of I. productum (Purcell) comb. nov. is also described for the firsttime. We consider Drymusa valida (Lawrence, 1964) a junior synonym ofIzithunzi capense (Simon) comb. nov. (new synonymy). We also provide adichotomous key for Izithunzi gen. nov. species. Fil: Labarque, Facundo Martín. Governo do Estado de Sao Paulo. Secretaria da Saude. Instituto Butantan; Brasil. California Academy of Sciences; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina Fil: Pérez González, Abel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina Fil: Griswold, Charles E.. California Academy of Sciences; Estados Unidos. San Francisco State University; Estados Unidos. University of California; Estados Unidos. The George Washington University; Estados Unidos

Sicariids are an infamous spider family containing two genera: the poorly known Sicarius Walckenaer and the medically important Loxosceles Heineken & Lowe. We present the first broad survey of the morphology of the family from a phylogenetic perspective in order to resolve its relationships. We scored morphological, behavioural and venom feature data for 38 taxa, including New and Old World species of both Sicarius and Loxosceles and three outgroups. Our results point to the monophyly of Sicariidae and its two genera as currently delimited, with the identification of novel synapomorphies for all of them. We present evidence of a group of ‘true’ Loxosceles composed of all members of the genus except those from the spinulosa species group. Sicarius have a very interesting phylogenetic structure, with species from the Americas and Africa forming reciprocally monophyletic groups. Thus, we resurrect Hexophthalma Karsch to accommodate African Sicariinae species. We discuss the evolution of venom proteins, spinning organs and cryptic appearance in Sicariidae. We delimit Sicarius to include only the 20 Neotropical species, and present a taxonomic revision of the genus. We redescribe nine previously known species, elevate one subspecies to species, and describe six new species from Argentina, Bolivia, Brazil and Peru. Sicarius levii sp. nov., from Argentina, is probably the largest known haplogyne spider in both body length and mass. Six specific names are considered junior synonyms of older names. All these species are illustrated and have their distributions mapped. We present an interactive key for identifying Sicarius species. Fil: Fiorini de Magalhaes, Ivan Luiz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina. Universidade Federal de Minas Gerais. Instituto de Ciências Biológicas; Brasil Fil: Brescovit, Antonio Domingos. Governo do Estado de Sao Paulo. Secretaria da Saude. Instituto Butantan; Brasil Fil: Santos, Adalberto J.. Universidade Federal de Minas Gerais. Instituto de Ciências Biológicas; Brasil

The genus Stedocys was known only from males. Here we describe the first females of the genus. Stedocys genitalia are atypical for Scytodidae. Males are distinguished by having the papal tarsus subequal or smaller than the tegulum, not prolonged apically, without prolateral blunt macrosetae; the tegulum long, inserted apically on the tarsus; embolus slightly shorter than bulb, aciculate distally, and females by lacking fovea or positioning ridges below the epigastric furrow, and by having an anterior epigynal pouch. In this contribution, we describe the female and redescribe the male of Stedocys leopoldi (Giltay, 1935), and describe male and female of Stedocys pagodas new species from China (Yunnan). The lack of a projection on the male palpal tarsus suggests that Stedocys is the sister group of all other genera of Scytodidae.

A new species of Drymusa Simon, 1891, from Region VII, Chile, is described and illustrated. The female genitalia is quite different from the other Drymusa species and even from most of the Scytodoidea, having two sclerotized sulci above the epigastric furrow that seemingly provide a guide for the embolus. The male copulatory bulb is also quite different from the other species, having a very long and flexible embolus. This Chilean species is the seventh species of Drymusa described from South America. The presence of a double row of teeth on the ventral surface of the proclaw and a single row on the retroclaw of legs I and II found on this and on other species of Drymusa provides further evidence to support the relationship between Drymusidae Simon, 1891, Periegopidae Simon, 1893 and Scytodidae Blackwall, 1864.

The female of Drymusa serrana Goloboff & Ramírez, 1991, is described. The presence of the species in San Luis provinces, Argentina, is confirmed. We provide descriptions of the web and egg-sacs.

The relationships of Scytodoidea, including the families Drymusidae, Periegopidae, Scytodidae and Sicariidae, have been con-tentious for a long time. Here we present a reviewed phylogenetic analysis of scytodoid spiders, emphasizing Periegops, theonly genus in the family Periegopidae. In our analysis the Scytodoidea are united by the fusion of the third abdominal entapo-physes into a median lobe, the presence of female palpal femoral thorns and associated cheliceral stridulatory ridges, a mem-branous lobe on the cheliceral promargin, and the loss of minor ampullate gland spigots. A basal split within Scytodoideadefines two monophyletic groups: Sicariidae and a group formed by Scytodidae as the sister group of Periegopidae plus Dry-musidae, all united by having bipectinate prolateral claws on tarsi I–II, one major ampullate spigot accompanied by a nubbin,and the posterior median spinnerets with a mesal field of spicules. Periegops is the sister group of Drymusidae, united by the regain of promarginal cheliceral teeth and a triangular cheliceral lamina, which is continuous with the paturon margin.

The genus Stedocys was known only from males. Here we describe the first females of the genus. Stedocys genitalia are atypical for Scytodidae. Males are distinguished by having the papal tarsus subequal or smaller than the tegulum, not prolonged apically, without prolateral blunt macrosetae; the tegulum long, inserted apically on the tarsus; embolus slightly shorter than bulb, aciculate distally, and females by lacking fovea or positioning ridges below the epigastric furrow, and by having an anterior epigynal pouch. In this contribution, we describe the female and redescribe the male of Stedocys leopoldi (Giltay, 1935), and describe male and female of Stedocys pagodas new species from China (Yunnan). The lack of a projection on the male palpal tarsus suggests that Stedocys is the sister group of all other genera of Scytodidae. Fil: Labarque, Facundo Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina Fil: Grismado, Cristian José. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina Fil: Ramírez Martínez, José de Jesús. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina Fil: Yan, Hengmei. Hunan Normal University; China Fil: Griswold, Charles. California Academy Of Sciences.; Estados Unidos