Semideciduous seasonal forest opiliofauna (Arachnida, Opiliones), State of Paraná, Brazil

Harvestmen are arachnids that play an important role in organic matter breakdown. However, there are many ecosystems in Brazil, including Conservation Units, which lack information about these organisms or are sub-sampled. Even in areas of Atlantic forest, a biome that hosts the greatest diversity and endemic rates of these arthropods in the world. In this perspective, the purpose of this study was to survey the harvestmen fauna in areas of Semideciduous Seasonal Forest in the Ilha Grande National Park, Paraná, southern Brazil, from February to November 2019, totaling 15 days and 60 hours, on six islands in the Paraná River. A total of 170 specimens was collected, distributed in five genera, comprising two species and three morphotypes. The low species richness may reflect the isolation of populations imposed by the island effect, however the study expanded the geographic distribution of Parapachyloides uncinatus and Discocyrtus invalidus, for which until then there was no record of occurrence in the Paraná State.

Semideciduous seasonal forest opiliofauna (Arachnida, Opiliones), State of Paraná, Brazil

Harvestmen are arachnids that play an important role in organic matter breakdown. However, there are many ecosystems in Brazil, including Conservation Units, which lack information about these organisms or are sub-sampled. Even in areas of Atlantic forest, a biome that hosts the greatest diversity and endemic rates of these arthropods in the world. In this perspective, the purpose of this study was to survey the harvestmen fauna in areas of Semideciduous Seasonal Forest in the Ilha Grande National Park, Paraná, southern Brazil, from February to November 2019, totaling 15 days and 60 hours, on six islands in the Paraná River. A total of 170 specimens was collected, distributed in five genera, comprising two species and three morphotypes. The low species richness may reflect the isolation of populations imposed by the island effect, however the study expanded the geographic distribution of Parapachyloides uncinatus and Discocyrtus invalidus, for which until then there was no record of occurrence in the Paraná State.(AU)

The disjunct pattern of the Neotropical harvestman Discocyrtus dilatatus (Gonyleptidae) explained by climate-driven range shifts in the Quaternary: Paleodistributional and molecular evidence.

The disjunct distribution of the harvestman Discocyrtus dilatatus (Opiliones, Gonyleptidae) is used as a case study to test the hypothesis of a trans-Chaco Pleistocene paleobridge during range expansion stages. This would have temporarily connected humid regions ('Mesopotamia' in northeastern Argentina, and the 'Yungas' in the northwest, NWA) in the subtropical and temperate South American lowlands. The present study combines two independent approaches: paleodistributional reconstruction, using the Species Distribution Modeling method MaxEnt and projection onto Quaternary paleoclimates (6 kya, 21 kya, 130 kya), and phylogeographic analyses based on the cytochrome oxidase subunit I molecular marker. Models predict a maximal shrinkage during the warm Last Interglacial (130 kya), and the rise of the hypothesized paleobridge in the Last Glacial Maximum (21 kya), revealing that cold-dry stages (not warm-humid ones, as supposed) enabled the range expansion of this species. The disjunction was formed in the mid-Holocene (6 kya) and is intensified under current conditions. The median-joining network shows that NWA haplotypes are peripherally related to different Mesopotamian lineages; haplotypes from Santa Fe and Córdoba Provinces consistently occupy central positions in the network. According to the dated phylogeny, Mesopotamia-NWA expansion events would have occurred in the last glacial period, in many cases closely associated to the Last Glacial Maximum, with most divergence events occurring shortly thereafter. Only two (out of nine) NWA haplotypes are shared with Mesopotamian localities. A single, presumably relictual NWA haplotype was found to have diverged much earlier, suggesting an ancient expansion event not recoverable by the paleodistributional models. Different measures of sequence statistics, genetic diversity, population structure and history of demographic changes are provided. This research offers the first available evidence for the historical origin of NWA disjunct populations of a Mesopotamian harvestman.

First Amazonian species of Maracaynatum, with comments on the genus (Opiliones: Laniatores: Samoidae).

Among Opiliones, the family Samoidae Sørensen, 1886 is a group of small Laniatores with a wide tropical distribution. Neotropical samoids are distributed mainly in the Caribbean subregion, with species recorded from insular localities and the Venezuelan coastal range. Previously, for continental South America only three genera and just a few specimens of unidentified Samoidae have been recorded from Brazil. In this paper we describe Maracaynatum isadorae sp. nov., the first record of the genus for Brazil and the first samoid described for the Amazon biome. We also provide an emended diagnosis for the genus and a map with its distribution.

Two new species of whip spider (Amblypygi): an epigean and a cave dwelling Charinus Simon, 1892 from Belize.

Central America is rich in whip spider species, mainly of the genera Phrynus and Paraphrynus (Phrynidae), but also includes few registers of Charinus (Charinidae) with no description of taxa. In this paper two new species of Charinus from Belize are described and illustrated (Charinus belizensis sp. nov. and Charinus reddelli sp. nov.) being the first species named from Central America. New records of Charinus victori Armas, 2010 from Puerto Rico, a comparative table listing the differential characters of the Caribbean and Central American species, and a distributional map of those species are also provided.

Taxonomic notes on the genus Auranus (Opiliones, Laniatores, Stygnidae), with description of two new species.

Among the Amazonian families of harvestmen the members of Stygnidae are better known due to the recent revision of the family and efforts of specialists describing new taxa in the last few years. Species of Amazonian genus Auranus Mello-Leitão, 1941, have been collected in several inventories that were carried out in different locations of the Amazon basin. In this paper we provide a new diagnosis for Auranus, and the description of two new species: Auranus leonidas sp. nov. and Auranus xerxes sp. nov. from the Brazilian states of Roraima and Amazonas, respectively. We also offer complementary genital descriptions of Auranus hehu Pinto-da-Rocha & Tourinho 2012, Auranus parvus Mello-Leitão, 1941, and Auranus tepui Pinto-da-Rocha & Tourinho 2012. Five species are recognized in Auranus, including the two new species described in this paper. The lamina parva modified into a calyx is proposed as putative synapomorphy for the genus Auranus. Therefore, A. hoeferscovitorum, which does not possess this character, is removed from Auranus. Instead we propose for it the new combination Verrucastygnus hoeferscovitorum comb. nov. We also provide a key to the males of Auranus, and a map with the distribution for all species examined in this work.

Cladistic analysis and description of three new species of the Chilean genus Nanophareus (Opiliones: Gonyleptidae: Pachylinae).

Three new species of the Chilean Pachylinae genus, Nanophareus Roewer, 1929 are described: N. bicornutus sp. nov. (Valle de Aconcagua, Zapallar, V Región de Valparaíso), N. maipu sp. nov. (La Rinconada, Quebrada de la Plata, Maipu, Región Metropolitana-Santiago), and N. polyhastatus sp. nov. (El Abanico, VIII Región de Bio-Bío). These three new species were included in a cladistic analysis that resulted in two equally most parsimonious trees (238 steps, C.I. = 0.38; R.I. = 0.51), corroborating the monophyly of Nanophareus. The proposed synapomorphies for Nanophareus remain largely unchanged: an external row of enlarged tubercles inserted amongst small ones on the lateral margin of dorsal scutum; the ventro-basal margin of the pedipalpal tibia curved at 90° in lateral view; and retrolateral seta on pedipalpal tibia with an apically bifid socket (socket and seta longer than pedipalpal tibia length), with additional small setae distally. The sister group of Nanophareus, as well as its subfamilial placement, are still unsettled issues that are here further discussed.

Revalidation of the Brazilian genus Discocyrtanus, with description of two new species (Opiliones: Gonyleptidae: Pachylinae).

The genus Discocyrtanus Roewer, 1929, is herein revalidated from the synonymy of Discocyrtus Holmberg, 1878, to include besides the type species Discocyrtanus goyazius Roewer, 1929, four other Brazilian species, two of them new-Discocyrtanus bugre sp. nov. and Discocyrtanus tocantinensis sp. nov.-and two newly transferred from Discocyrtus: Discocyrtanus oliverioi (H. Soares, 1945) comb. nov., and Discocyrtanus pertenuis (Mello-Leitão, 1935) comb. nov. Three species, Discocyrtus pectinifemur Mello-Leitão, 1937, Discocyrtus fimbriatus Mello-Leitão, 1939, and Discocyrtus canalsi Roewer, 1943, are considered junior subjective synonyms of Discocyrtanus pertenuis comb. nov.. A mix-up between labeling of original illustrations of two species of Discocyrtus described by Mello-Leitão is noted.

A new species of Charinus Simon, 1892 (Amblypygi, Charinidae) from termite nests in French Guiana.

The genus Charinus is represented by 51 species, distributed in all tropical regions. Their small size allows them to use a wide range of micro-habitats, from caves, litter to insect nests. The new species C. sillami sp. nov. was found into termite nests of three different species: Neocapritermes taracua, Spinitermes sp. and Embiratermes neotenicus. Only Paracharon caecus (Paleoamblypygi: Paracharontidae) was previously known to be associated with Isoptera. Eleven species of Charinus were previously known from Northern South America. Charinus sillami sp. nov. is the second species of the genus occurring in French Guiana. An updated key of Northern South-American species is provided.

Chileotrecha romero (Kraus, 1966) comb. nov. and Pseudocleobis patagonicus (Roewer, 1934) comb. nov. transferral from Mummuciidae to Ammotrechidae (Arachnida, Solifugae).

The solifuge species Mummucina romero Kraus, 1966, from Chile, and Mummucia patagonica Roewer, 1934, from Argentina, are here transferred from Mummuciidae Roewer, 1934 to Ammotrechidae Roewer, 1934. Chileotrecha romero (Kraus, 1966) comb. nov. and Pseudocleobis patagonicus (Roewer, 1934) comb. nov. are proposed. Comments on their morphology are made and previous distributional records are discussed. Pseudocleobis patagonicus is proposed as a nomen dubium. In addition, we confirm that female and immature specimens of the family Mummuciidae, just like males, can be reliably recognized based on features that had been suggested by Maury (1984).

Taxonomic revision of the genus Mayazomus Reddell & Cokendolpher, 1995 (Schizomida: Hubbardiidae), with description of five new species from Chiapas, Mexico.

The genus Mayazomus currently contains two species from southeastern Mexico. It was originally characterized by a strongly elongated pedipalp trochanter, united in its entire width to the femur; the patella strongly curved; the tibia with a large mesal apophysis opposable to tarsus; the spermathecae with two pairs of thin lobes subequal in length; and the presence of four or more setae on tergite II. In the present contribution, the species of the genus Mayazomus are revised and new diagnostic characters for the genus are proposed, including the correction that the female flagellum bears three rather than two annuli. The two known species are redescribed based on examination of the holotypes, plus newly acquired material representing both sexes (female previously unknown for one). Five new species from the Mexican state of Chiapas are described, based on adult males and females: Mayazomus tzotzil new species, Mayazomus aluxe new species, Mayazomus kaamuul new species, Mayazomus yaax new species, and Mayazomus loobil new species. Dimorphism in male pedipalps is reported for the first time for the genus. A dichotomous key is provided for identification of the seven species in the genus; and a distribution map is included. 

First record of the family Pseudochiridiidae (Arachnida, Pseudoscorpiones) from continental South America--a Pseudochiridium from a Brazilian cave.

The small pseudoscorpion family Pseudochiridiidae Chamberlin, 1923 comprises two genera and 12 extant species recorded from Asia (Burma, Christmas Island, Indonesia, India, Nepal, Malaysia, New Guinea, Philippines, Nicobars and Sumba), eastern, central and southern Africa (Chad, D.R. Congo, Kenya, South Africa, Tanzania), Madagascar, Seychelles (Aldabra), North America (Florida) and the Caribbean Islands of Dominican Republic and Cuba (Harvey 2013, Barba & Barroso 2013); one unidentified species is mentioned for the fauna of Mexico (Ceballos 2004). A fossil species has been described from Dominican amber by Judson (2007), who predicted the presence of this family in South America. 

Two new species of Piaroa (Arachnida: Schizomida, Hubbardiidae) from Colombia, with comments on the genus taxonomy and the flagellar setae pattern of Hubbardiinae.

Two new species of the genus Piaroa Villarreal, Tourinho & Giupponi, 2008, P. escalerete sp. nov. and P. bacata sp. nov. are described from Valle del Cauca, and Cundinamarca departments, Colombia, respectively. The female flagellum is fully illustrated for a Piaroa species for the first time; the generic diagnosis is also emended and the relationships of the new species with those previously described are discussed. New characters for Piaroa species, a new nomenclature for the chitinized arch and a reinterpretation of the Hubbardiinae flagellar setae pattern are proposed. A distribution map of the known species of Piaroa is provided. 

First Harvestman Record for the Juan Fernández Archipelago, Chile, with Morphological Notes on Acropsopilio chilensis (Opiliones: Caddidae: Acroposopilioninae).

Acropsopilio chilensis Silvestri, 1904 (Eupnoi: Caddidae: Acropsopilioninae), is recorded for Robinson Crusoe Island, Chile. This is the first harvestman species recorded for the Juan Fernández Archipelago and also the first extra-continental record for this species. During the comparison with continental co-specific specimens, some previously unknown, remarkable morphological characteristics were discovered, among them: the absence of ovipositor seminal receptacles and tracheal system, small and probably imperforate spiracles and the presence of a subdistal spiny structure, maybe a stylus, in the major branch of the penis. 

A new species of Chileotrecha Maury, 1987 (Solifugae: Ammotrechidae) from Argentina with notes on the genus.

The monotypic genus Chileotrecha Maury, 1987, includes Chileotrecha atacamensis Maury, 1987 from Atacama and Coquimbo regions in Chile. We describe Chileotrecha argentinensis n. sp., which is the first record of the genus from Argentina. Phylogenetic relationships of Chileotrecha with other genera of Ammotrechidae are discussed based on external morphology. We report for the first time the presence of blunt and clubbed setae in Ammotrechidae. We also report for the first time the presence of two pairs of microsetae in the posterior margin of genital plate and in the posterior margin of spiracular sternites I and II, and the presence of a single microseta on each side of postspiracular sternite I.

Bioclimatic profile and potential distribution of the Mesopotamian harvestman Discocyrtus testudineus (Holmberg, 1876) (Opiliones, Gonyleptidae).

The geographic range of the Neotropical harvestman Discocyrtus testudineus (Holmberg, 1876) (Gonyleptidae) is addressed by determining the species' bioclimatic profile and modeling its potential distribution. Analysis was performed on a record set of 71 localities, including literature records and 34 new localities reported here. The bioclimatic profile was characterized through extreme, median and dispersion features of the values of 19 bioclimatic variables across the record set. Predictive models were built with the presence-only methods MAXENT and, secondarily, BIOCLIM. Discocyrtus testudineus is a typical Mesopotamian harvestman, spreading across a wide region along the middle and lower Paraná River in subtropical / temperate Argentina, and extending, more or less continuously, up to the central province of Córdoba. Apparently diverging records (Paso de los Libres, on the Uruguay River, and Quilmes, on the southern coast of Rio de la Plata) proved to be predictable, even if suppressed from the dataset. Comparisons of cumulative frequencies curves and dispersion features (box-plots) were made with Discocyrtus dilatatus Sørensen, 1884 and Gryne orensis (Sørensen, 1884), other Mesopotamian species for which bioclimatic data are available. The relative importance of the bioclimatic variables used for modeling was also estimated.

A new Amazonian species of Cryptocellus (Arachnida, Ricinulei), with descriptions of its integumental structures and all free-living life stages.

A new species of Cryptocellus Westwood, 1874 is described, based on males, females and all free-living immature stages. Cryptocellus muiraquitan sp. nov. from Juruti, Pará, Brazil, is a member of the foedus group of species and probably closely related to Cryptocellus icamiabas Tourinho & Azevedo, 2007, C. abaporu Bonaldo & Pinto-da-Rocha, 2003 and C. simonis Hansen & Sørensen, 1904. The new species is illustrated using stereomicroscopy and scanning electron microscopy. The large diversity of integumental structures of the new species is described and compared to that of previously studied species of Cryptocellus and Pseudocellus Platnick, 1980.

The effectiveness of post-contact defenses in a prey with no pre-contact detection.

Most empirical and theoretical papers on prey-predator interactions are for animals with long-range detection, animals that can detect and react to predators long before these touch the prey. Heavy-bodied and chemically defended harvestmen (Arachnida, Opiliones) are an exception to this general pattern and rely on contact to detect arthropod predators. We examined the interactions between the Brazilian wandering spider Ctenus ornatus with harvestmen (Mischonyx cuspidatus) or control prey (Gryllus sp. and M. cuspidatus immature, both with soft integuments). Considering a prey-predator system in which fleeing from or reacting to a predator at a distance is not possible, we predicted both a high survival value of near-range defense mechanisms and that mortality would be higher in the absence of such defense mechanisms. We also expected the predator to behave differently when interacting with harvestmen or with a control prey without such defense mechanisms. Our results from laboratory experiments partially matched our predictions: First of all, histological sections showed that the integument of adult harvestmen is thicker than that of immature harvestmen and that of crickets. Adult harvestmen were less preyed upon than the control prey; the heavy armature increases the survival rate but the secretions from the scent glands do not. The predator did behave differently when attacking harvestmen compared to crickets. Despite the large size difference between predator and harvestmen, the protection provided by the armature allowed some of the harvestmen to survive encounters without pre-contact detection, thus greatly reducing the reliance on long-range detection to survive encounters with predators. Harvestmen call for theoretical and empirical work on prey-predator interactions that take into account the possibility that prey may not detect the predator before contact is established.

Redescription of Avicularia taunayi and notes on its habitat and geographical distribution (Araneae Theraphosidae Aviculariinae)

We redescribe the poorly known tarantula species Avicularia taunayi (Mello-Leitão, 1920) and present information on its geographical distribution and habits. The spermatheca of the female is unusual for the genus: short, broad, with a median slight curvature and lobes on its basal, median and distal portions. The male resembles other Avicularia species but can be distinguished by the presence of a tibial apophysis on leg I in conjunction with legs I and IV having roughly the same length and the presence of pale rings on the distal femora, tibiae and metatarsi. Additionally, males and females have three pairs of light brown spots extending from the dorsum to the lateral region of the abdomen. Avicularia taunayi is found in the Brazilian Cerrado, a savannah-like biome. It is one of the aviculariine species with the southernmost distribution, reaching as far South as the Tropic of Capricorn.

Description of the male, larva and nymphal stages of Cryptocellus iaci (Arachnida, Ricinulei), with an overview of tarsal sensilla and other integumental structures.

The male, larva and nymphal stages of Cryptocellus iaci Tourinho, Lo Man-Hung & Bonaldo, 2010, a species previously known only from a single female, are described based on specimens from around the type locality, in an area of both Terra Firme forest and igapó (flooded forests), at the Jufari River, Roraima State, Brazil. The specimens were illustrated using live photography, stereomicroscopy, and scanning electron microscopy, allowing us to examine and describe the large diversity of tarsal sensilla and other integumental structures in Cryptocellus and to compare them to those of the previously studied Pseudocellus. Based on the male somatic characters Cryptocellus iaci is placed in thefoedus species-group. Cryptocellus iaci has two sensilla of type 1 on the distal tarsomeres of legs III (DT III), while only one has been reported for Pseudocellus spp., suggesting a potential value in this type of character for systematic studies of the group.