The alien species Stenochrus portoricensis (Schizomida: Hubbardiidae): decreasing the Wallacean shortfall in the New World

The widely distributed species, Stenochrus portoricensis Chamberlin, 1922, is recorded for the first time from Costa Rica and Venezuela, and new occurrences from Brazil and Colombia are presented. Morphology of spermathecae from 14 localities is compared and illustrated. The need for studies to evaluate the potential status as an invasive species of S. portoricensis is commented on and a distribution map of the species in southern Central America and South America is given.(AU)

La especie exótica Stenochrus portoricensis Chamberlin, 1922 (Schizomida: Hubbardiidae): disminución del déficit de Wallace en el Nuevo Mundo. La especie de amplia distribución Stenochrus portoricensis Chamberlin, 1922 se registra por primera vez en Costa Rica y Venezuela, y se presentan nuevas ocurrencias en Brasil y Colombia. Se compara e ilustra la morfología de las espermatecas de especímenes provenientes de 14 localidades. Se comenta la necesidad de realizar estudios para evaluar el estatus potencial de S. portoricensis como especie invasora y se presenta un mapa de distribución de la especie en el sur de Centroamérica y Sudamérica.(AU)

Morphology of the arthrodial membrane gland in a Neotropical harvester (Arachnida: Opiliones)

We describe a gland in the arthrodial membrane of the coxa-trochanter articulation in the fourth pair of legs in the Neotropical harvester Mischonyx squalidus Bertkau, 1880. Externally the glandular area has a rough appearance with pores on its surface, with folds of the arthrodial membrane. Internally, its secretory cells have spherical secretory vesicles, smooth endoplasmic reticulum, mitochondria and ducts that exit from the cells and cross the arthrodial membrane. Histochemical tests indicate the presence of proteins and neutral glycoproteins. The function of the gland might be to produce lubricating products that allow better movement of the coxa-trochanter region.

Evidence of positive selection on six spider developmental genes.

Spiders constitute more than 49,000 described species distributed all over the world, and all ecological environments. Their order, Araneae, is defined by a set of characteristics with no parallel among their arachnid counterparts (e.g., spinnerets, silk glands, chelicerae that inoculate venom, among others). Changes in developmental pathways often underlie the evolution of morphological synapomorphies, and as such spiders are a promising model to study the role of developmental genes in the origin of evolutionary novelties. With that in mind, we investigated changes in the evolutionary regime of a set of six developmental genes, using spiders as our model. The genes were mainly chosen for their roles in spinneret ontogeny, yet they are pleiotropic, and it is likely that the origins of other unique morphological phenotypes are also linked to changes in their sequences. Our results indicate no great differences in the selective pressures on those genes when comparing spiders to other arachnids, but a few site-specific positive selection evidence were found in the Araneae lineage. These findings lead us to new insights on spider evolution that are to be further tested.

Three new species of Cosmetidae C.L. Koch, 1839 from South America (Opiliones: Cosmetidae).

Three new species of harvestmen are described based on morphology. Taito mayoruna spec. nov. from Jenaro Herrera province, Loreto, Peru is differentiated from other species of Taito Kury Barros, 2014 by features such as anal operculum armed, and femur IV with two retro-distal spines. Taito curupira spec. nov. from Porto Velho, Rondonia, Brazil is recognized by an H-shaped color pattern, femur IV curved dorsally and armed with medial prolateral and retrolateral tubercles. A third species herein described, Eulibitia chacuamarei spec. nov., from Trinidad, Casanare, Colombia is distinguished by the absence of a ladder mask and by the presence of blunt tubercles on areas I, III and the posterior margin. Penial morphology is described, and SEM micrographs are included.

On Spinopilar from Rio de Janeiro state with description of three new species (Opiliones, Laniatores, Cryptogeobiidae).

The genus Spinopilar Mello-Leitão, 1940 currently has seven species distributed in eastern Brazil, Argentina and Paraguay. Three species are hitherto known from Rio de Janeiro state (RJ), in the Brazilian Atlantic Forest. In this paper, five species from Rio de Janeiro state (RJ) are studied as follows: (1) Spinopilar armatus Mello-Leitão, 1940, the type species of Spinopilar, originally described without illustrations, is herein redescribed based on additional material from the metropolitan area of Rio de Janeiro city. (2) Spinopilar anomalis (Sørensen, 1932) is a species never recorded again after the original description. A new diagnosis is provided for S. anomalis based on a translation of the original Latin description. (3) Spinopilar jocheni spec. nov. is described from Barra de Guaratiba, Southeast RJ. It is characterized by the unarmed mesotergal areas. (4) Spinopilar martialis spec. nov. is described from Macaé, northern RJ. It is characterized by the pars stridens of the stridulatory organ on the pedipalpal femur, the unusual armature of scutal areas (2-2-10-10) and the extremely complex lobes of the stigmatic area in males, which connect the apophyses of coxa and trochanter IV. (5) Spinopilar magistralis spec. nov. is described from Búzios. It is characterized by extreme stoutness of leg IV and an elevated campaniform ocularium. A key is provided to 9 of the 10 species of Spinopilar and a new diagnosis is given for the genus. Two novel structures so far known only in Spinopilar are described: (1) a third type of pars stridens, which is different from the Tibangara-type and the Bissulla/Pseudopachylus-type both in topology and in structure of the ridges; (2) a proximal primary trochanteral cluster (PTC) composed of modified setae situated on the main apophysis of trochanter IV of males.

A remarkable new species of Agoristenidae (Arachnida, Opiliones) from Córdoba, Colombia

A new species of Leiosteninae (Opiliones, Agoristenidae) from the Colombian Caribbean, Avima tuttifruttisp. nov.García & Pastrana-M., is described and illustrated, based on two males from the montante forests of Tierralta (Córdoba department). The new species differs externally from other species of Avima by having one yellow hump on mesotergal area IV and green coloration on dorsal scutum. SEM images of the penis and a map showing its distribution are offered. This species represents the first record of a harvestman from the department of Córdoba and the eighth species of the subfamily recorded from the country.(AU)

An unusual cryptogeobiid from southeastern Brazil revisited (Opiliones, Laniatores, Gonyleptoidea)

The monotypic genus Bunostigma Mello-Leitão, 1935 is herein revisited. A detailed redescription of its type-species, Bunostigma singulare Mello-Leitão, 1935 from Rio de Janeiro state, eastern Brazil, is herein presented, providing in depth knowledge of this genus. Bunostigma is most closely related to Cryptogeobius Mello-Leitão, 1935, and as this genus, it has a stout complex apophysis on male coxa IV, lacking, however, a second complex on the stigmatic area. Bunostigma has an oblique elongate malleus, similar to that of Zalanodius Mello-Leitão, 1936 (as opposed to a globular malleus in Cryptogeobius). Bunostigma singulare has short legs, with some sexual dimorphism on its stoutness, a dorsal scutum entirely unarmed and an ocularium with an accessory central mound, although unarmed.(AU)

A relictual troglomorphic harvestman discovered in a volcanic cave of western Argentina: Otilioleptes marcelae, new genus, new species, and Otilioleptidae, new family (Arachnida, Opiliones, Gonyleptoidea).

The troglomorphic harvestman Otilioleptes marcelae gen. nov., sp. nov. from the basaltic cave Doña Otilia, Payunia region, Mendoza Province, Argentina, is described. Its systematic affinities were studied through cladistic and Bayesian analyses that included representatives of Gonyleptoidea; it was determined to represent a new monotypic family, Otilioleptidae fam. nov., occupying a basal position within the clade Laminata. This species shows accentuated troglomorphic traits, typical for troglobitic harvestmen: elongated appendages, depigmentation, reduction of eyes and fading of scutal sulci. Additionally, it almost lacks sexual dimorphism, the distal portion of coxa IV is not completely fused to the stigmatic segment, and penis morphology is remarkably divergent with other Laminata; these features cannot be attributed to cave adaptation and may reflect early lineage divergence. Otilioleptes marcelae is the first troglobitic gonyleptoid known from a lava tube. The xeric environments around the cave (Patagonian ecoregion) and the paleoenvironmental history of the area suggest the relictual character of O. marcelae. Scattered evidence supports a long time evolutionary scenario and a presumable relationship with the Chilean opiliofauna (especially with genus Osornogyndes). A comparative overview of all known troglobitic gonyleptoids is provided. The urgent need to protect this new species and its unique cave environment is emphasized.

Description of a new species of Surazomus (Arachnida: Schizomida), with comments on homology of male flagellum and mating march anchorage in the genus.

Surazomus saturninoae sp. nov. is described from eastern Amazon. The male has a pentagonal flagellum, similar to those of three other species in the genus. These four species are herein gathered as the arboreus-group of Surazomus. We present a brief synopsis of chaetotaxy description in hubbardiines and several homology proposals for the flagellum of the species in the arboreus-group: the posterior lobes may be homologous to the lateral lobes of hubbardiine species with trilobed flagella; the setal brush with 4-5 setae on the posterior lobe may be composed of one Dl2 seta and enlarged lobular microsetae; the single, median posterior coupling pocket may be homologous to the pair of posterior pockets seen in other hubbardiines; the single, median anterior coupling pocket may be homologous to the pair of pockets on the anterior border of the flagellum seen in other hubbardiines. Based on the morphology of these pockets and the chelicerae within Surazomus, we discuss the anchoring mechanism during the mating march.

The sensory equipment of a sandokanid: An extreme case of tarsal reduction in harvestmen (Arachnida, Opiliones, Laniatores).

The study of sensory structures has the potential to provide insights into the natural history and evolution of animals. The sensory structures of arachnids are usually concentrated on the pedipalps (the tritocerebral appendages) or on the distal podomere (tarsus) of the anterior walking legs, the latter being the case for armored harvestmen (Opiliones, Laniatores). Therefore, modifications of the tarsus could have direct impacts on the sensory equipment of these animals. Using scanning electron microscopy, we investigated the sensory equipment in an extreme case of reduction in tarsal articles in the harvestman Sandokan truncatus (Sandokanidae), which bears a single tarsomere in all legs, and the potential consequences of this reduction. Additionally, we review the literature on the natural history of the family Sandokanidae. Tarsomeres of all legs are equipped with gustatory sensilla, mechanoreceptors, and a pore organ, but wall-pored olfactory sensilla are restricted to tarsi I and II. Tarsi II present a higher density of olfactory sensilla and also putative campaniform sensilla (strain detectors), which indicates a special sensory function of this pair of legs. Other podomeres are covered with shelled sensilla, a probable chemoreceptor previously unreported in Opiliones. Overall, S. truncatus has types of sensilla largely comparable to harvestmen with longer and subdivided tarsi. However, S. truncatus also exhibits extra-tarsal sensory fields of sensilla basiconica (putative thermo-/hygroreceptors) in previously undescribed sites, and the unique pore organs. Our results establish a basis for further research investigating the natural history, as well as the evolutionary correlations and mechanistic causes of the tarsal reduction in this enigmatic lineage.

Ontogenetic variation in the sensory structures on the pedipalps of cosmetid harvestmen (Arachnida, Opiliones, Laniatores).

In arachnids, pedipalps are highly variable appendages that may be used in feeding, courtship, defense, and agonistic encounters. In cosmetid harvestmen, adults have pedipalps that feature flattened femora, spoon-shaped tibiae, and robust tarsal claws. In contrast, the pedipalps of nymphs are elongate with cylindrical podomeres and are adorned with delicate pretarsi. In this study, we used scanning electron microscopy to examine the distribution of cuticular structures (e.g., sensilla chaetica, pores) on the elements of the pedipalps of adults and nymphs of three species of cosmetid harvestmen. Our results indicate that there is considerable ontogenetic variation in the morphology of the trochanter, femur, patella, tibia, and tarsus. The pretarsus of the nymph has a ventral patch of setae that is absent from the adult tarsal claw. We observed this structure on all three cosmetid species as well as on the pedipalps of an additional seven morphospecies of nymphs collected in Belize and Costa Rica. This structure may represent a previously unrecognized autapomorphy for Cosmetidae. Examinations of the pedipalps of antepenultimate nymphs of additional gonyleptoidean harvestmen representing the families Ampycidae, Cranaidae, Manaosbiidae, and Stygnidae revealed the occurrence of unusual, plumose tarsal setae, but no setal patches on the tarsal claw.

Event-based biogeography of Eusarcus dandara sp. nov. (Opiliones: Gonyleptidae), an endemic species of the Northern Atlantic Rainforest of Brazil, and its closely related species.

Here, we describe a new species of Eusarcus and reconstruct the geographical evolution of its species group based on biogeographical event-based analysis. Eusarcus dandara sp. nov. has been recorded from Alagoas state, in northeastern Brazil, which represents an important range extension of the genus to the northern Atlantic Rainforest. We performed a cladistic morphological analysis based on new data and data from a previous systematic review of the genus to reconstruct the phylogenetic placement of the new species. This analysis resulted in six most parsimonious cladograms. We performed the biogeographical reconstruction using the Treefitter 1.3B1 algorithm for the clade of eight species that includes E. dandara sp. nov., and we tested the significance of the reconstructions. We found two alternative reconstructions depended on the differences in species relationships; both were significant (0.002 ≤ p ≤ 0.019). The phylogenetic placement of the new species is consistent with some expectations based on previous biogeographical studies of Atlantic Rainforest harvestmen. Reconstructions reveal the origin of the species group in the northeast region, in the Atlantic Rainforest plus interior and dry biomes, such as the Caatinga xeric shrubland and Cerrado savanna, with subsequent dispersal to the southeast region. Harvestmen are good models to study the historical biogeography of the Atlantic Rainforest, especially those species that are endemic, like most Eusarcus. We have demonstrated a complex history of the spatial evolution of the group and the importance of the adjacent drier biomes in the evolution of endemic organisms of the Atlantic Rainforest.

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.

Nine new species of the Eremobates scaber species group of the North American camel spider genus Eremobates (Solifugae, Eremobatidae).

Nine new species of the Eremobates scaber species group of the solifuge genus Eremobates Banks 1900 are described, eight of them from Mexico. These new species are: E. axacoa, E. bonito, E. cyranoi, E. fisheri, E. hidalgoana, E. jaliscoana, E. minamoritaana, E. zacatecana, and E. zapal and together increase the size of this species group to 23. A key to all species in the E. scaber species group is also provided.

Two new troglobiotic palpigrades (Palpigradi: Eukoeneniidae) from Brazil.

Two new species of troglobiotic Brazilian palpigrades are described: Eukoenenia jequitinhonha sp. n., found in Lapa do Córrego do Vieira cave (Caraí, Minas Gerais) and E. cavatica sp. n., found in Cazanga cave (Arcos, Minas Gerais). The importance of documenting the occurrence of troglobiotic species, even if they are represented by only a single specimen, is discussed.

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.

Description of two new species of Charinus Simon, 1892 from Brazilian caves with remarks on conservation (Arachnida: Amblypygi: Charinidae).

The genus Charinus comprises eleven described species in Brazil. Herein we describe two new species, Charinus caatingae sp n. and Charinus iuiu sp n., from caves of the state of Bahia, Brazil. Charinus caatingae is threatened, requiring special attention to its conservation. Furthermore, we present an updated identification key and a table of characters for the genus in the country.