Two new species of Caribbiantes, with the redescription of the type species and a review of male genital patterns in Antillean Stenostygninae (Opiliones: Laniatores: Biantidae).

Caribbiantes cubanus Šilhavý, 1973, type species of genus Caribbiantes Šilhavý, 1973, is redescribed based on abundant material from the type locality, providing new data on its morphological variability and penis morphology. Two new species of Caribbiantes are described, C. obtusus sp.

Systematic revision of the South American "" (Opiliones, Laniatores, Triaenonychidae).

The genus has long been the most speciose within the Opiliones family Triaenonychidae, comprising 63 species and subspecies distributed across New Zealand and South America. Recent molecular studies utilizing Sanger sequencing and ultraconserved elements (UCEs) have indicated that this genus is not monophyletic, and true are actually confined to New Zealand. Here, the morphology of all South American triaenonychids is re-examined and DNA sequence data compiled from three markers (18S rRNA, 28S rRNA and cytochrome oxidase subunit I) for a large number of triaenonychid species, including specimens from all areas with species currently and formerly classified in to reassess their phylogenetic position.

Under the hood: Phylogenomics of hooded tick spiders (Arachnida, Ricinulei) uncovers discordance between morphology and molecules.

Ricinulei or hooded tick-spiders are a cryptic and ancient group of arachnids. The order consists of around 100 highly endemic extant species restricted to the Afrotropics and the Neotropics along with 22 fossil species. Their antiquity and low vagility make them an excellent group with which to interrogate biogeographic questions.

Geometric regularity in webs of non-orb-weaving spiders.

Geometric regularity of spider webs has been intensively studied in orb-weaving spiders, although it is not exclusive of orb weavers. Here, we document the geometrically regular, repetitive elements in the webs of the non-orb-weaving groups Leptonetidae and Telemidae for the first time. Similar to orb weavers, we found areas with regularly spaced parallel lines in the webs of , sp.

Different environment, different reproductive strategies? Unexpected field observations in the harvestmen Discocyrtus prospicuus (Laniatores: Gonyleptidae).

The evolution of reproductive strategies depends on the relative balance between current benefits and future costs. Geographic variation in demographic and ecological factors has the potential to affect reproductive strategies by altering this optimal cost-benefit balance. Here, we studied a population of the harvestmen Discocyrtus prospicuus inhabiting an environment never studied before in this context: a tidal freshwater wetland.

On the problematic placement of the fossil arthropod Devonopilio hutchinsoni in Opiliones (Arachnida).

Harvestmen (Arachnida: Opiliones) were among the earliest terrestrial arthropods but their unmineralized exoskeletons are scarce and often fragmentary as fossils (Palencia et al. 2019). Consequently, the discovery and interpretations of fossil harvestmen from the early Palaeozoic can have disproportionate effects on the understanding of evolution in Opiliones.

Rectifying the identities of the males of two Micrathena species (Araneae: Araneidae), with report of the first case of intersexuality in the genus.

Despite extensive taxonomic work on the Neotropical fauna of the spider genus Micrathena Sundevall, for 27 out of 117 (23%) species only the female morphology has been described, and some of the previously hypothesized male-female matches have been proven erroneous. This work provides new insight about sex matching in two species: Micrathena ruschii (Mello-Leitão, 1945) and Micrathena lata Chickering, 1960. For Micrathena ruschii, the male previously hypothesized to belong to this species was collected with females in Itatiaia; we here present morphologically different males, also collected with females, in Macaé, both in Rio de Janeiro, Brazil.

Redescription of Promecostethus unifalculatus, the only known harvestman from Crozet Islands (Opiliones: Triaenonychidae).

Promecostethus unifalculatus Enderlein, 1909, is the only representative of the order Opiliones from the Crozet Islands. The species belongs to the family Triaenonychidae and is biogeographically interesting because it is a candidate for transoceanic dispersal, a very rare event in this ancient family. Despite this significance, P.

Three new species of Ochyrocera (Araneae, Ochyroceratidae) from Southeastern Brazil.

Three new species of the six-eyed  haplogyne and ecribellate spiders from the genus Ochyrocera Simon, 1891 are illustrated and described based on males and females from southeastern Brazil: Ochyrocera tinocoi new species (Sooretama, Espírito Santo state), Ochyrocera garayae new species (Linhares and Sooretama, Espírito Santo state) and Ochyrocera itatinga new species (Rio de Janeiro city, Rio de Janeiro state). The new species expand the distribution range of Ochyrocera in Brazil and increase to 50 the total number of species described, from which hitherto 33 species occur in South America, acknowledging the high diversity of the genus for the region.

Light from dark: A relictual troglobite reveals a broader ancestral distribution for kimulid harvestmen (Opiliones: Laniatores: Kimulidae) in South America.

A new troglobitic harvestman, Relictopiolus galadriel gen. nov et sp. nov.

Morphological tricks and blessed genitalia: rectifying the family placement of Fijicolana tuberculata (Opiliones: Laniatores: Zalmoxidae).

The type specimens of Fijicolana tuberculata Roewer, 1963 were re-examined and the male genital morphology is illustrated and described for the first time. Despite the presence of several morphological features that are typical of Samoidae, such as the presence of scopulae on legs III and IV, genital morphology unambiguously indicates that this species belongs to the Zalmoxidae rather than to the Samoidae. Fijicolana Roewer, 1963 is newly synonymized with Zalmoxis Sørensen, 1886.

Spider diversity (Arachnida: Araneae) in Atlantic Forest areas at Pedra Branca State Park, Rio de Janeiro, Brazil.

Background: There has never been any published work about the diversity of spiders in the city of Rio de Janeiro using analytical tools to measure diversity. The only available records for spider communities in nearby areas indicate 308 species in the National Park of Tijuca and 159 species in Marapendi Municipal Park. These numbers are based on a rapid survey and on an one-year survey respectively.

A companion to Part 2 of the World Checklist of Opiliones species (Arachnida): Laniatores - Samooidea, Zalmoxoidea and Grassatores incertae sedis.

Background: A series of databases is being prepared to list the valid species of Opiliones worldwide. This paper containing nomenclatural acts is meant to accompany Part 2, which includes the members of the infraorder Grassatores of the superfamilies Samooidea and Zalmoxoidea plus the Grassatores currently not allocated to any family (i.e.

World Checklist of Opiliones species (Arachnida). Part 2: Laniatores - Samooidea, Zalmoxoidea and Grassatoresincertae sedis.

Including more than 6500 species, Opiliones is the third most diverse order of Arachnida, after the megadiverse Acari and Araneae. This database is part 2 of 12 of a project containing an intended worldwide checklist of species and subspecies of Opiliones, and it includes the members of the suborder Laniatores, infraorder Grassatores of the superfamilies Samooidea and Zalmoxoidea plus the genera currently not allocated to any family (i.e.

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 multilocus approach to harvestman (Arachnida: Opiliones) phylogeny with emphasis on biogeography and the systematics of Laniatores.

The internal phylogeny of the arachnid order Opiliones is investigated by including molecular data from five molecular markers for ca. 140 species totalling 43 families of Opiliones. The phylogenetic analyses consisted of a direct optimization (DO) approach using POY v.

Sexually dimorphic tegumental gland openings in Laniatores (Arachnida, Opiliones), with new data on 23 species.

Sexually dimorphic glands often release sexual pheromones both in vertebrates and invertebrates. Species of Laniatores (Arachnida, Opiliones) seem to depend on chemical communication but few studies have addressed this topic. In this study, we review the literature for the Phalangida and present new data for 23 species of Laniatores.