The southern South American genus Guaranita includes tiny spiders (body length ~1 mm) that lead reclusive lives under ground-objects and run rapidly when disturbed. As a result, they have been poorly collected and studied. Here we report on a recent collection of Guaranita spiders from Argentina, describing one new species (G. auadae Huber sp. nov.) and the previously unknown female of G. dobby Torres et al., 2016. In addition, we provide CO1 barcodes for all (now five) known species, first SEM data, and first chromosome data for the genus. The diploid number of Guaranita goloboffi Huber, 2000 (2n♂ = 11) is among the lowest in araneomorph spiders with monocentric chromosome structure.

The spider genus Metagonia has been represented on the Galápagos Islands by two blind species inhabiting lava tubes on Isabela and Santa Cruz. Epigean relatives had not been found on Galápagos and were thus thought to be extinct. During a collecting trip in 2019 we found two epigean species and a third blind hypogean species. Here we describe these new species based on males and females, redescribe both previously known species, and add all five species to the recently published molecular phylogeny of Pholcidae, together with more than 30 further congeners from the mainland. Galápagos Metagonia is recovered as a monophyletic group within the South American–Caribbean M. potiguar group. Galápagos Metagonia is divided into an epigean clade and a hypogean clade. Each species is restricted to an individual island (Isabela or Santa Cruz; with one possible exception), suggesting that the epigean Metagonia species are native rather than introduced. ZooBank registration: http://zoobank.org/References/0812B715-8446-4B28-BCE0-6AB504BBEC7E.

The identification of spider species presents many challenges, since in most cases the characters used are from genital structures that are only fully developed in the adult stage, hence the identification of immatures is most often not possible. Additionally, these structures usually also present some intra-specific variability, which in some cases makes the identification of closely related species difficult. The genetic barcode technique (DNA barcodes), based on sequencing of the mitochondrial marker cytochrome c oxidase subunit I (COI), has proven a useful, complementary tool to overcome these limitations. In this work, the contribution of DNA barcoding to the taxonomy of the subfamily Amaurobioidinae is explored using the refined single linkage analysis (RESL) algorithm for the delimitation of operational taxonomic units (OTUs), in comparison with the assemble species by automatic partitioning (ASAP) algorithm, and presented in conjunction with an updated molecular phylogenetic analysis of three other markers (28S rRNA, 16S rRNA, Histone H3), in addition to COI. Of a total of 97 included species identified by morphology, 82 species were concordant with the operational taxonomic units obtained from RESL, representing an 85% correspondence between the two methods. Similar results were obtained using the ASAP algorithm. Previous observations of morphological variation within the same species are supported, and this technique provides new information on genetic structure and potentially cryptic species. Most of the discrepancies between DNA barcoding and morphological identification are explained by low geographic sampling or by divergent or geographically structured lineages. After the addition of many specimens with only COI data, the multi-marker phylogenetic analysis is consistent with previous results and the support is improved. The markers COI, closely followed by 28S, are the most phylogenetically informative. We conclude that the barcode DNA technique is a valuable source of data for the delimitation of species of Amaurobioidinae, in conjunction with morphological and geographic data, and it is also useful for the detection of cases that require a more detailed and meticulous study.

The male genitalia of pholcid spiders, which is one of the most species-rich spider families, are characterized by a procursus, which is a morphologically diverse projection of the copulatory organ. It has been shown that the procursus interacts with the female genitalia during copulation. Here, we investigate the function of the procursus in Gertschiola neuquena , a species belonging to the early branched and understudied subfamily Ninetinae, using behavioural and morphological data. Although many aspects of the copulatory behaviour of G. neuquena follow the general pattern described for the family, males use only one pedipalp during each copulation. Based on our micro-CT analysis of cryofixed mating pairs using virgin females, we can show that the long and filiform procursus is inserted deeply into the unpaired convoluted female spermatheca, and the intromittent sclerite, the embolus, is rather short and stout only reaching the most distal part of the female sperm storage organ. Histological data revealed that sperm are present in the most proximal part of the spermatheca, suggesting that the procursus is used to allocate sperm deeply into the female sperm storage organ. This represents the first case of a replacement of the sperm allocation function of the intromittent sclerite in spiders.

Una nueva especie del género neotropical de zodáridos Epicratinus Jocqué & Baert, 2005, E. santacruz, es descrita para el Departamento de Santa Cruz, Bolivia. Esta es la quinta especie descrita en el género, y la primera zodárida conocida para Bolivia.

Paratrochosina amica is an Allocosinae wolf spider species that inhabits grasslands and gardens in Uruguay and southern South America, where it has a wide distribution. In this study, we extended the representation of genetic data from previous studies by including specimens that cover most of the distribution range. Conversely to what has been reported for other species of the subfamily, P. amica shows similar body sizes in both sexes and males are the mobile sex that initiates courtship. As we are trying to understand the factors shaping sexual behaviour and size dimorphism in Allocosinae, studies in P. amica are crucial. We analysed the phylogenetic relationships and genetic diversity in this species. The analysis corroborated the monophyly of Allocosinae and P. amica, which is also located in the same phylogenetic position as reported in previous studies. The haplotype network suggests high connectivity between individuals from the studied localities. Finally, the GMYC analysis showed that the individuals belong to the same evolutionary lineage. Paratrochosina amica es una especie de araña lobo de la subfamilia Allocosinae que habita en pastizales y jardines de Uruguay y otras regiones del sur de Sudamérica, donde presenta una amplia distribución. A diferencia de otras especies de esta subfamilia, P. amica posee tamaños corporales similares en ambos sexos y los machos son quienes buscan pareja activamente e inician el cortejo. Dado que se está intentado entender los factores que modelan los comportamientos sexuales y dimorfismo de tamaño en Allocosinae, los estudios en esta especie se vuelven clave. En este trabajo se amplía la representación de datos genéticos de estudios previos, incluyendo especímenes que abarcan una mayor parte de su distribución, y se infieren sus relaciones filogenéticas y analiza su diversidad genética. Los resultados del análisis filogenético corroboran la monofilia de Allocosinae y de P. amica, y ésta a su vez se ubica en la misma posición en el árbol filogenético como lo reportado previamente. La red de haplotipos sugiere una alta conectividad entre los individuos de las localidades estudiadas. Finalmente, el análisis de GMYC muestra que todos los individuos analizados pertenecen a un mismo linaje evolutivo. Paratrochosina amica es una especie de araña lobo de la subfamilia Allocosinae que habita en pastizales y jardines de Uruguay y otras regiones del sur de Sudamérica, donde presenta una amplia distribución. A diferencia de otras especies de esta subfamilia, P. amica posee tamaños corporales similares en ambos sexos y los machos son quienes buscan pareja activamente e inician el cortejo. Dado que se está intentado entender los factores que modelan los comportamientos sexuales y dimorfismo de tamaño en Allocosinae, los estudios en esta especie se vuelven clave. En este trabajo se amplía la representación de datos genéticos de estudios previos, incluyendo especímenes que abarcan una mayor parte de su distribución, y se infieren sus relaciones filogenéticas y analiza su diversidad genética. Los resultados del análisis filogenético corroboran la monofilia de Allocosinae y de P. amica, y ésta a su vez se ubica en la misma posición en el árbol filogenético como lo reportado previamente. La red de haplotipos sugiere una alta conectividad entre los individuos de las localidades estudiadas. Finalmente, el análisis de GMYC muestra que todos los individuos analizados pertenecen a un mismo linaje evolutivo.