RESUMO
The family Nemesiidae was once among the most species-rich of mygalomorph spider families. However, over the past few decades both morphological and molecular studies focusing on mygalomorph phylogeny have recovered the group as paraphyletic. Hence, the systematics of the family Nemesiidae has more recently been controversial, with numerous changes at the family-group level and the recognition of the supra-familial clade Nemesioidina. Indeed, in a recent study by Opatova and collaborators, six nemesiid genera were transferred to the newly re-established family Pycnothelidae. Despite these changes, 12 South American nemesiid genera remained unplaced, and classified as incertae sedis due to shortcomings in taxon sampling. Accordingly, we evaluate the phylogenetic relationships of South American nemesioid species and genera with the principle aim of resolving their family level placement. Our work represents the most exhaustive phylogenomic sampling for South American Nemesiidae by including nine of the 12 genera described for the continent. Phylogenetic relationships were reconstructed using 457 loci obtained using the spider Anchored Hybrid Enrichment probe set. Based on these results Nemesiidae, Pycnothelidae, Microstigmatidae and Cyrtaucheniidae are not considered monophyletic. Our study also indicates that the lineage including the genus Fufius requires elevation to the family level (Rhytidicolidae Simon, 1903 (NEW RANK)). In Pycnothelidae, we recognize/delimit five subfamilies (Diplothelopsinae, Pionothelinae NEW SUBFAMILY, Prorachiinae NEW SUBFAMILY, Pselligminae NEW RANK, Pycnothelinae). We also transfer all the 12 South American nemesiid genera to Pycnothelidae: Chaco, Chilelopsis, Diplothelopsis, Flamencopsis, Hermachura, Longistylus, Lycinus, Neostothis, Prorachias, Psalistopoides, Pselligmus, Rachias. Additionally, we transferred the microstigmatid genus Xenonemesia to Pycnothelidae, and we propose the following generic synonymies and species transfers: Neostothis and Bayana are junior synonyms of Pycnothele (NEW SYNONYMY), as P. gigas and P. labordai, respectively (NEW COMBINATIONS); Hermachura is a junior synonym of Stenoterommata (NEW SYNONYMY), as S. luederwaldti (NEW COMBINATION); Flamencopsis is a junior synonym of Chilelopsis (NEW SYNONYMY), as C. minima (NEW COMBINATION); and Diplothelopsis is a junior synonym of Lycinus (NEW SYNONYMY), as L. ornatus and L. bonariensis (NEW COMBINATIONS). Considering the transferred genera and synonymies, Pycnothelidae now includes 15 described genera and 137 species. Finally, these results provide a robust phylogenetic framework that includes enhanced taxonomic sampling, for further resolving the biogeography and evolutionary time scale for the family Pycnothelidae.
RESUMO
The female Mygalomorphae spiders are sedentary and long-lived organisms that spend most of their lives inside their burrows. Neoichnological studies provide relevant information that can help the recognition of these structures in paleosols. Body fossils of spiders are known since the Carboniferous and burrowing is a primitive behavior in Mygalomorphae spiders. However, trace fossils attributable to ground-dwelling spiders are still poorly documented in the geological record. In this work, we examine the burrows and burrowing behavior of Rachias intermedius Soares, 1944 (Araneae: Mygalomorphae: Nemesiidae) in its natural environment and discuss the characteristics that can be used as ichnotaxobases for recognition of fossil spider burrows. Three major architectures, straight shaft with a terminal ovoid chamber, J-shaped winding shaft with the terminal chamber, and Y-shaped with a terminal teardrop-shaped chamber, are described and compared to morphologically similar ichnogenera, like Capayanichnus, Loloichnus, Macanopsis, and Psilonichnus. Differences in burrow shape and architecture are linked with the spider's sex and ontogenetic stage. Pedipalps, chelicerae, and fangs are used for soil excavation, forming a variety of burrow wall ornaments represented by delicate sub-horizontal parallel ridges, irregular knobby micro-relief surface with soil structures attached to the wall, rounded pits, and millimeter-scale vertical striations along the burrow length. A thick inorganic clay lining covers the inner burrow wall, a feature that has not been described for spider burrows yet. These characteristics allow distinguishing spider burrows from burrows produced by other soil-dwelling arthropods. They should be used for spider burrow recognition in paleosols, mainly the millimeter-scale vertical striations that had not been documented before. The data discussed herein improve the knowledge about spider burrowing behavior and the mechanism that play the main role in preserving these burrows' features in the fossil record.
RESUMO
The ischnocoline genus CatumiriGuadanucci, 2004 comprises four species distributed in Argentina, Brazil, Chile, and Uruguay. The type species Catumiri petropoliumGuadanucci, 2004 is known only from the male. We here provide a new diagnosis for Catumiri, describe the female of C. petropolium, and report new records of this species from Parque Nacional da Serra dos Órgãos, Reserva Biológica do Tinguá and Parque Nacional da Serra da Bocaina, Rio de Janeiro, Brazil. We also expand the distribution of Catumiri parvum (Keyserling, 1878) to Parque Nacional de Aparados da Serra, Praia Grande, Santa Catarina, Brazil, Alegrete, Rosário do Sul, Santana do Livramento, Pinheiro Machado, Bagé, and Jaguarão, all from Rio Grande do Sul, Brazil and Cerro de Los Cuervos, Lavalleja, Uruguay.
RESUMO
Four new species of the mygalomorph spider genus StenoterommataHolmberg, 1881 are described from Southeastern and Central Brazil. They are among the first described species that occur in the Brazilian Cerrado: S. neodiplornata Ghirotto & Indicatti, n. sp. from São Paulo state, in areas of Atlantic Forest, of savanna and of seasonal forest (Cerradão); S. chavarii Ghirotto & Indicatti, n. sp. from Botucatu, São Paulo state, in ecotonal areas of Atlantic Forest and Cerrado, as well as open anthropized areas similar to savannas; S. bodoquena Ghirotto & Indicatti, n. sp. from Bonito, Mato Grosso do Sul state, in areas of Atlantic Forest with Cerrado influences and seasonal forest; S. egric Ghirotto & Indicatti, n. sp. from Ibitipoca mountain range, Lima Duarte, Minas Gerais state, in Atlantic Forest and savanna areas. All new species are differentiated by the unique morphology of genitalia. Information on the natural history of S. neodiplornata Ghirotto & Indicatti, n. sp., S. bodoquena Ghirotto & Indicatti, n. sp. and S. egric Ghirotto & Indicatti, n. sp. is provided. Stenoterommata neodiplornata Ghirotto & Indicatti, n. sp. is the third species of the genus that can inhabit trunks and upper branches of the highest part of the trees. In addition, it is presented the first record of the genus for the Central Brazil, S. bodoquena Ghirotto & Indicatti, n. sp. from Mato Grosso do Sul.
RESUMO
The female Mygalomorphae spiders are sedentary and long-lived organisms that spend most of their lives inside their burrows. Neoichnological studies provide relevant information that can help the recognition of these structures in paleosols. Body fossils of spiders are known since the Carboniferous and burrowing is a primitive behavior in Mygalomorphae spiders. However, trace fossils attributable to ground-dwelling spiders are still poorly documented in the geological record. In this work, we examine the burrows and burrowing behavior of Rachias intermedius Soares, 1944 (Araneae: Mygalomorphae: Nemesiidae) in its natural environment and discuss the characteristics that can be used as ichnotaxobases for recognition of fossil spider burrows. Three major architectures, straight shaft with a terminal ovoid chamber, J-shaped winding shaft with the terminal chamber, and Y-shaped with a terminal teardrop-shaped chamber, are described and compared to morphologically similar ichnogenera, like Capayanichnus, Loloichnus, Macanopsis, and Psilonichnus. Differences in burrow shape and architecture are linked with the spider's sex and ontogenetic stage. Pedipalps, chelicerae, and fangs are used for soil excavation, forming a variety of burrow wall ornaments represented by delicate sub-horizontal parallel ridges, irregular knobby micro-relief surface with soil structures attached to the wall, rounded pits, and millimeter-scale vertical striations along the burrow length. A thick inorganic clay lining covers the inner burrow wall, a feature that has not been described for spider burrows yet. These characteristics allow distinguishing spider burrows from burrows produced by other soil-dwelling arthropods. They should be used for spider burrow recognition in paleosols, mainly the millimeter-scale vertical striations that had not been documented before. The data discussed herein improve the knowledge about spider burrowing behavior and the mechanism that play the main role in preserving these burrows' features in the fossil record.