Phylogenomic analysis, reclassification, and evolution of South American nemesioid burrowing mygalomorph spiders

An integrative taxonomy of the genus Stasimopus Simon 1892 (Araneae: Mygalomorphae) of the Karoo with the description of nine new species and a Stasimopus maraisi Hewitt 1914 male

The genus Stasimopus Simon 1892 is endemic to Southern Africa, but is historically largely understudied. This paper provides a taxonomic revision for the Stasimopus species of the Karoo region of South Africa and includes the description of nine new species (S. dylani sp. nov., S. finni sp. nov., S. hamartia sp. nov., S. ignis sp. nov., S. karooensis sp. nov., S. malesociatus sp. nov., S. tera sp. nov., S. theaei sp. nov. and S. venterstadensis sp. nov.). A description of the genetically matched S. maraisi Hewitt 1914 male is provided. The original S. maraisi male is designated to its own new species (S. malesociatus sp. nov.). An identification key is provided for species occurring in the Karoo region. This is the first integrative taxonomy for the genus that includes morphological, geometric morphometric as well as genetic data.

Review of the American genus Bolostromus Ausserer, 1875 with the description of fourteen new species (Araneae, Cyrtaucheniidae)

The family Cyrtaucheniidae is seldom found in the Americas, only 10 species are known to occur. Herein we described fourteen new species for the family Cyrtaucheniidae, all belonging to the genus Bolostromus from Central America and South America: Bolostromus busu n. sp. (female); B. devriesi n. sp. (female); B. epiphyticus n. sp. (male, female); B. fonsecai n. sp. (male); B. hubeni n. sp. (male, female); B. italoi n. sp. (female); B. laheredia n. sp. (male); B. losrios n. sp. (male); B. nischki n. sp. (male); B. urku n. sp. (male), B. primus n. sp. (male); B. pristirana n. sp. (male); B. stridulator n. sp. (male), and B. valdivia n. sp. (female). Photographs of the type specimens of: Bolostromus fauna (male and female); Bolostromus gaujoni (male); B. holguinensis (female juvenile); B. insularis (female juvenile); B. pulchripes (female); B. riveti (male) and, B. venustus (female) are provided, as well as a distribution map of all species.

Four new species of mygalomorph spiders (Araneae, Halonoproctidae and Theraphosidae) from the Colombian Pacific region (Bahía Solano, Chocó)

The Colombian Pacific coast is an amazing natural region, immersed in one of the most unknown biodiversity hotspots in the world. An expedition carried out in the north of this area, at the Jardín Botánico del Pacífico (JBP) in Bahía Solano, Chocó, focused on studying the diversity of the mygalomorph spider fauna, allowed us to discover four new species included in the families Halonoproctidae and Theraphosidae. The trapdoor species Ummidiasolanasp. nov., and the theraphosids species Euthycaeluscunampiasp. nov. (Schismatothelinae), Melloinapacificasp. nov. (Glabropelmatinae), and Neischnocolusmecanasp. nov. (Theraphosinae) are illustrated, diagnosed, and described in detail. Photographs of somatic features and copulatory organs and a distribution map are provided. Morphological, taxonomical, and biogeographical aspects are discussed for each species. All these taxonomic novelties represent the first records of these genera for the region, expanding the range of geographic distribution of each of them. This work constitutes the first effort focused on characterizing the community of Mygalomorphae species in the Chocó Biogeographic Region.

Correlation with a limited set of behavioral niches explains the convergence of somatic morphology in mygalomorph spiders

Understanding the drivers of morphological convergence requires investigation into its relationship with behavior and niche space, and such investigations in turn provide insights into evolutionary dynamics, functional morphology, and life history. Mygalomorph spiders (trapdoor spiders and their kin) have long been associated with high levels of morphological homoplasy, and many convergent features can be intuitively associated with different behavioral niches. Using genus-level phylogenies based on recent genomic studies and a newly assembled matrix of discrete behavioral and somatic morphological characters, we reconstruct the evolution of burrowing behavior in the Mygalomorphae, compare the influence of behavior and evolutionary history on somatic morphology, and test hypotheses of correlated evolution between specific morphological features and behavior. Our results reveal the simplicity of the mygalomorph adaptive landscape, with opportunistic, web-building taxa at one end, and burrowing/nesting taxa with structurally modified burrow entrances (e.g., a trapdoor) at the other. Shifts in behavioral niche, in both directions, are common across the evolutionary history of the Mygalomorphae, and several major clades include taxa inhabiting both behavioral extremes. Somatic morphology is heavily influenced by behavior, with taxa inhabiting the same behavioral niche often more similar morphologically than more closely related but behaviorally divergent taxa, and we were able to identify a suite of 11 somatic features that show significant correlation with particular behaviors. We discuss these findings in light of the function of particular morphological features, niche dynamics within the Mygalomorphae, and constraints on the mygalomorph adaptive landscape relative to other spiders.