Gustavo Hormiga’s research while affiliated with George Washington University and other places

Tropical wandering spiders (Ctenidae) are a diverse group of cursorial predators with its greatest species richness in the tropics. Traditionally, Ctenidae are diagnosed based on the presence of eight eyes arranged in three rows (a 2–4–2 pattern). We present a molecular phylogeny of Ctenidae, including for the first time representatives of all of its subfamilies. The molecular phylogeny was inferred using five nuclear (histone H3, 28S, 18S, Actin and ITS‐2) and four mitochondrial (NADH, COI, 12S and 16S) markers. The final matrix includes 259 terminals, 103 of which belong to Ctenidae and represent 28 of the current 49 described genera. We estimated divergence times by including fossils as calibration points and biogeographic events, and used the phylogenetic hypothesis obtained to reconstruct the evolution of the eye conformation in the retrolateral tibial apophysis (RTA) clade. Ctenidae and its main lineages originated during the Paleocene–Eocene and have diversified in the tropics since then. However, in some analyses Ctenidae was recovered as polyphyletic as the genus Ancylometes Bertkau, 1880 was placed as sister to Oxyopidae. Except for Acantheinae, in which the type genus Acantheis Thorell, 1891 is placed inside Cteninae, the four recognized subfamilies of Ctenidae are monophyletic in most analyses. The ancestral reconstruction of the ocular conformation in the retrolateral tibial apophysis clade suggests that the ocular pattern of Ctenidae has evolved convergently seven times and that it has originated from ocular conformations of two rows of four eyes (4–4) and the ocular pattern of lycosids (4–2–2). We also synonymize the monotypic genus Parabatinga Polotov & Brescovit, 2009 with Centroctenus Mello‐Leitão, 1929. We discuss some of the putative morphological synapomorphies of the main ctenid lineages within the phylogenetic framework offered by the molecular phylogenetic results of the study.

The Mounded Posterior Median Eyes (MPME) clade is a group of linyphiid spiders characterized by having posterior median eyes (PME) on a mound. The species diversity of this lineage, especially in the Neotropical region, is still largely unknown. In this study, we tackled one of the MPME groups, the genus Diplothyron Millidge, 1991. We have studied numerous specimens from both museums and freshly collected specimens to monograph Diplothyron. We also compiled both morphological and behavioral data from Diplothyron and representatives of higher-level lineages within Linyphiidae and several potential MPME groups to infer the phylogenetic relationships. We redescribed the type species, Diplothyron fuscus Millidge, 1991 and described the previously unknown male, and six new species: Diplothyron ballesterosi sp. nov., D. dianae sp. nov., D. monteverde sp. nov., D. nubilosus sp. nov., D. sandrae sp. nov. and D. solitarius sp. nov. We also transferred the following species from Linyphia to Diplothyron based on the study of the type material: D. chiapasia (Gertsch & Davies, 1946) comb. nov., D. linguatulus (F.O. Pickard-Cambridge, 1902) comb. nov., D. nigritus (F.O. Pickard-Cambridge, 1902) comb. nov., D. simplicatus (F.O. Pickard-Cambridge, 1902) comb. nov. and D. trifalcatus (F.O. Pickard-Cambridge, 1902) comb. nov. Diplothyron species are mainly found in the cloud forests of Central and South America, with the distribution stretching from the Colombian Andes to the Mexican Sierra Madre across the Central American mountain chains. We also provide a detailed morphological comparison between Diplothyron and closely related genera in the MPME clade, focusing on the genital morphology, including identification keys to both the MPME genera and species of Diplothyron. Our cladistic analyses recovered Diplothyron as a monophyletic group placed within the MPME clade. A newly circumscribed lineage now includes the genera Diplothyron, Dubiaranea Mello-Leitão, 1943; Linyphia Latreille, 1804; Lomaita Bryant, 1948; Microlinyphia Gerhardt, 1928; Neriene Blackwall, 1833; Notiohyphantes Millidge, 1985; Novafrontina Millidge, 1991 and Pityohyphantes Simon, 1929.

Five new species of mimetid spiders from China are described: Mimetus subulatus n. sp., M. clavatus n. sp., M. dentatus n. sp., M. niveosignatus n. sp. and M. uncatus n. sp. The phylogenetic placement of these new species is inferred based on a cladistic analysis of an expanded version of the morphological dataset of Benavides and Hormiga (2020). The new species form a clade that can be distinguished from other Mimetus species by the presence of a subtegular apophysis between paracymbium and subtegulum, pilose cuticular projections on the membranous part of the conductor in the male palp and by a bicameral structure of the spermathecae in females. The new species are part of a clade that includes Mimetus syllepsicus Hentz, 1832, the type species of the genus. The genus Mimetus as currently circumscribed is not monophyletic, as the clade that includes all the Mimetus species also includes the genera Australomimetus Heimer, 1986 and Anansi Benavides and Hormiga, 2017, corroborating the results of Benavides and Hormiga (2020).

We have revised the linyphiid genera Jalapyphantes and Selenyphantes. Jalapyphantes now includes five species, one of them new (J. tricolor sp. nov.). Selenyphantes now consists of six species of which five are new (S. costaricensis sp. nov., S. gaimani sp. nov., S. iztactepetl sp. nov., S. orizabae sp. nov. and S. volcanicus sp. nov.). To infer the phylogenetic position of Jalapyphantes and Selenyphantes, we analysed nucleotide sequence data from five markers (16S,18S, 28S, COI and histone H3) combined with morphological and behavioural data. Both genera are monophyletic and sister to each other. Both Jalapyphantes and Selenyphantes are included within the newly circumscribed Pocobletus clade, which includes all known species of Pocobletus plus several undescribed species. Pocobletus has nomenclatural priority over the junior synonyms Exechopsis, Exocora and Graphomoa.