Phylogeny and biogeography of harmochirine jumping spiders (Araneae: Salticidae).

We use ultraconserved elements (UCE) and Sanger data to study the phylogeny, age, and biogeographical history of harmochirine jumping spiders, a group that includes the species-rich genus Habronattus, whose remarkable courtship has made it the focus of studies of behaviour, sexual selection, and diversification. We recovered 1947 UCE loci from 43 harmochirine taxa and 4 outgroups, yielding a core dataset of 193 UCEs with at least 50 % occupancy. Concatenated likelihood and ASTRAL analyses confirmed the separation of harmochirines into two major clades, here designated the infratribes Harmochirita and Pellenita. Most are African or Eurasian with the notable exception of a clade of pellenites containing Habronattus and Pellenattus of the Americas and Havaika and Hivanua of the Pacific Islands. Biogeographical analysis using the DEC model favours a dispersal of the clade's ancestor from Eurasia to the Americas, from which Havaika's ancestor dispersed to Hawaii and Hivanua's ancestor to the Marquesas Islands. Divergence time analysis on 32 loci with 85 % occupancy, calibrated by fossils and island age, dates the dispersal to the Americas at approximately 4 to 6 million years ago. The explosive radiation of Habronattus perhaps began only about 4 mya. The phylogeny clarifies both the evolution of sexual traits (e.g., the terminal apophyses was enlarged in Pellenes and not subsequently lost) and the taxonomy. Habronattus is confirmed as monophyletic. Pellenattus is raised to the status of genus, and 13 species moved into it as new combinations. Bianor stepposus Logunov, 1991 is transferred to Sibianor, and Pellenes bulawayoensis Wesolowska, 1999 is transferred to Neaetha. A molecular clock rate estimate for spider UCEs is presented and its utility to inform prior distributions is discussed.

Combining genomic, phenotypic and Sanger sequencing data to elucidate the phylogeny of the two-clawed spiders (Dionycha).

The importance of morphology in the phylogenomic era has recently gained attention, but relatively few studies have combined both types of information when inferring phylogenetic relationships. Sanger sequencing legacy data can also be important for understanding evolutionary relationships. The possibility of combining genomic, morphological and Sanger data in one analysis seems compelling, permitting a more complete sampling and yielding a comprehensive view of the evolution of a group. Here we used these three data types to elucidate the systematics and evolution of the Dionycha, a highly diverse group of spiders relatively underrepresented in phylogenetic studies. The datasets were analyzed separately and combined under different inference methods, including a novel approach for analyzing morphological matrices with commonly used evolutionary models. We tested alternative hypotheses of relationships and performed simulations to investigate the accuracy of our findings. We provide a comprehensive and thorough phylogenetic hypothesis for Dionycha that can serve as a robust framework to test hypotheses about the evolution of key characters. We also show that morphological data might have a phylogenetic impact, even when massively outweighed by molecular data. Our approach to analyze morphological data may serve as an alternative to the proposed practice of arbitrarily partitioning, weighting, and choosing between parsimony and stochastic models. As a result of our findings, we propose Trachycosmidae new rank for a group of Australian genera formerly included in Trochanteriidae and Gallieniellidae, and consider Ammoxenidae as a junior synonym of Gnaphosidae. We restore the family rank for Prodidomidae, but transfer the subfamily Molycriinae to Gnaphosidae. Drassinella is transferred to Liocranidae, Donuea to Corinnidae, and Mahafalytenus to Viridasiidae.

Systematics and evolution of ground spiders revisited (Araneae, Dionycha, Gnaphosidae).

Gnaphosidae Pocock are a very diverse spider family with remarkable spinning organ morphology. Although the family has received intense taxonomic attention in recent years, its intergeneric relationships remain obscure. A phylogenetic analysis of Gnaphosidae genera was performed to untangle the evolutionary history of the family. A matrix of 324 morphological characters, scored for 71 gnaphosid genera and 29 outgroup taxa, was analysed through parsimony and Bayesian phylogenetic inference. Gnaphosidae are not recovered as a monophyletic group, neither were most of the previously proposed intrafamiliar groupings. In accordance with the phylogenetic results obtained, Vectius Simon and Hemicloea Thorell are transferred to Trochanteriidae, and Xenoplectus Schiapelli & Gerschman de Pikelin to Liocranidae. Micaria Westring, Nauhea Forster and Verita Ramírez & Grismado (and some related genera) are probably not gnaphosids, although their phylogenetic placement is uncertain. Gnaphosidae s.s. are defined as spiders with enlarged piriform gland spigots, longer and wider than the major ampullate gland spigots. Within Gnaphosidae s.s., well-supported clades allow the redefinition, on the basis of quantitative phylogenetic evidence, of Gnaphosinae Pocock, Zelotinae Platnick, Herpyllinae Platnick, Drassodinae Simon, Prodidominae Simon rank res. and the newly proposed Leptodrassinae subfam. nov. Many genera are not assigned to subfamily given their poorly supported and unstable relationships. The homology and evolution of structures such as the claw tuft clasper, the spinning organs and the modification of cheliceral promargin are discussed.

Twenty years, eight legs, one concept: describing spider biodiversity in Zootaxa (Arachnida: Araneae).

Zootaxa published more than a thousand papers on Araneae from 2002 to the present, including descriptions of 3,833 new spider species and 177 new genera. Here we summarise the key contributions of Zootaxa to our current knowledge of global spider diversity. We provide a historical account of the researchers that have actively participated as editors, and recognize the more than 1,000 reviewers without whom none of this would have been possible. We conduct a simple analysis of the contributions by authors and geographic region, which allows us to uncover some of the underlying trends in current spider taxonomy. In addition, we examine some of the milestones in twenty years of spider systematic research in Zootaxa. Finally, we discuss future prospects of spider taxonomy and the role that Zootaxa and its younger sister journal Megataxa will play in it. We would like to dedicate this contribution to the memory of Norman I. Platnick, a crucial figure in the advancement of spider systematics.

The fossil record of spiders revisited: implications for calibrating trees and evidence for a major faunal turnover since the Mesozoic.

Studies in evolutionary biology and biogeography increasingly rely on the estimation of dated phylogenetic trees using molecular clocks. In turn, the calibration of such clocks is critically dependent on external evidence (i.e. fossils) anchoring the ages of particular nodes to known absolute ages. In recent years, a plethora of new fossil spiders, especially from the Mesozoic, have been described, while the number of studies presenting dated spider phylogenies based on fossil calibrations increased sharply. We critically evaluate 44 of these studies, which collectively employed 67 unique fossils in 180 calibrations. Approximately 54% of these calibrations are problematic, particularly regarding unsupported assignment of fossils to extant clades (44%) and crown (rather than stem) dating (9%). Most of these cases result from an assumed equivalence between taxonomic placement of fossils and their phylogenetic position. To overcome this limitation, we extensively review the literature on fossil spiders, with a special focus on putative synapomorphies and the phylogenetic placement of fossil species with regard to their importance for calibrating higher taxa (families and above) in the spider tree of life. We provide a curated list including 41 key fossils intended to be a basis for future estimations of dated spider phylogenies. In a second step, we use a revised set of 23 calibrations to estimate a new dated spider tree of life based on transcriptomic data. The revised placement of key fossils and the new calibrated tree are used to resolve a long-standing debate in spider evolution - we tested whether there has been a major turnover in the spider fauna between the Mesozoic and Cenozoic. At least 17 (out of 117) extant families have been recorded from the Cretaceous, implying that at least 41 spider lineages in the family level or above crossed the Cretaeous-Paleogene (K-Pg) boundary. The putative phylogenetic affinities of families known only from the Mesozoic suggest that at least seven Cretaceous families appear to have no close living relatives and might represent extinct lineages. There is no unambiguous fossil evidence of the retrolateral tibial apophysis clade (RTA-clade) in the Mesozoic, although molecular clock analyses estimated the major lineages within this clade to be at least ∼100 million years old. Our review of the fossil record supports a major turnover showing that the spider faunas in the Mesozoic and the Cenozoic are very distinct at high taxonomic levels, with the Mesozoic dominated by Palpimanoidea and Synspermiata, while the Cenozoic is dominated by Araneoidea and RTA-clade spiders.

A taxonomic revision of the ground spiders of the genus Apopyllus (Araneae: Gnaphosidae).

The American gnaphosid genus Apopyllus Platnick & Shadab is found from southern Mexico to southern Argentina. It can be diagnosed by the complex shape of the RTA, by the membranous tegular extension, the long coiled embolus, the retrolateral incision on the cymbium, the long convoluted copulatory duct extending anteriorly to the copulatory openings and by the presence of paramedian epigynal pockets and of an anterior ridge on the epigynum. The RTA characters are important in species taxonomy but the complex shape and variation of the RTA hampers identification, especially regarding the two most common species: A. suavis (Simon) and A. silvestrii (Simon). In this paper the genus is revised, the genital morphology is described, and homology between its components and those of other genera is discussed. Apopyllus suavis is considered a senior synonym of Apopyllus pauper (Mello-Leitão) and A. iheringi (Mello-Leitão). Four new species are described from Brazil: A. aeolicus, A. atlanticus, A. centralis and A. gandarela.