Cladistic analysis supports the monophyly of the Neotropical crab spider genus Epicadus and its senior synonymy over Tobias (Araneae : Thomisidae)

Abstract

The present paper presents a cladistic analysis of the spider genus Tobias Simon, 1895. The analyses were based on a matrix with 29 terminal taxa scored for 86 morphological characters, with a dataset tested under two methodologies for character weighting (i.e. equal and implied weighting). Both analyses supported the paraphyletic relationship of Tobias with Epicadus Simon, 1895, with the former considered a junior synonym of the latter (new synonymy). Onocolus, Epicadinus and Epicadus form a clade supported by two synapomorphies, corroborating previous taxonomic assumptions regarding the proximity of these genera. Epicadus has two lineages: the ‘pustulosus clade’, comprising bark-like individuals that camouflage themselves on tree trunks and branches, and the ‘heterogaster clade’, which consists of a group of spiders that present a wide range of polychromatism and use flowers as hunting sites. Synonymies are presented and a new combination for all species previously assigned as part of Tobias is proposed. Epicadus now comprises nine species.

First record of Epicadus trituberculatus (Taczanowski, 1872) (Araneae, Thomisidae, Stephanopinae) in the Brazilian Northeast

“…In Brazil, this species was recorded in the South, Southeast, Midwest, and North regions. These regions match the Brazilian biomes: Atlantic Forest, Amazon, Cerrado, Pampa, and Pantanal (Machado et al 2017(Machado et al , 2018. In the Atlantic Forest, this species was mainly observed in dense and mixed rainforest ecosystems characterized by constant rainfall throughout the year.…”

“…These spiders are diurnal sit-and-wait predators that are often found in vegetation, mainly on flowers or leaves. Some species are cryptically colored and are able to change their coloration to camouflage themselves in their environment, such as (Machado et al 2017(Machado et al , 2018. Epicadus species can be recognized by their globose opisthosoma with a set of conical projections and a median spire on the fovea region; for more details, see Silva-Moreira and Machado (2016) and Machado et al (2018).…”

A taxonomic review of the crab spider genus Sidymella (Araneae, Thomisidae) in the Neotropics

“…The presence of cheliceral teeth, which was previously considered as a synapomorphy for this group (Ono 1988), was recovered as a plesiomorphy by Benjamin (2011), and this subfamily remains as the most controversial and the least studied group in Thomisidae; it has many genera in need of revision and a considerable number of species yet to be described (Benjamin 2011). Based on the work of Mello-Leitão (1929), subsequent efforts were made to update the taxonomy of some Neotropical stephanopines (Lise , 1981Bonaldo and Lise 2001;Machado et al 2015Machado et al , 2017Silva-Moreira and Machado 2016;Prado et al 2018). However, many genera are still known only from the original descriptions and poor diagnoses, and the accurate identification of many species is practically impossible.…”

On the Australian bark crab spider genus Stephanopis: taxonomic review and description of seven new species (Araneae: Thomisidae: Stephanopinae)

“…Scanning electron microscopy images were taken using a Philips XL 30 Field Emission ESEM at the Centro de Microscopia e Microanálises (CEMM) of PUCRS. All measurements are in millimeters and the abbreviations related to somatic and genital features are adapted from Machado et al (2017) and Machado et al (2018). Anatomical abbreviations: ALE, anterior lateral eyes; AME, anterior median eyes; PLE, posterior lateral eyes; PME, posterior median eyes; Pcym, paracymbium; PrsP, pars pendula; RTA, retro lateral tibial apophysis; RTAvbr, retrolateral tibial apophysis' ventral branch; CO, copulatory openings; the median area of the epigynal plate, previously called "median field" by the present authors, is reinterpreted and now called atrium (Fig.…”

“…The thomisids comprise the seventh largest family of spiders with 2163 species described in 170 genera (World Spider Catalog, 2019). Among the currently accepted groups in Thomisidae, the subfamily Stephanopinae has been the focus of many recent revisions (Benjamin, 2013;Benjamin, 2015;Machado et al, 2015;Benjamin, 2016;Silva-Moreira & Machado, 2016;Machado et al 2017;Machado et al, 2018;Prado et al, 2018). However, most of its component genera are still little known and poorly diagnosed, resulting in a lack of resolution and the consistent recovery of a polyphyletic phylogeny (Benjamin et al, 2008;Benjamin, 2011;Wheeler et al, 2017).…”