RESUMEN
Asymmetrical rates of cladogenesis and extinction abound in the Tree of Life, resulting in numerous minute clades that are dwarfed by larger sister groups. Such taxa are commonly regarded as phylogenetic relicts or "living fossils" when they exhibit an ancient first appearance in the fossil record and prolonged external morphological stasis, particularly in comparison to their more diversified sister groups. Due to their special status, various phylogenetic relicts tend to be well-studied and prioritized for conservation. A notable exception to this trend is found within Amblypygi ("whip spiders"), a visually striking order of functionally hexapodous arachnids that are notable for their antenniform first walking leg pair (the eponymous "whips"). Paleoamblypygi, the putative sister group to the remaining Amblypygi, is known from Late Carboniferous and Eocene deposits, but is survived by a single living species, Paracharon caecus Hansen, 1921, that was last collected in 1899. Due to the absence of genomic sequence-grade tissue for this vital taxon, there is no global molecular phylogeny for Amblypygi to date, nor a fossil-calibrated estimation of divergences within the group. Here, we report a previously unknown species of Paleoamblypygi from a cave site in Colombia. Capitalizing upon this discovery, we generated the first molecular phylogeny of Amblypygi, integrating ultraconserved element sequencing with legacy Sanger datasets and including described extant genera. To quantify the impact of sampling Paleoamblypygi on divergence time estimation, we performed in silico experiments with pruning of Paracharon. We demonstrate that the omission of relicts has a significant impact on the accuracy of node dating approaches that outweighs the impact of excluding ingroup fossils, which bears upon the ancestral range reconstruction for the group. Our results underscore the imperative for biodiversity discovery efforts in elucidating the phylogenetic relationships of "dark taxa", and especially phylogenetic relicts in tropical and subtropical habitats. The lack of reciprocal monophyly for Charontidae and Charinidae leads us to subsume them into one family, Charontidae, new synonymy.
RESUMEN
A new species of Charinus is described and illustrated from the Brazilian Atlantic Forest. Charinus ruschiisp. n. is found in Santa Lúcia reserve, Espírito Santo state, and is sympatric with Charinus brasilianus and Charinus montanus. The new species can be easily distinguished from the other species of the genus by the combination of the following characters: number of spines on the pedipalp tarsus, size and shape of the female genitalia, shape of the sternum and number of teeth in the cheliceral claw. The behavioral repertory is also described for this species based on five hours of qualitative and 24 hours of quantitative observations in order to define the behavioral categories. Five behavioral categories were detected and 21 behavioral acts. The most conspicuous category was Immobility, followed by Antenniform leg movement, Environmental exploration, Self-grooming, and Feeding. It was also found that juveniles spend longer time inside the shelter, even during peaks of adult activity, which could be related to a survival strategy.
RESUMEN
A new species of the genus Sarax Simon, 1892 is described from Panay Island, Philippines. Sarax curioi sp. n. is the second species of the genus from the country and can be distinguished from the other Philippine species (Sarax brachydactylus Simon, 1892) by the sclerotized granules of the pedipalp surface, the spines of the pedipalp distitibia, the number of denticles of the chelicerae claw and the shape of the denticles of the chelicerae basal segment. Sarax newbritainensis Rahmadi and Kojima, 2010 is newly recorded from New Ireland Island, Papua New Guinea.