The discovery of Neotropical Lepidosira (Collembola, Entomobryidae) and its systematic position

Systematics of Willowsia jacobsoni (Börner, 1913) (Collembola, Entomobryidae): morphology, postembryonic development, distribution, mitogenome and phylogeny

Willowsia jacobsoni (Börner, 1913) occurs in the Pantropical region, yet its evolutionary history and origin is poorly understood. Herein, morphological, molecular, and distributional data are used to evaluate the systematics of W. jacobsoni, providing novel descriptions and comparisons of its postembryonic development, a multi-locus molecular phylogeny for the Entomobryinae, and the first mitochondrial genome sequence for this species. Developmental stages of dorsal chaetotaxy are compared with other species of the genus and the head development is presented for the first time to Willowsia, including a new interpretation of primary and secondary chaetae. Bayesian and maximum likelihood analyses based on three genes (COI, 16S and 28S) were used to infer phylogenetic relationships for 35 Entomobryinae taxa, including 11 species of Willowsia. While the phylogenetic placement of W. jacobsoni was inconclusive, relationships of other Entomobryinae species were recovered with high support for the first time, including some that rendered Willowsia polyphyletic, corroborating with previous studies. We also characterized the mitogenome of a representative from the Chinese population of W. jacobsoni, which is the second one from this genus to be published. The species is recorded here for the first time in Brazil and Singapore, in addition to being the first record of the genus in Brazil. Considering that the genus has a great diversity in Asia, including several records of W. jacobsoni, this species was possibly introduced in America, or even in Africa. This comprehensive study of W. jacobsoni sheds light on the complexities surrounding its systematics, postembryonic development, and phylogenetic relationships among members of scaled and unscaled Entomobryinae.

Phylogenomics and systematics of Entomobryoidea (Collembola): marker design, phylogeny and classification

Entomobryoidea has been the focus of phylogenetic studies in recent years owing to a divergence between morphological and genetic data. Recent phylogenies have converged on the sister relationship of Orchesellidae with the remaining Entomobryoidea, and on the non-monophyly of the traditional Paronellidae and Entomobryidae, but still lack resolution. Known molecular phylogenies of the superfamily differ greatly between mitogenomic and multilocus markers. For this reason, we designed universal single-copy orthologue (USCO) and ultraconserved element (UCE) marker sets specific for Entomobryoidea, based on 11 genome assemblies. Upon the newly designed 3406 USCOs and 4030 UCEs, we analysed 34 species covering all Entomobryoidea families and major subfamilies. New data for 26 species were mined from whole-genome sequencing. Phylogenetic inference confirmed the Orchesellidae as an independent family and the Entomobryinae remained the most puzzling taxon gathering scaled and unscaled lineages of both traditional Entomobryidae and Paronellidae. To accommodate Paronellides, Zhuqinia and related genera, Paronellidinae subfam. nov. is proposed within Entomobryidae. The sampled representatives of Paronellinae were recovered as the sister group of (Seirinae+Lepidocyrtinae), suggesting that reduction on the dorsal macrochaetotaxy and trunk sensillar pattern may have occurred independently within the Lepidocyrtinae and Paronellinae or represent their symplesiomorphy posteriorly modified in the Seirinae. The current systematics of the superfamily are revised here, with Entomobryidae now comprising six subfamilies, including all taxa with smooth dens. Our data also point out that all the main events of cladogenesis of the families and subfamilies of Entomobryoidea occurred during the Jurassic. Our genome-scale phylogenomics provides a complete, reliable example for systematics of Entomobryoidea, as well as other invertebrates in the big data era.

A Survey of the Brazilian Dicranocentrus Schött (Collembola, Orchesellidae, Heteromurini) with the Description of a New Species and Notes on the Genus

Dicranocentrus Schött is the most diverse and widespread taxon of Neotropical Orchesellidae. In Brazil, the genus is represented by 11 species found in humid forested areas of Atlantic and Amazon forests domains. Here we describe in detail Dicranocentrus abestado sp. nov. from Chapada Diamantina, Caatinga domain, Brazil. The new species belongs to the marias group sensu Mari-Mutt, due to the absence of most posterior macrochaetae on the dorsal head, and resembles other Neotropical species with 3, 2 and 2 central macrochaetae on abdominal segments I-III. However, the new species is unique especially by its reduced colour pattern combined with its empodial complex morphology. We compare Dicranocentrus abestado sp. nov. with 27 other taxa from the New and Old World, including all species with 3 macrochaetae on the first abdominal segment; provide notes and details on the morphology of the compared species plus identification keys to Brazilian and all species of the genus with similar abdominal chaetotaxy. We also discuss the current taxonomical knowledge on Brazilian Dicranocentrus and provide notes on its chaetotaxy and Heteromurinae systematics.