Willowsia, Shoebotham, 1917

Cipola, Nikolas Gioia, Katz, Aron D., Bu, Yun & Godeiro, Nerivania Nunes, 2025, Systematics of Willowsia jacobsoni (Börner, 1913) (Collembola, Entomobryidae): morphology, postembryonic development, distribution, mitogenome and phylogeny, Zootaxa 5604 (3), pp. 201-233 : 227

On Willowsia polyphyly

Willowsia was previously recovered as a monophyletic taxon based on morphological data ( Zhang et al. 2011), although this was hypothesized through an analysis using a single (and likely inappropriate) outgroup, Americabrya arida ( Christiansen & Bellinger, 1980) . However our results, based on molecular data, corroborate previous studies on Willowsia polyphyly, as well as the nonexistence of Willowsiinae ( Zhang et al. 2014, 2015, 2016, 2017; Katz et al. 2015b; Zhang & Deharveng 2015; Ding et al. 2019; Cipola & Katz 2021).

Regarding our tree, the large clade gathering the 12 Willowsia sampled taxa mixed with other Entomobryinae genera was recovered as the sister group of Neotropical scaled Entomobryinae ( Lepidocyrtoides Schött, 1917 and Lepidosira ), although with low support (pp = 0.37; bs = 60). This grouping may be reasonable, considering that most Entomobryoidea taxa have type I scales ( Mari Mutt 1979; Zhang et al. 2014, 2016; Cipola et al. 2014, 2017, 2018, 2022; Nunes et al. 2019), probably a plesiomorphic condition of Entomobryidae , kept like this only in W. japonica within the clade. Regardless, the branch gathering seven Asian Willowsia taxa (pp = 0.77; bs = 73) likely belongs to another genus, and this is probably due to the independent emergence of scales, as already observed to other Entomobryinae taxa ( Zhang et al. 2014). Our results indicated that the type of body scales has no phylogenetic significance for sustaining or helping to split Willowsia , since different types of scales appear mixed in our phylogeny ( Fig. 14 ). In this sense, new analyses using the same species but new samples need to be done to confirm if E. multifasciata , Sinella curviseta and S. longisensilla were correctly identified, since they were the only unscaled Entomobryinae within the clade with the Willowsia species.

Figures

FIGURE 14. Bayesian conditional clade distribution gene tree for Entomobryinae based on three loci (COI, 16S, and 28S). Branch labels denote clade support (Bayesian posterior probabilities/maximum likelihood bootstraps), with hyphens (-) indicating incongruent tree topology between Bayesian and maximum likelihood analyses. Monophyletic constraints at nodes for outgroups (Dicranocentus, Seira, Seira + Lepidocyrtus), Entomobryinae, and Entomobryinae + Seira + Lepidocyrtus are marked with asterisks (*). Node labels with high support (i.e., posterior probabilities> 0.90; bootstraps> 80) and the taxon label for the newly sequenced Willowsia jacobsoni are highlighted in bold. Green, blue, and red branches represent Willowsia lineages with body scale morphology (type I–III), respectively. Scale bar represents substitutions/site.