New insights into the systematics of Entomobryoidea(Collembola: Entomobryomorpha): first instar chaetotaxy, homology and classification

The largest superfamily Entomobryoidea is one of the key groups in Collembola.However,incorrect recognition of chaetotaxic homology within Entomobryoidea severely impedes the accurate species comparison of adults and phylogenetic reconstruction.Traditional classification of the superfamily at suprageneric level is disputable in the light of recent advances.Transformational homology of tergal chaetotaxy was traced and revised based on 38 species of first instar and partial early instars.Morphological phylogenetic reconstructions were reconstructed mainly relying on first instar characters using both parsimony and likelihoodbased algorithms.Outgroup selection and several rogue taxa impacted on resolution and support of otherwise well-supported clades.Integrating published molecular phylogeny,a revised classification of three families and nine subfamilies was presented:Orchesellidae,Entomobryidae and Paronellidae.Orchesellidae includes all basal taxa having a short fourth abdominal segment.Cyphoderidae and Microfalculidae taxa were sunk into Paronellidae.New Paronellidae was divided into two subfamilies:Paronellinae(Paronellini+Cyphoderini+Bromacanthini)and Salininae(Cremastocephalini+Callyntrurini).Microfalculidae(Microfalcula)was closer to Salina and Akabosia and thus transferred into Cremastocephalini.This study erected a new classification framework for Entomobryoidea based upon comprehensive phylogenies.Chaetotaxic homologization across a wide range provided a standardized,comparable,powerful tool for taxonomy.