Classification of the flea families (Siphonaptera): I. Family Hystrichopsyllidae (Part 5)

Based on analysis of homologous character states and considering the molecular-biological data (Whiting et al., 2008), phylogenetic relationships of the tribes and subfamilies of the family Hystrichopsyllidae are discussed. In some cases, homologous states of the skeleton characters mark the clades revealed by the moleculargenetic analysis, but are shared by taxa from other clades. In contrast to the molecular-genetic data, morphological characters indicate the phylogenetic integrity of the family Hystrichopsyllidae. Morphological characters depict the subfamily Anomiopsyllinae as a monophyletic taxon (having synapomorphic states of the metaphragma, metasternite, and the mesosternal apodeme) closest to the subfamilies Neopsyllinae and Rhadinopsyllinae. The subfamilies Neopsyllinae, Rhadinopsyllinae, and Stenoponiinae have a non-thickened metasternite; the former two subfamilies also have in common a similar structure of articulation of the digitoid with the clasper, type of the metaphragma modification, and the presence of the sclerotized central sclerite. Homologous modifications of the metaphragma are also present in fleas of the subfamily Stenoponiinae. Close to this group are the subfamily Hystrichopsyllinae whose representatives also possess non-thickened metasternal apodemes, and the subfamily Listropsyllinae with its frontal sclerotized tubercle being a specialized modification of the frontal sclerotized fold. A specific feature shared by fleas of the subfamilies Hystrichopsyllinae and Listropsyllinae is the presence of the metasternal furca with high sharp processes and a high medial ridge. The closeness of these taxa is supported by the results of molecular-genetic analysis. The subfamilies Doratopsyllinae and Ctenophthalminae (tribes Ctenophthalmini and Carterettini) are united by the type of the attachment of the mesopleural rod to the special ridge at the upper margin of the mesopleuron. According to the molecular-genetic data, the tribe Neotyphloceratini is related to these subfamilies, even though its members have no ridge on the mesopleuron. The similarity in the structure of the furca (the presence of high dorsal processes with rounded apices and a high median ridge) and in the length ratio of the fulcrum lobes relates the subfamilies Ctenophthalminae and Dinopsyllinae.