A Case of a New Ectoparasitic Fungal Infection of the Ant Lasius distinguendus (Hymenoptera, Formicidae) with Description of Xenomorphomyces formicartus gen. et sp. nov. (Capnodiales, Readerielliopsidaceae)

This study presents the first case of an ectoparasitic fungal infection of ants from southern Russia with the description of a new species Xenomorphomyces formicartus V.A. Iliushin & I.Y. Kirtsideli, sp. nov. of a new genus Xenomorphomyces gen. nov. belonging to the family Readerielliopsidaceae. The new species was found on Lasius distinguendus worker ants within a single nest in the Botanical Garden of the Southern Federal University, Rostov-on-Don, Rostov Region, Russia. The paper evaluates the phylogenetic position of the parasitic fungus within the Readerielliopsidaceae family based on the morphological observations and multilocus phylogenetic analysis. The family Readerielliopsidaceae belongs to the Capnodiales order, the class Dothideomycetes. Partial sequences of the loci encoding ribosomal polymerase II second-largest subunit (RPB2), 28S rDNA (LSU) and internal transcribed spacer rDNA region (ITS1-5.8S-ITS2) were analyzed. The asexual morph of X. formicartus was described. A comprehensive analysis of pathogenicity was performed using live ants, histological and micro-CT studies. The sequence data, as well as macro- and micromorphological characteristics, distinguish X. formicartus from all known species in the Readerielliopsidaceae.