Ophiocordyceps desmidiospora, a basal lineage within the 'Zombie-Ant Fungi' clade

摘要

The genusOphiocordycepscontains the most diverse assemblage of fungi that attack ants worldwide and are remarkably well adapted to the specific ecologies of their hosts.Desmidiospora myrmecophilaThaxt. is closely related to other ant-pathogenic species withinOphiocordyceps, possibly specific to queens, but the sheer infrequency of encounters and previously unsuccessful attempts to culture this fungus has precluded any meaningful assessment until now. A new record ofDesmidiospora myrmecophilafrom Louisiana was found infecting a foundressCamponotus pennsylvanicusqueen, the same host species favored by the more common and ubiquitous ant-pathogenicOphiocordyceps unilateralisclade found in the same geographic locality. To evaluate a long-held assumption that these fungi represent synanamorphs of a single species, we sampled ourDesmidiosporaspecimen along with the localO. unilateralispopulation for molecular comparison. We are able to present for the first time the in vitro characteristics and morphology ofDesmidiospora myrmecophila, as well as a phylogenetic context for this fungus based on combined molecular analysis of representative members of the Ophiocordycipitaceae. Our results place theDesmidiospora myrmecophilalineage within the genusOphiocordyceps, with a basal affiliation to theOphiocordyceps unilateraliscore clade; thus, in accordance to the "One Fungus-One Name" (1F1N) rule, we propose a new synonym to suppressDesmidiosporain protection ofOphiocordyceps, i.e.,O. desmidiospora. These results further implicate this species as an important and quintessential example of cryptic diversity among an already taxonomically diverse and ecologically important group of fungi.