Phylogenetic placement of an unusual coral mushroom challenges the classic hypothesis of strict coevolution in the Apterostigma pilosum group ant-fungus mutualism

Abstract

The ~50 million-year-old fungus-farming ant mutualism is a classic example of coevolution, involving ants that subsist on asexual, fungal biomass, in turn propagating the fungus clonally through nest-to-nest transmission. Most mutualistic ants cultivate two closely related groups of gilled mushrooms, whereas one small group of ants in the genus Apterostigma cultivates a distantly related lineage comprised of the G2 and G4 groups. The G2 and G4 fungi were previously shown to form a monophyletic group sister to the thread-like coral mushroom family Pterulaceae. Here, we identify an enigmatic coral mushroom that produces both fertile and sterile fruiting structures as the closest free-living relative of the G4 fungi, challenging the monophyly of the Apterostigma-cultivated fungi for the first time.

Citation

Dentinger, Bryn T.M.; Lodge, D.Jean; Munkacsi, Andrew B.; Desjardin, Dennis E.; McLaughlin, David J. 2009. Phylogenetic placement of an unusual coral mushroom challenges the classic hypothesis of strict coevolution in the Apterostigma pilosum group ant-fungus mutualism. Evolution. 9999: doi:10.1111/j.1558-5646.2009.00697.