Michael KringsThomas, N.TaylorNora DotzlerGianna Persichini2014-06-272014-06-272012Mycologia, 104(4), 2012, pp. 835-844http://hdl.handle.net/123456789/3384Documented fossil evidence of zygomycetous fungi is rare. A conspicuous fungal fossil, Jimwhitea circumtecta gen. et sp. nov., occurs in permineralized peat from the Middle Triassic of Antarctica. The fossil is interpreted as a mantled zygosporangium that buds from a macrogametangium subtended by a sac-like macrosuspensor. The macrogametangium is united at its tip with a mlCrogametangium which is subtended by a microsuspensor. This configuration is strikingly similar to the zygosporangium-gametangia complexes seen in certain modern Endogonaceae. Co-occurring with j. arcumtecta are isolated propagules closely resembling the zygosporangium ofj. circumtecta and a portion of a sporocarp containing zygosporangia embedded in a gleba. Several of the sporangia are borne on ovoid or e~ongate structures, which we interpret as gametangia. These fossils offer an exceptionally detailed view of the morphology and reproductive biology of early Mesozoic zygomycetes.enEndogoneFremouw Formationgametangiumhyphal mantleJimwhitea circumtectaper-mineralized peatsporocarpzygosporangiumArticle