Fungal spores from the Palaeogene El Foyel Group of Ñirihuau Basin, Argentina

Abstract

AbstractThe El Foyel Group is defined in the western section (Andean) of the Ñirihuau Basin, Argentina (41°44′S–71°30′W). It consists of three units: the Troncoso, Salto del Macho and Río Foyel formations. The age of the group and of the formations is still controversial. We studied the fungal remains recovered from 14 palynological samples from outcrops in the group with the intention of providing data to solve this problem. The fungal assemblage found is highly diverse and it is mostly composed of spores of different affinities (mainly ascomycetes). We identified 38 species from 18 genera (Anatolinites,Dictyosporites,Didymoporisporonites,Diporicellaesporites,Diporisporites,Dyadosporites,Exesisporites,Foveodiporites,Hypoxylonites,Inapertisporites,Lacrimasporonites,Monoporisporites,Multicellites,Papulosporonites,Pluricellaesporites,Polycellaesporonites,Staphlosporonitesand one indet.). Moreover, we propose two new species (Hypoxylonites foyelensissp. nov. andPluricellaesporites patagonicussp. nov.) and a new combination (Dyadosporites annulatuscomb. nov.). Most of the species were recovered from samples from the Troncoso Formation (21), while the Salto del Macho and Río Foyel formations showed lesser diversity.Anatolinites subcapsilaris,Dyadosporites subovalis,Inapertisporites subovoideus,Monoporisporites singularovalisandMulticellites ellipticus, biomarkers from the Middle Eocene appeared in the Troncoso and Salto del Salto del Macho formations; whereas indicators of the Eocene–Oligocene, such asDyadosporites elsikii,Didymoporisporonites panshanensis,Foveodiporites elegans,Lacrimasporonites fusoidesandMulticellites leptaleus, were mainly recorded in the Río Foyel Formation. The appearance of the biomarkers mentioned above reinforces the Palaeogene age proposed for the El Foyel Group in previous palynological studies. The record ofHypoxylonites ater(Miocene) in the Salto del Macho formation would expand its range as far back as the Palaeogene.