The lycophytes of the La Golondrina Formation (Permian), Santa Cruz Province, Argentina: Systematic revision, biostratigraphy and palaeoecology

Abstract

The Permian lycophytes of the La Golondrina Formation (Santa Cruz province, Argentina) have remained unstudied for almost 50 years. This study reviews material described by Archangelsky in 1960 and increases the representation of specimens via new collections from the lower and middle members of the formation. The lycophytes, previously assigned to typical Laurasian genera, are re-analyzed and re-assigned to Gondwanan genera where appropiate. Two new lycophyte taxa, Bumbudendron patagonicum comb. nov. and Cyclodendron golondrinensis sp. nov. are proposed, and two specimens are retained under open nomenclature until better preserved material becomes available. Based on this study, the biostratigraphic range of Bumbudendron is extended to the Permian, whereas Cyclodendron remains a useful Permian stratigraphic index as previously suggested. Palaeoecological inferences derived from growth habit, floristic association and sedimentary facies indicate that these plants developed under micro- to meso-thermal, humid conditions.