A gondwanan Jurassic bryoflora? Anatomically preserved bryophytes in geothermal paleoenvironments from the Jurassic of Patagonia, Argentina

Abstract

The Deseado Massif, which is located in the western part of the Santa Cruz Province, Argentina, contains numerous hot spring deposits related to the final stages of the Bahía Laura Complex. The aim of this study is to analyze the first Jurassic deposits with permineralized bryophytes at La Bajada hot spring-related locality, expanding the diversity of Jurassic bryophytes with anatomical preservation. >200 fossiliferous petrographic thin sections were examined, leading to the discovery of four bryophyte morphotypes of leafy and thallose gametophytes. Detailed comparisons between each morphotype and extant and extinct bryophytes were carried out. The morphotypes described here may have various phylogenetic affinities, based on the latest comprehensive phylogenetic analyses of extant bryophytes. Although morphotypes described here do not represent the oldest representative for the lineages they represent, each of the studied fossils has a consistent set of diagnostic characters that relates them to specific nodes within bryophyte phylogeny. Moreover, the affinities of morphotype A with Marchantiales and Neohodgsoniales suggest affinities with the clade that is composed of these two orders together with Sphaerocarpales. Affinities of morphotypes B, C and D are more ample and related to different orders including within Bryophyta sensu stricto.