RECONSTRUCTION AND PHYLOGENETIC SIGNIFICANCE OF A NEW EQUISETUM LINNAEUS SPECIES FROM THE LOWER JURASSIC OF CERRO BAYO (CHUBUT PROVINCE, ARGENTINA)
Keywords:Equisetales, Equisetum, Systematics, Jurassic, Patagonia
AbstractWe describe Equisetum dimorphum sp. nov. from the Lower Jurassic of Chubut Province, Patagonia, Argentina. This new species is based on fertile and vegetative remains preserved as impressions of stems, leaves, strobili, transversal sections of the stems showing their anatomy, and terminal pagoda-like structures. The fine-grained sedimentary matrix also preserved detailed impressions of epidermal features. The morphological characters allow a whole-plant reconstruction and assignment to Equisetum. Equisetum dimorphum sp. nov. shows a mosaic of morphological characters that are commonly present in other Mesozoic forms and representatives of the two extant Equisetum subgenera, e.g., sunken stomata and a blunt strobilus apex. Compared to other well-known Mesozoic equisetalean taxa, Equisetum dimorphum sp. nov. appears to be most closely related to a group of Jurassic Equisetum-like plants including Equisetum laterale Phillips and Equisetites ferganensis Seward. Additional evidence for the morphological stasis of the fertile and vegetative organs of extant horsetails is supplied with this new material, adding further support to the hypothesis that the extant horsetails are a successful group that has undergone only little morphological changeover time and that has been present, nearly worldwide, since Jurassic times.
How to Cite
Authors publishing in Ameghiniana have the option of making their article freely available online. Authors opting for the Open Access must pay a fee of $300 (US dollars) to cover article-processing costs and to ensure the article is made open access. Please contact the Production Team after the acceptance of your manuscript if you are interested in making your article Open Access. This option implies by default a license Creative Commons Attribution Non-Commercial-NoDerivs License (CC BY NC ND). If your funding institution requires a different licensing option please communicate this to the Production Team after the acceptance of your manusctipt.