RECONSTRUCTION AND PHYLOGENETIC SIGNIFICANCE OF A NEW EQUISETUM LINNAEUS SPECIES FROM THE LOWER JURASSIC OF CERRO BAYO (CHUBUT PROVINCE, ARGENTINA)

Authors

  • Andres Elgorriaga Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Pabellón nº 2, Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina.
  • Ignacio H. Escapa Consejo Nacional de Investigaciones Científicas y Técnicas, Museo Paleontologico Egidio Feruglio, Avenida Fontana 140, Trelew 9100, Chubut, Argentina.
  • Benjamin Bomfleur Department of Palaeobiology, Swedish Museum of Natural History, P.O. Box 50007, SE-104 05 Stockholm, Sweden.
  • Rubén Cúneo Consejo Nacional de Investigaciones Científicas y Técnicas, Museo Paleontologico Egidio Feruglio, Avenida Fontana 140, Trelew 9100, Chubut, Argentina.
  • Eduardo G. Ottone Instituto de Estudios Andinos Don Pablo Groeber-Consejo Nacional de Investigaciones Científicas y Técnicas, Departamento de Ciencias Geológicas, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Pabellón n° 2, Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina.

DOI:

https://doi.org/10.5710/AMGH.15.09.2014.2758

Keywords:

Equisetales, Equisetum, Systematics, Jurassic, Patagonia

Abstract

We 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.

Author Biography

Andres Elgorriaga, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Pabellón nº 2, Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina.

estudiante de paleontologia - paleobotanica

Published

2014-10-11

How to Cite

Elgorriaga, A., Escapa, I. H., Bomfleur, B., Cúneo, R., & Ottone, E. G. (2014). RECONSTRUCTION AND PHYLOGENETIC SIGNIFICANCE OF A NEW EQUISETUM LINNAEUS SPECIES FROM THE LOWER JURASSIC OF CERRO BAYO (CHUBUT PROVINCE, ARGENTINA). Ameghiniana, 52(1), 135-152. https://doi.org/10.5710/AMGH.15.09.2014.2758

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