A new marattiaceous fern from the Lower Jurassic of Patagonia (Argentina): the renaissance of Marattiopsis

ESCAPA, IGNACIO; BOMFLEUR, BENJAMIN; CÚNEO, RUBÉN; SCASSO, ROBERTO

JOURNAL OF SYSTEMATIC PALAEONTOLOGY

CAMBRIDGE UNIV PRESS

Lugar: Cambridge; Año: 2014

1477-2019

We here describe Marattiopsis patagonica sp. nov. (Marattiaceae) based on vegetative and fertile foliage impressions fromthe Lower Jurassic of Chubut Province, Patagonia, Argentina. The new species exhibits a unique combination ofvegetative and reproductive features, including a prominent basal auricle; finely undulate, denticulate, to serrulate pinnulemargins; interstitial fibres (venuli recurrentes) alternating with regular veins; submarginal position and distinctive relativelength of synangia (about 1220% of the pinnule width); and relatively small number of sporangia pairs per synangium(usually 14 or 16). The new species is assigned to the morphogenus Marattiopsis, since it shows no characters that wouldallow an unambiguous placement in any of the modern genera, Marattia s.s., Ptisana, or Eupodium. The newly establishedparaphyly of the Marattia s.l. species has a profound impact on the classification of fossil species. In this context, weprovide a brief assessment of the significance of the fossil Marattiopsis for phylogenetic and biogeographicalinterpretations. It appears that essentially modern marattioid ferns, including Marattiopsis, which are commonlyconsidered to be typical elements of tropical areas of the northern hemisphere during the Mesozoic, may have left animportant but largely ignored fossil record in subtropical Gondwana.