First megafloristic record for the Chubut Group at Somuncurá-Cañadón Asfalto Basin: An angiosperm dominated flora from the Upper Cretaceous Puesto Manuel Arce Formation, Patagonia Argentina

Abstract

The first association of fossil plant impressions in the Chubut Group at the Somuncurá-Cañadón Asfalto Basin is described herein. The mid-Cretaceous megafloral assemblage from Patagonia, Argentina was recovered from the Puesto Manuel Arce Formation. The taphocenosis consists mostly of leaves preserved as impressions, although a variety of cuticle remains are also present. Angiosperms are both quantitatively and qualitatively the main component of the flora (at least 9 leaf morphotypes recognized). A few ferns and conifers complete the plant assemblage. The angiosperm leaves exhibit physiognomic heterogeneity with a variety of well-defined venation patterns. The myrtophyll morphotype (Myrtoidea sp.) and palmatilobed palinactinodromous leaves (Bamfordphyllum crassivena gen. et sp. nov.) are significant components of the assemblage. Flora characters are consistent with the Cenomanian – earliest Turonian age proposed for the Puesto Manuel Arce Formation. Comparisons were made with coeval Patagonian and extra-regional floras which suggest both local as well as long-distance Gondwanan links.