Kaokoxylon zalesskyi (Sahni) Maheshwari in the upper levels of Caturrita Formation, Parana Basin, southern Brazil

Abstract

Kaokoxylon zalesskyi, a conifer wood, is described from deposits of the Parana Basin considered, by the associated fauna, of Late Triassic age. It was identified in the uppermost levels of a third-order sedimentary sequence (SSM2), previously included in the Caturrita Formation. The fossil wood was found in the base of a mudstone/siltstone interval which upper levels furnished a rich and diversified plant assemblage composed of shoots of a Brachyphyllum Brongniart and Pagiophyllum Heer, impressions of reproductive and vegetative structures of Bennettitales, isolated leaves of Podozamites sp., and other wood fragments that include a Taxaceae and other gymnosperms of unknown affinities. An insect wing, and many conchostraca and fish scale remains are also present in the same succession, which gradually covers fluvial sandstones bearing many important fossil vertebrate record. The complex tectonic context of the central Rio Grande do Sul State, the associated vertebrate fauna and the unique character of the associated flora, without Dicroidium Gothan representatives, bring some uncertainty about the age, but motivate the continuity of paleofloristic studies seeking for (i) the refinement of the stratigraphic framework of the Lower Mesozoic levels of the Parana Basin, and (ii) its relation with other southwestern Gondwana areas.

Key words: Kaokoxylon zalesskyi, Coniferales, Santa Maria 2 Sequence, Upper Triassic, Brazil.