Leandro C.A. Martínez

El registro de maderas fósiles de Leguminosae de Sudamérica

The fossil wood record of Leguminosae from South America. the Leguminosae has an extensive fossil wood record worldwide. In South America 56 records with affinity to Leguminosae were counted. Each record is analyzed and unpublished data is also included. the Leguminosae is the most palaeoxylological diverse family of South America. It has an extensive temporal record, from the Palaeocene to the Pleistocene, and a broad geographical span, from Patagonia to north colombia.

Estípite de Palmera en El Campaniano del Grupo Neuquén, Provincia del Neuquén, Argentina

Abstract. PALM TRUNK IN THE CAMPANIAN OF NEUQUÉN GROUP, NEUQUÉN PROVINCE, ARGENTINA. In this paper a new species of fossil palm is described from the Auca Mahuevo locality, where the Anacleto Formation (Campanian) crops out, in the Neuquén province, Argentina. The described fossils correspond to palm trunks, referred to the genus Palmoxylon Schenk. These stems were compared with other species of this genus and with extant representatives of the family Arecaceae, and such comparisons allowed to assign it to a new species, Palmoxylon garridoi sp. nov. Martínez. The fossil record of palms in the Anacleto Formation suggests warm climate conditions in the Campanian of the Neuquén Group, and also extends the biochron of this genus in Argentina.

Proposals for quantifying two characteristics of tracheid pitting arrangement in gymnosperm woods

Abstract: Arrangement of tracheid radial pits is frequently superficially mentioned in extant gymnosperm wood anatomy descriptions. However, pitting arrangement is a key character for delimiting fossil-genera and fossil-species in gymnosperm woods. We propose two new indices for measuring and quantifying the radial pitting arrangement in fossil and extant woods. The first one, contiguity percentage index (Cp) indicates if the pit rows are contiguous (=in contact or touching) with other rows in the above and below pit borders, and has values from 0 to 100%. The second one, seriation index (Si) is an average of the seriation of the pits and is given as a numerical value equal or greater than 1, when pits are exclusively ordered in uniseriate columns the wood has a value of 1. These indices are useful for quantifying the pitting arrangement and for helping to characterize the type of radial pitting (araucarian/mixed/abietinean), particularly in fossil woods. These new indices also allow to use these two characters as continuous instead of discrete, making them more suitable for certain taxonomic or statistic analysis.