METHOD OF PALEOANATOMICAL STUDY APPLIED TO THE TAXONOMY OF GONDWANA GYMNOSPERMOUS WOODS (UPPER PALEOZOIC)

Abstract

The terminology used in the paleoanatomical study of gymnospermous woods, proceeding from Carboniferous and Permian of Gondwana, is characterized by vagueness of criteria regarding the selection of the characteristics of taxonomic value. In this regard, a greater negligence is comparatively emphasized in relation to the pith than the other units that composed the stem and the lack of uniformity in the nomenclature used in primary and secondary xylem paleoanatomy. Such procedures have led to elaboration of incomplete generic and specific descriptions, to the difficulty of comparison between the specimens and, often, to the inadequate taxonomic. Thus, aiming at the definition of the features of taxonomic value and the standardization of terminology, a methodology based on proposition and discussion of the anatomical characteristics of the pith and primary and secondary xylem used to inter-taxa differentiation of the Gondwana gymnospermous woods is presented. Notes about the anatomy of the other units of stem, neighboring the secondary xylem, and illustrations of taxa that exhibit the characters considered are also presented.