Chitinozoaires du genre Alpenachitina dans le Dévonien moyen du Brésil; Intérêt stratigraphique et relations phylogénétiques

Subsurface samples from the Paraná Basin (southern Brazil) have yielded abundant and well-preserved chitinozoa. Two new taxa, Alpenachitina matogrossensis sp. nov. and A. petrovinensis sp. nov. are described and illustrated. In the lower part of the borehole, in strata corresponding to the Early Givetian, the latter succeeds the former and both coexist with Alpenachitina eisenacki Dunn & Miller, 1964. The phylogenetic relationship of these three taxa are discussed.