Anatomy of a new probable pteridosperm stem from the Late Carboniferous of Argentina

A new genus and species, Amosioxylon australis, based on an anatomically preserved stem from the Late Carboniferous Jejenes Formation, Argentina, is described. The specimen is six cm in diameter and has some features usually found in pteridosperms, including the presence of several vascular segments surrounded by secondary xylem. The pycnoxylic wood resembles progymnosperms and the tissue between the vascular strands, with reticulate thickenings and pits, is similar to the transfusion tissue found in extant conifers and cycads. According to the available evidences a relationship with primitive pteridosperms is suggested.