Revision and description of two new species of Charliea Mamay from Pennsylvanian strata in New Mexico and Utah, USA

Abstract

Originally, Charliea Mamay was considered to be a pinnately compound leaf having linear–oblong ultimate segments with apices divided into two to four, nearly equal truncated lobes when it was described from the Upper Pennsylvanian of New Mexico. However, evaluation of the type material and newly collected specimens of the generitype as well as other fossils representing two new species demonstrates that the ultimate segments are alternately arranged in two rows (two-ranked) on a narrow stem and that the fossil is not a pinnately compound leaf, but a leafy plagiotropic shoot. Moreover, the apical lobes of the ultimate segments are rounded to pointed and not truncated as first thought. The new species, C. guntheri and C. readii, are distinguished from the generitype, C. manzanitana Mamay, in the shape and size of the ultimate segments (here termed leaves), and the smaller number of veins entering the apical lobes. Charliea guntheri and C. readii occur in the Lower Pennsylvanian of Utah and the Upper Pennsylvanian of New Mexico, respectively, and extend the stratigraphic range of the genus significantly. As a consequence, Charliea seems to exhibit what may be referred to as a modified ‘Lazarus effect’ since the species assigned to it occur at the base and top of the Pennsylvanian but not in the intervening interval.