(2575) proposal to conserve the name Protocupressinoxylon with a conserved type against Protobrachyoxylon (fossil plants)

Abstract

The genus Protocupressinoxylon was established by Eckhold for fossil coniferwoods with annual rings more or less distinct, tracheid pitting in various transitional arrangements, both horizontal and end walls of ray parenchyma cells smooth, resin canals absent, cross-field pits cupressoid, axial parenchyma occasionally present. Eckhold included Protobrachyoxylon eboracense R. Holden in the protologue of Protocupressinoxylon. As the only species name included in Protobrachyoxylon by Holden P. eboracense is necessarily the original type of that generic name. Thus, as was pointed out by Philippe, Eckhold's name was nomenclaturally superfluous and illegitimate when published, and must be typified by P. eboracense. Consequently, Protobrachyoxylon is the legitimate name for the genus currently known as Protocupressinoxylon, unless conservation of the latter name is proposed and accepted. Despite some inconveniences, conservation of the name Protocupressinoxylon is proposed here considering that the legitimate name, Protobrachyoxylon, has fallen into oblivion. By contrast, Protocupressinoxylon has been widely used in palaeobotany for fossil woods ranging from Permian to Cretaceous from all over the world (21 countries from the five continents). More than 40 references to the genus were found in the literature, including contributions on anatomy and taxonomy, paleoecology and paleoclimatology, and biogeography. In xylological literature Protocupressinoxylon is used by most authors as the name of a fossil genus including woods with transitional tracheid pitting and both araucarioid and/or the cupressoid cross-fields, which causes difficulties with the circumscription of the genus. However, a detailed analysis of the available information demonstrates that the prevailing usage of the generic name Protocupressinoxylon is for wood with cupressoid cross-fields. It is proposed that conservation of Protocupressinoxylon be with a conserved type in view of the fact that the original specimens of the species names included in the protologue are lost or do not match the diagnosis. The conserved type proposed is Protocupressinoxylon malayense Roggeveen.