On a new species of the calamitalean fossil-genus Annularia from the Douro Basin (lower Gzhelian; NW Portugal)

This paper deals with a new species of the calamitalean fossil-genus Annularia von Sternberg, Annularia noronhai sp. nov., from the Douro Basin (lower Stephanian C/lower Gzhelian, Upper Pennsylvanian), in north-western Portugal. A. noronhai sp. nov. is distinguished mainly by its lanceolate leaves with acuminate to caudate apices, which are characterised by having a very elongate mucro. Among the known species of Annularia, Annularia spinulosa is the most similar. In this study, we also reassess the taxonomic status of A. spinulosa based on comparisons between its type specimen (holotype) and specimens from Douro Basin described to this fossil-species.

Automated summary

A new species of the calamitalean fossil-genus Annularia von Sternberg, Annularia noronhai sp. nov., from the Douro Basin in Portugal was discovered, characterized by lanceolate leaves with elongate mucro. The closest known species to this new discovery is Annularia spinulosa. The taxonomic status of A. spinulosa was reevaluated through comparisons with its type specimen and specimens from the Douro Basin.