Anatomically preserved gymnosperm axes are relatively abundant in Permian localities of Antarctica, but their anatomy has rarely been studied in detail, which limits comparison with other Gondwanan morphotaxa. Here we describe a silicified trunk collected from the Upper Permian Buckley Formation at Coalsack Bluff, in the central Transantarctic Mountains. The trunk has a small heterogeneous pith approximately 4 mm in diameter containing conspicuous sclerotic nests, endarch primary xylem maturation, paired leaf traces, and secondary xylem of the Araucarioxylon type. Comparison with contemporaneous gymnosperm axes from Antarctica indicates that the Coalsack Bluff trunk represents a new Permian morphotaxon for the region. The anatomical characters of the pith and secondary xylem suggest an affinity with the genus Kaokoxylon Kräusel, previously reported from Permian and Triassic localities of Southern Africa, South America, India, and Australia.
Silicified trunk, Gymnosperm, Kaokoxylon, Permian, Antarctica