Mixoxylon australe gen. et sp. nov., a unique homoxylous wood with non-angiosperm affinity from the Lower Cretaceous of Antarctica (Albian, James Ross Island)

Abstract

A unique homoxylous wood is described from the Albian Lewis Hill Member of the Whisky Bay Formation on James Ross Island as Mixoxylon australe Chernomorets & Sakala, gen. et sp. nov. This fossil taxon shows an unusual combination of features in having indistinct growth rings with a significantly wider earlywood zone than latewood zone, tracheids with scalariform to araucarian pitting, exclusively uniseriate rays with distinctly pitted both tangential and horizontal walls and araucarioid to podocarpoid cross-field pits. Its characteristics are intermediate between Phoroxylon Sze and Sahnioxylon Bose & Sah, so a new genus is proposed. Its systematic affinities are dubious, but it represents the southernmost evidence of the homoxylous Mesozoic wood with scalariform pitting described so far.