DOUBLING THE KNOWN LYCOPSID DIVERSITY OF THE WUDA TUFF COAL-FORMING FLORA, INNER MONGOLIA, CHINA

Two new species of arborescent lycopsid have been recognized in the Asselian (earliest Permian) Wuda Tuff flora, located in the Wuda Coalfield, Inner Mongolia, China. First, Diaphorodendron sp. nov. is represented by compressions of the trunk surface and leaves. This species is the first discovered representative of Diaphorodendron with definitive Permian age and is the first compression specimen of the genus from the Cathaysian paleofloral province. Its discovery corroborates the genus’ presence in Late Paleozoic Cathaysian coal forests after D. rhombicum Wang had been described from a Cathaysian coal ball of Late Carboniferous-Early Permian strata, but compression specimens remained elusive. Distinct leaf cushion morphology precludes the compression material here described from diagnosis as D. rhombicum Wang. Second, Sigillaria sp. nov. is a slender tree, 3-6 cm in diameter, represented by compressions and casts of the trunk surface and leaves, and is the second species of Sigillaria Brongniart described from the Wuda Tuff flora after S. cf. ichthyolepis Presl, a broad tree that is routinely 30 cm in diameter. Key distinctions in leaf cushion morphology exist between slender and broad sigillariaceous specimens in the tuff, and anatomical features of the trunks preclude all possible ontogenetic and developmental pathways by which the smaller tree could be interpreted as a juvenile of the larger tree. To this end, the slender Sigillaria Bronginart specimens are considered a distinct species. The recognition of these new species yields a doubling of the known lycopsid diversity of the Wuda Tuff flora and suggests greater community complexity than previously expected.