Ignatov, M.S., U.N. Spirina, T.V. Voronkova & S.V. Polevova. 2024. On the moss genus Gomankovia from the Upper Permian of the Russian Platform

Arctoa (2024) 33: 71–79

doi: 10.15298/arctoa.33.09

The Upper Permian moss genus Gomankovia was described in 1990 and remained poorly known, mostly by a single, well-preserved leaf. Recently collected additional material revealed more than 40 new specimens of this genus. Its variation in leaf shape and laminal cell areolation is described. The specimens were cut, showing the transverse costal structure, which is formed mostly of large, moderately thick-walled cells, with only a few cells with thicker walls. The costa has several lateral branches, which preclude an immediate comparison of Gomankovia with any modern moss group. Sections of costa are studied with transmission electron microscopy, and, despite the compression type of preservation, it appeared possible to reconstruct the original structure of the costa. Generally, it lacks differentiation similar to costa of extant mosses of similar size of plants and leaf shape and size. There is no way to refer Gomankovia to any extant group; however, its relationship to some extinct lineages is possible.