Orthothecida, Marek, 1966

Kouchinsky, Artem, Bengtson, Stefan, Landing, Ed, Steiner, Michael, Vendrasco, Michael & Ziegler, Karen, 2017, Terreneuvian stratigraphy and faunas from the Anabar Uplift, Siberia, Acta Palaeontologica Polonica 62 (2), pp. 311-440 : 391

Orthothecida sp. indet. 1

Fig. 51F–H.

Material.—Three phosphatic internal moulds, SMNH X5854–5856, from sample K2/21 (section 3, Fig. 3), Medvezhya Formation, western Anabar Uplift, Siberian Platform, Russia. Correlated with the upper Fortunian Stage.

Remarks.—The fossils are internal moulds of thecae with low transverse rugae, a moderate apical angle and more rapidly tapered extended apex with a rounded end. The moulds are slightly bent dorso-ventrally (?) in a single plane, which passes through the narrower sides of the broadly oval cross-section.