Silurian cyathaspidid heterostracans of Northern Eurasia

• Published in: Estonian Journal of Earth Sciences
• Main Author: Tiiu Märss
• Format: Article in Journal/Newspaper
• Language: English
• Published: Estonian Academy Publishers 2019
• Subjects: Heterostraci; Cyathaspididae; Wenlock; Ludlow; Přidoli; Silurian; Northern Eurasia; Geology; QE1-996.5; Severnaya Zemlya; Novaya Zemlya
• Online Access: https://doi.org/10.3176/earth.2019.11; https://doaj.org/article/7d59b7a5e3e643b2af0b6bb46cff5808

Silurian cyathaspidid heterostracans discovered from the East Baltic, North Timan, the Central and Southern Urals, and the Novaya Zemlya and Severnaya Zemlya archipelagoes in 1970‒2006 were studied. Earlier known taxa Archegonaspis schmidti (Geinitz, 1884), Archegonaspis lindstroemi Kiaer, 1932, Archegonaspis integra (Kunth, 1872) and Tolypelepis undulata Pander, 1856 were identified and described. Archegonaspis bimaris Novitskaya, 1970 is synonymized under A. schmidti (Geinitz) and Tolypelepis mielnikensis Dec, 2015 under Tolypelepis undulata Pander, 1856. Three new taxa, Archegonaspis bashkirica sp. nov., Cyathaspis alexanderi sp. nov. and Tolypelepis bedovensis sp. nov., were established, while two taxa, Archegonaspis lindstroemi? Kiaer and Tolypelepis sp. indet., remained in open nomenclature. The new subfamily Archegonaspidinae subfam. nov. was created. It is shown that besides details of the morphology of shields and plates, sculpture characteristics can be utilized in taxonomy. The material described complements the taxonomic content as well as the spatio-temporal distribution data of the species of the family Cyathaspididae.