A reassessment of the problematic Ediacaran genus Orbisiana Sokolov 1976
View / Open Files
Publication Date
2018-10Journal Title
Precambrian Research
ISSN
0301-9268
Publisher
Elsevier BV
Volume
316
Pages
197-205
Type
Article
Metadata
Show full item recordCitation
Kolesnikov, A., Liu, A., Danelian, T., & Grazhdankin, D. (2018). A reassessment of the problematic Ediacaran genus Orbisiana Sokolov 1976. Precambrian Research, 316 197-205. https://doi.org/10.1016/j.precamres.2018.08.011
Abstract
The genus Orbisiana was established in 1976 by B.S. Sokolov based on a collection of seven specimens within core material from a borehole drilled through the Ediacaran-age Gavrilov Yam Formation of the Moscow Basin, Russia. Here we reassess the original material for the type species Orbisiana simplexSokolov 1976, which was long considered to be lost; fix the holotype of the type species; and revise the original diagnosis of the genus and species. Pyritisation of the fossils, which are preserved in finely laminated shales, allows three-dimensional morphological characterisation of this taxon using X-ray microtomography (μCT). Morphological and taphonomic analyses of the type material and additional three-dimensionally preserved specimens from the Verkhovka Formation (Vendian of the White Sea area) suggest that Orbisiana simplex consisted of submillimetric to millimetric globular chambers arranged in compact, grape-like clusters, or forming sinuous to linear aggregates. Occasionally, aggregates can bifurcate, with no appreciable change in chamber dimensions or shape. The phylogenetic affinity of Orbisiana remains uncertain, but its chambered construction, putative agglutinated structure of the chamber walls, and compact, occasionally branching chamber arrangement are shared with agglutinated tests of the Ediacaran genus Palaeopascichnus. Our reassessment and systematic study of the genus Orbisiana sheds new light on one of the least studied members of the late Ediacaran macroscopic biota.
Sponsorship
NERC
Funder references
Natural Environment Research Council (NE/L011409/2)
Identifiers
External DOI: https://doi.org/10.1016/j.precamres.2018.08.011
This record's URL: https://www.repository.cam.ac.uk/handle/1810/285052
Rights
Licence:
http://www.rioxx.net/licenses/all-rights-reserved
Statistics
Total file downloads (since January 2020). For more information on metrics see the
IRUS guide.