Data from: A new tetraradial olivooid (Medusozoa) from the Lower Cambrian (Stage 2) Yanjiahe Formation, South China
Data files
Nov 18, 2019 version files 13.37 MB
Abstract
Octapyrgites elongatus n. gen. n. sp., a relatively rare, tetraradial olivooid (Cnidaria, Medusozoa), is described from Bed 5 of the Yanjiahe Formation (Cambrian Stage 2) near Yichang, China. Though similar to Olivooides and Quadrapyrgites from the Fortunian Stage in consisting of a partially corrugated (long.) periderm with a quadrate (transv.) apical portion and V-shaped apertural lobes, O. elongatus is substantially larger than other olivooids. The elongate apical region of O. elongatus is similar to four-sided Anaconularia anomala, though with a flat tip that may have been an adaption for a sessile mode of life. As in other olivooids, embryonic development in O. elongatus may have been direct. Lastly, the paucity of olivooids and the absence of pentaradial cnidarians and carinachitids in Cambrian Stage 2 indicate a marked decline in the disparity of cnidarians near the Fortunian/Cambrian Age 2 boundary, when by contrast bilaterians underwent rapid diversification.
Usage notes
Movie 1: Microtomographic reconstruction and rendering of Octapyrgites elongatus n. gen. n. sp.