Ivantsov A.Yu.*, Zakrevskaya M.A. 2025. The last jellyfish of the Precambrian // Invert. Zool. Vol.22. No.1: 56–67 [in English].
Laboratory of the Precambrian organisms, Borissiak Paleontological Institute RAS, Profsoyuznaya st. 123, Moscow 117997 Russia.
Andrey Ivantsov: ivancov@paleo.ru ORCID https://orcid.org/0000-0001-8341-7431
Maria Zakrevskaya: zakrevskaya@paleo.ru ORCID https://orcid.org/0000-0001-5622-0430
* Corresponding author
doi: 10.15298/invertzool.22.1.05
ABSTRACT: The late Precambrian is traditionally considered the time of the flourishing of coelenterates sensu lato. Many dozens of fossil taxa from late Ediacaran (Vendian) deposits were interpreted as morphologically diverse jellyfishes. However, a progress in paleontological studies of the Precambrian biota allows us to short significantly the list of presumable cnidarians. Firstly, a number of them is recognized as various taphonomic variations. Secondly, intact attachments of these so-called jellyfishes to the substratum and their associations with stems of frond-like petalonamids are established. At present, Staurinidia crucicula Fedonkin, 1985 is suggested to be the only jellyfish of the late Precambrian. Here, we analyze in details morphological features of Staurinidia. This observation allows us to affiliate this fossil to cnidarians due to presence of elongated tentacles surrounding massive body and a radially branching gastrovascular system with a single central oral opening. In turn, a presence of the tetraradial symmetry, rounded, low and wide body shape and a branched, relatively small gastric cavity as well as the absence of a stem and theca hint to the affinities of this fossil with the scyphomedusae. The restriction of the fossil itself to a burial event horizon of the Flinders-Belomorian style indicates a benthic lifestyle of this Precambrian jellyfish.
KEY WORDS: Late Precambrian, Ediacaran, Vendian, southeastern White Sea, Cnidaria, Scyphozoa, Staurinidia.