Rugoconites

Rugoconites
Temporal range: Cryogenian - Ediacaran 670–550 Ma
Reconstruction of Rugoconites, an extinct organism
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: †Trilobozoa
Genus: †Rugoconites
Glaessner & Wade 1966
Species
  • R. enigmaticus (type) Glaessner & Wade 1966
  • R. reguibatensis Hachour et al., 2023
  • R. tenuirugosus Wade, 1972
Synonyms
  • Lorenzinites Glaessner & Wade, 1966
  • Wadea Jenkins, 1992

Rugoconites is a genus of Ediacaran biota found as fossils in the form of a circular or oval-like impression preserved in high relief, six or more centimeters in diameter. The fossils are surrounded by frills that have been interpreted (Wade 1972) as sets of tentacles. The bifurcating radial ribs, spreading from a central dome, serve to distinguish this genus from the sponge Palaeophragmodictya, and may represent the channels of the gastrovascular system.[1] Fossils of Rugoconites have been interpreted as early sponges,[2] although this is countered by Sepkoski et al. (2002), who interpreted the organism as a free-swimming jellyfish-like cnidarian; similar to Ovatoscutum.[3] However, the fossil is consistently preserved as a neat circular form and its general morphology does not vary, therefore a benthic and perhaps slow-moving or sessile lifestyle is more likely. Ivantstov & Fedonkin (2002), suggest that Rugoconites may possess tri-radial symmetry and be a member of the Trilobozoa.[4]

Rugoconites have been reported in clusters; this may represent a social/colonial way of life, or simply accumulation by the action of currents, sea-floor processes, or possibly preservational conditions.[5]

The Rugoconites genus may contain two species: Rugoconites enigmaticus and Rugoconites tenuirugosus, the latter being less dome-shaped and having smaller and more numerous radial ridges than the former.[6] However, due to the dubious nature of R. tenuirugosus, its taxonomy is still unclear, and it has been suggested that a new genus named Wadea should be erected for ''R." tenuirugosus.[7]

In 1966, Martin Glaessner along with Mary Wade unearthed the external mould of a form which possessed a small central disc that had eleven radiating lobes from its centre that they named Lorenzinites rarus.[8] This form was also compared to the top of some Rugoconites specimens.[8] The fossil of Lorenzinites rarus was, however, reconsidered to be a Rugoconites enigmaticus specimen despite his original observations and placed it along with the genus in the synonymy of Rugoconites.[9] The genus was then forgotten about and needs further examination.

  1. ^ Fedonkin, M. A.; Cope, J. C. W.; Whittington, Harry Blackmore; Conway Morris, S. (1985-10-17). "Precambrian metazoans: the problems of preservation, systematics and evolution". Philosophical Transactions of the Royal Society of London. B, Biological Sciences. 311 (1148): 27–45. Bibcode:1985RSPTB.311...27F. doi:10.1098/rstb.1985.0136. S2CID 84598490.
  2. ^ Gehling, James G.; Rigby, J. Keith (March 1996). "Long expected sponges from the Neoproterozoic Ediacara fauna of South Australia". Journal of Paleontology. 70 (2): 185–195. Bibcode:1996JPal...70..185G. doi:10.1017/S0022336000023283. ISSN 0022-3360. S2CID 130802211.
  3. ^ Sepkoski, J.J.; Jablonski, D. (2002). ""A Compendium of Fossil Marine Animal Genera"". Bulletins of American Paleontology.
  4. ^ Ivantsov, Andrei Yu; Fedonkin, Mikhail A. (2002). "Conulariid–like fossil from the Vendian of Russia: a metazoan clade across the Proterozoic/Palaeozoic boundary". Palaeontology. 45 (6): 1219–1229. Bibcode:2002Palgy..45.1219I. doi:10.1111/1475-4983.00283. ISSN 1475-4983. S2CID 128620276.
  5. ^ Boan, Phillip C.; Evans, Scott D.; Hall, Christine M. S.; Droser, Mary L. (2023-03-13). "Spatial distributions of Tribrachidium, Rugoconites, and Obamus from the Ediacara Member (Rawnsley Quartzite), South Australia". Paleobiology: 1–20. doi:10.1017/pab.2023.9. ISSN 0094-8373. S2CID 257521294.
  6. ^ "Rugoconites". Ediacaran.org.
  7. ^ Lipps, Jere H.; Signor, Philip W. (2013-11-21). Origin and Early Evolution of the Metazoa. Springer Science & Business Media. ISBN 978-1-4899-2427-8.
  8. ^ a b "The Late Precambrian fossils from Ediacara, South Australia | the Palaeontological Association".
  9. ^ The Dawn of Animal Life: A Biohistorical Study. CUP Archive. 20 June 1985. ISBN 9780521312165.