Siphonophrentis gigantea

Siphonophrentis gigantea is an extinct species of giant rugose coral.[1] It lived during the Middle Devonian period of the Paleozoic era.

Siphonophrentis gigantea
Temporal range: Middle Devonian
Siphonophrentis gigantea CMBB-0001.jpg
Scientific classification
O'Connell 1914
S. gigantea
Binomial name
Siphonophrentis gigantea
(Lesueur 1821)


Siphonophrentis gigantea was aquatic, like all coral. It is part of the phylum Cnidaria, and possessed a polyp that lived inside of its calyx. It had a limestone skeleton (the only part that survives fossilization) covered with soft tissue, and would have anchored themselves by the apical end to the sea bed, while the tentacles of the polyp caught prey.

According to one study,[2] Siphonophrentis gigantea may have been a deep-water species of coral. The limestone matrix of one specimen was tested for calcium carbonate, which is made up of microfossils.[3] This would indicate that the matrix was rich in nutrients when the rock was formed, meaning it was likely in deep water where nutrients are more plentiful. Because of this, the species likely had no association with Zooxanthellae (a microorganism that has a symbiotic relationship with most extant coral),[4] and therefore was likely colorless and unable to photosynthesize.

This study also indicated that this species grew upwards at a rate of approximately 15.21 centimetres (5.99 in) every 399 days (a year in the Devonian).[5]


  1. ^ (Lesueur, 1821). "Siphonophrentis gigantea; YPM IP 218504; North America; USA; Kentucky; Jefferson County; Falls of the Ohio".{{cite web}}: CS1 maint: numeric names: authors list (link)
  2. ^ McCall, Christian R (18 October 2018). "Exceptional new fossil of Siphonophrentis gigantea". PeerJ Preprints. doi:10.7287/peerj.preprints.27282v2.
  3. ^ Elsevier. "Profiles of Drug Substances, Excipients and Related Methodology, Volume 41 - 1st Edition".
  4. ^ Birkeland, Charles (1997). Life and Death of Coral Reefs. Springer Science & Business Media. pp. 98–99. ISBN 978-0-412-03541-8.
  5. ^ Scrutton, Colin T. (1964). "Periodicity in Devonian Coral Growth". Palaeontology. 7, Part 4: 552–558. ISSN 0031-0239 – via Biodiversity Heritage Library.