Brooksella is an enigmatic star-shaped Cambrian fossil found in the Conasauga Formation of Alabama and Georgia.[1] These fossils are often referred to as "star-cobbles" for their distinct lobate appearance, generally with 6 or more lobes.

Brooksella
Temporal range: Middle Cambrian
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Porifera
Class: Hexactinellida
Order: Reticulosa
Family: Protospongiidae
Genus: Brooksella
Walcott, 1896
Type species
Brooksella alternata
Walcott, 1896

Brooksella was first described in 1896 by Charles Doolittle Walcott, who believed them to be medusoid body fossils of cnidarians.[2][3] Later researchers have offered other explanations, from diagenetic gas bubbles to burrow traces. The most accepted identity is that they are hexactinellid sponges, based on observed spicules, ostia, and internal structure.[1] In 2023, a group of researchers suggested that Brooksella is a pseudofossil, finding no support for previous interpretations of it as a sponge or a trace fossil.[4][5]

References

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  1. ^ a b Ciampaglio, Charles N.; Babcock, Loren E.; Wellman, Carrie L.; York, Angela R.; Brunswick, Holly K. (August 2006). "Phylogenetic affinities and taphonomy of Brooksella from the Cambrian of Georgia and Alabama, USA". Palaeoworld. 15 (3–4): 256–265. doi:10.1016/j.palwor.2006.10.002.
  2. ^ Walcott, Charles (1896). "Fossil Jelly Fishes from the Middle Cambrian Terrane". Proceedings of the United States National Museum. 18 (1086): 611–614. doi:10.5479/si.00963801.18-1086.611. Archived from the original on 7 December 2023. Retrieved 7 December 2023.
  3. ^ Walcott, Charles (1898). "Fossil Medusae" (PDF). Monographs of the United States Geological Survey. XXX. Archived (PDF) from the original on 16 September 2016. Retrieved 31 August 2015.
  4. ^ "Is the middle Cambrian Brooksella a hexactinellid sponge, trace fossil or pseudofossil?". EurekAlert!. 24 February 2023. Archived from the original on 24 September 2023. Retrieved 8 May 2024.
  5. ^ Nolan, M.R.; Walker, S.E.; Selly, T.; Schiffbauer, J. (2023). "Is the middle Cambrian Brooksella a hexactinellid sponge, trace fossil or pseudofossil?". PeerJ. 11: e14796. doi:10.7717/peerj.14796. PMC 9969855. PMID 36860767.