Sea pansy

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Sea pansy
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Cnidaria
Class: Octocorallia
Order: Pennatulacea
Family: Renillidae
Genus: Renilla
R. reniformis
Binomial name
Renilla reniformis
(Pallas, 1766)

The sea pansy, Renilla reniformis, is a species of soft coral in the family Renillidae.[1] It is native to warm continental shelf waters of the Western Hemisphere.[2][3] It is frequently found washed ashore on North East Florida beaches following northeasterly winds or rough surf conditions. It also can often be found living intertidally completely buried in the sand. Its predator is the striped sea slug, Armina tigrina.

The sea pansy is a collection of polyps with different forms and functions.[1] A single, giant polyp up to two inches in diameter forms the anchoring stem (peduncle). This peduncle can be distended to better anchor the colony in the substrate. The pansy-like body bears many small, anemone-like feeding polyps. A cluster of tentacleless polyps form an outlet valve that releases water to deflate the colony. If the colony is on a sand bar at low tide, it usually deflates and becomes covered with a thin film of silty sand. Small white dots between the feeding polyps are polyps that act as pumps to expand the deflated colony. The feeding polyps secrete a sticky mucus to trap tiny organisms suspended in the water. The colony’s rigidity and purple color come from calcium carbonate spicules throughout the polyp’s tissues.

The sea pansy is strikingly bioluminescent when disturbed because of the interplay between a luciferase (Renilla-luciferin 2-monooxygenase) and green fluorescent protein (GFP). Both molecules have recently become extremely important in biology.[4] It also produces secondary metabolites for chemical defence that may make it an interesting source of marine natural products.[5]

A draft genome of R. reniformis was sequenced in 2018, producing a haploid genome size of 172 megabases (Mb). This makes it one of the most small and compact coral genomes discovered to date[6]


  1. ^ a b Williams GC (2011-07-29). "The global diversity of sea pens (Cnidaria: Octocorallia: Pennatulacea)". PLOS ONE. 6 (7): e22747. Bibcode:2011PLoSO...622747W. doi:10.1371/journal.pone.0022747. PMC 3146507. PMID 21829500.
  2. ^ "Renilla reniformis (Pallas, 1766)". World Register of Marine Species. Retrieved 2022-10-20.
  3. ^ "Sea Pansy (Renilla reniformis)". Encyclopedia of Life. Retrieved 2022-10-20.
  4. ^ Ruppert E, Fox R (1988). Seashore Animals of the Southeast. University of South Carolina Press. ISBN 0872495353.[page needed]
  5. ^ Clavico EE, De Souza AT, Da Gama BA, Pereira RC (October 2007). "Antipredator defense and phenotypic plasticity of sclerites from Renilla muelleri, a tropical sea pansy". The Biological Bulletin. 213 (2): 135–40. doi:10.2307/25066629. JSTOR 25066629. PMID 17928520. S2CID 24742847.
  6. ^ Kayal E, Bentlage B, Pankey MS, Ohdera AH, Medina M, Plachetzki DC, Collins AG, Ryan JF (2018). "Phylogenomics provides a robust topology of the major cnidarian lineages and insights on the origins of key organismal traits". BMC Evolutionary Biology. 18 (1): 68. Bibcode:2018BMCEE..18...68K. doi:10.1186/s12862-018-1142-0. ISSN 1471-2148. PMC 5932825.

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