Home Guide to Opisthobranchs Aplysiida Stylocheilus polyomma

Stylocheilus polyomma

Stylocheilus polyomma (Mörch, 1863)

Stylocheilus polyomma @ El Hierro 17-10-2012 by Aketza Herrero

Taxonomy
 

Superdomain

Biota  

 

Kingdom

Animalia  

 

Phylum

Mollusca  

 

Class

Gastropoda  

 

Subclass

Heterobranchia  

 

Infraclass

Euthyneura  

 

Subterclass

Tectipleura  

 

Order

Aplysiida  

 

Superfamily

Aplysioidea  

 

Family

Aplysiidae  

 

Genus

Stylocheilus  

 

Species

Stylocheilus polyomma  (Mörch, 1863)

 
 Classification according to Bouchet et al. (2017)
Taxonomic source: World Register of Marine Species (AphiaID: 1445911).
Taxonomic note: There was a long time discussion about the identity of Stylocheilus longicauda (Quoy & Gaimard, 1825) and Stylocheilus striatus (Quoy & Gaimard, 1832). Unfortunately these authors noted that S. striatus was probably the same as S. longicauda, beginning a confusion which has persisted until the present. Today most researchers consider that there are two species of Stylocheilus: S.striatus, with dark longitudinal lines, a mottled colour pattern and compound papillae, and S.longicauda with a uniform yellow or green colour, simple papillae, without lines and an extremely long slender ‘tail’. Despite these species were clearly differentiated, Yonow (2012) reverted back to the confusion by ignoring evidence presented by Rudman (1999) that they are distinct species.

According to Bazzicaluppo et al. (2020) Stylocheilus striatus is a cryptic species complex formed by three allopatric different species: the name S. striatus is retained for an Indo-Pacific species, while the names S. polyomma and S. rickettsi are resurrected for species inhabiting the Western Atlantic and the Eastern Pacific respectively. These authors also state that “Whereas Bursatella has colonised the Mediterranean, most likely from tropical Atlantic populations (Bazzicalupo et al. 2018), Stylocheilus has not. Even though benthic and pelagic species of Stylocheilus are present in both the Red Sea (Yonow, 2008) and the Canary Islands (Ortea et al., 2008), and favourable conditions have allowed the dispersal of several other species of sea slugs across the Suez Canal (Crocetta et al. 2013; Zenetos et al. 2017) and the Gibraltar Strait (Valdés et al. 2013), something must be preventing species of Stylocheilus from making such a move”.

In our opinion is is mostly because of a water temperature and / or sality issue. For these reasons, as the only Stylocheilus species present in the Atlantic Ocean would be S.polyomma (its native distribution range is from Florida to Brazil), and until genetic analysis are performed on the Canary Islands specimens, the most probable ID for the Canary Islands is, effectively, S.polyomma.

Synonyms

  • Aplysia striata Quoy & Gaimard, 1832 (original)
  • Notarchus polyomma Mörch, 1863
  • Stylocheilus lineolatus Gould, 1852

Description
Stylocheilus polyomma is a medium sized sea slug, reaching up to 65mm, it has a translucent body with patches of greens, browns and white, and often with many branched papillae. This species is distinguished by fine longitudinal brown-to-black lines usually interrupted by ‘eyespots’ with bright blue centres; it has a swelling present in the middle of body, where the parapodial lobes protect a large gill and the anal siphon. The rhinophores and oral tentacles are long and slender. It may have few or numerous villi, depending on the population.

Biology
It can be locally common in algal beds and shallow water, especially during the breeding season, but this does not happen every year. Releases a purple dye when disturbed.

Etymology

  • Stylocheilus. From Latin “stylus”, column, pillar + from Greek χεῖλος, “cheilos”, lip, edge.
  • Polyomma. From Greek “Poly”, multiple and “ὄμμα”, eye in reference to the multiple bright-blue eyespots scattered along the body.

Distribution
Although Stylocheilus striatus is actually a group of cryptic species with an apparently circumglobal subtropical distribution, a recent work by Bazzicalupo et al. (2020) confirmed that there are three distinct species of Stylocheilus striatus and that they are allopatric; the name S. striatus is retained for an Indo-Pacific species, while the names S. polyomma and S. rickettsi are resurrected for species inhabiting the Western Atlantic (type location is Virgin Islands) and the Eastern Pacific respectively. Eastern Atlantic populations are believed to be Stylocheilus polyomma until molecular analysis are performed on specimens from this area to confirm this adscription.

Known georeferenced records of the species: Stylocheilus polyomma
Sources:
: OBIS
: GROC 2010-2011
: Enric Madrenas
: João Pedro Silva
: Bernard Picton
: GBIF.ORG		 : OPK
: VIMAR
: Manuel Ballesteros.
: M@re Nostrum
: Altres fonts
: Marine Regions

Abundance

    Western Mediterranean: ☆☆☆☆☆
    Eastern Mediterranean: ☆☆☆☆☆
    Atlantic Ocean: ★☆☆☆☆
Month

This chart displays the monthly observation probability for Stylocheilus polyomma based on our own records.

More pictures

Stylocheilus polyomma by Danny van Belle
Stylocheilus polyomma @ Sardina, Gran Canaria, Spain 7-08-2012 by Aketza Herrero
Stylocheilus polyomma @ El Hierro 17-10-2012 by Aketza Herrero
Stylocheilus polyomma @ El Hierro 17-10-2012 by Aketza Herrero
Stylocheilus polyomma @ Gran Canaria by Sabina Lopez
Stylocheilus polyomma @ Gran Canaria by Mario Matute

Bibliography

    Bacallado JJ, Ortea J, Moro L, et al. 2008. Inventario de los moluscos de la marina de Arrecife, Lanzarote. Canarias Conservación.:1–32. Available from https://www.canariasconservacion.org/LA%20MARINA/DOC-16-Inventario%20de%20los%20moluscos%20de%20la%20marina%20de%20arrecife%202008.pdf.
    Ballesteros M, Madrenas E, Pontes M. 2025. OPK - Opistobranquis. Available from https://opistobranquis.info/.
    Bazzicalupo E, Crocetta F, Gosliner TM, et al. 2020. Molecular and morphological systematics of Bursatella leachii de Blainville, 1817 and Stylocheilus striatus Quoy & Gaimard, 1832 reveal cryptic diversity in pantropically distributed taxa (Mollusca : Gastropoda : Heterobranchia). Invert. Systematics. 34(5):535–538. https://doi.org/10.1071/IS19056.
    Caballer M, Ortea J, Rivero N, et al. 2015. The opisthobranch gastropods (Mollusca: Heterobranchia) from Venezuela: an annotated and illustrated inventory of species. Zootaxa 4034 (2): 201–256.
    Caballer M, Narciso S, Rivero N, et al. 2022. Nudibranquios y otras babosas marinas de Venezuela. Caracas. Venezuela: Explora Ediciones.
    Camacho-Garcia Y, Gosliner T, Valdes A. 2005. Guía de Campo de las babosas marinas del Pacífico Este tropical. S.l.: California Academy of Sciences.
    Cervera JL, Calado G, Gavaia C, et al. 2004. An annotated and updated checklist of the opisthobranchs (Mollusca: Gastropoda) from Spain and Portugal (including islands and archipelagos). Boletín Instituto Español de Oceanografía, 20 (1-4): 1-111. L.
    Frank, B. et al. 1998 2014. Stylocheilus striatus accessed through: JaxShells.org on 2014-12-14. Available from http://www.jaxshells.org/astria.htm.
    Goodheart JA, Ellingson RA, Vital XG, et al. 2016. Identification guide to the heterobranch sea slugs (Mollusca: Gastropoda) from Bocas del Toro, Panama. Marine Biodiversity Records. 9(1):56. https://doi.org/10.1186/s41200-016-0048-z.
    Imamoto J. 2001 2014. Stylocheilus striatus accessed through: Umiushi.info on 2014-12-14. Available from http://www.umiushi.info/kanri/photo_sql_eng.php?act=PSP&gakumei1=Stylocheilus&gakumei2=striatus&location_code=0000#.
    Long SJ. 2006. Bibliography of Opisthobranchia 1554-2000. Bayside Books & Press, Tustin, CA, U.S.A. 672p.
    Malaquias MA, Calado GJP. 1997. The malacological fauna of Salvage Islands - 1. Opisthobranch Molluscs. Bol. Mus. Mun. Funchal, 49(281): 149-170.
    Malaquias M, Calado G, Padula V, et al. 2009. Molluscan diversity in the North Atlantic Ocean: new records of opisthobranch gastropods from the Archipelago of the Azores. Marine Biodiversity. 2:e38.
    McDonald G. 2009. Bibliographia Nudibranchia. 2nd Online Edition, Annotated. 1072 pp  Institute of Marine Sciences, University of California, Santa Cruz. Available from http://escholarship.org/uc/item/8115h0wz.
    Ortea J, Moro L, Bacallado JJ, et al. 2008. Nuevas aportaciones a la fauna de opistobranquios (Mollusca: Gasteropoda) de las islas Canarias. Vieraea 36: 129-136. 36:129–136.
    Ortea J, Espinosa J, Caballer M, et al. 2012. Initial inventory of the seaslugs (Opisthobranchia and Sacoglossa) from the expedition Karubentos, held in May 2012 in Guadeloupe (Lesser Antilles, Caribbean Sea). Revista de la Academia Canaria de Ciencias 24: 153-182.
    Quoy JRC, Gaimard JP. 1832. Voyage de découvertes de l’ “Astrolabe” exécuté par ordre du Roi, pendant les années 1826-1829, sous le commandement de M. J. Dumont d’Urville. Zoologie, Tome 2. J. Tatsu.
    Rudman WB. 1999. Stylocheilus longicauda & Stylocheilus citrina Nomenclatural discussion. Sea Slug Forum. Available from http://www.seaslugforum.net/stylnome.htm.
    Rudman W.B. et al. 1998 2010. Stylocheilus striatus accessed through: Sea Slug Forum on 2014-12-14. Available from http://seaslugforum.net/showall/stylstri.
    Valdés A, Hamann J, Behrens DW, et al. 2006. Caribbean sea slugs: a field guide to the opisthobranch mollusks from the tropical northwestern Atlantic. Washington: Sea Challengers Natural History Books. 289 pp.
    Wirtz P, Debelius H. 2003. Mediterranean and Atlantic invertebrate guide. Hackenheim, Germany: ConchBooks.
    WoRMS Editorial Board. 2025. World Register of Marine Species. WoRMS. Available from http://www.marinespecies.org.
    Yonow N. 2012. Opisthobranchs from the western Indian Ocean, with descriptions of two new species and ten new records (Mollusca, Gastropoda). ZooKeys. 197:1–129. https://doi.org/10.3897/zookeys.197.1728.

    Bibliography based on the works by Steve Long, 2006. Bibliography of Opisthobranchia 1554-2000 and Gary McDonald, 2009. Bibliographia Nudibranchia, with later updates from other resources.

Further reading

Cite this article as:

Pontes, Miquel (2012-2025) "Stylocheilus polyomma" in OPK-Opistobranquis. Published: 19/01/2015. Accessed: 03/02/2025. Available at (https://opistobranquis.info/en/?p=17597)