Stylocheilus striatus

Stylocheilus striatus (Quoy & Gaimard, 1832)

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

Class: Gastropoda  Cuvier, 1797
Subclass: Heterobranchia  J.E. Gray, 1840
Clade: Euthyneura Spengel, 1881
Clade: Euopisthobranchia  Jörger et al., 2010
Clade: Aplysiomorpha  Pelseneer, 1906
Superfamily: Aplysioidea  Lamarck, 1809
Family: Aplysiidae  Lamarck, 1809
Genus: Stylocheilus  Gould, 1852
Species: Stylocheilus striatus (Quoy & Gaimard, 1832) [Aplysia]

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..


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

Stylocheilus striatus is a medium sized opisthobranch, 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 long tail and a swelling is present in the middle of body, where the parapodial lobes enclose a large gill and an anal siphon. The rhinophores and oral tentacles are long and slender. It may have few or numerous villi, depending on the population. Releases a purple dye when disturbed.

It can be locally common in algal beds and shallow water, especially during the breeding season, but this does not happen every year.


  • Stylocheilus. From Latin “stylus”, column, pillar + from Greek χεῖλος, “cheilos”, lip, edge.
  • Striatus. From Latin “striatus”, striated, grooved.

Circumglobal. Subtropical. There are reports from Australia, Galápagos, Brasil, Caribbean, Philippines, Florida, Hawaii, Cape Verde, Gulf of Mexico, SW India, Maldives, Zanzibar, Mauritius, La Réunion, Mayotte, and Madagascar.

Known georeferenced records of the species: Stylocheilus striatus
: GROC 2010-2011
: Enric Madrenas
: João Pedro Silva
: Bernard Picton
: Manuel Ballesteros.
: M@re Nostrum
: Altres fonts
: Marine Regions


    Western Mediterranean:
    Eastern Mediterranean:
    Atlantic Ocean:
This chart displays the observation probability for Stylocheilus striatus based on our own records.


Stylocheilus striatus @ Tulamben, Bali by Cix Cutez @ Nudibase (Facebook)
Bloom of Stylocheilus striatus amidst the algae Avrainvillea amadelpha
at 50 meters (Jan 7th, 2015) (YouTube)
Stylocheilus longicauda by Shane Siers (

More pictures


Further reading

Cite this article as:

Ballesteros, Manuel, Enric Madrenas, Miquel Pontes et al. (2012-2017) "Stylocheilus striatus" in OPK-Opistobranquis, Published: 19/01/2015, Accessed: 18/12/2017 at (

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