Polycera hedgpethi

Polycera hedgpethi  Er. Marcus, 1964

Polycera hedgpethi @ France by Pascal Girard
















































Polycera hedgpethi  Er. Marcus, 1964

 Classification according to Bouchet et al. (2017)
Taxonomic source: World Register of Marine Species (AphiaID: 140835).

  • Polycera gnupa Er. Marcus & Ev. Marcus, 1967

Species with a typical length of about 15 mm, with a maximum recorded size of 50 mm in California. The base color of the body is translucent white, sprayed with a large number of small dark spots that give it a greyish, brown or even black appearance. Its body is dotted with small tubercles that are usually lighter in color or even yellow, distributed more or less regularly along the body. The head has, in its anterior part, between 4 and 6 thin tentacles with a white base and a yellow distal ring that may or may not reach the tip, more or less dotted with gray or black spots. The rhinophores are translucent white, have between 8 and 12 lamellae, and are dotted with dark spots, mainly on the anterior side, while the posterior side is finely dotted with white. The distal end of the rhinophores is yellow and they emerge from tall rhinophoral sheaths also dotted with dark spots. The edges of the notum form two thin translucent white ridges (almost without dark spots) with some aligned tubercles that are sometimes spotted with yellow. The gill is located in the middle of the dorsum, and is formed by 7 to 10 non-retractile gill leaves, dotted with dark spots and with yellow ends, arranged in a circle and protected by 6 gill appendages (3 on each side). Gills have the  same color pattern as the head tentacles. The foot is narrow and has the same color as the body, although the edges appear less pigmented, so they have a white appearance. A light-coloured, often discontinuous dorsal ridge connects the gills to the end of the animal’s sharp tail, which is tipped with yellow.

This species occurs at shallow depths, generally up to a maximum of 10 meters, near the bryozoans of the genus Bugula on which it feeds. In tropical seas it is usually found in reefs but in the rest of the world it usually appears near ports, on floating docks, piles, etc. always close to its food source. The spawn is a wide, spirally wound, gelatinous ribbon containing small white eggs, also located near its food.


  • Polycera. From Greek “polys”, many + “keras”, horns.
  • Hedgpethi. Dedicated to Prof. Joel Walker Hedgpeth, (1911-2006), Californian pycnogonid taxonomist and ecologist at Pacific Marine Station, Dillon Beach. Active between the 1930s-1980s (and director of the Marine Science Laboratory, Newport, Oregon between 1965 to his retirement in 1973), but also publishing at least until 2000. Hegdpeth had the largest private collection of books dealing with the sea shore in the world.

Species with cosmopolitan distribution. First described in California, today it is observed all over the world, off the coast of North America, in West Africa, South Africa, New Zealand, Australia, Japan, in France (where it is abundant in L’Etang de Thau, but also It is found in Salses-Leucate and in Cap d’Agde), in Italy both on the western and eastern coasts (Adriatic Sea), in Slovenia… In Spain it has been found in the Bay of Biscay but also on the Costa Brava in the breakwater of the Port of Roses. Its distribution near the commercial ports might be accidental, linked to maritime transport, being transported on the hull of ships, or in ballast waters.

Known georeferenced records of the species: Polycera hedgpethi
: 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 monthly observation probability for Polycera hedgpethi based on our own records.



More pictures


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    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 (2023) "Polycera hedgpethi" in OPK-Opistobranquis. Published: 14/09/2014. Accessed: 20/04/2024. Available at (https://opistobranquis.info/en/?p=14413)

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