Hermaea bifida

Hermaea bifida (Montagu, 1815)

Hermaea bifida @ Es Caials 20/02/2010 by Miquel Pontes
Taxonomy
Class: Gastropoda  Cuvier, 1797
Subclass: Heterobranchia  J.E. Gray, 1840
Clade: Euthyneura  Spengel, 1881
Clade: Panpulmonata  Jörger et al., 2010
Clade: Sacoglossa  von Ihering, 1876
Superfamily: Limapontioidea  J.E. Gray, 1847
Family: Hermaeidae  H. Adams & A. Adams, 1854
Genus: Hermaea  Lovén, 1844
Species: Hermaea bifida (Montagu, 1815) [Doris]

Synonyms

  • Doris bifida Montagu, 1815 (original)
  • Hermaea hancockii Trinchese, 1877
  • Physopneumon carneum A. Costa, 1864
  • Physopneumon corneus Costa A., 1864

Description
This species can reach a size of more than 20 mm but specimens generally found on seaweeds measure just a few millimeters. The body is narrow, elongated, with a semitransparent and slightly yellowish-green hue. Cerebral ganglia, some reproductive and digestive organs, such as the buccal bulb and the esophagus, can be seen by transparency, for instance, two reddish-brown or brown lines, corresponding to the digestive gland can be seen, one on each side of the back, passing very close to the base of the cerata and reaching almost the end of the queue. The head is very short and with two rounded lobes at its anterior margin. The rhinophores are located well ahead of the body and are auriculate, open at its outer side, semitransparent and decorated with white granulations on the tip, in their middle and between the two insertion points into the head. The tip of the rhinophres shows two lobulations, a longer dorsal one and a ventral somewhat shorter one. The cerata are semitransparent and can be extended or contracted a lot, becoming long and slender when the animal is in motion but short and thick when the animal is at rest. The cerata, when fully extended are thin at the base and go wider until near the apex, where there is a conical tubercule on the apex and several subapical tubercules (up to 4-5). In small specimens of about 4-5 mm, the cerata are inserted into the body single or in pairs, and are often of very different sizes. In larger specimens there can be up to 9-10 groups of 2-3 cerata on each side of the body. Within cerata, digestive gland is seen as a narrow, longitudinal, straight and brown cord having perpendicular leads which are directed toward the tip of the tubercules. There could be translucent white granulations on the cerata surface, especially at the tip of the tubercules. The anal papilla is located directly in front of the heart area and is short and shaped conical, having white granulations near its base. The genitalia orifices are located at the right side of the body, between the base of the rhinophore and the insertion of the first cerata. The foot is relatively narrow, colored greenish-yellow and has two rounded lobes at the front side; may show whitish granulations on the foot margins.

Biology
This sacoglossan species lives in shallow places among Rhodophyceae algae such as Griffithsia flosculosa, of which apparently it feeds on and acquires the algae rhodoplasts that confer the reddish-brown color to the digestive gland of the animal. It has been collected in shallow water (2-3 m) among Rhodophyceae algae of the genus Lophosiphonia. The spawn is a flat spiral ribbon of about 5 mm in diameter, with white eggs measuring 50 microns in diameter.

Etymology

  • Hermaea. Derived from Hermes, character in Greek mythology.
  • Bifida. From Latin bifidatus, divided in two.

Distribution
This species is known in Atlantic waters, around the British Isles, in the Strait of Skagerrak (separating Norway from Denmark), in the Iberian Peninsula and in the western Mediterranean. It has also been cited in the Caribbean Sea. In the Iberian Peninsula it has been cited in Galicia, all along the Portuguese coast, in the Atlantic coast of Andalusia, in the Strait of Gibraltar, the southeastern coast and, in the Catalan coast, in several locations of the Costa Brava like Cadaqués, Cala Aiguafreda (Begur), Cala Margarida (Palamos) and Tossa de Mar.

Known georeferenced records of the species: Hermaea bifida (z-200).
Sources:
: OBIS : OPK
: GROC 2010-2011 : VIMAR
: Enric Madrenas : Manuel Ballesteros.
: João Pedro Silva : M@re Nostrum
: Bernard Picton : Other sources
: GBIF.ORG : Marine Regions

References for the species: Hermaea bifida

    Galicia: Rolán (1983). Portugal: De Oliveira (1895), Hidalgo (1917), Nobre (1936), Machado and Fonseca (1997, as H. cf. bifida), Calado et al. (1999, 2003). Andalucía (Atl.): Cervera, García-Gómez and Ortea (1991, as H. boucheti). Gibraltar: García-Gómez (2002). Levante: Fez (1974), Templado (1982b, 1983, 1984), Marín and Ros (1988). Catalunya: Ballesteros (datos no publicados) [Palamós, Tossa de Mar].

    Sources: Cervera et al., 2004, Ballesteros, 2007, McDonald, 2006 and other sources.

Abundance

        Western Mediterranean:0 Stars
        Eastern Mediterranean:0.0 Stars
        Atlantic Ocean:0.0 Stars
This chart displays the observation probability for Hermaea bifida
based on our own records.

More pictures

Bibliography

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:

Ballesteros, Manuel, Enric Madrenas, Miquel Pontes et al. (2012-2017) "Hermaea bifida" in OPK-Opistobranquis, Published: 14/05/2012, Accessed: 23/04/2017 at (http://opistobranquis.info/en/rRgD3)

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