Knoutsodonta albonigra

Knoutsodonta albonigra (Pruvot-Fol 1951)

• Lamellidoris albonigra Pruvot-Fol, 1951
• Onchidoris albonigra (Pruvot-Fol 1951)

Description
Specimens of this species are small and flattened, reaching no more than 6-7 mm in length. The background color of the body is whitish with numerous irregular black spots on the back giving it a dark tone. All the back is covered by small conical papillae, the outer ones may slightly exceed the body margin. A long and robust mantle spicules frame can be seen through the dorsum of the animal, central spicules are set transversely, the marginal ones set radially and among them there are obliquely set spicules. The white rhinophores are retractable, having 7-10 lamellae; the rhinophoric hole is smooth. The gill is composed by about 7 whitish gill leaves arranged in a circle, the interbranquial area is black, home of the anal opening and 2-3 papillae as the ones in the rest of the dorsum. Below the mantle margin, the tight marginal spicules can be seen by transparency. The foot is white but there is a patch of reddish-violet color due to the internal organs. The mouth is surrounded by a rounded lump or oral veil lacking any labial palps.

Biology
Nothing is known of this uncommon species biology, only that, as other species of this genus, lives under stones where encrusting sponges and bryozoans abound. Spawn is about 4 mm in diameter, and consists of an spiral of 2-3 turns; white eggs have about 125 microns in diameter, and apparently are laid one after another in an irregular helical path within the gelatinous frame of the spawn cord.

Etymology

• Knoutsodonta, from the Greek meaning “lame tooth”, to represent nudibranch species that lack a rachidian or middle tooth.
• Albonigra, from Latin “alba” (white) and “nigra” (black).

Distribution
Of all the species of the genus in European waters this is the easiest one to identify by the numerous black blotches on the back that give it a dark appearance. However it is one of the least known species because it is a rare finding. So far it is strictly of Mediterranean distribution, the type specimen of the original description by Pruvot-Fol came from Banyuls-sur-mer, only four more specimens have been cited in the Bay of Naples. In the Catalan coast it has been observed in Cadaqués and in some other location of the Costa Brava.

Known georeferenced records of the species: Knoutsodonta albonigra
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

References for the species: Knoutsodonta albonigra

Catalunya: Ballesteros (1980, 1985), Ortea & Ballesteros (1982), Domènech et al. (2002), Ballesteros (datos no publicados) [Cala Sant Antoni].
General: Perrone, 1986a:25; Schmekel & Portmann, 1982:118
Sources: Cervera et al., 2004, Ballesteros, 2007 & 2016, McDonald, 2006 and other sources.

Abundance

Western Mediterranean:
Eastern Mediterranean:
Atlantic Ocean:

More pictures

Knoutsodonta albonigra by Manuel Ballesteros

Knoutsodonta albonigra by Enric Madrenas

Bibliography

1246567 Knoutsodonta albonigra items 1 entomological-society-of-america author asc 1 https://opistobranquis.info/wp-content/plugins/zotpress/
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

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