Tayuva maculosa

Tayuva maculosa (Bergh, 1884)

Tayuva maculosa @ Costa Brava by Enric Madrenas

Taxonomic note: The recent and thorough revision of the Discodorididae by Dayrat (2010), based on morphological and internal anatomy characters, brought to light the existence of synonymous species from different seas around the world and reduced the number of valid species within the Discodorididae family. Such was the case of Discodoris maculosa, a well-known Mediterranean species that was included in the species Tayuva lilacina, a species with a very wide circumtropical distribution and in temperate seas such as the Mediterranean. However, new molecular phylogenetic studies revealed that Tayuva lilacina was a rather complex of different species masked with a very similar morphology. This point has been demonstrated by the recent work of Fernández-Vilert et al (2025) in which, after genetically analysing various specimens of Tayuva from different parts of the world, they discovered four different cryptic groups, proposing the transfer of the Mediterranean specimens, which correspond to Discodoris maculosa Bergh, 1884 to the new combination Tayuva maculosa, and the specimens from the north-eastern Atlantic, which correspond to Discodoris confusa Ballesteros, Llera and Ortea, 1985 are resurrected as the new combination Tayuva confusa. Fernández-Vilert et al (2025) also comment that the genus Peltodoris forms a clade very close to Tayuva, documenting several cases of previous synonymies of species initially classified as Peltodoris, for which reason they propose obtaining more genomic information to study these groups and their possible synonymy.

Synonyms

• Discodoris maculosa Bergh, 1884
• Diaulula hummelincki (Ev. Marcus & Er. Marcus, 1963)
• Discodoris hummelincki (Ev. Marcus & Er. Marcus, 1963)
• Discodoris ketos gila (Er. Marcus & Ev. Marcus, 1970)
• Peltodoris hummelincki Ev. Marcus & Er. Marcus, 1963
• Tayuva ketos gila Er. Marcus & Ev. Marcus, 1970

Description
This is a medium to large doridacean species whose Mediterranean specimens can reach 60 mm in length. The body is flattened and of leathery texture. The general coloration of the back is brownish-gray with abundant rounded greenish-brown different sized spots. All the back is adorned with numerous small conical tubercles tightly placed. In some samples there could be a kind of discontinuous middle dorsal white line running from the inter-rhinophoric area to the gill area, and is formed by the alignment of white tubercles. The entire back of the animal, including tubercles has abundant internal spiculation. The rhinophores are slightly yellowish with brown lamellae and the apex has the shape of a club; the rhinophoric sheath has 12-14 small tubercles along its upper margin. There are 6 tripinnate gills with yellowish-white leaves surrounding the anal papilla; the branchial sheath is slightly elevated and has a lobed top edge. The underside of the mantle and the sidewalls of the body have abundant brownish-red spots of different sizes. The foot is quite wide, whitish but with numerous reddish-brown stains and marks. The mouth has two short white oral palps.

Biology
This species is usually located at shallow depth under stones, from tidal pools to several meters deep. In this habitat, because of its coloration and flattened appearance, the animals may easily overlooked or being confused with encrusting sponges, on which they feed as other members of the family Discodorididae. The spawn is a whitish spiral of about 20 mm in diameter filled with 90 microns eggs.

Etymology

• Maculosa. From Latin “maculosa”, spotted.

Distribution
Last genetic works on this species (Fernández-Vilert et al., 2025) assign the name Tayuva maculosa to the Mediterranean specimens of this species, so in the Iberian Peninsula it has been reported in the Strait of Gibraltar, in the Andalusian Mediterranean coast, on the Levantine coast and in Catalonia. In the Catalan coast it has been observed in northern Costa Brava (Sant Antoni and Es Caials in Cadaqués and Cap Falco in Roses), among other places. Specimens cited in the Atlantic, especifically those on the Cantabrian coast and Canary Islands as classified now as Tayuva confusa.

More pictures

Bibliography

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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

• Biodiversity Heritage Library
• BiologiaMarina.org
• CIESM Atlas of Exotic Species in the Mediterranean
• El Litoral de Granada
• Flickr pictures
• Interim Register of Marine and Nonmarine Genera
• MedSlugs (Med)
• NCBI GenBank
• OBIS - Search by Taxon
• Sea Slug Forum
• Sea Slugs of Hawaii
• The SlugSite
• Vibrant Sea
• World Register of Marine Species

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