Doto fragilis

Doto fragilis (Forbes, 1838)

• Doto aurita Hesse, 1872
• Doto pinnigera Hesse, 1872
• Melibaea fragilis Forbes, 1838
• Melibaea minuta Forbes, 1844

Description
With a body size up to 40mm it is one of the bigger Doto, although Mediterranean specimens are generally smaller. Body base colour is yellowish-brown and shows a line of white dots along the border of the oral veil and the body flanks from the base of the rhinophores to the tail. It has two rows of up to 9 cerata along the sides of the back. Each cera is formed by rings of tubercles that bear no apical marks but have scattered white dots more dense to the tip of each tubercle. Pseudobranchs are very developed transversally. The back has clusters of white dots between cerata. Rhinophores are retractile and of the same colour of the body. Rhinophoral sheaths are trumpet-shaped with a smooth rim lined with white dots and a distinctive crest visible ahead of their base.

Biology
Found at relatively shallow depth (above 20 m), this species feeds on the hydrarians Nemertesia antennina and N. ramosa. These animals keep a perfect mimicry on the hydrozoans so they are very difficult to observe by the naked eye. The existence of specimens in the colonies can be guessed when spawns are observed on them. Spawns form long white undulated ribbons laid on the hydrarians it lives on. The animal is frequently found at the base of the hydrarian.

Etymology

• Doto. From Latin “doto”, gifted.
• Fragilis. From Latin “fragilis”, fragile, weak.

Distribution
This species is common around the British Isles and the northern French Brittany, with a general distribution from Norway to the Mediterranean, where we had no previous reports until March, 6th, 2021 when Paqui Serra and Oriol Planes found a specimen at L’Escala, Girona, Spain (see pictures below).

Known georeferenced records of the species: Doto fragilis

Sources:
OBIS GROC 2010-2011 Enric Madrenas João Pedro Silva Bernard Picton GBIF	OPK VIMAR Manuel Ballesteros M@re Nostrum Altres fonts Marine Regions

Similar species
Doto hystrix, an Atlantic species similar in colour but with conical tubercles on cerata. Doto lemchei, smaller, paler with white glands visible on the tips of the tubercles.

Videos

More pictures

Doto fragilis 24042008 by Jean Michel Crouzet

Doto fragilis Two individuals at the base of Nemertesia ramosa. Maidens, North Channel, Northern Ireland, -30m. 17 June 2008. – Photograph ©Bernard Picton

Doto fragilis by Bernard Picton

Doto fragilis @ L’Escala, Girona, Spain 6.03.2021 by Paqui Serra i Oriol Planes

Doto fragilis @ L’Escala, Girona, Spain 6.03.2021 by Paqui Serra i Oriol Planes

Doto fragilis @ L’Escala, Girona, Spain 6.03.2021 by Paqui Serra i Oriol Planes

Bibliography

1246567 Doto fragilis 1 eunomia-revista-en-cultura-de-la-legalidad 50 creator asc 1 14566 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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