Pleurophyllidiella paucidentata   O'Donoghue,  1932 (Sea Slug)
Organism information awaits expert curation
Class: Gastropoda

Size: The largest specimen measures 11 mm long by 4.5 mm wide and 3.25 mm high.

Color: The color of the whole animal, except the dorsum is a dirty, pale yellow; the dorsum is dark grey, almost black with the ridges a greyish white, but the dark color varies in intensity and exhibits three or four transverse bands. The stalk of the rhinophores is similar in color, but the tips orange yellow; the sides of the body, head, and foot are of the same orange yellow color.

The body is low, flattened, and tongue-shaped; it is obtusely rounded at the front end, and bluntly pointed posteriorly. The dorsum is marked by a series of 10-12 longitudinal, raised ridges of which the median three pass right to the posterior end and the next one on each side nearly that far. In certain specimens these ridges may unite or divide, but this is not similar in any two individuals. Much lower and less conspicuous ridges lie between the others. The dorsum extends outwards as a well-marked mantle flange from the sides of the body and anteriorly passes across as a ridge with a notch in the median line. Cnidophore sacs occur all along the margin of the mantle and show as tiny yellow dots.
The sides of the body are vertical. The head is well marked and produced dorsally into the cephalic veil characteristic of the family; the dorsal surface of the veil is smooth and it bears no caruncle. When this veil is contracted it appears bilabiate on the ventral side. The anterior lip is much wider and capable of considerable expansion, and the ventral lip is narrower but carried out laterally into indistinct lappets. The mouth appears as a perforation just in front of the middle of the lower lip. The foot is well developed, bluntly rounded with a thickened margin at the anterior end, and passes over posteriorly into a pointed tail which is quite distinct from the dorsum. It is marked off from the body wall by a well-developed flange. The rhinophores are short and finger-shaped and bear a few low, inconspicuous longitudinal folds. They lie close together on the dorsal surface of the head immediately beneath the notch in the middle of the dorsum. There is no trace of gills, and the lateral lamellae are reduced to two small longitudinal folds on the underside of the mantle where it joins the body wall at the anterior end. The larger of the folds is just less than 1 mm long and the other only half this size. When the mantle is expanded sideways the lateral lamellae are diminished and might easily be overlooked.
The genital aperture lies near the anterior end about half-way up on the side of the body, and the anus lies posterior to this and higher up on the body wall. Buccal complex is provided with a chitinous lining of irregular shape. This is furnished with masticatory edges provided with numerous bluntly conical projections arranged in three or four rows. The radula contains fewer teeth than is usual in the family and has 32 or 33 rows of teeth of which 2 are not fully formed.
The formula of the first row is 0.1.0, of the second 1.1.0, of the third 2.1.1, of the fifth, and of a complete row further back The median tooth has a roughly rectangular base wider than long; its hinder corners are rounded and the front ones produced into short points. In the middle of the hinder edge is a rounded notch. From the base arises a median long-pointed spine, and this is flanked by six, slightly curved, shorter spines on each side. All the spines arise well back on the base and not from its edge. The first lateral tooth has a roughly rectangular base, wider than long, with its sides slightly curved and its corners rounded, except the front mesial one which is produced into a short point. The base bears ten long sharp spines, which arise about half-way back and form a group nearer the mesial than the lateral margin. The second lateral tooth has an almost square base with curved sides and rounded corners. It bears a curved, pointed blade, with eight long spines on it projecting forwards. The remaining lateral teeth have an irregular base with a simple, curved, pointed blade and no spines. They gradually decrease in size from within outwards.

Synonym (s)

Common Name (s)
Economic Importance and Threats



• Tamil Nadu, Pamban INDIA
• Tamil Nadu, Gulf of Mannar INDIA

Literature Source(s)
  • O'Donoghue, CH (1932) Notes on Nudibranchiata from southern India Journal of Molluscan Studies The Malacological Society of London 20(3) 141-166 Available at -
  • Society for the Management of European Biodiversity Data (2009) World Register of Marine Species (WoRMS) Available at -

Page last updated on:2010-11-26

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