Pseudoilbia lineata
Miller & Rudman, 1968

Superfamily: RUNCINOIDEA
Family: Ilbiidae


North Island, New Zealand


Holotype. On Corallina at low tide. Bream Tail, sth end of Langs Beach, NE New Zealand. 21 August 1963. Photo: M.C.Miller [digitally enhanced by WBR]

The body, when extended, broad, being widest and highest about the middle. Head end of the notum weakly bilobed and the hind end rounded. The surface of the notum is thrown into irregular transverse folds. The foot is about the same width as the notum, and is rounded in front. At the posterior end the foot extends beyond the body by between a quarter and a fifth of the total length. On the sole of the foot, at a point about one-fifth of the length from the hind end, there is a prominent depression and from this a narrow groove runs to the tip. The anus opens in the mid-line beneath the posterior overhang of the notum. No gill; renal pore nor genital aperture were visible.

At each end of the notum there is a translucent white area, each roughly a sixth of the notal surface; the rest is mottled with black in five distinct longitudinal bands separated by four narrow pigmentless zones which appear orange red due to the digestive gland showing through the skin. Immediately behind the black region is a narrow transverse stripe of orange red (the digestive gland) and this is followed by a broad zone of opaque white granules. Eyes clearly visible through two circular pigmentless areas at the front end of the black region. Sides of the body lightly speckled with black and on each side a narrow band of opaque white granules running the length of the notum. The 'tail' is translucent white with an oval area of opaque white granules in the centre. The sole of the foot is lightly speckled with black, with a fairly wide translucent white border.

This species lacks gizzard plates. The radular formula is 2.0.2. It is known from a single animal approximately 3 mm long alive

  • Miller, M.C. & Rudman, W.B. (1968) Two new genera and species of the superfamily Runcinoidea (Mollusca Gastropoda: Opisthobranchia) from New Zealand. Transactions of the Royal Society of New Zealand, 10(19): 183-189.
Authorship details
Rudman, W.B., 2005 (February 9) Pseudoilbia lineata Miller & Rudman, 1968. [In] Sea Slug Forum. Australian Museum, Sydney. Available from