The Phyllidiella zeylanica is a dorid nudibranch, a marine gastropod mollusk. They were first described in Sri Lanka by Keelart in 1859 hence the name Zeylonika. They are known as the Ceylon Phyllidiella in some areas.
Phyllidiella zeylanica have an elongated oval shape and rows of tubercles running longitudinally around the body, curving to meet on the anterior and posterior. The colour varies greatly in Tanzania from a dull purple to a slightly brighter pink purple. Black lines which are not always continuous line the body between the rows of tubercles. The rhinophores are black and are retractable as can be seen in the images below. A black longitudinal stripe is present on the sole of the foot. They grow up to 12 centimeters in length but they are usually smaller.
IN THE WILD
Phyllidiella zeylanica are the most common nudibranchs seen in Tanzanian waters. They are usually seen singly but occasionally in pairs. They have the ability to secrete toxic substances which provides protection against predators. They seem more tolerant of being photographed than most other nudibranchs. They usually retract their rhinopores and stop moving whereas others will usually head for cover.
The Phyllidiella zeylanica is found across the Indian ocean and in the west Pacific.
The Phyllidiella zeylanica feed mainly feed on certain species of sponge.
They are simultaneous hermaphrodites and mating takes place by darting. The individual who darts the other first becomes the dominant male and the other the female. Eggs are laid on a solid substrate and when they hatch the larvae become planktonic before growing into adults.
PHYLLIDIELLA ZEYLANICA CLASSIFICATION
Species: Phyllidiella zeylanica
The Reef Guide fishes, corals, nudibranchs & other invertebrates
East and South Coasts of Southern Africa
Dennis King & Valda Fraser