Variation in the Diacria trispinosa group, new interpretation of colour patterns and description of D. rubecula n. sp. (Pteropoda)

The development of the initial stages of the colour pattern on the ventral shell side in the eight taxa of the Diacria trispinosa group is studied. A new species: D. rubecula, is split off from D. maculata on the basis of the discriminating value of these initial colour patterns. The relation of the taxa in the group is discussed and their distributions are compared.