Exploring novel taxonomic character sets in the Mollusca: the Cribrarula cribraria complex (Gastropoda: Cypraeidae) as a case study

Abstract

The goal of this dissertation is to explore novel and non-traditional taxonomic characters that may be useful for mollusks, and combine them with radular and shell characters to carry out a taxonomic review of the genus Cribrarula (Cypraeidae). Shells in this genus have conspicuous dorsal spots, but like odler cowries, lack sculpture, spines, and other shell characters commonly used in gastropod taxonomy. For these reasons, cowrie shells are considered uninformative. The study of dorsal spots (DS) and related characters suggest that at least in this complex, the dorsal spots may represent a record of the mantle papillae. If the hypothesis is correct, then DS may provide information on the soft parts that previously was only available from the study of live or preserved specimens. Each species in the complex has a species-specific range of DS, marginal spots, and allied characters, thus suggesting that they may be useful in distinguishing species in the complex. The odontophore cartilage provides support for the radula and attachment for the muscles responsible for feeding. Although intimately connected to the radula and known since the 1800's, the taxonomic value of the odontophore has been overlooked. A study of odontophore variation in the family Cypraeidae proposes the structure as a novel taxonomic character, potentially applicable to most mollusks. The Cribrarula cribraria Linnaeus, 1758 complex is reviewed, and twelve species and six subspecies are recognized on the basis of multivariate analyses of shell characters, the radula, odontophore, and geographic distribution. The shell, radula, odontophore and distributional maps are illustrated for each taxon. The nominal species, cribraria, ranges from East Africa to the Central Pacific, and several populations are distinctive enough to be recognized as subspecies. The other eleven species are restricted to narrower ranges along the periphery of the distribution of cribraria. During the review of Cribrarula, a new species from New South Wales was described as C. gravida Moretzsohn, 2002.