59.1 Jan. 7 Are radular tooth characters of the gastropod Conus informative for taxonomy and phylogeny? KOHN, A.J.*; MEYER, C.P.; Univ. of Washington, Seattle; Univ. of California, Berkeley email@example.com
Conus radular teeth are independently operating, hypodermic needle-like structures that inject paralytic neuropeptides to overcome prey. We tested the hypotheses that 1) they are sufficiently complex to provide discrete and quantitative characters useful in evaluating the range of intraspecific variation within and interspecific differences among closely related species, and 2) phylogenies constructed from radular tooth character matrices are congruent with those based on mitochondrial gene sequence data. For both hypotheses we selected three functional species groups from our current gene sequence database of more than 200 congeners. Radular characters evaluated included the number, size, shape, and configuration of barbs, blades, and serrated edges, and presence or absence of a waist, spur, or cusp. In an earlier study Nishi and Kohn showed that nine quantitative characters were sufficient, either singly or in combination, to distinguish a set of 11 molluscivorous Conus species, concluded to be distinct but closely related on the basis of shell characters, from one another. Species-level molecular phylogeny suggests that all extant molluscivorous Conus species arose from a single common ancestor. Phylogenetic analysis of radular tooth characters in this clade also indicates a high degree of congruence with the molecular phylogeny. In the second functional group, that of piscivorous species, molecular genetic evidence suggests multiple origins within the genus. Taxonomies based on gene sequence and shell characters agree. Molecular and radular tooth morphology-based phylogenetic hypotheses are somewhat less congruent than in the molluscivorous species group. Data on the third group, vermivorous species of the Western Atlantic region, are currently being analyzed.