Dear Manuel et al.,
This is interesting. Could you please cite a paper that discusses radular
morphology in terms of construction and function?
Andrew K. Rindsberg
Geological Survey of Alabama
-----Original Message-----
From: Conchologists List [mailto:[log in to unmask]] On Behalf Of
Manuel J. Tenorio
Sent: Wednesday, April 20, 2005 2:22 PM
To: [log in to unmask]
Subject: Re: Why are radulae sometimes so useful, yet other times almost
useless for taxonomic assignent?
Dear friends,
Radular characters are specially useful in those families in which they have
become highly specialised, like toxoglossa: conidae, turridae and
terebridae. Conidae are among the most diverse and highly specialised
gastropods from the point of view of the radular characters. Of course,
radular diversification has to do with the diet, and in the case of conidae
a specific diet has a specific radula, namely piscivorous, molluscivorous,
vermivorous or "specialised" (like Conus californicus, for instance). DNA
studies have shown that species diversification in conidae is closely
related with changes in dietary habits as well. In fact, conidae can be
grouped depending on radular characters ranging from "primitive" (no barb,
no serration, small and numerous teeth, etc) to highly specialised (more
than two barbs, few large teeth, etc.). Of course, ontogenic changes do
occur, and these have been documented in a few cases (i.e. Conus ermineus,
or Conus fergusoni), hence adult specimens radular characters are to be
considered in order to avoid misleading results. ALso, statistic analysis
must be used, so the study of a representative sample of a given species or
population must be performed in order to verify the consistence in radular
morphology, something that usually (and fortunately) occurs among conidae.
IN any case, radular morphology in conidae is useful for species separation,
but it has to be considered together with other traits: shell morphology,
ecology, egg capsules, etc.
Manuel Jimenez Tenorio
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