> I put a locally-collected Williamia krebsii Mørch, 1877 under the scope
> yesterday to confirm. The same topology is seen in the Melampidae (except
> for Blauneria, which has the opposite orientation). Despite the similarity
> in their embryonic chirality, I've always thought of Pyramidellidae
> (Heterobranchia) and the Melampid-Siphonaria (Eupulmonata) lineages as very
> distant phylogenetically.

My own thoughts are that the so-called Archaeopulmonata are not in any
way related to the Pulmonata, but are derived from the basal
Opisthobranchia. They all have the typical opisthobranch hyperstrophic
dextral protoconch (sinistral in Blauneria, of course), including
Amphibola.

I was preparing a small fossil "limpet" (from a brand-new Oligocene
locality with a totally unexpected and oh-so-rare intertidal fauna)
under the binoc when I noticed that it had a hyperstrophic protoconch.
But when I tried to clean it the protoconch fell off, and being a
small fraction of a millimeter in size, there was no way I could
reattach it. However I'd guess that this was a siphonariid with
symmetrical teleoconch; Siphonaria is also present in this fauna. As
an aside, this fauna  (Nerita, Cellana, and various other
patellomorphs, gigantic ?Terebralia, hipponicids, ellobiids) kills
dead the hypothesis being spouted by some that NZ was completely
inundated in the Oligocene.

--
Regards
Andrew Grebneff
Dunedin, New Zealand
Fossil preparator
Mollusc, Toyota & VW van fanatic

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