I am not going to suggest a candidate for this dubious "honor".
However, Linnaeus would NOT be the first name to come to my mind.  He
was the "father of taxonomy" and for that, malacologists are indebted
to him; but they have no more claim on him than mammalogists,
ornithologists, herpetologists, ichthyologists, and innumerable other
"ists", not the least of which is botanists.  I'm sure Linnaeus didn't
consider himself a "sheller".  He certainly couldn't be called a
malacologist, since he didn't recognize mollusks as a distinct
entity.  He divided the animal kingdom into seven major categories
(the actual concept of "phylum" came about later) - mammals, birds,
reptiles, amphibians, fishes, insects, and worms.  The mollusks,
along with most other invertebrates, he classified as "worms".  His
objective was to name and classify all objects of nature - mineral,
plant, and animal.  He did this not to provide a foundation for other
sciences, nor to compile a body of information, but for the process
itself - he enjoyed classifying things.  He was a great naturalist,
but there is no indication that he had any special affinity for what
we know as the mollusks.  They were just one of the many elements
which his ambitious project required him to deal with.  Given the
many prominent individuals who have devoted their entire professional
lives to the study of mollusks, I'd have to say Linnaeus would be a
poor choice for "best sheller".
Paul M.