Reconstructing historical egocentric social networks in malacology: can eponyms serve as a proxy for contacts?

During the 19th and 20th century eponyms have been widely used in taxonomy to honour collectors of material on which new taxa have been based. Also have new taxa been dedicated to author-colleagues. Five cases are discussed to trace the extend of overlap between eponyms and known contacts of the author, using different sources of historical data (source publications of the author, provenance data in collections, correspondence archive, reprint administration). Authors have had personal preferences in the extend to which they dedicated eponyms to persons they were in contact, either indirectly (field collectors) or directly (field collectors, cabinet collectors or collegial authors). Eponyms named after a person who is known to have authored malacological papers strongly suggests that there was contact between the two authors (correspondence and/or exchange of material). If eponyms were given in reciprocation their contacts were likely to be relatively strong. Eponyms may be used as a proxy for contacts of the author if the contextual information is taken into account.