Taxonomic publications: past and future - Senckenberg Museum

Burckhardt & Mühlethaler (eds): 8 th GfBS Annual Conference Abstracts 46
Re-interpretation of the distribution and biogeography of helicinid snails on the
Lesser Antilles and Puerto Rico (Mollusca: Gastropoda: Neritopsina)
Ira Richling
Although fairly known, the geological history of the Caribbean region still remains
subject of controversial discussions. The same applies to an even higher degree to
our understanding of distribution patterns of flora and fauna in this area where
vicariance and dispersal hypotheses were repeatedly contrasted (e. g. summarised
by Dávalos, 2004). Therefore exact systematics and data on the distribution of
different groups of organisms are urgently needed. Due to their low mobility land
snails provide an excellent example for such studies. A preliminary revision of the
helicinid fauna of the Lesser Antilles and Puerto Rico will exemplarily highlight
possible misinterpretations of biogeographic issues based on wrong systematic
classification.
Applying previous classifications (Wagner, 1907-1911; Baker, 1926, 1940) the
helicinid snail fauna of the Lesser Antilles and Puerto Rico appears to be more
closely related to the fauna of the Greater Antilles with a comparably similar
assemblage of the present genera, although greatly depleted in the diversity. Besides
others most of the Lesser Antillean species were assigned to Alcadia and subgenera
and only few to Helicina.
New studies based on reliable anatomical characters, such as the structure of the
female reproductive system and the embryonic shell, reveal that the genus Alcadia is
completely absent from these islands with only two exceptions, contrasting the
situation on Jamaica, Cuba and Hispaniola. The helicinid assemblage is clearly
dominated by the highly diversified genus Helicina. The Puerto Rican subgenus
Striatemoda has to be transferred from Alcadia to Helicina. Contrary to conclusions
reached by following previous classifications these results hereby render the fauna of
the Lesser Antilles and Puerto Rico remarkably distinct from the Greater Antilles
where the genus Helicina is only represented by very few species.
Whereas Cuba, Hispaniola and Jamaica each harbours only endemic species of
Helicinidae, some of the species of the Lesser Antilles show a wider distribution on
several islands. Population-based studies of certain species mainly on Guadeloupe,
Dominica and Martinique allow hypotheses about their diversification. Data will be
given for Helicina fasciata, Helicina rhodostoma and Helicina platychila.
Org. Divers. Evol. 5, Electr. Suppl. 13 (2005)