World Congress of Malacology Antwerp ... - Unitas Malacologica

fragment of about 2200 bp of the mitochondrial genome including parts of the COI, parts of the 16S
rRNA and parts of the COIII genes as genetic markers. A haplotype analysis of 87 samples shows
conspecifity of bioeroders, nestlers and sponge-dwelling specimens in three haplotype groups, with a
maximum genetic divergence of 1.8%. All three groups contain Croatian and Italian specimens,
whereas Spanish and Portuguese samples occur only in one group. These preliminary results suggest
gene flow between Croatian and Iberian populations on one hand and Croatian and Italian
populations on the other hand. The extent of gene flow between Italian and Iberian populations is,
due to the limited sample size, not sufficiently demonstrated. Additional sequences from Spain and
Portugal and Italy may help elucidate the gene flow within this morphologically and genetically
variable species.
Land-snail diversity in a threatened limestone formation in Odukpani, Cross River State,
Nigeria
Oke, Chris O.
Department of Animal & Environmental Biology, Faculty of life science, university of Benin, Benin
city, Edo State, Nigeria,
Email: chrisomaoke@yahoo.com
The land snail fauna of a threatened limestone formation in Odukpani is studied using a combination
of direct search (for 1hour) and litter-sieving techniques. A total of 423 specimens comprising 52
species/morphospecies belonging to nine molluscan families were collected from seven sample plots.
Each plot yielded between 19 and 98 specimens (mean 70.5 ± 31.72). The diversity per plot ranged
from 7 to 34 (mean 19.14, ± 9.74). Extrapolation suggests that the true diversity lies around 72
species. Nine snail families were represented, of which the most prominent was the carnivorous
Streptaxidae. The streptaxids dominated the molluscan fauna in diversity of species and number of
individuals. Twenty-one (40%) species and 158 (37%) individuals of streptaxid land snails was
recorded from the study area. Our study reveals high land snail species richness in Odukpani
limestone cave in spite of low abundances and small sample size. Some of the species found were
new records for the region and probably new to science. The conservation of the limestone cave is
advocated so as to protect its unique biodiversity.
Bivalvia: Inventories and taxonomy in the Indian Ocean
Oliver, Graham P.
Department of Biodiversity & Systematic Biology, National Museum of Wales, Cathays Park,
Cardiff, CF10 3NP, Wales, UK,
Email: graham.oliver@museumwales.ac.uk
Currently there is no inventory of marine bivalves specific to the Indian Ocean. The OBIS Indo-
Pacific Mollusk Database includes the Indian Ocean but is a tool primarily for the systematic
malacologist. Smaller regional inventories would be more valuable for conservation management,
impact surveys, ecology and teaching. The taxonomy behind such inventories should be as accurate
and contemporary as possible and should allow comparable identifications within and between
regions. There are many regional species lists from the 19 th and early 20 th centuries but their
taxonomies are not comparable and the identifications require verification. Many are supported by
museum collections and if consulted can give these older lists enhanced value. A much greater
involvement at the local level is needed to progress this work. Without revision, amalgamation of
previous lists into an ocean inventory would be unwise.
There is superfluity of bivalve names for some taxa but recent taxonomic revisions indicate that there
is also under-estimation of species-richness. This arises from uncritical synonymisation as well as a
multitude of undescribed smaller or cryptic taxa. The largest discrepancy exists with the
Galeommatoidea.
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