World Congress of Malacology Antwerp ... - Unitas Malacologica

The value of analyzing Pisidium faunas
Killeen, Ian
53 Charleville Square, Rathfarnham, Dublin 14, Ireland,
Email: iankilleen@eircom.net
Species of the genus Pisidium (Sphaeriidae) are the most diverse and numerically abundant group of
bivalves in European lowland river systems. However, there have been relatively few studies that
have examined the fauna in detail within a large river catchment. Samples of Pisidium were collected
from 158 sites on the River Thames, England and 18 of its tributaries. Quantitative sampling of
Pisidium is problematic and thus the aim was to collect between 200 and 500 individuals at each site
which were then analyzed quantitatively. All individuals were identified and the numbers of each
species converted to a percentage of the whole sample. Twelve species of Pisidium (75% of the
British fauna) were recorded from the Thames catchment. The results showed many differences in
species composition and relative abundance both between rivers and within individual rivers from
upstream to downstream. There was some evidence of a correlation between species
distribution/abundance and environmental factors (habitat and water quality). Species relationships
were also examined using Bray-Curtis similarity. Sampling of selected sites in successive years
demonstrated that the sampling method used for the study gave results on the species’ composition
and relative abundance that were both representative of the site, and repeatable.
A further aspect of the study was on Pisidium tenuilineatum Stelfox, 1918, a species which is
believed to rare across its European range and is Red Data listed in several countries, including
Britain. Prior to this study, P. tenuilineatum was known only from a few sites in the River Thames
and some of its tributaries. During the present study it was recorded in 15 of the 19 rivers, and at 96
of the 158 individual sample sites. Thus, the Thames catchment has a high conservation value and the
data gathered should allow a more informed conservation and management policy to be developed.
Cutting the Gordian knot of a taxonomic impediment
A plea for MOTU-numbers (Molecular Operational Taxonomic Units)
Klee, B.; Hyman, I.; Wiktor, A.; Haszprunar, G.
Zoologische Staatssammlung München, Münchhausenstr. 21, D-81247 München, Germany,
Email: Barbara.Klee@zsm.mwn.de; isabelhyman@gmail.com; awiktor@biol.uni.wroc.pl;
haszi@zsm.mwn.de
Current activities in molecular taxonomy and various barcoding initiatives are defining a large
number of organismic units. However the “taxonomic impediment”, i.e. the lack of taxonomic
specialists, hinders the validation of (known or new) names of these taxonomic units and thus the
application of these units, which often but not always reflect species boundaries, for other biological
questions.
Based on previous experience with OTU-number-systems such as the L-numbers in ichthyology
(catfish family Loricariidae) or the pupae-numbers for chironomid midges (Diptera) in entomology
we propose the establishment of MOTU-numbers based on COI-sequences at the genus to family
level. Each MOTU-number is at least correlated with (1) the GenBank-Codes of the sequenced
specimens, (2) named and geo-referenced location and legitimization of the source of specimens, and
(3) location (e.g. inventory numbers of collections), type and availability of (strongly encouraged)
vouchers. Noteworthy “taxonomic indexing” or “species banks” can also be established on MOTUs,
a web-based information system on the given MOTU-numbers is necessary in any case. Despite the
doubtless advantages of the MOTU-number-system, the establishment of code-based and therefore
stabilized names based on any species concept, which then can be correlated with a (or several)
MOTU-number(s), remains a significant and highly valuable step in the inference of taxa.
This theoretical proposal is illustrated by the species-rich genus Limax (Stylommatophora) as a case
study. While the full taxonomic establishment under the current rules of nomenclature will need
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