D. Massemin, S. Clavier & J.-P. Pointier 
Pisidium punctiferum and Eupera viridans from French Guiana 
Figure 5. Distribution area of Eupera viridans. 
could be enlarged to Cuba, Costa Rica (Volkmer- 
Ribeiro & Machado, 2009), Texas and Florida (Heard, 
1979) and to the Upper Mississippi River Basin too 
(Illinois), but as an introduced species (Sneen et al., 
2009). The discovery of E. viridans in French Guiana 
would be the first record of this species for the South 
American continent. However, this information must 
be taken with caution, because the systematic of this 
genus remains confusing and misidentifïcations may 
occur in the literature. 
In the Lesser Antilles, Eupera viridans is common 
in marshes, canals and ponds, attached to the aquatic 
végétation or to wood débris (Pointier, 2008). In 
French Guiana, the 44 observed specimens were 
collected in a single spot at Leblond [Sinnamary 
watershed (04°46'37" N / 53°07’08" W)], an altered 
stream under entropie pressures such as illégal gold- 
mining or domestic sewages (Comité de Bassin de 
Guyane, 2006); this Bivalvia appears like a not 
sensitive taxa in terms of bio indication. Punctually 
distributed and first mentioned on the South America 
continent, the species lias a patrimonial value for 
French Guiana. 
In conclusion, we hâve to mention that the 
détection 
of minute clams is difficult in the coloured and 
charged in wood débris of the Guiana freshwaters. 
Lack of studies on this group together with these 
characteristics i.e. small size, difficult visual détection, 
explains the late discovery ofrelatively abundanttaxa 
on this territory. Sampling method is also an 
explanatory factor. Without a standardized collect 
protocol, knowledge on freshwater molluscs remains 
uncompleted (Massemin et al., 2009). The use of a 
hand net with very small mesh size (200 pm) would 
be a good alternative to collect minute species. In 
2010, three new species of freshwater molluscs (one 
Gastropoda and two Bivalvia) from French Guiana 
were found using this technique, increasing the 
number of freshwater species mentioned from this 
overseas department. Why couldn’t the discovery of 
other species be expected in the future? 
Acknowledgements 
Simon Clavier is grateful to DIREN 973, to EDF 
GUYANE for finding the sampling in the Sinnamary 
watershed, and to the teams of HYDRECO and NT2 
Aquatic Environmental Lab (AEL). 
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