 |
| see note below* |
Physa acuta (also
known as Physella acuta) is a
well-known biologically invasive species that is now distributed over much of the world. It was originally described
by Draparnaud in 1805 from the Garonne River in France and initially thought to
be indigenous to Europe. Beginning in
2002, reports were made that perhaps the species was not native to Europe, but
was native to North America making it an invasive species to Europe and
Asia. Recently, Lydeard et al. (2016) (http://www.bioone.org/doi/full/10.4002/040.059.0213)
in the journal Malacologia,
synthesized available reproductive, anatomical, fossil, and phylogenetic data
and provided a compelling case that the species is indeed indigenous to North
America and was introduced and described in France.
Recently, Maxim Vinarski, added considerable knowledge on
the biologically invasive history of P.
acuta in a paper published in Biological Invasions (http://link.springer.com/article/10.1007/s10530-016-1339-3). Vinarski surveyed a range of literary sources
and examined molluscan collections to determine the first record of P. acuta
in the countries of Europe, Transcaucasia, and Central Asia and trace their
route of invasion. Interestingly, he
determined that the earliest records of P.
acuta in the New World can be traced
back to 1742 suggesting that the species may have gained a stronghold sometime
possibly in the 17th century.
He hypothesized that its introduction was due either to accidental
transport by humans or long-distance dispersal.
The continued spread throughout the Palearctic appears to be due to
anthropogenic factors.
Vinarski’s research has really shed considerable light on the spread of a problematic, biologically invasive mollusk species.
Literature Cited
Lydeard, C., D.
Campbell, and M. Golz. 2016. Physa
acuta Draparnaud, 1805 should be treated as a native of North America, not
Europe. Malacologia 59(2):347-350.
Vinarski, M.
V. 2017.
The history of an invasion: phases of the explosive spread of the physid
snail Physella acuta through Europe,
Transcaucasia and Central Asia. Biol.
Invasions 19:1299-1344.
*The Figure is a 'portrait' of a giant
specimen of P. acuta from thermal waters (Bad Villach) of Austria. In Central
Europe (Poland, Austria) this species sometimes produces such thermal races
characterized by enlarged shell size. It was once described as a species
'variety': Physa acuta var. thermalis. The shell is from the Natural
History Museum of Vienna collection.
