The exact
type locality for this species is unknown, but it is probably the
Main river in Southern Germany. but in reality the species occurs in the western to central
Palaearctic. It is in fact one of the most widely distributed species in the entire family Neritidae.
Europe is one of the locations where
Theodoxus fluviatilis is known to occur. The species occurs widely in Western Europe, and it is also widespread in the north of
Ireland, It lives in
Great Britain, Belgium, Luxembourg, Liechtenstein, and Monaco. In central Europe, this species has been recently introduced in the
Austrian Danube, where it was first recorded in
Tulln,
Lower Austria in 2001. In the
Czech Republic, it is now extinct in Bohemia; the only findings were in the
Elbe river near
Litoměřice in 1917, and in Hungary. provided a detailed bibliography of the distribution of
T. fluviatilis in
Germany. The indigenous distribution of
T. fluviatilis included all of the large rivers:
Rhine,
Main,
Moselle,
Neckar,
Weser,
Elbe and
Oder. In Northern Europe, this species is found in Denmark, No other
Theodoxus species reaches the
Baltic Sea. It has the northernmost
distribution of the genus Theodoxus and it is also the northernmost species of all Neritidae. In Eastern Europe this snail occurs in Estonia, and in Russia from western Russia In Ukraine and in Crimea it is non-indigenous, and was first recorded in the area in 1955. It also occurs in Moldova. In Southern Europe,
Theodoxus fluviatilis lives in Albania, In Macedonia and Albania it occurs in
Lake Ohrid (which spans the border of the two countries) as the subspecies
Theodoxus fluviatilis dalmaticus. It is found on the mainland of
Greece and also on
Crete. It is known to occur in the mainland of Italy
Asia and Africa In Asia,
Theodoxus fluviatilis is found in
Turkey. It can also be found in
Iran, in the provinces of
Kerman,
Gilan,
Mazandaran,
Fars,
Hormozgan,
Lorestan and
Khorasan. In Africa this species occurs in Algeria,
Prehistoric biogeography Shells of
Theodoxus fluviatilis have been found in an
Upper Paleolithic archaeological site in the cave
Caldeirão,
Pedreira (Tomar),
Tomar Municipality, Portugal, and also in a site from about 6000 years B.P. of
Litorina age on the Åland Islands. Bunje (2005) hypothetized that the ancestral range of
Theodoxus fluviatilis was the
Ponto-
Pannonian region (southern Ukraine, Romania and Hungary). Bunje suggested that the species first colonized northern Italy, Greece and Turkey; in the second phase it colonized Spain, France and Germany; and finally in the
Holocene it colonized the British Isles, Sweden and the Baltic Sea. In 2002, German
malacologist Peter Glöer summarized the distribution of this species during the
Pleistocene and
Holocene epochs. ==Description==