Planorbella duryi?
Francesco Potorti`
<http://pot.potorti.it/acquari/molluschi/Planorbella%20duryi.jpg>
-EC-
> Enrico, quindi questa secondo te č una Planorbella duryi?
Per me si. Fra l'altro a me ne nascono sia con il guscio rosso maculato
come la tua che giallo ambra.
Ciao Enrico
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Corrado
> Enrico, quindi questa secondo te è una Planorbella duryi?
> <http://pot.potorti.it/acquari/molluschi/Planorbella%20duryi.jpg>
con l'intenzione di farti capire meglio, ti riporto un pezzo di un libro in
inglese, di un mio amico, l'amico non è inglese, ed anche il libro pur
essendo scritto in inglese è scritto da uno studioso non inglese:
Planorbella duryi (Wetherbey, 1879) / anceps (Menke, 1830) - 5, 6, 9, 11,
15.
These North-American snails were called Helisoma trivolvis (Say, 1818) in
former Czech
literature. This species is the most common snail of aquariums through the
whole territory.
Unfortunately, we are not able to identify the material to the species
level, but the
occurrence of both mentioned species is very probable. Obviously, there are
some
inconsistencies in the recent malacological literature. Glöer, P (2002)
assesses P. duryi as
a rare species and does not mention its occurrence in aquariums. On the
contrary, he
regards P. anceps as a common snail of European aquariums and expects its
penetration
to the wild nature. On the other hand, Leiss, A. & Reischütz, P.L. (1996)
published many
findings of P. duryi from aquariums. That material was identified according
to Burch, J.B.
& Tottenham, J.L. (1980) (Reischütz, pers. comm.). When we perform
identification
according to Glöer, P (2002) and Burch, J.B. & Tottenham, J.L. (1980) we can
obtain
different results. A juvenile of P. anceps, figured by Glöer, P (2002), is
conchologicaly
very close to P. duryi f. seminole after Burch, J.B. & Tottenham, J.L.
(1980). Therefore,
we conclude that more correct will be to label our material as P. duryi with
respect to
encountering some population of P. duryi f. seminole [sensu Burch, J.B. &
Tottenham, J.L.
(1980)]. The species was also introduced to Africa. In general,
identification of non-native
species will be connected with some problems either due to their occurrence
in different
conditions or because their population are fragmented. Further investigation
on European
Planorbella population is badly needed.
ciao
Francesco Potorti`
>Further investigation on European Planorbella population is badly
>needed.
Grazie dell'interessante citazione.
Però dovrebbe essere possibile distinguere almeno fra Planorbella e
Planorbarius, o anche qui siamo sulle sabbie?