Pomacea (pomacea) scalaris (D'Orbigny, 1835)



Pomacea scalaris Pomacea scalaris, Paraguay River, near Caceres, Mato Grosso State, Brasil.
Collected from mud and grass, September 2001.
Pomacea scalaris Pomacea scalaris, notice the sharp shell shoulder. The shell is somewhat similar to the Pomacea diffusa shell, but the shoulder is much more pronounced.
Pomacea scalaris Pomacea scalaris, view from above. Pomacea scalaris
Pomacea scalaris shell.
(picture not licenced under creative commons)


Shell: Olive green to brown shell with faint or without darker stripes. Most remarkably in Pomacea scalaris is the step-like shell shoulders, somewhat comparable with those in Pomacea diffusa and Pomacea bridgesii, although more pronounced. Its name scalaris is obviously derived from the shell shape (scalariform).
Operculum: The operculum is corneous and the structure is concentric with the nucleus close the centre of the shell.
Eggs: Laid above the water surface on objects or vegetation (see picture below).

Pomacea scalaris
Pomacea scalaris depositing the eggs on a trunk above the waterlevel.
(picture not licenced under creative commons)

Distribution: This snail species can be found in Argentina and Brasil. However, Reeve (1856) originated his shell sample from Bolivia.
Similar to: Pomacea scalaris looks similar to Pomacea diffusa, to which it's probably closely related to. In Pomacea scalaris, the shell shoulder is much more angulated, in such extent that it almost carinated.



Creative Commons License
Except where otherwise noted, this page is licensed under a
Creative Commons Attribution-NonCommercial-ShareAlike 2.5 License