Freshwater Molluscan Shells
Chilinidae native only to the temperate southern regions of South America, one genus,
Chilina, with 23 species listed by Pilsbry (1911) for the area east of the Andes.
Pilsbry goes on to indicate
"Chilina occupies the temperate and cold zones of South America from the Tropic of Capricorn to Cape Horn [and the Falkland Islands] ...Within their area, the Chilinidae are abundant snails in all suitable stations... They swarm in springs, small streams, lakes, and in some places the margins of rivers. They are most abundant southward, becoming rarer and local toward the northern borders of their range. The species from west of the Andes are in all cases, so far as we know, distinct from those east ot the divide....
The eastern fauna ... inhabits a comparitively arid region, poorly watered by roughly parallel streams flowing southeastward into the Atlantic. Each of the principal river systems has its own series of freshwater mollusks, in large part distinct specifically or racially from those of other rivers."
Brace, (1983) indicates that they are adapted through both physical and behaviorial features to burrowing in soft substrates . He also suggests that morphological evidence supports the relationship of Chilina, and by inferance, the rest of the Basommatophorans, to primitive opistobranch gastropods.
Chilina fluminea Orbigny, Buenos Aires Province, Argentina
Chilina dombeiana (Bruiguiere, 1789),
Rio Negro province, Argentina
Chilina globosa Sowerby
1841. Buenos Aires Province,
Marshall, 1933 Rio Negro