Data from: Evaluating shell variation across different populations of a freshwater snail

The freshwater snail Potamopyrgus antipodarum has become a model system
for studying invasion ecology, host–parasite coevolution, the maintenance
of sexual reproduction and ecotoxicology. One understudied aspect of this
snail is the variation in morphology within and among populations, which
could provide insights into ecological differences across its native
range. In this study of 17 New Zealand lake populations of P. antipodarum
we used linear measurements and geometric morphometrics to compare several
aspects of shell size and shape. We found that, except for those from Lake
Te Anau, most lake populations of P. antipodarum differ slightly in shape,
but differ significantly in size and in the presence of spines, where
larger and spinier snails are found in deeper regions. These striking
distinctions in size and shell armature, but not in shape, suggest that
the various components of form are under different selective regimes.
Snails from Lake Te Anau are different in both shape and size, implying
that this population is diverging from the rest of the species in multiple
ways, making it an interesting study population for further research.