The abstract of his presentation was:
Land snails are important organisms
to understand biogeographical changes in different
regions. Their low dispersion ability produces a
particular population structure that resembles
historical patterns of genetic diversity. I compared
genetic patterns in two different species:
scalariformis (Orthalicidae) from the coast of
Peru and Systrophia
helicycloides (Scolodontidae) from the western
Amazonian basin. Both species presented a high
mutation rate in their mitochondrial genome and also
a high intraspecific divergence.
B. scalariformis shows two different lineages which correspond to its different morphotypes. El Niño Southern Oscillation ant the coastal desert could have played a key role in the modeling of the genetic structure in this land snail. On the other hand, S. helicycloides shows lineages with widely distributed and also restricted haplotypes. The actual genetic structure in S. helicycloides seems to be influenced by historical geoclimatic changes, like the rise of the Andes or Pleistocene refuges that both may have produced lineage differentiation. In this case, actual river dynamics could be influential on the distribution of the genetic diversity.
According to Romero, the
populations of Bostryx
are influenced by the
El Nino cycles and their influence on the expanding
and contracting ‘lomas’ vegetation islands in the
coastal desert. On the contrary, the
populations seem to
have been mixed under the influence of the river
dynamics in the Madre de Dios region.