[Terrestrial gastropods zoogeography in Southern Tamaulipas, México]

Biogeography of Mexican terrestrial mollusks is poorly known, although many studies have described some of their biological aspects. This study aimed to contribute with new information on the distribution of terrestrial mollusks in this region of high altitudinal, topographic and climatic variations of Southern Tamaulipas State, México. For this, terrestrial gastropods were surveyed from December 1990 to November 2006. A total of 525 samples were obtained from 121 localities, characterized with different vegetation types. The primary zoogeographical feature was the presence of many endemic taxa, with 45 species or subspecies, representing the 43%, the highest value for Northeastern México. In addition, a total of 24 species (23%), were of Neotropical and Neartic distributions, and 15 species or subspecies (14%) exhibited Neotropical distributions. Furthermore, the family Spiraxidae showed the largest number of endemic species, with 17 species and two subspecies, and had the largest number of endemic species (27) for Northeastern México.