Buffalo Pebblesnail

The mantle is black, or shows dark pigmentation. This pigmentation is also seen in the nape, the anterior part of the snout, the top of the tentacles, and along the edge of the peristome (the margin of the gastropod shell). The radula of Gillia altilis looks like a single serrated blade, with 51-55 rows of teeth. Each row has 2 central basocones, 3-4 central octocones, 8-9 lateral teeth, ca. 30 inner marginal teeth and 6-9 outer marginal teeth.

Gillia altilis is native to the Atlantic coastal drainage of North America. It occurs from New York State and Vermont south to South Carolina. In some regions where Gillia altilis is native, populations are declining or not very abundant: for example, in Vermont, this species is considered to be an invertebrate species in "greatest conservation need". This snail is listed as a species of special concern in its native range in New York State, where the species is ranked as S1 (very vulnerable due to low abundance of species and/or required habitat), protected U SC (unprotected at present but of special concern due to increasing evidence of vulnerability) and globally as G5 (rare but not vulnerable). Loss of habitat due to anthropogenic modifications, pesticides and competition with introduced species are considered the major threats to declining or vulnerable gastropod populations in New York State.

This snail has a radula that is specialized, exhibiting overall larger but fewer cones and cusps on the various teeth, which are adapted for grazing on coarser food particles than are eaten by related snails in the subfamily Lithoglyphinae.