Allometrisissa

Allometrisissa is a genus of small, terrestrial snails, terrestrial pulmonate gastropod mollusks in the family Hydrobiidae. The genus was first described by the German zoologist Karl Friedrich Hermann in 1804. Allometrisissa species are characterized by their small size, typically ranging from 2 to 4 millimeters in length, and their smooth, glossy shells. The shells are usually ovate or oval in shape, with a distinct aperture and a columellar tooth.

The genus is distributed in Europe, with the majority of species found in the Mediterranean region. Allometrisissa species are known to inhabit a variety of habitats, including forests, grasslands, and agricultural areas. They are generally herbivorous, feeding on plant material such as leaves, flowers, and fruits.

The taxonomy of the genus Allometrisissa is complex, with many species described in the past that are now considered synonyms or subspecies of other species. As of 2021, the genus includes approximately 15 recognized species, with the most well-known being Allometrisissa helvetica, which is found in Switzerland and Italy.

Allometrisissa species are of interest to scientists due to their small size and unique adaptations to their environments. They are also of interest to collectors and hobbyists, who appreciate their beauty and rarity. However, their small size and limited distribution make them vulnerable to habitat loss and other environmental threats. Conservation efforts are ongoing to protect these species and their habitats.