Saxonellidae

Saxonellidae is a family of small, freshwater snails, aquatic gastropod mollusks in the superfamily Lymnaeoidea. The family contains two genera, Saxonella and Pyrgulopsis, with a total of about 15 species. Saxonellidae are characterized by their small size, typically less than 10 mm in length, and their smooth, rounded shells. They are found in freshwater habitats, including ponds, lakes, and slow-moving streams, primarily in the Northern Hemisphere.

The family is notable for its unique reproductive strategy, known as parthenogenesis. In some species, females can reproduce asexually, producing offspring without fertilization. This is particularly common in the genus Saxonella. The family also exhibits a high degree of genetic diversity, with some species showing significant genetic differentiation between populations.

Saxonellidae are of interest to researchers studying the evolution of reproductive strategies and the genetic basis of speciation. Their small size and relatively simple life cycle make them suitable for laboratory studies. However, due to their small size and often cryptic nature, they are not well-studied compared to other freshwater gastropods.