Geoplanidae is a family of flatworms known commonly as land planarians or land flatworms.

These flatworms are mainly predators of other invertebrates, which they hunt, attack and capture using physical force and the adhesive and digestive properties of their mucus. They lack water-retaining mechanisms and are therefore very sensitive to humidity variations of their environment.

Because of their strict ecological requirements, some species have been proposed as indicators of the conservation state of their habitats. They are generally animals with low vagility (dispersal ability) and with very specific habitat requirements, so they can be also used to accurately determine the distribution of biogeographic realms. Today the fauna of these animals is being studied to select conservation priorities in the Atlantic rainforest in Brazil.

At the other extreme, one species in this family, Platydemus manokwari has become an invasive species in both disturbed and wild habitats in the Pacific Islands, and has damaged the endemic land snail fauna. This species has been found in Europe (France) in 2013 for the first time, and in 2015 in New Caledonia, Wallis and Futuna Islands, Singapore, Solomon Islands, Puerto Rico (first record in the Caribbean), and Florida, USA.

...