Freshwater crab Nature (IUCN); of the species for which data are available, 32% are threatened with extinction. For instance, all but one of Sri Lanka's 50 freshwater crab species are endemic to that country, and more than half are critically endangered. Freshwater crab There are around 1,300 species of freshwater crabs, distributed throughout the tropics and subtropics, divided among eight families. They show direct development and maternal care of a small number of offspring, in contrast to marine crabs which release thousands of planktonic larvae. This limits the dispersal abilities of freshwater crabs, so they tend to be endemic to small areas.
Freshwater snail the highlighted families consist entirely of freshwater species, but some of them also contain, or even mainly consist of, marine species.) The following cladogram is an overview of the main clades of gastropods based on the taxonomy of Bouchet & Rocroi (2005), modified after Jörger et al. (2010) and simplified with families that contain freshwater species marked in boldface: (Marine gastropods (Siphonarioidea, Sacoglossa, Amphiboloidea, Pyramidelloidea) are not depicted within Panpulmonata for simplification. Some of these highlighted families consist entirely of freshwater species, but some of them also contain, or even mainly consist of, marine species.) The Neritimorpha are a group