This family represents the true frogs and, together with the Leptodactylidae (southern or tropical frogs), contains the largest number (well exceeding 100) of genera. The teeth are bicuspid, with a small cusp located on the labial slope of the conical tooth tip. Teeth are continuously replace...
Forexample,aspeciesmaydelineate(描述)anecoregion(生态区)orindicateanenvironmentalconditionsuchasadiseaseoutbreak,pollution,speciescompetitionorclimatechange.Indicatorspeciescanbeamongthemostsensitivespeciesinaregion,andsometimesactasanearlywarningtomonitoringbiologists.—http://en.wikipedia.org/wiki/Indicator_species ...