Starting in the 1860s, the terrestrial and freshwater molluscs of Trinidad and Tobago have been fairly well studied.
Thomas Bland published the first paper mentioning terrestrial molluscs in 1861.
[1] Robert John Lechmere Guppy discovered and identified many more species from 1864 onwards, and along with Edgar Albert Smith was responsible for the earliest comprehensive species lists.
The list here includes all the non-marine mollusks found in Trinidad and Tobago's ecosystem including native, introduced and invasive species alike.
Freshwater gastropods include: Ampullariidae Ancylidae Hydrobiidae Physidae Planorbidae Thiaridae Land gastropods include: Helicinidae Neocyclotidae Diplommatinidae Annulariidae Truncatellidae Veronicellidae Achatinidae Ferussaciidae Streptaxidae Succineidae Vertiginidae Gastrocoptidae Valloniidae Amphibulimidae Bulimulidae Orthalicidae Simpulopsidae Urocoptidae Scolodontidae Gastrodontidae Philomycidae Euconulidae Helicarionidae Strophocheilidae Charopidae Trichodisccinidae Thysanophoridae Freshwater bivalves include: Mycetopodidae Sphaeriidae (=Pisidiidae) Lists of non-marine molluscs of nearby countries and islands: