shore islands such as the giant centipede (Scolopendra gigantea), the largest centipede species in the world. A few species of large tarantulas may be found in forested areas and even in houses at the forest edge such as the Trinidad chevron tarantula (Psalmopoeus cambridgei), as well as the Trinidad dwarf tarantula (Cyriocosmus elegans) and the pinktoe tarantula (Avicularia avicularia). The arthropod life of Trinidad and Tobago has not been well studied and it is an entomologist's paradise waiting to be discovered, with many species remaining undocumented. There are approximately 70 species of land snails ranging in size from the giant South American land snail (Megalobulimus oblongus) to the tiny Gastrocopta snails. Many species of crustaceans (terrestrial, freshwater and marine) are among the other invertebrates that may be easily observed in Trinidad and Tobago such as the Caribbean hermit crab (Coenobita clypeatus), stream crayfish (Macrobrachium crenulatum) and spotted spiny lobster (Panulirus guttatus). There are nine species of scorpions in Trinidad and Tobago including the medically important Trinidad thick-tailed scorpion (Tityus trinitatis) and slender-tailed scorpion (Tityus tenuicauda). Aquatic communities There are a number of wetland habitats on both Trinidad and Tobago that foster vital aquatic ecosystems. The Bon Accord Lagoon on Tobago is a vital mangrove habitat and home to a population of spectacled caimans as well as a number of wetland bird species. The Caroni Swamp on the west coast of Trinidad has a fairly high level of salinity (compared to other major wetlands on the island) and is an important breeding and feeding habitat for several bird species (including magnificent flocks of scarlet ibis (one of the National Birds)) and several marine fishes and invertebrates. The Nariva Swamp of the east coast is the largest freshwater swamp on Trinidad and has a Ramsar Convention status of wetland of international importance. It and its associated river system of canals and rivers is home to a vast array of aquatic life, including a very small population of the highly endangered West Indian manatee, the green anaconda, the spectacled caiman, the mata mata turtle and the common Suriname toad. The plant community in the swamp include various mangroves, moriche palms and bloodwood trees. There are many small rivers and streams throughout the islands. Over 40 species of freshwater fish have been recorded in Trinidad and Tobago. The world-famous guppy is a common native fish; particularly so in the mountain streams of Trinidad, where