The non-marine molluscs of Dominica are species of land and freshwater molluscs, i.e. land snails, land slugs and one small freshwater clam that are part of the wildlife of Dominica, an island in the Lesser Antilles. In malacology, the non-marine molluscs of an area are traditionally listed separately from the marine molluscs (those molluscs that live in full-salinity saltwater). Dominica is a Caribbean island, part of the Windward Island chain of the Lesser Antilles. Fifty-five species of non-marine molluscs have been found in the wild in Dominica, including sixteen endemic species of land snails, species which occur nowhere else on Earth. Dominica is a mountainous, 750 km2, volcanic, tropical island. It is undeveloped compared with most other Caribbean islands, and it is known for its wildlife and unspoiled natural landscapes. The rugged terrain includes a great deal of tropical rainforest, numerous rivers, and several officially protected areas, including Morne Trois Pitons National Park and Cabrits National Park. The rich natural landscapes of Dominica provide suitable habitat for a wide range of different species of wildlife, including many rarities, and a relatively large number of species of non-marine molluscs, both native and introduced. Living in the wild in Dominica there are 54 species of gastropods, (11 species of freshwater gastropods including 2 neritids that live in brackish water, 43 species of land gastropods) and 1 species of freshwater bivalve.

History of surveys of land gastropods

The first records of land gastropods from Dominica were published by the English naturalist Robert John Lechmere Guppy in 1868. During his visit (a vacation which he turned into an active malacological field trip) Guppy collected a total of 20 species from Dominica. Out of these twenty, he described 9 as new species. Subsequently, additional records were added by Thomas B. Bland (1869), A. D. Brown (1881), George French Angas (1884), Edgar Albert Smith (1888, 1888) and Henry Augustus Pilsbry (1892). Four surveys of the terrestrial malacofauna were carried out in the 2000s: 2001 (Ramnath), 2003, 2005 (Robinson, Fields & Zimmerman) and 2008 (Hovestadt). These studies were summarized in 2009.

Land gastropods overview

The list of Dominican land gastropods contains 43 species, making it one of the richest known faunas of land snails and slugs in the Lesser Antilles. Of these, 16 species (38%) are endemic to the island. The endemic species of Dominican gastropods are mainly found on the leeward (or Caribbean Sea) side of the island. Amphibulima pardalina, Diplopoma sp., Laevaricella perlucens, Naesiotus stenogyroides and Veronicella sp. are very restricted in range, and probably meet the IUCN-criteria for Critically Endangered species. Amphibulima browni and Lucidella sp. are likely to meet the criteria for being listed as endangered species. There are striking faunal relationships with the islands of Guadeloupe and Martinique. Furthermore, 9 of the species (21%) are widespread, and 13 species are considered to have been introduced into Dominica. The landsnail fauna can be analyzed according to the elevational range of the species. There is a distinction between the windward (east) and leeward (west) side of the island, according to the parishes in which the localities are situated. While most species exhibit a rather wide elevational range, several are restricted in this respect. Very few species only occur at lower elevations: Diplopoma, Allopeas, Beckianum and Huttonella species. These taxa are largely introduced species. Some species are restricted to higher localities: Lucidella sp., veronicellids (except the introduced Veronicella cubensis and Veronicella sloanei), Naesiotus stenogyroides, Amphibulima pardalina and Laevaricella perlucens. These do not occur, however, on the upper slopes of the higher peaks, but seem to be restricted to the hygrophytic vegetation zone, i.e. the cloud forest. Many localities have a rather low species richness. For example, in surveys from 2001–2008, at six localities no snails were encountered; at the remaining 64, species richness ranged from 1 to 17 (mean 4.54). Taking into account the rareness of species, the southeast of the island scores well when the total diversity is considered. The area of Freshwater Lake in Morne Trois Pitons National Park is a biodiversity hotspot for land snails. However, several other localities situated in the national parks are also important areas for the occurrence of endemic species: the Syndicate Parrot Preserve and the Lake Boeri area. These national parks lie on the leeward side of the island at relatively high elevations (above 600 m).

Freshwater gastropods

The systematic list uses scientific names including the authority, and is arranged according to families: Neritidae Planorbidae Thiaridae Physidae Neritiliidae Ampullariidae

Land gastropods

Helicinidae Neocyclotidae Pomatiidae Veronicellidae Succineidae Subulinidae Streptaxidae Bulimulidae Amphibulimidae Oleacinidae Scolodontidae Haplotrematidae Agriolimacidae Pleurodontidae The following species have been reported from Dominica in the literature, but supporting material has not been found. These species, recorded due to inaccuracies of provenance of specimens or misidentifications, should be removed from the faunal list of the island:

Freshwater bivalves

Sphaeriidae