in Sri Lanka - Ministry of Environment

Provisional Checklist of Marine Aquatic Shelled Molluscs Of Sri LankaExcluding Freshwater GastropodsMalik FernandoPart 1: Provisional Checklist of Species of Gastropods in Sri LankaPart 2: Provisional Checklist of Species of Bivalves in Sri LankaThe Phylum MOLLUSCA Cuvier, 1795 contains numerous classes that include animals ofnumerous forms, both terrestrial and aquatic. This checklist deals only with aquatic forms,carrying external shells consisting of one or two pieces, in the classes Gastropoda and Bivalviainhabiting marine and brackish waters (see box 01).Box 01Phylum Mollusca Cuvier, 1793Class: Aplacophora von Hering, 1876 – Spiny, shell-lessmolluscsClass: Polyplacophora Blainville, 1816 – chitons; with 8-shellplatesClass: Monoplacophora Odhner, 1940 – cap-shell molluscs;deep seaClass: Gastropoda Cuvier, 1795 – snails; includes shell-lessslugsClass: Bivalvia Linnaeus, 1758 – bivalves; clams, mussels,oystersClass: Scaphopoda Keferstein in Bronn, 1862 – tusk shellsClass: Cephalopoda Cuvier, 1797 – octopuses, squids,cuttlefishes and nautilusesAfter de Bruyne, 2003Box 02CLASSGAS-TROPO-DAORDER 6 10SUPERFAM-ILY30 28FAMILY 60 42BIVAL-VIAGENERA 173 113SPECIES 469 287Terrestrial forms are found only among the Gastropoda (some species in OrdersArchitaenioglossa & Pulmonata) and consist of terrestrial and arboreal species; these areexcluded from this checklist. The great majority of species in this class are wholly marine; aminority occurs in brackish water, some ranging into water that may be fresh in tidal rivers.Others are entirely freshwater inhabitants (some species in Orders Neritopsina, Sorbeoconcha& Pulmonata) and are excluded from this checklist. The Order Opisthobranchia contains mostlyspecies with no shells or greatly reduced shells that are internal; however, a few families ofspecies with external shells are included here.The Bivalvia are wholly aquatic and essentially marine with very few freshwater species. As allthree undoubted species of freshwater bivalves (Family Unionidae) have been collected andphotographed they have been included in the checklist. One record reported by Hadl (1974)from a single specimen is excluded; it was probably a misidentification referring to a brackishwater species (Family Corbiculidae) that is included here.The species in this list have been arranged in natural orders according to de Bruyne (2003)pages 309 to 316. The list is simplified to some extent, the species being listed under Class,Sub-class, Order, Superfamily and Family; the divisions Superorder, Suborder and Subfamilyare not employed except in three instances where the subfamily category has been used.384