Micronesica 35-36:244-270. 2003 Prosobranch gastropods of Guam BARRY D. SMITH Marine Laboratory University of Guam Mangilao, Guam 96923 U.S.A. email:
[email protected] Abstract—Based on records from invertebrate collections at the University of Guam, specimens cataloged at other institutions, and the published literature, there are 895 species of prosobranch gastropods from Guam. The vast majority of the species are marine, but terrestrial and aquatic prosobranchs are included. Most the species recorded to date are conspicuous, epibenthic species from shallow reef habitats, but some species have been taken from depths up to 400 m. Microgastropods less than 7 mm in size have been poorly investigated to date. Comparison of prosobranch gastropods from Guam and Enewetak reveal that some 56% of the species occurring at Enewetak are found in Guam. Introduction Molluscs have been collected in Guam since the arrival of the earliest inhabitants (Thompson, 1945). Despite the long history of European contact with the island, scant attention was given to systematic investigation of the fauna until the collections of Quoy and Gaimard (1824–1826; 1830–1834). Hidalgo (1904– 1905) was the first to produce a catalog that included molluscs from Guam, but his emphasis was mostly on the Philippine Islands fauna. This catalog was followed by a series of unpublished lists produced by shell collectors and shell club members during the last several decades. Synoptic collections of molluscs from Guam and Micronesia were started by faculty of the University of Guam in the mid-1960s. These collections are housed in the Richard E. Dickinson Memorial Mollusc Collection at the University of Guam Marine Laboratory.