Please use this identifier to cite or link to this item: https://www.um.edu.mt/library/oar/handle/123456789/64849
Title: The archaeogastropoda (Mollusca: Prosobranchia) in Maltese coastal waters : a computerised multiple entry key and biogeographical review
Authors: Sant, Michael J.
Keywords: Biodiversity -- Malta
Crustacea -- Malta
Biogeography -- Malta
Ecology -- Malta
Issue Date: 2001
Citation: Sant, M. J. (2001). The archaeogastropoda (Mollusca: Prosobranchia) in Maltese coastal waters : a computerised multiple entry key and biogeographical review (Master's dissertation).
Abstract: A total of 84 species belonging to the Superorder Archaeogastropoda (Mollusca: Prosobranchia) have been recorded from the coastal waters of the Maltese Islands (Central Mediterranean). Certain species e.g. those belonging to the Trochidae, are important (and sometimes abundant) components of various marine ecosystems. Six species are doubtful records; of the latter, three are species alien to the Mediterranean waters. The Archaeogastropoda occurring in Maltese waters were reviewed in terms of the diversity of their shell morphology, and their biogeographic affinities. Data on shell morphology, ecology and biogeography was collected for all species, both from detailed examination of an extensive collection of reference specimens and from the literature. The accurate identification of molluscs is a critical problem frequently encountered in ecological and conservation research. Consequently, the shell morphology data is analysed and organised according to quality and reliability (in terms of usefulness for identification). A major difficulty in the choice of shell character is the intraspecific variety of shell forms. For example, shell colour is usually a highly variable character in most species, but may be an important diagnostic character distinguishing between species like Gibbula divaricata and G. rarilineata (Ghisotti & Melone, 1972). The practical difficulties in the identification of Archaeogastropod shells are discussed. Given that unique diagnostic shell characters are frequently not available, the use of a combination of shell characters is rendered possible by the use of a multiple entry key. The advantages and limitations intrinsic to the use of multiple entry keys (in contrast to dichotomous keys) are analysed in terms of practicality and ease of use. Identification software is a useful tool facilitating the identification of species for ecological and conservation applications. The identification software Linnaeus II © (version 2.1 for Windows), provided by the Expert Center for Taxonomic Identification (ETI) of the Biodiversity Center, University of Amsterdam was customised to allow the generation of a multiple entry key, using the shell morphology data collected. The biogeographic affinities of Archaeogastropod species occurring in Maltese waters were analysed using the Linnaeus II © software. The local archaeogastropod fauna is shown to be derived from that of the western Mediterranean; the difference between archaeogastropod diversity in Maltese waters and that of the eastern Mediterranean is significant. As suggested by the literature reviewed, the Mediterranean archaeogastropod fauna is shown to be almost entirely derived from that of the Lusitanian province.
Description: M.SC.BIOLOGY
URI: https://www.um.edu.mt/library/oar/handle/123456789/64849
Appears in Collections:Dissertations - FacSci - 1965-2014
Dissertations - FacSciBio - 1966-2014

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