Systematics, Ontogeny, Osteology and Historical Biogeography of Fossil and Living Gars (Actinopterygii, Lepsosteiformes)

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DEB-9707705 Grande The gars (Lepisosteidae) are members of a very long-lived assemblage that is thought by most ichthyologists to be the most primitive living group of Neopterygii (a group that contains about half of all species of vertebrate animals). The seven, living species of gars are today restricted to the eastern-America region, from southeastern Canada to Cuba. Extinct species of gars, some over 100 millions years old, document that gars were once widespread, occurring on both American continents, Europe, Africa, Madagascar, and India. Drs. L. Grande (of the Field Museum in Chicago) and W. Bemis (of the University of Massachusetts) will carry out the first comprehensive study of comparative anatomy, biogeography, and ecology (including paleoecology) among all living and numerous extinct species of gars. Their study will be anchored in thorough, detailed examination of skeletal variation but they also will examine living material to following developmental stages of critical morphological characters. Several fossil species will be described and species-level taxonomic problems will be resolved. A resolved genealogy (phylogeny) of lepisosteid species and of primitive neopterygian groups is expected to yield critical information regarding major questions surrounding the Earth's history, biodiversity, and patterns of biological extinction. The work also will provide extremely relevant data towards resolution of one of the major questions in ichthyology: the origin of teleost fishes.