PARENT SESSION

Systematics/Zoogeography 2 -- Session Chair: Robert Anderson-- Nelson Hall East, Goodwin Forum

PHYLOGEOGRAPHIC RELATIONSHIPS OF ENDEMIC RODENT SPECIES OF THE GALAPAGOS ISLANDS. Scott A. Clement, Robert C. Dowler and Loren K. Ammerman. Department of Biology, Angelo State University, San Angelo, TX.

ABSTRACT- Seven endemic species of rodents (three extinct and four extant) have been described historically within the Galapagos Islands, the first collected by Charles Darwin in 1835. Relationships within this group are poorly understood, but it is believed that all endemic rodents belong to one of two genera: Oryzomys or Nesoryzomys. Beyond that, relationships of the Galapagos endemics to mainland South American rodents of the tribe Oryzomyini are also poorly understood. Although morphometric and molecular analyses have been performed, there has been no comprehensive study that includes all four extant species, much less, all seven endemics. This study specifically targets the four extant species of the Galapagos Islands (Oryzomys bauri, Nesoryzomys fernandinae, Nesoryzomys swarthi, and Nesoryzomys narboroughi) in an attempt to construct a phylogeny based on DNA sequences of these species and closely related species of South America. DNA sequences from the mitochondrial control region (D-loop) were amplified using standard PCR protocol, cloned into bacterial vectors, and sequenced using a Licor-IR2 DNA analyzer. Preliminary haplotypic patterns derived from the sequences suggest Galapagos endemics form a monophyletic lineage, in which exist two distinct clades, one containing Oryzomys bauri and a mainland form, Oryzomys xantheolus, and the other containing the three members of the genus Nesoryzomys.

KEY WORDS: Galapagos