ANDRUS, NICOLE1,2*, DAVID BOGLER2, ALAN TYE3, GERALD GUALA2, and JAVIER FRANCISCO-ORTEGA1,2. 1Florida International University Departement of Biological Sciences, University Park, Miami, FL 33199; 2Fairchild Tropical Garden 11935 Old Cutler Road, Coral Gables, FL 33156-4299; 3Charles Darwin Research Station, Puerto Ayora, Santa Cruz, Galapagos Islands. - Preliminary Molcular Evidence for the Origin of Darwiniothamnus (Asteraceae).
Darwiniothamnus (Asteraceae: Astereae) is one of the seven
plant genera endemic to the Galapagos Islands. Based on morphological
grounds the genus, although distinct, has been suggested to be closely
related to South American Erigeron; however this hypothesis
needs to be tested by rigorous phylogenetic methods. In this study a
preliminary phylogeny of the ITS region of the nuclear ribosomal DNA
is presented. This phylogeny suggests that Darwiniothamnus is
nested within the Erigeron clade, which is composed of
Aphanostephus, Conyza and Erigeron. Upon further
analysis it appears that Darwiniothamnus may be sister to E.
thrincioides and E. bellioides which are both from the
Antilles. Further studies are currently in progress to confirm this
possible biogeographical connection between the Caribbean basin and
the Galapagos Islands. These additional studies will include putative
relatives from Mexico, Chile and the Revillagigedo Islands of the
Pacific Ocean.
Key words: Darwiniothamnus, Galapagos Islands