New insights in the phylogenetic relationships, character evolution, and biogeography of Calceolaria (Calceolariaceae)

COSACOV, A.; SÉRSIC, A.N.; SOSA, V.; DE-NOVA, A.; NYLINDER, S.; COCUCCI, A.A.

AMERICAN JOURNAL OF BOTANY

BOTANICAL SOC AMER INC

Año: 2009 vol. 96 p. 2240 - 2255

0002-9122

Biogeographical patterns and diversifi cation processes in Andean and Patagonian fl ora are not yet well understood.  Calceolaria  is a highly diversifi ed genus of these areas, representing one of the most specialized plant – pollinator systems because fl owers produce nonvolatile oils, a very unusual fl oral reward. Phylogenetic analyses with molecular (ITS and  matK ) and morphological characters from 103  Calceolaria  species were conducted to examine relationships, to understand biogeographic patterns, and to detect evolutionary patterns of fl  oral and ecological characters. Total evidence analysis retrieved three major clades, which strongly correspond to the three previously recognized subgenera, although only subgenus  Rosula  was retrieved as a monophyletic group. A single historical event explains the expansion from the southern to central Andes, while different parallel evolutionary lines show a northward expansion from the central to northern Andes across the Huancabamba Defl ection, an important geographical barrier in northern Peru. Polyploidy, acquisition of elaiophores, and a nototribic pollination mechanism are key aspects of the evolutionary history of  Calceolaria . Pollination interactions were more frequently established with  Centris  than with  Chalepoge-nus  oil-collecting bee species. The repeated loss of the oil gland and shifts to pollen as the only reward suggest an evolutionary tendency from highly to moderately specialized pollination systems. Key  words:     Andes;   Calceolaria ; Calceolariaceae;  Centris ;   Chalepogenus;  elaiophore; morphological evolution; nototribic; oil fl owers; polyploidy; sternotribic.