[Abstract] Advances in the phylogenetic and biogeographical study of the genus Celtis (Celtidaceae) for Southern South America

CHAMORRO, D.; MOGNI, V.; OAKLEY, L. J.; ORTIZ, J. P.; PRADO, D. E.

BIOCELL

INST HISTOL EMBRIOL-CONICET

Año: 2018 vol. 43

0327-9545

The genus Celtis (Celtidaceae) is represented by around six woody taxa in Southern South America, whose biogeographical distribution is restricted to the Domain of Neotropical Seasonal Dry Forests, and to the subtropical Chaco and Espinal regions. The genus presents important taxonomic problems; one of the most emblematic cases is that of C. ehrenbergiana (Klotzsch) Liebm., considered a very ample taxon encompassing both C. pallida Torr. and C. tala Gillies ex Planch. In addition, other entities of unclear taxonomical status are C. brasiliensis (Gardner) Planch., C. chichape (Wedd.) Miq., C. iguanaea (Jacq.) Sarg. y C. pubescens (Kunth) Spreng. These taxonomic problems no longer tolerate the classical morphological studies, therefore they will be additionally analyzed through the amplification and sequencing of molecular markers (ITS, trnL-F, rps16 y ndhF). Then, the morphological and molecular data will be combined to define the taxonomic entities correctly, to give a more complete and accurate idea of the phylogenetic pattern, as well as to infer the biogeographic history of the genus in South America. After extensive field sampling in Argentina and Paraguay and consultation of specimens in national and international herbaria, a detailed morphological study was carried out. Through a Principal Components and Groups Analysis, relevant preliminary results were obtained. First, it is confirmed that what is currently considered in Argentina as C. ehrenbergiana actually involves three entities: C. tala, C. pallida var. pallida and C. pallida var. discolor Hunz. & Dottori. Besides, an additional complex of species can be defined, consisting of C. brasiliensis, C. iguanaea and C. chichape; this reveals that only with morphological characteristics these entities cannot be resolved. Finally, the molecular techniques were optimized to start with DNA extractions and amplification of nucleotide sequences, thus completing the phylogenetic and biogeographical analysis.