CONGRESO
LXV CONGRESSO NACIONAL DE BOTÂNICA
BOTÁNICA
XXXIV ERBOT - Encontro Regional de Botânicos MG, BA, ES 18 A 24 DE OUTUBRO DE 2014 - SALVADOR - BAHIA - BRASIL
Latinoamericano de
Botânica na América Latina: conhecimento, interação e difusão
PLIO-PLEISTOCENE DIVERSIFICATION OF CEREUS MILL
(CACTACEAE, CEREEAE)
AUTOR(ES):Gislaine Angélica Rodrigues Silva;Marlon Machado;Cecília
Leiko Jojima;Evandro Marsola de Moraes;Fernando Faria Franco;
INSTITUIÇÃO:
Universidade Federal de São Carlos - Campus Sorocaba
Universidade Estadual de Feira de Santana
Cacti is a family of angiosperms with a predominantly Neotropical
distribution ranging from southern Canada to Patagonia in Argentina, with
main centers of diversity occurring in arid regions. The family Cactaceae
originated in the Oligocene and its major lineages diverged during the
Miocene, around 10-5 Ma. The diversification times in the internal branches
of these lineages are still poorly known. Within the BCT clade (tribes
Browningieae Buxbaum, Cereeae Salm-Dyck, and Trichocereeae Buxbaum),
Cereus is a genus comprising around 30 predominantly South American
species distributed in four subgenera: Oblongicarpi, Ebneria, Mirabella and
Cereus. In order to study patterns of diversification in time and space in
Cereus, we sampled trnS-trnG cpDNA sequences from representatives of all
subgenera, in a total of 38 sequences. We conduced phylogenetics analysis
using several outgroups from the BCT clade: Pilosocereus arrabidae,
Arrajadoa
rhodantha, Matucana
intertexta,
Oreocereus
celsianus,
Samaipaticereus corroanus, Haageocereus pseudomelanostele, Rauhocereus
riosaniensis, Micranthocereus densiflorus, Stetsonia coryne, and Browningia
hertlingiana. We calibrated the tree assuming 6.57 (4.34-9.66) Ma for stem
group and 5.28 (3.16-7.9) for crow group as the estimated age of the BCT
clade. Moreover, we tested the ancestral distribution of these taxa in
relationship to 10 areas: Caatinga, Cerrado, Atlantic Forest, Pampa,
Missiones, Pantaneira, Chaco, Anden regions (Bolivia and Peru), and
northern South America. Our data suggests a non-monophyletic status for
Cereus and also for three of its subgenera (Oblongicarpi, Ebneria and
Cereus). The biogeographic data indicates a clear vicariant pattern between
lineage clustering species from open vegetation (Cerrado or Caatinga) with
lineage composed by species from mostly open habitats within the Brazilian
Atlantic Forest. The beginning of diversification of the main branches in
Cereus was dated to have occurred around the Pliocene-Pleistocene
transition (4.17 - 1.17 Ma), and the majority of species diversification
events to have occurred during the Quaternary. These results support that
both Neogene orogenic events and Pleistocene climatic oscillations have
contributed to shape the diversification of modern lineages in South
America (FAPESP).
Key words: Cereus, trnS-trnG, diversification time