Abstract Detail

Systematics Section/ASPT

Larridon, Isabel [1], Walter, Helmut E. [2], Guerrero, Pablo C. [3], Samain, Marie-Stéphanie [4].

An integrative approach to understanding the evolution and biodiversity of Copiapoa (Cactaceae), a threatened genus from Chile’s coastal desert.

Over two thirds of the species of the endemic Chilean cactus genus Copiapoa are threatened according to the IUCN Red List criteria. Despite their ecological importance as keystone species in Chile’s coastal desert, and the fact that they are well loved by cactus enthusiasts, the evolution and biodiversity Copiapoa had not yet been studied using molecular approaches. In this study, sequence data of three plastid DNA markers (rpl32-trnL, trnH-psbA, ycf1) were analysed using maximum likelihood (RAxML) and Bayesian inference (MrBayes) methods. A molecular phylogenetic hypothesis of 39 different Copiapoa taxa was established, including all commonly recognised species, many infraspecific taxa, and multiple individuals where possible. The ancestral states of four morphological characters (BayesTraits), and the ancestral (RASP) and current species distributions (MaxEnt) were estimated. In our results, many previously recognised taxa are well supported. However, the genetic diversity between most infraspecific taxa and some closely related species is too low to differentiate between them using plastid DNA markers. The phylogenetic results indicate that several species need to be recircumscribed. A new infrageneric classification conforming to monophyletic species groups that can be distinguished morphologically and also largely correlate in their biogeographical distribution is suggested. Further study of some of the closely related species, e.g. Copiapoa angustiflora vs. C. esmeraldana, C. calderana vs. C. marginata, and the taxa of the Cinerei clade are needed to correctly assess their status. For the latter group, a population genetic study is being carried out using microsatellite markers. The preliminary results confirm the conclusions of the prior phylogenetic study that the Cinerei clade includes only two species, i.e. C. cinerea and C. gigantea. Additionally, in C. cinerea, three subspecies (cinerea, columna-alba, and krainziana) can be distinguished morphologically that are weakly supported by the population genetic data. A better understanding of the evolution and biodiversity of Copiapoa will allow allocating conservation resources to the most threatened lineages.

Related Links:
Research Group Spermatophytes website

1 - Ghent University, Biology Department, K.L. Ledeganckstraat, Ghent, 9000, Belgium
2 - The EXSIS Project: cactaceae ex-situ & in-situ conservation, Casilla 175, Buin, Chile
3 - Universidad de Concepción, Departamento de Botánica, Casilla 160C, Concepción, Chile
4 - Instituto de Ecología, A.C., Centro Regional del Bajío, Avenida Lázaro Cárdenas 253, Pátzcuaro, Michoacán, 61600, Mexico

Keywords:
Atacama Desert
evolutionary biogeography
conservation
cpDNA
infrageneric classification
morphology
species distribution modelling
systematics
Cactaceae.

Presentation Type: Oral Paper:Papers for Sections
Session: 5
Location: Salon 9/The Shaw Conference Centre
Date: Monday, July 27th, 2015
Time: 8:45 AM
Number: 5004
Abstract ID:256
Candidate for Awards:None