Juliana Chacón
Address
LMU Department für BiologieSystematische Botanik und Mykologie
Menzinger Straße 67
80638 München
Germany
Contact
| Fon: | +49 89 17861-251 |
| Fax: | +49 89 172638 |
| Email: |  |
| Room: | 230, second floor |
Documents
Current Ph.D. project
Inferring the biogeography of the Colchicaceae, the non-Neotropical sister clade to the mainly Neotropical Alstroemeriaceae
Abstract
While biogeography has a long history, it is only recently that methods have become
available that can fully exploit the information contained in molecular trees and
relevant to biogeographic history, namely topology, node support, and branch lengths.
We are interested in comparing three methods, statistical dispersal-vicariance analysis,
dispersal-extinction-cladogenesis under maximum likelihood optimization, and the
continuous-time Markov chain approach implemented in the Bayesian program BEAST,
using the Colchicaceae as our study system. This presents a natural expansion of
the work carried out during the first two years on the sister group of Colchicaceae,
Alstroemeriaceae. Except for three species in Australia and New Zealand, the latter
are endemic to the Neotropics, where they comprise 200 species in three genera. The
Colchicaceae, by contrast, have 16 genera (245 – 250 species) and occur on all
continents except South America (and Antarctica). It is this geographic “replacement”
and the highly disjunct worldwide range of the Colchicaceae that we hope to understand.
Alstroemeriaceae and closely related Liliales families (e.g., Petermanniaceae) have
macrofossils that can be used to calibrate genetic distances, and a preliminary
chronogram for the Colchicaceae shows that several of their lineages are ancient.
The large disjunct range, together with the apparent mix of old and young divergence
events, make the Colchicaceae an especially worthwhile system in which to carry out
ancestral area reconstruction, taking into account dispersal and extinction. Plant
material and plastid sequences for species from 15 of the genera are in hand, but
support is needed to slightly enhance species sampling and to generate sequences
from the nuclear genome. Our working hypothesis is that Colchicaceae diverged from
their sister clade Alstromeriaceae sometime in the Turonian and somewhere in East Gondwana
(plausibly Antarctica or Australia). They reached Africa from there, and subsequently
India, Eurasia, and North America (via Beringia).
Additional comments
The work on Colchicaceae is a natural expansion of the first part of my Ph.D., about
the biogeography and evolution of the Alstroemeriaceae (see below). The following two
papers summarize some of the main findings of that first stage:
Chacón J., C.M. Baeza, and S.S. Renner (2012):
Ribosomal DNA distribution and a genus-wide phylogeny reveal chromosome rearrangements in
Alstroemeria (Alstroemeriaceae). Submitted to the American Journal of Botany, 2012-03-08.
Chacón J., M. Camargo de Assis, A.W. Meerow, and S.S. Renner (2012):
From east Gondwana to Central America: historical biogeography of the Alstroemeriaceae. Journal of Biogeography in press.
 Gloriosa superba (Colchicaceae) Photo taken in the New South Wales herbarium (NSW) in Sydney, Australia |
Colchicum bulbocodium (Colchicaceae) Photo of a plant grown at the Munich Botanical Garden. |
New insights into the biogeography of the Austral floristic realm from a complete phylogeny for the Alstroemeriaceae
Abstract
Alstroemeriaceae consists of the Neotropical Alstroemerioideae with the genera
Alstroemeria (75 spp.) and Bomarea (120 spp., mostly in the
Northern Andes except for four species in Chile) and the disjunct Luzuriagoideae
with the genera Luzuriaga (4 spp.) and Drymophila (2 spp.).
Luzuriaga has three species in temperate South America and one,
Luzuriaga parviflora, in New Zealand, while the two species of
Drymophila occur in Eastern Australia and Tasmania. This makes the
Alstroemeriaceae a typical member of the Austral floristic realm.
We have sequenced 138 species from throughout the family’s distribution range,
using Colchicaceae as outgroup. A total of 3189 aligned nucleotides from the
chloroplast DNA regions matK, ndhF and rbcL, the mitochondrial gene matR,
and the nuclear ribosomal ITS were analyzed. A recently discovered fossil of
Luzuriaga from New Zealand (to be described J. Conran and colleagues)
was used to constrain relaxed and strict molecular clock models, alternatively
with fossils of Smilax and the root age of Liliales. Maximum likelihood trees
show that Alstroemeria and Bomarea are mutually monophyletic
and together form the sister clade of Drymophila and Luzuriaga.
The Brazilian species of Alstroemeria form a clade that is embedded
within the Chilean and Argentinean species. Luzuriaga parviflora is
embedded among the South American Luzuriagas. Based on the clock models,
Alstroemeriaceae originated in Cretaceous East Gondwana, coeval with other
members of the Austral floristic realm, such as Proteaceae, Atherospermataceae,
Restionaceae, and Nothofagaceae.
The diversification of the Alstroemerioideae and Luzuriagoideae clades occurred
during the Eocene, c. 44 Ma ago, when Australia and South America where
still partly connected, and Antarctica was still forested. In southern South America,
Alstroemeria began to diversify c. 26 Ma ago, before the main uplift
of the Andean cordillera and it then expanded east into Brazil, where it radiated
during the middle Miocene, c. 13 Ma ago. Bomarea diversification commenced
later, c. 18 Ma ago, and this lineage expanded and diversified northwards
throughout the Pliocene and into the Pleistocene, as cloud forests and páramos
began covering the cordilleras. The presence of L. parviflora in New Zealand
is likely a result of long distance dispersal from Patagonia, and the New Zealand
Luzuriaga fossil appears to represent a stem lineage.
Sources of pictures
Alstroemeria mangnifica subsp. magenta (Alstroemeriaceae): http://www.chileflora.com/
Alstroemeria violacea (Alstroemeriaceae): http://www.nolana.com/Alstroemeria_lomas/
Bomarea multiflora (Alstroemeriaceae): Dr. Santiago Madriñán, Laboratorio de Botánica y Sistemática, Universidad de los Andes, Bogotá, Colombia
Bomarea salsilla (Alstroemeriaceae): http://www.chileflora.com/
Bomarea patinii (Alstroemeriaceae): http://www.wikipedia.org/
 Alstroemeria magnifica subsp. magenta |
 Alstroemeria violacea |
|
 Bomarea multiflora |
 Bomarea salsilla |
|
 Bomarea spec. |
Last update: 2012-04-24