Table Of ContentMolecular evolution, phylogenetics and biogeography in southern
hemispheric bryophytes with special focus on Chilean taxa.
Dissertation
zur
Erlangung des Doktorgrades (Dr. rer. nat.)
der Mathematisch-Naturwissenschaftlichen Fakultät
der
Rheinischen Friedrich-Wilhelms-Universität Bonn
vorgelegt von
Rolf Blöcher
aus
Biedenkopf/Lahn
Bonn 2004
Angefertigt mit Genehmigung der Mathematisch-Naturwissenschaftlichen Fakultät
der Rheinischen Friedrich-Wilhelms-Universität Bonn
1. Referent: Prof. Dr. Jan-Peter Frahm
2. Referent: Prof. Dr. Wilhelm Barthlott
Tag der Promotion: 20. Dezember 2004
Diese Dissertation ist auf dem Hochschulschriftenserver der ULB Bonn
http://hss.ulb.uni-bonn.de/diss_online elektronisch publiziert
meinen Eltern,
Doris und Horst Blöcher
Contents
1 Introduction...........................................................................................................1
2 A comparison of the moss floras of Chile and New Zealand................................9
2.1 Introduction...................................................................................................9
2.2 Comparison.................................................................................................10
2.3 Results........................................................................................................11
2.4 Discussion...................................................................................................12
3 A preliminary study on the phylogeny and molecular evolution of the
Ptychomniaceae M. Fleisch. (Bryopsida) with special emphasis on Ptychomnion
ptychocarpon and Dichelodontium............................................................................21
3.1 Introduction.................................................................................................21
3.2 Material & Methods.....................................................................................25
3.3 Results........................................................................................................30
3.3.1 Sequence Variation..............................................................................30
3.3.2 Genetic distances.................................................................................32
3.3.3 Phylogenetic analysis...........................................................................33
3.4 Discussion...................................................................................................37
4 The systematic affinities of selected Gondwanan bryophyte taxa based on
molecular sequence data..........................................................................................42
4.1 Introduction.................................................................................................42
4.2 Material and Methods..................................................................................45
4.3 Results........................................................................................................49
4.3.1 Sequence variation..............................................................................49
4.3.2 Phylogenetic analysis...........................................................................49
4.3.3 Synthesis. ............................................................................................53
4.4 Discussion...................................................................................................54
5 Molecular evolution, phylogenetics and biogeography of the genus Lepyrodon
(Lepyrodontaceae, Bryopsida) ..................................................................................58
5.1 Introduction.................................................................................................58
5.1.1 The genus Lepyrodon..........................................................................58
5.1.2 Morphological relationships within the genus.......................................58
5.1.3 The systematic position of Lepyrodontaceae.......................................59
5.2 Material & Methods.....................................................................................60
5.3 Results........................................................................................................67
5.3.1 Sequence variation..............................................................................67
Contents
5.3.2 Phylogenetic analysis...........................................................................70
5.4 Discussion...................................................................................................79
5.4.1 Genetic results.....................................................................................79
5.4.2 Phylogenetic and taxonomic results.....................................................82
5.4.3 Biogeographical implications................................................................86
6 Molecular circumscription and biogeography of the genus Acrocladium
(Bryopsida)................................................................................................................89
6.1 The genus Acrocladium ..............................................................................89
6.1.1 Status of Acrocladium..........................................................................89
6.1.2 Distribution of Acrocladium..................................................................90
6.1.3 Ecology of Acrocladium........................................................................90
6.2 Material & Methods.....................................................................................91
6.3 Results........................................................................................................98
6.3.1 Sequence variation..............................................................................98
6.3.2 Genetic distances...............................................................................101
6.3.3 Phylogenetic analysis.........................................................................104
6.4 Discussion.................................................................................................106
6.4.1 The status of A. auriculatum and A. chlamydophyllum.......................106
6.4.2 Possible explanations for the disjunct distribution of Acrocladium.....108
7 Molecular evolution, phylogenetics and biogeography of the genus Catagonium
(Plagiotheciaceae, Bryopsida).................................................................................111
7.1 Introduction...............................................................................................111
7.1.1 Morphological characterisation ..........................................................112
7.2 Material & Methods...................................................................................115
7.3 Results......................................................................................................122
7.3.1 Phylogenetic results...........................................................................122
7.3.2 Indel matrix ........................................................................................130
7.3.3 Genetic distances...............................................................................131
7.4 Discussion.................................................................................................136
7.4.1 The ‘Northern South American’ species.............................................136
7.4.2 The systematic position of C. nitens ssp. maritimum.........................137
7.4.3 The relationship within Catagonium nitens.........................................137
8 The 'Gondwana connection' and their genetic patterns in bryophytes..............140
9 Summary..........................................................................................................146
Contents
10 Acknowledgements.......................................................................................149
11 References...................................................................................................152
Index to tables
Index to figures
Appendix
1 Introduction 1
1 Introduction
Biologists have long been fascinated by the existence of disjunct distributions of
certain plant and animal taxa. Especially the southern temperate disjunctions
between southern South America and New Zealand have attracted their attention.
The taxa characterized by these distribution patterns are assumed to share a
common history. Generally two different hypotheses are used to explain their disjunct
distribution. The first can be described by the term ‘vicariance’ which refers to
disjunct distribution patterns as a result of the splitting of populations by e.g. the
fragmentation of landmasses (e.g. Croizat et al., 1974). The second hypothesis
explains the existing distribution patterns based on long distance dispersal events.
For the first explanation based on vicariance events an understanding of the past
fragmentation processes of the continental landmasses is necessary. The former
connection of the recent southern continents in a large landmass, the Gondwana
continent, is nowadays widely accepted. Over a period of c. 180 Myr mainly
continental drift led to the recent formation of the continents (e.g. McLoughlin, 2001).
During the Permian to Jurassic period the supercontinent Pangea consisted of a
northern land mass, Laurasia and a southern land mass Gondwana, that were partly
separated by an ocean, the Tethys. During that time Pangea extended from high
northern to high southern latitudes covering substantial climatic gradients
(McLoughlin, 2001). The early Cretaceous floras of Gondwana were conifer and
pteridosperm dominated and differed little from that of the Jurassic. By the mid-
Cretaceous angiosperms were already important elements of the cool temperate flora
of the southern Gondwana continent. These forest types appear to be quite similar to
that found in the temperate regions of the southern hemisphere today, possibly
offering good conditions for the ancestors of recent temperate rainforest taxa. The
breakup of the Gondwana continent started in the late Jurassic (c. 152 Myr BP) with
sea-floor spreading between Africa and Madagascar (2004; Scotese & McKerrow,
1990). The separation of Africa from a landmass comprising e.g. recent South
America, Antarctica, Australia and New Zealand was completed about 105 Myr BP.
New Zealand as part of the continental block ‘Tasmantia’ separated about 80 Myr BP
from Australia which was at the time still connected via Antarctica to South America.
1 Introduction 2
Lastly, the separation of the continents South America, Antarctica, and Australia was
completed about 30 Myr BP (McLoughlin, 2001).
Southern temperate disjunct taxa presumably once had a continuous distribution
range on the Gondwana continent, their recent distribution caused by separation of
populations concomitant with the breakup of Gondwana (e.g. Darlington, 1965; Du
Rietz, 1960; Godley, 1960; Skottsberg, 1960). The term 'vicariance' Recent taxa are
the result of evolutionary processes which since then have taken place since in the
disjunct populations. A southern hemispheric disjunction caused by vicariance is also
assumed for many bryophyte taxa (e.g. Schuster, 1969). In a later review of the
phytogeography of bryophytes, Schuster (1983) gives many examples of mosses and
liverworts with Gondwana distribution patterns (e.g. Dendroligotrichum,
Lepidoleanaceae, and Polytrichadelphus magellanicus). Matteri (1986), Seki (1973),
and most recently Villagrán (2003) give detailed information of phytogeographical
relationships of bryophytes from specific areas of southern South America. They
classify the bryophyte taxa according to their overall distribution pattern. A detailed
study about the evolution of the Gondwana relict moss family Hypopterygiaceae is
provided by Kruijer (2002).
The other hypothesis explaning the disjunct distribution of southern hemispheric taxa
is long distance dispersal defined by van Zanten & Pócs (1981) as dispersal over
more than 2,000 km distance. Van Zanten (1976) designed germination experiments
in which bryophyte spores received a treatment comparable to the conditions of long
distance disperal by wind (jet stream) in the southern hemisphere. Van Zanten (1978)
proved experimentally that especially widespread species had spores which were still
able to germinate after the experimental treatment and were therefore assumed able
to survive long distance dispersal. Species confined to a small distribution range, e.g.
Catharomnion ciliatum restricted to New Zealand/Australia, did not germinate after
two months of treatment.
Most recently Muñoz et al. (2004) tested the correlation between near-surface wind
direction and speed and floral similarity of certain areas in mosses, liverworts, lichens
and pteridophytes. They found a stronger correlation between floristic similarity and
maximum wind connectivity in mosses, liverworts and lichens than with geographic
proximity. They concluded that wind is the main force determining current plant
distribution.
1 Introduction 3
After introducing the two principal explanation models of southern hemispheric
disjunct distribution patterns, methods of phylogenetic reconstruction are presented.
Traditionally, morphological similarities are used as indicators of close relationship.
Decisions on which characters are regarded as conserved or derived are supported
by the analysis of fossils. Also, determination of the timing of evolutionary processes
is based on the fossil record. Fossil pollen has helped to reconstruct historical
distribution ranges, especially in trees. In the last 20 years the use of molecular
methods have gained more and more importance. Today, molecular data in
combination with the fossil record are used to estimate relative clade divergence or
calibrate data for age estimates of certain clades. In bryophytes molecular sequence
data have proven indispensable for phylogenetic analyses on different taxonomic
levels (for review see: Quandt & Stech, 2003). However, especially when fossils are
rare one relies on indicative methods for studying the time scale of evolution. For
instance, the breakup sequence of the Gondwana continent can be used as a time
sequence (McLoughlin, 2001) to fit the cladograms of phylogenetic analyses (e.g.
Frey et al., 1999; Schaumann et al., 2003). Additional geological events possibly
relevant for understanding the history of disjunct southern temperate rainforest taxa
are e.g. temporary flooding of parts of South America, the formation of the Andes, the
Isthmus of Panama and the Atacama desert.
The classical example of a disjunct distribution in the southern hemisphere is that of
the southern beech Nothofagus (e.g. van Steenis, 1971). There are contrasting
opinions on whether vicariance or dispersal events are responsible for the distribution
of Nothofagus. Manos (1997) analyses molecular sequence data and fossil records
and concludes that Nothofagus was widely distributed in the southern hemisphere
before the breakup of Gondwana. The disjunction of Nothofagus is interpreted by him
as vicariance, for the Australasian taxa in combination with multiple extinction events.
In contrast, Swenson et al. (2001) explained Australasian disjunctions by
colonization, i.e. long distance dispersal, and extinction events. The colonization
hypothesis is supported by findings of Pole (1994; 2001) who questions the
persistence of continous temperate forest in New Zealand during the Tertiary on the
basis of periodic ‘gaps’ in pollen records especially of plant taxa commonly
1 Introduction 4
associated with temperate rainforest vegetation. He therefore suggests that the New
Zealand flora is mainly a result of long distance dispersal.
Another example of a taxon with a mainly southern hemispheric disjunct distribution
range is the angiosperm genus Gunnera. This taxon has an even wider distribution
than Nothofagus, including Africa and extending into North America. Wanntorp &
Wanntorp (2003) based their reconstruction of Gunnera evolution on genetic as well
as on morphological analyses supported by fossil and pollen data. Most of the
phylogenetic results were in accordance with the chronology of the Gondwana
breakup. Only few phenomena were interpreted as dispersal events in the late
Tertiary.
In bryophytes only few of the recent taxa can be related to fossils in order to predict
their evolutionary age (e.g. Pallaviciniaceae, Frey, 1990; Schuster, 1982). Well
preserved fossils are very rare. The earliest moss fossils were reported from the
carboniferous (e.g. Goffinet & Hedderson, 2000; Krassilov & Schuster, 1984).
Muscites guescelini from the Triassic (South Africa) is sometimes regarded as the
earliest known representative of the pleurocarpous lineage in bryophytes (Krassilov &
Schuster, 1984). Most of the younger fossils originate from tertiary Baltic and Saxon
amber (e.g. Frahm, 2004). Only few examples were reported from the Early
Pleistocene (e.g. Weymouthia mollis, Jordan & Dalton, 1995) and from the Late
Pleistocene/Holocene (e.g. Hylocomiaceae, Willerslev et al., 2003).
The only example of DNA sequences of fossil mosses was reported only recently.
Willerslev et al. (2003; 2004) used samples from ice cores from Sibiria as template in
PCRs for animal and plant taxa. They successfully presented partial rbcL sequence
data of 300,000 to 400,000 year old bryophyte taxa related to the Hylocomiaceae
and Bryales, respectively. However, this is a rare case where very old plant material
is sufficiently well preserved for use in molecular phylogeny. Also, the fossils are
difficult to relate to living taxa and most of them do not provide a time record for
interpreting bryophyte evolution.
For disjunct southern hemispheric bryopyhte taxa few molecular based studies
addressing their distribution exist. An example is the liverwort genus Monoclea which
occurs in southern temperate rainforests of New Zealand and Chile and in tropical
rainforests in northern South to Central America. Analysis of cpDNA sequence data
Description:Cretaceous angiosperms were already important elements of the cool temperate . range is the angiosperm genus Gunnera. New Zealand – S.
