Evolution and diversification of the Hookeriales (Bryopsida) with emphasis on Distichophyllum (Daltoniaceae) and its allied genera [Elektronische Ressource] / vorgelegt von Boon Chuan Ho

Boon Chuan Ho

Informations

• Publié par: rheinische_friedrich-wilhelms-universitat_bonn
• Publié le: 01 janvier 2010
• Nombre de lectures: 12
• Langue: English
• Poids de l'ouvrage: 31 Mo

Extrait

Evolution and Diversification of the
Hookeriales (Bryopsida) with emphasis on
Distichophyllum (Daltoniaceae)
and its allied genera.
Dissertation
zur
Erlangung des Doktorgrades (Dr. rer. nat.)
der Mathematisch-Naturwissenschaftlichen Fakultät
der Rheinischen Friedrich-Wilhelms-Universität Bonn
vorgelegt von
Boon Chuan Ho
aus
Singapur
Bonn, Januar 2010 Angefertigt mit Genehmigung der Mathematisch-Naturwissenschaftlichen Fakultät
der Rheinischen-Friedrich-Wilhelms-Universität Bonn.
Gedruckt mit Unterstützung des Deutschen Akademischen Austauschdienstes.
Erstgutachter: Prof. Dr. Jan-Peter Frahm
Zweitgutachter: Prof. Dr. Dietmar Quandt
Fachnahes Mitglied Prof. Dr. Thomas Litt
Fachangrenzendes Mitglied Prof. Dr. Wolfgang Böhme
Tag der Promotion: __.III.2010
Diese Dissertation ist auf dem Hochschulschriftenserver der ULB Bonn
http://hss.ulb.unibonn.de/diss_online elektronisch publiziert.
Erscheinungsjahr: 2010

Meiner Familie
und meinen verstorbenen Großeltern gewidmet


Dedicated to my family
and late grandparents


献给我的家人
与已故祖父母


III

Contents:

General Introduction 1

Chapter 1
The gametophyte strikes back: testing opposing morphological
concepts on the haploid and diploid generations in the moss order
Hookeriales (Bryopsida) 4

Chapter 2
Molecular Evolution and Diversification of Daltoniaceae (Hookeriales,
Bryopsida) with emphasis on unrevealing the phylogeny of
Distichophyllum and its allies 40

Chapter 3
New and Noteworthy records of Distichophyllum (Daltoniaceae,
Bryopsida) and allied genera in Asia and Australasia 84

Chapter 4
Proposal to conserve the name Distichophyllum Dozy & Molk.
(Daltoniaceae) with a conserved type 114

Summary 117
Acknowledgments 119
References 121
List of Abbreviations and Symbols 131
List of Figures 133
List of Tables 136
List of Appendices 138
Curriculum Vitae 149

IV GENERAL INTRODUCTION

General Introduction

The Hookeriales include ca. 650 species of predominantly tropical and Southern
temperate pleurocarpous mosses that prefer humid forest habitats. Although, a small
number of Hookerialean species occurs naturally in the northern temperate especially in
Europe and North America, a few have been introduced through horticultural practice (e.g.
Calyptrochaeta apiculata in United Kingdom). Hence, these mosses are often considered
‘exotic looking’ to bryologists from the north temperate countries. Nevertheless, for the last
ca. 35 years, the circumscriptions and systematics of these mosses has become a
challenging topic of debate. Putting emphasis on different morphological characters and
thus proposing contradictory classifications, the genera have been rearranged in various
ways by different authors. The different systematic concepts based on morphology range
from two to nine families (e.g., Miller 1971, Crosby 1974), while the first molecular pilot
phylogeny based on four-genes (Buck et al. 2005) put forward a seven-family
classification and accepted 52 genera.

The Daltoniaceae has 14 genera occurring mainly in tropical Asia, Australasia and
Southern South America, but less prominent in tropical America and Africa where
members of the other Hookerialean families are more common. The family is among the
most diverse in terms of habitat adaption from aquatic, to terrestrial (on soil or humus), to
decaying wood, to epiphytes (including true epiphylls). About half the number of accepted
species within the Daltoniaceae belongs to the genus Distichophyllum, the focus of the
present research.

Although a molecular phylogeny is available for the Hookeriales, several relationships
among the currently accepted families remain unclear (Buck et al., 2005). Thus the main
task of Chapter 1 was to resolve the backbone relationship of the Hookeriales. This is
essential prior to studies of the focus of this research project, i.e. the Daltoniaceae. To
improve previous phylogeny to show relationships in the Hookeriales, efforts are made to
improve taxon sampling by including the type species of each genus when possible, and
increasing sampling of larger genera to better represent them in terms of biogeography
and morphology. In addition, samples from several genera which were once associated
with the orders or considered within the Hookeriales were also included to test or
ascertain previous untested phylogenetic suggestions. Apart from the original four gene
markers used in a previous study (Buck et al. 2005), a fast evolving non-coding region
(nrITS I & 2) is added to improve resolution and statistical support. Past classifications
1 GENERAL INTRODUCTION

and phylogenies based on different morphological concepts with biased emphasis on
either generations of the life cycle of this group, these gametophytic and sporophytic
characters were analyzed to detect convergent evolution and to test various phylogenetic
concepts.

Such contrasting classifications are not unique within the Hookeriales but apply to many
groups of mosses. Nevertheless, the controversial classification history and disagreement
about whether gametophyte or sporophyte characters are providing more phylogenetic
information would make the Hookeriales a perfect group to test this long-standing issue in
systematic bryology. Moreover, the study could test and confirm the presence of
reversibility in morphological characters and to determine its frequency of occurrences.

Chapter 2 of the dissertation focused on the relationships of the large genus
Distichophyllum and its allied genera such as Leskeodon and Distichophyllidium which are
much smaller in terms of species numbers. A genus of ca. 100 accepted species today, has been generally subdivided into two sections. However, some authors
such as Fleischer (1908) and Matteri (1975) have commented that the two traditional
sections put forward by Brotherus (1907, 1925) have no standing. One of the objectives,
thus, is to ascertain if the two proposed sections under Distichophyllum are reflected in
the phylogenetic reconstruction. If not, what would be the best division of the large genus.
On the other hand, several smaller genera recognized today were segregates from
Distichophyllum. Peristome features, particularly the exostome ornamentation, was one of
the criteria use for delimiting the genera. It is hypothesized that peristomial features,
although not a good character to delimit families and higher ranks, is good for recognizing
genera (Buck, 1991, 2007). This study will test the validity of using exostome
ornamentation for generic delimitation within the Daltoniaceae.

A worldwide taxonomical monograph of Distichophyllum does not exist and thus often
hampering accurate identification of this large and morphological diverse genus.
Consequently, misidentifications of specimens are not uncommon. To avoid isolation of
DNA from misidentified voucher specimens, all voucher used in DNA isolation are re-
identified or re-confirmed. This also avoids different concepts of species delimitation in
identifications by different persons whom have identified the specimens. This procedure
has surprisingly accumulated several new and noteworthy country or island records.
Some taxonomical knowledge is also accumulated while trying to accurately identify some
challenging species. The new and noteworthy records, along with taxonomical
2 GENERAL INTRODUCTION

clarifications of some of the lesser known species are presented in Chapter 3 of the
dissertation.

As one of the common approach to start a project, the initial phase was spent collecting
and reviewing literature. While doing so, it was found that the name Distichophyllum is an
illegitimate name according to the International Code of Botanical Nomenclature (ICBN). A
series of linked nomenclatural problems arises with this new but correct interpretation of
the legitimacy of Distichophyllum. Hence, in order to keep the well-known name in current
use and to avoid numerous new binomials to replace all the names under
Distichophyllum, a proposal to conserve Distichophyllum should be summated for
considerations by the nomenclature committee of the ICBN. A modified version of this
proposal is presented in Chapter 4.

3 CHAP 1: TESTING MORPHOLOGICAL CONCEPTS IN DIFFERENT GENERATIONS

Chapter 1:

The gametophyte strikes back: testing opposing
morphological concepts on the haploid and diploid
generations in the moss order Hookeriales
(Bryopsida)

To be submitted to “Molecular Phylogenetics and Evolution”


Contents
1.1. Introduction 6
1.1.1. Taxonomic importance of the peristome 7
1.1.2. The gametophyte strikes back 7
1.1.3. Other ways of using morphology 8
1.1.4. The rise of molecular phylogeny 8
1.2. Material and Methods 10
1.2.1. Taxon Sampling and molecular protocols 10
1.2.2. DNA sequence editing and alignment 18
1.2.3. DNA data analyses 19
1.2.4. Morphological data and ancestral state reconstruction 20
1.3. Results 25