Babblers, Biogeography and Bayesian Reasoning M G Department of Zoology
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Babblers, Biogeography and Bayesian Reasoning M G Department of Zoology
Babblers, Biogeography and Bayesian Reasoning MAGNUS GELANG Department of Zoology Stockholm University 2012 Babblers, Biogeography and Bayesian Reasoning Doctoral dissertation 2012 Magnus Gelang Department of Zoology Stockholm University SE-106 91 Stockholm Sweden Department of Vertebrate Zoology Swedish Museum of Natural History PO Box 50007 SE-104 05 Stockholm Sweden [email protected] © Magnus Gelang, Stockholm 2012 ISBN 978-91-7447-438-1 Cover illustration: Large wren babbler Turdinus macrodactyla, Bodogol, Java, Indonesia. Photo: Magnus Gelang. Printed in Sweden by US-AB, Stockholm 2012 Distributor: Department of Zoology, Stockholm University ABSTRACT In this thesis, I try to proceed one step further towards an understanding of the biogeographic processes forming the distribution patterns of organisms that we see today. Babblers and warblers are diverse groups of passerines that are phylogenetically intermixed with other groups in the superfamily Sylvioidea. First, the gross phylogeny of the babblers and associated groups was estimated. Five major lineages of a well-supported monophyletic babbler radiation were recovered, and we proposed a new classification at family and subfamily level. Further, the genus Pnoepyga was excluded from Timaliidae, and we proposed the new family Pnoepygidae fam. nov. Second, the systematic position was investigated for the Albertine Rift taxon Hemitesia neumanni, which was found to be nested within the almost entirely Asian family Cettidae, and possible biogeographical scenarios were discussed. We concluded that the most plausible explanation involved late Miocene vicariance in combination with local extinctions. Third, the historical biogeography of a Leiothrichinae subclade, the Turdoides babblers and allies, was inferred. We concluded that the Middle East region probably played an important role in the early history of this clade, followed by local extinctions in this region. Fourth, a Bayesian method to reconstruct the historical biogeography under an event-based model was proposed, where the total biogeographic histories are sampled from its posterior probability distribution using Markov chains. In conclusion, I believe that, especially with more sophisticated methods available, we will see an increasing number of studies inferring biogeographic histories that lead to distribution patterns built up by a combination of dispersals and vicariance, but where these distributions have been extensively reshaped, or litterally demolished, by local extinctions. Therefore, my answer to the frequently asked question dispersal or vicariance? is both, but not the least: extinctions. Keywords: Africa, Asia, Bayesian inference, biogeography, Cettidae, dispersal, extinction, Middle East, persistence, Sylvioidea, Sylviidae, Timaliidae, vicariance. LIST OF PAPERS I Gelang, M., Cibois, A., Pasquet, E., Olsson, U., Alström, P. & Ericson, P. G. P. (2009) Phylogeny of babblers (Aves, Passeriformes): major lineages, family limits and classification. Zoologica Scripta. 38(3): 225–236. II Irestedt, M., Gelang, M., Sangster, G., Olsson, U., Ericson, P. G. P. & Alström, P. (2011) Neumann´s warbler Hemitesia neumanni (Sylvioidea): the sole African member of a Palaeotropic Miocene avifauna. Ibis. 153: 78–86. III Gelang, M., Pasquet, E., Cibois, A., Alström, P. & Ericson, P. G. P. (submitted) Ancestral ranges concealed by local extinctions: the historical biogeography of the African and Asian Turdoides babblers and allies (Aves: Passeriformes). m.s. IV Gelang, M. & Bohlin, A. (submitted) Bayesian inference of total biogeographic history under an event-based model. m.s. The published papers are reprinted with permission from the publishers. No part of this thesis must be reproduced without permission. CONTENTS INTRODUCTION 1 The Study Group 1 The Old World in the Neogene Time 2 Event-Based Biogeography 3 Conditional Probabilities and Bayesian Methods 4 RESULTS AND DISCUSSION 5 Phylogenetic Relationships 5 Phylogenetic Biogeography 7 A New Method in Historical Biogeography 8 CONCLUSIONS 9 REFERENCES 10 ACKNOWLEDGEMENTS 14 INTRODUCTION To explain the origin and history of an organism is tricky, but it is crucial for the understanding of the organisms biology. Biogeography is an interdisciplinary field containing both biotic, abiotic and mathematical components, which aims to reconstruct the history in terms of distribution ranges, diversity patterns etc. To make such reconstructions we may need to investigate both phylogenetic relationships, geological and climatological history and ecology and general biology of the study group, as well as other factors that might have influenced the distributions. To me, this complexity is what makes biogeography such a stimulating field. In my work, I have studied a group of birds that inhabits large parts of the Old World, and whose phylogenetic relationships were, at the beginning of my work, poorly known. During the course of my PhD project, many questions have been answered, but even more questions have arised. For me personally, it has been a journey streching over many horizons and which has taken me both into and out of tangled bushes, both litterally and metaphorically. The project started with much focus on babblers in Southeast Asia, i.e. birds and a region well familiar to me, but ended in relatively new environments, such as mathematical and computational, and with a focus on the Middle East. This has been a fantastic journey with quite a few tough but stimulating challenges. The Study Group Babblers and warblers constitute a large portion of the passerine superfamily Sylvioidea, which comprises about 25% of the passerine species diversity (Dickinson, 2003). While babblers are typically stocky, small to medium-sized birds showing extraordinary social behaviours, warblers are generally small neatly built birds without the sociality shown by babblers (Collar & Robson, 2007). However, the two groups, as traditionally treated, can almost be considered ecological groups and both are represented in a number of sylvioid clades where often phylogenetically intermixed (e.g. Beresford et al., 2005; Alström et al., 2006; Johanssson et al., 2008). Traditionally, both Timaliidae (babblers) and Sylviidae (warblers) were included in the “Old world insectivorous group” (Hartert, 1910; Mayr & Amadon, 1951; Deignan, 1964). Beecher (1953) proposed a phylogeny of oscines based on jaw musculature, dividing oscines in the two major groups Sylvioidea and Timalioidea. Together with a large number of passerine groups most babblers were placed in Timalioidea, but only fragments of his research have been corraborated in later studies. Among the morphological characters which have been proposed to be diagnostic for Timaliidae are unspotted juvenile plumage, presence of rictal bristles and scutellated tarsus (Sibley & Ahlquist, 1990 and references therein). Jean Delacour made major contributions to the knowledge of babblers (e.g. Delacour, 1946, 1950) by subdividig the babblers into major groups. Sibley & Ahlquist (1990) proposed a revolutionary phylogeny of birds based on DNA-DNA hybridization. In this extensive study, they excluded the Australian babblers (i.e. genera Garritornis and Pomatostomus) and placed typical babblers together with warblers and white-eyes. In recent studies (Barker et al., 2002, 2004; Ericson & Johansson, 2003; Beresford et al., 2005; Alström et al., 2006; Johansson et al., 2008), a major pattern of distinct clades has been proposed, but with either poorly supported, unresolved or conflicting relationships among the families of Sylvioidea. 1 Regarding babblers, Alice Cibois and Eric Pasquet with colleagues have made several important studies (Cibois et al., 1999, 2001, 2010; Cibois, 2003a, 2003b; Pasquet et al., 2006). Among many findings, they excluded a number of taxa, included the genera Zosterops and Sylvia, and found several paraphyletic genera of babblers. Recently, other studies have resolved important parts of the babbler tree, such as white-eyes and allies (Moyle et al., 2009), laughingthrushes and allies (Lou et al., 2009), barwings (Dong et al., 2010a) and scimitar babblers (Dong et al., 2010b; Reddy & Moyle, 2011). The phylogenetic relationships of the clade containing Cettidae etc. have been extensively studied by Per Alström and Urban Olsson with colleagues (e.g. Alström et al., 2007, 2008, 2011a, 2011b; Olsson et al., 2004, 2005, 2006). The Old World in the Neogene Time Paleogene Neogene Quaternary The Neogene period follows the Paleogene Period Epoch Age (MY) period and is succeeded by the Quatenary period (Fig. Holocene 0–0.0117 1). The Neogene period is subdivided into the Miocene epoch (ca. 23–5.3 million years ago (MYA)) and the Pleistocene 0.0117–2.588 Pliocene epoch (ca. 5.3–2.6 MYA), and Pliocene is Pliocene 2.588–5.332 followed by the Pleistocene epoch (ca. 2.6 MYA–12 000 years before present) in the Quaternary period. The geographical region covered in this thesis was affected by some important changes during the Neogene period. After the warm later part of Oligocene, this warm Miocene 5.332–23.03 climate remained during Miocene and a peak in temperature occurred around 15 MYA. After this, the climate started to change towards the cooler Pliocene (Zachos, 2001). Further, India continued to collide with Asia, resulting in the uplift of the Himalayas (Hall et Oligocene 23.03–33.9 al., 2008). Africa collided with Eurasia, causing the closure of the Tethys sea (Vrielnyck et al., 1997; Rögl, Eocene 33.9–55.8 1998), which together with global fall of sea levels caused land bridges between Africa and Asia. In the Paleocene 55.8–65.5 mid-Miocene, extensive laurel forests covered much of Fig. 1. Overview of the Cenozoic era. the area from northern Africa to eastern Asia Only the Neogene epochs are shown to (Mandaville, 1977; Utescher et al., 2007; Fernándezscale. Palacios et al., 2011). As a result of aridification and cooling of the climate, these forests were shrinking in the end of Miocene, while areas of grassland expanded throughout the region (Mandaville, 1977; Retallack, 1992; Vrba, 1993; Flower & Kennett, 1994; Jacobs et al., 1999). During Pliocene, the concerned geographic area looked much as we see it today (Vrielnyck et al., 1997; Hall et al., 2008; Hall, 2009). 2 Event-Based Biogeography Evolutionary processes linked to geology and to geological processes is a corner stone in this thesis. These processes, the biogeographic events, are often both components of the main question of a biogeographic study and key components in the inference of the biogeographic history. Below, I pay some attention to these events, mainly following Cox & Moore (2006) and references therein. Dispersal is when an organism, or a population, colonizes one place from another. Dispersal can be subdivided into jump dispersal and range extension, where the former refers to an across barrier dispersal, and the latter refers to an increase of range area. Extinction is when an organism, or a population, disappears from either a range unit or globally. In biogeographic analyses, extinction can be divided into global extinction, local extinction and range contraction, but global extinction is typically not used in this kind of analyses. Obviously, extinctions are not straight-forward to infer as they normally lead to incomplete data rather than available information. Vicariance is when an organism, or a population, is split by an abiotic process such as when a land mass is subdivided geologically and its inhabitants survives in both of its new units. The object lesson of vicariance is the break-up of Gondwana into Antarctica, Australasia and South America (e.g. Barker et al., 2002, 2004; Ericson et al., 2002a, 2002b). Vicariance has often been the concurrent explanation of distribution patterns to that of explanations involving dispersal. Persistence is when an organism, or a population, survives in its range. The term duplication is often used almost synonymously albeit with the meaning of including a radiation. Parallell to this term is co-speciation among host and parasite (Ronquist, 1998). For decades, the debate on the relative importance of dispersal and vicariance (e.g. Nelson & Platnick, 1980; Wiley, 1988; Chesser & Zink, 1994; Zink et al., 2000; Via, 2001) has sometimes been nearly bitter, but fortunately this debate has also contributed to a more nuanced knowledge and has resulted in a consensus where a combination of events should be taken into account. Among the most prominent contribution is the parsimony-based Dispersal-Vicariance Analysis (DIVA; Ronquist, 1997, 1998), which was the first available event-based approach to biogeography. DIVA applies a simple three-dimensional cost matrix where the costs of dispersal and extinction are both set to 1, and the costs of vicariance and duplication are both set to 0. Therefore, a DIVA analysis favours duplications and vicariance events over dispersals and extinctions, which in turn leads to the typical scenario with widespread ancestors and underestimation of dispersals and extinctions (Ronquist, 1996; Sanmartín, 2003; Clarke et al., 2008; Buerki et al., 2010). While an analysis performed by DIVA needs a fully bifurcate tree (Ronquist, 1996), Nylander et al. (2008) proposed a way of parse a set of sampled trees (e.g. from the target distribution from an Bayesian estimation of phylogeny) in DIVA. From these, the marginal probabilities of ancestral ranges can be calculated, which enable us to account for phylogenetic uncertainties. During the last decade, a maximum likelihood approach has started to play an increasingly important role in the field of historical biogeography. The maximum likelihood is inferred under the Dispersal-Extinction-Cladogenesis (DEC; Ree & Smith, 2005; Ree et al., 2008) model. The DEC model has proven to infer plausible reconstructions (Clarke et al., 2008; Buerki et al., 2010), especially as additional data from geology 3 etc. can be included in the analysis. Also Bayesian approaches in biogeography have been proposed (Moore and Donoghue, 2009; Sanmartín et al., 2008). Conditional Probabilities and Bayesian Methods Especially during the last decades, Bayesian methods have revolutionized biological sciences in general, and phylogenetic research in particular (Huelsenbeck et al., 2001b; Beaumont & Rannala, 2004). Bayesian methods rely on the relations of conditional probabilities explained in Bayes´ theorem, P H ∣D = P D∣H P H P D , (1) which, in this case, states that the posterior probability of a hypothesis given some data, P(H|D), equals the product of the likelihood of the data given the hypothesis, P(D|H), and the prior probability of the hypothesis, P(H), normalized by the marginal probability of the data, P(D). The marginal probability is the probability of the data integrated over all possible hypothesis, as shown in equation 3, Paper IV. A very simple metaphore, or comparison, of the proportionality between the posterior probability and the numerator in Bayes´ theorem is that our knowledge (cf. posterior probability) is proportional to some observation (cf. likelihood) and our assumption (cf. prior probability). Bayes´ theorem relies on conditional probabilities. This subject needs some further explanation. We take the likelihood as an example, where the probability of the data is conditioned on the hypothesis. This can also be expressed as the probability of the data to fit the hypothesis, or the probability of the data to be true in the light of the hypothesis. In practice, the likelihood may be calculated as the joint probability of the conjunction of the data and hypothesis. If we look at the prior probability of the hypothesis, this is the probability for the hypothesis to be valid regardless of the data, thus if we are unaware of the data. The denominator in Bayes´ theorem is typically impossible to calculate in phylogenetic tasks, and therefore we choose to pay interest to the probability distributions of the components in Bayes theorem. We solve the problems of calculating the marginal probability by using the proportionality of the posterior probability and the product of the likelihood and the prior, and use Markov chains to approximate these distributions. Practically, we seek a local optimum in a parameter space, equivalent to the desired posterior probability distribution. The use of Markov methods to perform statistical sampling to get the expectation of a function is widely used, particularly by using the “Metropolis-Hastings-Green algorithm” (Metropolis et al., 1953; Hastings, 1970; Green, 1995) on Metropolis-coupled Markov chain Monte Carlo (MC3). If we think of the parametric space as a landscape where mountains represent local optima, we want the chains to climb uphill but still not to get stuck on just any hill (local suboptimum). Instead, we want the chains to be able to traverse over valleys and so leave a smaller hill to reach higher summits. This is performed in basically three ways. We let a chain take a random step. If this step is uphill the step is 4 accepted, if downhill the step is accepted with a probability proportional to the step. The second way to facilitate a chain to cross a valley is to “flatten” the landscape. This is made by letting different chains be affiliated to different “temperatures”, where a chain affiliated with a high temperature traverses a landscape which appears to be “melted” and therefore the summits and valleys appear flattened. The third way is to apply incremental heating schemes on a set of chains, where the states can be swapped between chains and where we pay attention to the state of the “cold” chain (Geyer, 1991; Geyer and Thompson, 1995). In all, methods applying incrementally heated MC3 have proven efficient in phylogenetic research (Yang & Rannala, 1997; Larget & Simon, 1999; Huelsenbeck & Ronquist, 2001; Drummond & Rambaut, 2007). Once the MC3 have found the desired local optimum (the target posterior probability distribution), the states of the cold chain is sampled and the posterior probability is calculated as the frequency of a state among these samples. RESULTS AND DISCUSSION Phylogenetic Relationships This thesis relies on molecular data in one way or the other. In paper I, the main source of sequence data was obtained from fresh material (blood- or tissue samples), while in paper II and paper III the main source was from museum study skins. Extraction, amplification and sequencing of DNA were performed using standard protocols (QiaGene), which were modified when appropriate such as for the study skins. In these cases, we mainly followed Irestedt et al. (2006), and extra effort was put on design of primers. In general, fragment lengths of about 200–350 base pairs were amplified for the skins. Phylogenies were reconstructed using both Bayesian and maximum likelihood methods, but in all cases we have chosen to rely on Bayesian inference as the main approach. Phylogenetic estimations were performed using MRBAYES (Huelsenbeck & Ronquist, 2001a), and molecular dating was performed using BEAST (Drummond & Rambaut, 2007). Further, inferences were made on the datasets partitioned on loci following the substitution models proposed by the Akaike criterion (Akaike, 1974). 5 * * * ** * * * * * * * * * * * * * * * * * * * * * * * * * * * * * Timaliidae * Zosteropinae * * Timaliinae * Sylviidae * * * Pellorneinae * * ** * Muscicapa Alauda Panurus Hirundo Acrocephalus Donacobius Thamnornis Megalurus Pnoepyga albiventer Pnoepyga pusilla Prinia Pycnonotus Aegithalos Phylloscopus Myzornis pyrrhoura Parophasma galinieri Sylvia atricapilla Lioparus chrysotis Chrysomma sinense Fulvetta vinipectus Rhopophilus pekinensis Chamaea fasciata Paradoxornis gularis Paradoxornis nipalensis Paradoxornis verreauxi Yuhina diademata Yuhina flavicollis Yuhina gularis Stachyris whiteheadi Speirops lugubris Zosterops japonica Lophozosterops javanicus Heleia crassirostris Lophozosterops superciliaris Stachyris chrysaea Macronous gularis Dumetia hyperythra Timalia pileata Spelaeornis chocolatinus Stachyris nigriceps Stachyris striolata Pomatorhinus ochraceiceps Pomatorhinus schisticeps Xiphirhynchus superciliaris Alcippe poioicephala Graminicola bengalensis Turdinus macrodactyla Gampsorhynchus rufulus Schoeniparus rufogularis Malacocincla abbotti Kenopia striata Pellorneum ruficeps Illadopsis cleaveri Ptyrticus turdinus Napothera epilepidota Jabouilleia danjoui Rimator pasquieri Babax lanceolatus Garrulax sannio Garrulax leucolophus Turdoides jardinei Kupeornis gilberti Phyllanthus atripennis Garrulax erythrocephalus Cutia nipalensis Leiothrix argentauris Heterophasia melanoleuca Liocichla steerii Actinodura souliei Minla cyanouroptera Minla ignotincta * * * * ** Leiothrichinae ©MrEnt * * Pnoepygidae Lanius Corvus Fig. 2. The five loci phylogeny of babblers modified from paper I (fig. 1) estimated by Bayesian inference. Posterior probability over 95 % are shown as asterisk, and main clades concerned in the proposed taxonomy in paper I are visualized in coloured boxes. Although Cibois (2003) recognised a pattern of main clades of babblers, the support was relatively low in parts of the phylogeny. Based upon this work, we extended the analysis both regarding taxonomic sampling and number of loci to better resolve the babbler tree and establish the family limits for the group. In paper I, we recognise five main clades of babblers (fig. 2) and we also exclude the wren babbler genus Pnoepyga from the babbler radiation. A novel classification is proposed for these five main clades. The parrotbills (Paradoxornis), Sylvia warblers, the enigmatic and monotypic genus Myzornis and a few others form a well supported clade which we refer to as Sylviidae. Sylviidae is sister to a large clade, which consists of four major clades. The entire clade is referred to as Timaliidae, and we propose a subfamily classification following the four main 6 clades. The white-eyes, formerly Zosteropidae, and the yuhinas form a clade which we refer to as Zosteropinae. A second clade comprising “tree babblers” (Stachyris, Macronous etc.), scimitar babblers (Pomatorhinus) and the genus Timalia is referred to as Timaliinae. The third clade, which consists mostly of “jungle babblers” (e.g. Malacocincla and Illadopsis) and wren babblers (e.g. Napothera and Turdinus) is referred to as Pellorneinae, while the last clade, which comprises e.g. laughingthrushes (Garrulax and Babax), “song babblers” (e.g. Leiothrix and Heterophasia), and the genus Turdoides, is referred to as Leiothrichinae. The excluded genus Pnoepyga is proposed to form the new family Pnoepygidae based on both morphological and genetic characteristics. No other genus is represented in this family (fig. 2), which therefore only comprises three or four species, depending on which taxonomy is followed. The family Pnoepygidae is distributed from the Himalayas through China and Southeast Asia to the Indonesian archipelago, reaching all the way to Timor. All members inhabit mountain and hill forests and are shy and secretive (Collar & Robson, 2007). In paper II, we find a surprising phylogenetic affiliation of Neumann´s warbler from the Albertine Rift valley in eastern Africa. This warbler is nested within the Old World family Cettidae, which consists mainly of the genera Cettia and Tesia, with some other additions. An attempt to explain this pattern from a biogeographical point of view is further discussed below. In paper III, we estimate the phylogenetic relationships of the clade containing the genera Turdoides, Kupeornis and Phyllanthus (paper I ) and Garrulax cinereifrons (based on unpublished data). Turdoides is revealed to be paraphyletic. This large genus forms two major clades, one comprises most of the African taxa, whereas the other contains most of the Asian-Arabian taxa. Interestingly, Garrulax cinereifrons is inferred to be sister to T. malcolmi, and T. nipalensis is inferred to be sister to the Kupeornis-Phyllanthus clade. Phylogenetic Biogeography The surprising phylogenetic position of Hemitesia neumanni inferred in paper II poses two intriguing biogeographical questions, how did this aberrant pattern arise, and which underlying processes have played the most important role in this case? We propose two competing explanations, where either a long-distance dispersal has occurred from Asia to Africa which resulted in this sole African member of the clade, or that the historical geographic distribution of the ancestor to Hemitesia and its closely related Cettidae taxa covered an area comprising both Africa and Asia and where habitat fragmentations caused a vicariance scenario in combination with local extinctions. We suggested that the latter explanation is most plausible, although long-distance migration is found in closely related species, such as Urosphena squameiceps which migrates from Japan, north-east China and adjacent countries to Southeast Asia (Collar & Robson, 2007). In paper III, we investigate a similar pattern, but where the investigated clade is more diverse, and the African portion is of roughly equal size as the Asian part. Further, a small number of taxa in this clade are found in the Middle East. This, in combination with the African and Indian representatives makes this an interesting group for studying the role of the Middle East and local extinctions connected to the late Miocene aridifications, something also adressed in paper II. The 7 debate on the relative importance of dispersal or vicariance adressed above has put much light on biogeographic events. In paper II and III, we discuss the role of extinctions connected to the cooling and drying during the end of the Miocene. We find no firm support for this in paper II, although we find indications of these processes in paper III. Many recent papers on biogeography adress the question dispersal or vicariance? (e.g. Sanmartín, 2003; Gorog et al., 2004; Bartish et al., 2010). Our paper suggests that much attention should also be paid on extinctions. With respect to the Turdoides clade in paper III, we find that the Middle East seems to have played an important role initially, but as a result of extinctions there is low diversity in this area today. We discuss the role of the mid-Miocene forest cover over Africa and Asia and land-bridges in the Middle East as prerequisites for past range extensions and dispersals. I think it is relevant to think of the Middle East and adjacent areas as an important region, which role for the present pattern of African and Asian diversity may be strongly underestimated. Further, the large portion of open habitat taxa in the Turdoides clade, compared to the other clades in Timaliidae, and the timing of its initial radiations resembles those of some other groups. Among others, these are the tyrant flycatchers of the New World (Ohlson et al., 2008), and the chameleons of southern Africa (Tolley et al., 2008), which radiated and colonized open habitats during the global shift from C3 to C4 plants during the mid to late Miocene. A New Method in Historical Biogeography In paper IV, a Bayesian approach to infer the historical biogeography under an event-based model, given a phylogeny and taxon distributions, is proposed. Among the main differences from available methods, this approach handles total histories instead of stepping through the nodes of a phylogeny or “pruning” a phylogenetic tree. This enables details of the histories to be less likely to have happened but which instead can lead to a history which is overall more likely, as the probability of the total history is considered. To implement the biogeographic events in the analysis, we need a model on which the biogeographic properties of a history depend. Such a model is proposed as a collection of arguments (Φ; equation 2 in paper IV) from which the events for each node can be coded, given a history and the taxon distributions. These arguments concord with the definitions of biogeographical events, and the model Φ is shown as pseudo-code, to facilitates the usage of the model in other applications by other analysts. Compared to the DEC model (Ree & Smith, 2005; Ree et al., 2008) and DIVA (Ronquist, 1997, 1998) our arguments accept polytomies which is, according to my opinion, an important advantage although phylogenetic uncertainties are not taken into account. Further, the Φmatrix can either invoke the four events used in DIVA, or extend these with the division of dispersal to jump dispersal and range extension, and extinction to local extinction and range contraction, as invoked in the DEC model. To use Bayesian inference to estimate the posterior probability of an history given the data and the model, we include the model in the likelihood function and we make two assumptions: we assume the ranges in each node of a history to be multinomially distributed, and we assume the events in a history to be independent. If we accept these assumptions, we can use the proportionality in Bayes´ theorem to explore the probability distributions. If we denote any target distribution π(•), 8 then the posterior probability distribution of a history (h) given some data (D) and the arguments is proportional to the likelihood function of the data conditioned on the history, the arguments and some stochastic parameters and the target prior probability distribution as h∣ D , ∝ f D∣h , , , (2) where f(•) is the likelihood function. The advantages, or disadvantages, of Bayesian reasoning is the prior. Typically, a prior distribution which is conjugate to the posterior distribution is chosen. The conjugate to the multinomial distribution is the Dirichlet distribution (Fergusson, 1973), which is frequently used in many field of Bayesian inference, not at least in biological applications such as in phylogenetic analyses (e.g. Huelsenbeck & Ronquist, 2001; Drummond & Rambaut, 2007). ©MrEnt To be able to implement variables from a Dirichlet distribution in our method, we need to sample a number of variables equal in numbers to the number of event types. This can be made in various ways, and we useNicatoridae a stick-breaking process (fig 3), where randomly chosen breaking points Alaudidae Panurus "Sphenoeacus group" Pycnonotidae Cisticolidae Hirundinidae Acrocephalidae on an imagined stick of the length 1 (one breaking point less than the desired number of variables) Pnoepygidae Locustellidae Donacobidae Bernieridae Aegithalidae Cettidae Phylloscopidae generates some variablesHylia (the pieces of the broken stick). In our case these breaking points are Erythrocercus Sylviidae Zosteropinae Timaliinae Pellorneinae Leiothrichinae drawn from an equal distribution. The pieces of the stick represent the variables, and those are ordered in concordance with the assumed order of event types applied in our method (pdispersal < pextinction < ppersistence < pvicariance). 0 θ3 θ4 θ1 K1 K2 θ2 1 K3 Fig. 3. Visualization of a stick-breaking process on an imagined stick of the length 1, where four variables ordered θ1–θ2 are generated on a 3-simplex (K1–K3). CONCLUSIONS One of the main findings in this thesis is the existence of five well supported major lineages of babblers, each one proposed to be referred to at family or subfamily level. The exclusion of the genus Pnoepyga and proposal of the new family Pnoepygidae, as well as the inferred phylogenetic positions of the genera Myzornis, Kupeornis, Phyllanthus and Hemitesia and the species Turdoides nipalensis and Garrulax cinereifrons add significantly to the general knowledge of babblers. Of the biogeographical findings presented in this thesis, the hypothetical scenario that includes vicariance in combination with local extinctions as an explanation for the origin of Hemitesia is of obvious interest, especially when a similar history is inferred for the Turdoides clade. The importance of the Middle East for a group that is today mostly found outside this region is intriguing, and this illustrates the importance of considering extinctions when reconstructing historical biogeography. 9 One additional contribution of this thesis to the field of biogeography is the methodological improvement of event-based biogeography by describing a method that takes the total histories into account and by using Bayesian inference in a such context. The relative role of different biogeographical events may vary extensively between clades and areas. In my opinion persistence, vicariance and dispersal are the general underlying processes of present distribution patterns, but these patterns might have been extensively deformed or delimited by local extinctions. REFERENCES Akaike, H. (1974) Information theory as an extension of U. (2011) Vicariance or long-distance dispersal: the maximum likelihood principle. In B. N. historical biogeography of the pan-tropical Petrov & F. 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I want to pass the warmest thanks to the coauthors of the papers in this thesis. Your contributions have been, and continue to be crucial. Your patience with my extreme lack of speed has also been extraordinary! Thank you Alexis Bohlin, Alice Cibois, Eric Pasquet, George Sangster, Martin Irestedt, Per Alström, Per Ericson and Urban Olsson! I am also grateful to Sören Nylin, Mari Källersjö and Kjell-Arne Johanson, the members of my review commitee. You came up with a lot of good advices, and you made the annual reports to both friendly and concise meetings. My work and my time on the museum would have been nothing at all without the wonderful hospitality from my collegues. Thanks of you, every hour in the lab, in field, on conferences, birding, at the pizzeria or at the pub have been a pure pleasure! Thank you Jan Ohlson, Martin Irestedt, Ulf Johansson, George Sangster, Johan Dalsätt, Te-Yu Liao and Dario Zuccon! I wish that I have had the possibility to spend more time with the staff at the Vertebrate Department. The good atmosphere at Verte, with all the various discussions, jokes and comments at the lunch room, and the kind-hearted friendship among the entire staff is something I look back on with particular delight. Thank you Peter Nilsson, Peter Mortensson, Ingrid Cederholm, Nisse Jacobsson, Bosse Delling, Ulf Johansson, Ann-Katrin Gustafsson, Sven Kullander, Erik Åhlander, Bodil Kajrup, Thord Fransson, as well as the former staff Göran Frisk, Jonas Nordin, Jonathan Ready among others! I have spent days and nights in the Molecular Systematics Laboratory at the museum. Your hospitality and support has been enormous! Thank you Pia Eldenäs, Ewa Sjödin, Love Dahlen, Bodil Cronholm, Keyvan Mirbakhsh, Martin Irestedt and others, including all of you Post Docs and PhD´s who passed through the lab! I also want to thank the friends in Copenhagen, Jon Fjeldså, Knud Jønsson, Pierre-Henri Fabre for great discussions and nice birding moments etc. Knud is especially thanked for keeping an eye open for treacherous topez! This thesis would not have been possible to write without all samples obtained from museums and other institutions. I am indebted to Göran Frisk and Ulf Johansson (Swedish Museum of Natural History), Eric Pasquet (Muséum National d´Histoire Naturelle, Paris), Alice Cibois (Natural History Museum of Geneva), Jon Fjeldså and Jan Bolding Kristensen (Zoological Museum, Copenhagen), Silke Fregin (Ernst-Moritz-Arndt-Universität Greifswald), Mikhail Kalyakin (Zoological Museum of Moscow), David Willard (Field Museum, Chicago), Sharon Birks (University of Washington Burke Museum), Kristof Zyskowski (Peabody Museum of Natural History and Yale University), Michel Louette (Royal Museum for Central Africa, Tervuren), Storrs Olson (Museum of Natural History, Smithsonian Institution) and Urban Olsson (Göteborg University). I also wish to express 14 my warmst regards to my Indonesian friends Irham Mohammad and Dewi Praviradilaga, for nice times in field and a great support regarding permissions etc. A number of friends have made serious contributions to this thesis, in a wider sense. First of all, I like to thank Ola Marklund with whom I started my scientific career by playing in our gardens as kids and collecting insects, various kinds of feces etc., which later turned to intensive birding around the globe. I am pleased to thank Johannes Persson and Joakim Fagerström who I spent a lot of time with, both in field, while studying and not the least by sharing uncountable hours of good music! I also thank my parents and my sister, Pelle, Gittan and Johanna. You have supported me throughout my life, and we have shared many moments together that have lead to my PhD in one way or the other. An extra thanks to Pelle for your 24-7-support on computer questions and programming problems! Jan Ohlson and Jenni Andersson – your hospitality is beyond any comparison! I cannot even figure out how much you have contributed to this thesis. First of all by letting me stay in your house for hundreds of nights, and also for beeing such good friends in any situation and by inducing a considerable increase of my egg-and-bacon consumption! Last, but far from least, I thank my beloved family. You have had an endless patience, and you have played an almost unvisible but still the most prominent part of this thesis. Above all, I would like to thank you for reminding me about the most important things in life – far beyond scientific papers and impact factors! Bettina, Hanna-Lina, Leo och Maja, TACK för att ni finns och för att ni är så himla goa!!! 15