The tree, the network, and the species

To enrich the Hennigian internodal conception of species, a new formalization of the definition of the species concept is proposed. This rigorous definition allows for considerable unification of the various, and sometimes conflicting, techniques of species delimitation used in practice. First, the domain of such a definition is set out, namely, the set of all organisms on Earth, past, present, and future. Next, the focus is on the genealogical relationship among organisms, which provides the key to analysing the giant or global genealogical network (GGN) connecting all these organisms. This leads to the construction of an algorithm revealing the topological structure of the GGN, from families to lineages, ending up with a definition of species as equivalence classes of organisms corresponding to branches of the 'tree of life'. Such a theoretical definition of the species concept must be accompanied by various recognition criteria to be operational. These criteria are, for example, the ill-named 'biological species concepts', 'phylogenetic species concepts', etc., usually, but wrongly, presented as definitions of the species concept. Besides clarifying this disputed point, the definition in the present study displays the huge diversity of the scales (time-scale and population size) involved in actual species, thus explaining away the classical problems raised by previous attempts at defining the species concept (uniparental reproduction, temporal depth of species, and hybridization).  © 2006 The Linnean Society of London, Biological Journal of the Linnean Society , 2006, 89 , 509–521.     

The internodal species concept: a response to 'The tree, the network, and the species'

Samadi and Barberousse attempt to provide a precise, formal definition of the species category that is faithful to the internodal species concept (Samadi S, Barberousse A. 2006. The tree, the network, and the species. Biological Journal of the Linnean Society 89: 509–521). Here, it is argued that their study is technically flawed. Most of the necessary corrections to their definitions are provided in order to accurately portray the internodal concept. It is then argued that the internodal concept is fundamentally flawed; it does not solve the 'classical problems' that Samadi and Barberousse claim it does. In particular, it does not allow for the possibility of interspecies hybridization. In addition, the proposal is unworkable in practice, and also theoretically problematic because it entails that, in many lineages, speciation events are taking place every few generations.  © 2008 The Linnean Society of London, Biological Journal of the Linnean Society , 2008, 93 , 865–869.     

The Species Delimitation Uncertainty Principle

If, as Einstein said, "it is the theory which decides what we can observe," then "the species problem" could be solved by simply improving our theoretical definition of what a species is. However, because delimiting species entails predicting the historical fate of evolutionary lineages, species appear to behave according to the Heisenberg Uncertainty Principle, which states that the most philosophically satisfying definitions of species are the least operational, and as species concepts are modified to become more operational they tend to lose their philosophical integrity. Can species be delimited operationally without losing their philosophical rigor? To mitigate the contingent properties of species that tend to make them difficult for us to delimit, I advocate a set of operations that takes into account the prospective nature of delimiting species. Given the fundamental role of species in studies of evolution and biodiversity, I also suggest that species delimitation proceed within the context of explicit hypothesis testing, like other scientific endeavors. The real challenge is not so much the inherent fallibility of predicting the future but rather adequately sampling and interpreting the evidence available to us in the present.     

Species: the concept, category and taxon

The term species by itself is vague because it refers to the species concept, the species category and the species taxon, all of which are distinct although related to one another. The species concept is not primarily a part of systematics, but has always been an integral part of basic biological theory, It is based on evolutionary theory and applies only to sexually reproducing organisms. The species concept and the phyletic lineage concept are quite distinct although they are related to one another. The important aspect of the species concept is lack of gene flow between different species, and hence the defining criterion of the species is genetic isolation. The species concept is often considered as non‐dimensional, both in time and space. Species possess three different major properties, namely genetic isolation, reproductive isolation and ecological isolation; these properties evolve at different times and under the effect of different causes during the speciation process. Speciation requires an external isolating barrier during the initial allopatric phase in which genetic isolation evolves and must reach 100% efficiency. The subsequent sympatric phase of speciation occurs after the disappearance of the external isolating barrier when members of the two newly evolved species can interact with one another and exert mutual selective demands on one another. Much of the reproductive and ecological isolation evolves during this secondary sympatric phase. The species category is a rank in the taxonomic hierarchy and serves as the basis on which the diversity of organisms is described; it is not the same as the species concept. The species category applied to all organisms, sexually and asexually reproducing. The species taxon is the practical application of the species category in systematics with the recognition of species taxa requiring many arbitrary decisions. No single set of rules exist by which the species category can be applied to all organisms. Recognition of species taxa in asexually reproducing organisms is based on amount of variation and gaps in the variation of phenotypic features associated with ecological attributes of these organisms as compared with similar attributes in sympatric species taxa of sexually reproducing organisms. Species taxa are multidimensional in that they exist over space–time and often have fuzzy borders. Because recognition of species taxa, including those in sexually reproducing organisms, depends on many arbitrary decisions especially when dealing with broad geographical and temporal ranges, species taxa cannot be used as the foundation for developing and testing theoretical concepts in evolutionary theory which can only be done with the non‐dimensional species concept.     

Systematics of the Saharo‐Arabian clade of the Palearctic naked‐toed geckos with the description of a new species of Tropiocolotes endemic to Oman

Geckos are one of the most species‐rich, abundant, and widely distributed of all Squamata lineages and present several characteristics that have made them favorite model organisms for biogeographical, ecological, physiological, and evolutionary studies. One of the key aspects of any comparative study is to have a robust, comprehensive phylogeny, and an updated taxonomy. Recently, the Infraorder Gekkota has been the subject of several phylogenetic analyses and taxonomic revisions at different levels. Despite all these phylogenetic and taxonomic advances, there are still some groups whose systematics and taxonomy remain highly problematic. Maybe one of the most poorly resolved groups in spite of decades of intensive research by many herpetologists are the so‐called Palearctic naked‐toed geckos of the family Gekkonidae. This group of nocturnal geckos distributed from Mauritania across North Africa, Arabia, southwestern and central Asia to northern India, western China and southern Mongolia is characterized by the synapomorphy of lack of adhesive subdigital pads. Within the Palearctic naked‐toed geckos, the Saharo‐Arabian clade comprised by the genera Pseudoceramodactylus, Stenodactylus, and Tropiocolotes is the clade with the largest distribution range. At the same time, it is one of the problematic groups, presenting poorly supported phylogenetic relationships, with the genus Tropiocolotes being recovered non‐monophyletic in all analyses despite its morphological uniformity. To reassess the phylogeny of the Palearctic naked‐toed geckos with a special interest in the systematics of Tropiocolotes, we assembled a dataset comprising 298 gecko specimens from 283 different species (including all Tropiocolotes species but one) belonging to 122 of a total of 124 described gecko genera. This dataset included the nuclear c‐mos, ACM4, RAG1, RAG2, and PDC and the mitochondrial ND2 gene. To further investigate the relationships within Tropiocolotes and to revise the systematics of the south Arabian endemic species Tropiocolotes scorteccii, we used an integrative approach including information from the nuclear MC1R and c‐mos, the mitochondrial 12S, 16S, cytb genes, and morphological data from nine of the 10 described Tropiocolotes species. The phylogenetic analyses of the Gekkota dataset recovered a similar topology for the Palearctic naked‐toed geckos to previous studies, but in this case, Tropiocolotes was recovered monophyletic in all analyses, with high support in two of them. The results of the analyses of three datasets specifically assembled to test the effect of both gene sampling and taxon sampling in the monophyly of Tropiocolotes, and the internal relationships of the Palearctic naked‐toed geckos clearly showed that both the number and kind of characters (nuclear or mitochondrial data) and the number of taxa played a fundamental role in recovering the correct phylogenetic relationships. The phylogenetic analyses within Tropiocolotes suggested the existence of high levels of undescribed diversity in the south Arabian T. scorteccii, including a new genetically and morphologically distinct species endemic to Oman (Tropiocolotes confusus sp. nov. ). Our study using a large dataset, including several loci and a dense taxon sampling within Gekkota and especially within Tropiocolotes, has proved a valuable strategy to address the monophyly of Tropiocolotes and the relationships within the Saharo‐Arabian Palearctic naked‐toed geckos. The integrative systematic approach including several samples of south Arabian T. scorteccii based on many years of fieldwork has, once more, uncovered a new species endemic to this region. This highlights the importance of this area of Arabia as a reservoir of reptile endemicity and biodiversity, which is likely linked to the high degree of habitat heterogeneity and the effect of the monsoons. Obviously, based on this and previously published evidence, south Arabia represents an area with still high levels of undiscovered diversity.     

物种与物种多样性

本文首先讨论生物物种的科学概念和生物学本质，分析物种客观存在的自然属性和物种概念的局限性，认为物种的生物学属性和物种多样性的科学属性之间有着本质联系。物种多样性研究的实质是研究生物物种的生物学多样性。度量物种多样性程度有多种方法，但物种数目是物种多样性程度最直接、也是最基本的表达，估计物种多样性数目是当前国际上物种多样性研究的核心与热点内容。物种多样性产生的根源是物种形成，物种绝灭速率是维持物种多样性的关键因素。本文简要总结了物种形成与绝灭的基本模式和机制，通过分析生物地理区系与物种多样性研究的密切关系，说明物种的区系成份分析是物种多样性大尺度格局研究的重要内容。     

The Mecyclothorax beetles (Coleoptera,Carabidae, Moriomorphini) of Tahiti,Society Islands

The 101 species of Mecyclothorax Sharp known to inhabit Tahiti Island, French Polynesia are taxonomically revised, including 28 species that are newly described: Mecyclothorax claridgeiae sp. n., Mecyclothorax jeanyvesi sp. n., Mecyclothorax poria sp. n., Mecyclothorax aano sp. n., Mecyclothorax papau sp. n., Mecyclothorax manina sp. n., Mecyclothorax everardi sp. n., Mecyclothorax ramagei sp. n., Mecyclothorax pitohitiensis sp. n., Mecyclothorax curtisi sp. n., Mecyclothorax hoeahiti sp. n., Mecyclothorax ninamu sp. n., Mecyclothorax kokone sp. n., Mecyclothorax paahonu sp. n., Mecyclothorax kayballae sp. n., Mecyclothorax ehu sp. n., Mecyclothorax papuhiti sp. n., Mecyclothorax tuea sp. n., Mecyclothorax taatitore sp. n., Mecyclothorax konemata sp. n., Mecyclothorax arboricola sp. n., Mecyclothorax rahimata sp. n., M. oaoa sp. n., Mecyclothorax maninapopoti sp. n., Mecyclothorax hunapopoti sp. n., Mecyclothorax fefemata sp. n., Mecyclothorax maninamata sp. n., and Mecyclothorax niho sp. n. Mecyclothorax muriauxioides Perrault, 1984 is newly synonymized with Mecyclothorax muriauxi Perrault, 1978. Lectotypes are designated for: Thriscothorax altiusculus Britton, 1938; Thriscothorax bryobius Britton, 1938; Mecyclothorax globosus Britton, 1948: and Mecyclothorax sabulicola Britton, 1948. Dichotomous identification keys augmented by dorsal habitus and male aedeagal photographs are provided to the various species-groups and all included species. The spermatophore of Mecyclothorax papau sp. n. is described, with the ampulla and collar found to correspond dimensionally to the length of the internal sac flagellar plate. Variation among characters of the female reproductive tract is presented for all newly described plus other representative species comprising the radiation. Taxa are assigned to species groups, modified from the classification of G.G. Perrault, based on derived character states polarized using the Australian outgroup taxon Mecyclothorax punctipennis (MacLeay). Much of the species-level diversity on this small Pacific island is partitioned allopatrically over very small distributional ranges. No species is shared between Tahiti Nui and Tahiti Iti, and nearly all species in Tahiti Nui are geographically restricted to one ridgelike massif of that volcano. Cladistically similar species are often distributed on different massifs suggesting that vicariance associated with erosional valley formation has facilitated speciation, however several instances in which sister species occupy sympatric distributions on the same ridge system demonstrate that speciation may also occur across extremely localized landscapes. Such localized differentiation is facilitated by the low vagility of these small-bodied, flightless predators whose fragmented populations can persist and diverge within spatially limited habitat patches. The intense philopatry of Tahitian Mecyclothorax spp. coupled with the highly dissected landscape has produced the geographically densest adaptive radiation on Earth. This radiation has occurred very rapidly, with species durations averaging 300,000 yr; a speciation rate similar to that observed in Hawaiian Oliarus planthoppers and Laupala crickets, and East African Rift lake cichlid fishes.     

Evolutionary morphology of whip spiders: towards a phylogenetic system (Chelicerata: Arachnida: Amblypygi)*

The aim of this study is to present a cladogram and phylogenetic system and to use this to discuss the phylogeny and biogeography of the Amblypygi. A total of 29 morphological structures were studied, their plesiomorphic and apomorphic characters or character states were identified, and the resulting data matrix was analysed. As a result, the ‘old’Charontidae or Pulvillata emerge as a paraphyletic group; the genus Paracharon is the sister group of all other amblypygids, which are now termed Euamblypygi. The ‘new’Charontidae (sensu Quintero: the genera Stygophrynus and Charon) are the sister group of the Phrynida or Apulvillata; together they form the Neoamblypygi. The relationships of the genera of the Charinidae cannot be resolved with the available data. They may be a paraphyletic group. The genus Catageus is a possible candidate for being the sister group of the Neoamblypygi. The new system allows a discussion of the phylogeny and biogeography of whip spiders. It also points to unresolved taxa and thus indicates the questions future research should address.     

Morphological differentiation among closely related species with disjunct distributions: a case study of Mediterranean Cyclamen L. subgen. Psilanthum Schwarz (Primulaceae)

In Cyclamen subgenus Psilanthum , previous authors have recognized three species ( C. repandum, C. balearicum and C. creticum ), with C. repandum subdivided into three subspecies (ssp. repandum , ssp. peloponnesiacum and ssp. rhodense ), and two varieties (var. vividum and var. peloponnesiacum ) within C. repandum ssp. peloponnesiacum . To examine the validity of this classification and the degree of morphological differentiation among closely related endemic taxa with disjunct distributions, we undertook analyses of three quantitative and eight qualitative morphological traits of flowers and leaves, most of which have previously been used without statistical comparison in the classification of the different taxa. Cyclamen balearicum showed high levels of morphological differentiation from all other taxa in subgenus Psilanthum consistent with its specific status. In contrast, morphological differentiation between C. creticum and subspecies of C. repandum was similar to that among the three subspecies of C. repandum . When compared with a recent molecular phylogeny of this subgenus, our results suggest that C. creticum may best be described as a geographical subspecies of C. repandum . The two varieties of C. repandum ssp. peloponnesiacum showed few significant differences for individual traits and their overall morphology is very similar to each other. The morphology of plants at three sites on Corsica strongly suggest, consistent with molecular data, the occurrence of hybrid populations between C. balearicum (outside of its previously recognized distribution) and local C. repandum .  © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society , 2002, 139 , 133–144.     

Evidence for parallel ecological speciation in scincid lizards of the Eumeces skiltonianus species group (Squamata: Scincidae)

We identify instances of parallel morphological evolution in North American scincid lizards of the Eumeces skiltonianus species group and provide evidence that this system is consistent with a model of ecological speciation. The group consists of three putative species divided among two morphotypes, the small-bodied and striped E. skiltonianus and E. lagunensis versus the large-bodied and typically uniform-colored E. gilberti. Members of the group pass through markedly similar phenotypic stages during early development, but differ with respect to where terminal morphology occurs along the developmental sequence. The morphotypes also differ in habitat preference, with the large-bodied gilberti form generally inhabiting lower elevations and drier environments than the smaller, striped morphs. We inferred the phylogenetic relationships of 53 skiltonianus group populations using mtDNA sequence data from the ND4 protein-coding gene and three flanking tRNAs (900 bp total). Sampling encompassed nearly the entire geographic range of the group, and all currently recognized species and subspecies were included. Our results provide strong evidence for parallel origins of three clades characterized by the gilberti morphotype, two of which are nested within the more geographically widespread E. skiltonianus. Eumeces lagunensis was also nested among populations of E. skiltonianus. Comparative analyses using independent contrasts show that evolutionary changes in body size are correlated with differences in adult color pattern. The independently derived association of gilberti morphology with warm, arid environments suggests that phenotypic divergence is the result of adaptation to contrasting selection regimes. We provide evidence that body size was likely the target of natural selection, and that divergences in color pattern and mate recognition are probable secondary consequences of evolving large body size.     

Evolutionary Phycology: Toward a Macroalgal Species Conceptual Framework

Species concepts formalize evolutionary and ecological processes, but often conflict with one another when considering the mechanisms that ultimately lead to species delimitation. Evolutionary biologists are, however, recognizing that the conceptualization of a species is separate and distinct from the delimitation of species. Indeed, if species are generally defined as separately evolving metapopulation lineages, then characteristics, such as reproductive isolation or monophyly, can be used as evidence of lineage separation and no longer conflict with the conceptualization of a species. However, little of this discussion has addressed the formalization of this evolutionary conceptual framework for macroalgal species. This may be due to the complexity and variation found in macroalgal life cycles. While macroalgal mating system variation and patterns of hybridization and introgression have been identified, complex algal life cycles generate unique eco-evolutionary consequences. Moreover, the discovery of frequent macroalgal cryptic speciation has not been accompanied by the study of the evolutionary ecology of those lineages, and, thus, an understanding of the mechanisms underlying such rampant speciation remain elusive. In this perspective, we aim to further the discussion and interest in species concepts and speciation processes in macroalgae. We propose a conceptual framework to enable phycological researchers and students alike to portray these processes in a manner consistent with dialogue at the forefront of evolutionary biology. We define a macroalgal species as an independently evolving metapopulation lineage, whereby we can test for reproductive isolation or the occupation of distinct adaptive zones, among other mechanisms, as secondary lines of supporting evidence.     

Three new species of Stiphrornis (Aves: Muscicapidae) from the Afro-tropics,with a molecular phylogenetic assessment of the genus

We describe three new species of forest robin in the genus Stiphrornis; two from West Africa and one from the Congo Basin. Each species represents a distinct phylogenetic lineage based on genetic analysis. In addition to genetic differentiation, each new species is diagnosable from other Stiphrornis lineages by morphology, and by plumage. One of the new species appears to be restricted to the Central and Brong-Ahafo Regions of Ghana, and another is restricted to Benin and the Central Region of Ghana. In Ghana, these two new species presumably come into contact with Stiphrornis erythrothorax (Western Region of Ghana and westward), and there is evidence that one of the new species has a distinguishably different song from erythrothorax. The distribution of the third new species is primarily on the south bank of the Congo River, near the city of Kisangani. Recognition of these species provides additional evidence that Afrotropical forests are harbouring substantial cryptic diversity, and that our knowledge of the drivers of this diversity remains poorly documented across the region.

http://www.zoobank.org/urn:lsid:zoobank.org:pub:BF2A0BE6-1140-4EFF-9035-380D61AB03AE     

The Species Concept as a Cognitive Tool for Biological Anthropology

Taxonomy is caught between the search for the “perfect” theory and an elusive biological variability. The lack of major advances in issues related to how “species” and other taxonomic categories are defined suggests that perhaps we should avoid excessively rigid formalism in this regard. The risk is a separation between elegant but useless theories and confusing applications of the taxonomic tools. Communication is one of the main functions of taxonomy, and stability one of the main parameters that taxonomy users should be sensitive to. An excess of stability may generate anachronistic consequences while continuous revisions may make the tool of taxonomy scarcely practical. The current tendency pushes toward more and more fragmentation of biologically valid taxa. While taxonomy specialists enjoy such challenges, many taxonomy users feel a bit nervous and discouraged when trying to use a tool that is constantly changing. Debates over taxonomy would seem particularly unrewarding for fields with limited samples and scarce biological diversity, such as palaeoanthropology. In this context, where the information available is rarely sufficient to supply consistent taxonomical evidence, there are frequently excessive efforts to create debate on species separations. The risk is that we maintain the debate on a purely theoretical level, or else we distrust a reliable use of taxonomy. A compromise (and recommended) choice between these two extremes would be to rely on shared and reasonable interpretations of homogeneous evolutionary units, without diving into fine‐grained issues that will remain, however, unresolved. Taxonomy should be a tool, not the goal, of the evolutionary biologist. Our mind needs discrete and recognizable objects to structure our perception of reality. There is no reason to expect that nature works the same way. Am. J. Primatol. 75:10‐15, 2013. © 2012 Wiley Periodicals, Inc.     

Botany without borders: barcoding in focus

This recent meeting, held on the campus of the University of British Columbia, attracted 1200 delegates and a vast array of talks, but was notable for a remarkable showing of talks and posters on DNA barcoding in plants, spread through many sessions. The Canadian Centre for DNA Barcoding defines barcoding as ‘species identification and discovery through the analysis of short, standardized gene regions known as DNA barcodes’. This approach is somewhat controversial in animals ( Rubinoff et al., 2006 ), although it has been shown to be useful and reliable in many metazoan taxa ( Meyer & Paulay 2005 ; Hajibabaei et al., 2007 ), in which the mitochondrial cytochrome oxidase I (COI) gene is used. However, in land plants, COI evolves far too slowly to be useful, and there is no obvious single universal alternative ( Fazekas et al., 2008 ). Genes that work well in one taxon may perform poorly in other taxa. Additionally, some perfectly good plant species, reproductively isolated and morphologically and ecologically distinct, are too young to show much sequence divergence at most loci. Nevertheless, as we saw at this conference, progress has been made towards identifying genes that serve many of the functions of DNA barcodes, at least in some plant taxa.     

Species,speciation and human evolution

Human evolution is considered from the perspective of the recognition concept of species, which views species as an epiphenomenon of shared fertilisation systems in sexually reproducing organisms. It is argued that this concept predicts the controversial pattern of punctuated equilibrium, and offers an understanding of the hominid fossil evidence in line with that pattern. Changes in the nature of the fertilization system in the human lineage over time are discussed in relation to the pattern of morphological continuity between proposed species.     

Papulosa amerospora accommodated in a new family (papulosaceae, sordariomycetes, ascomycota) inferred from morphological and molecular data

To investigate the systematic position of the unitunicate pyremomycetePapulosa amerospora, we performed phylogenetic analyses of SSU rDNA sequences from 37 ascomycetes. Among these sequences were some new ones from taxa that might be related toPapulosa: Hyponectriaceae (Hyponectria buxi, Monographella nivalis), Phyllachorales (Phyllachora graminis), and Xylariales (Barrmaelia melanotes, Poronia punctata). Our results showed 100% bootstrap support for a clade of all unitunicate pyrenomycetes, the class Sordariomycetes. We also found strong support for recognizing the subclasses Hypocreomycetidae and Xylariomycetidae. The remaining taxa, belonging to subclass Sordariomycetidae, appeared as a polyphyletic group in one analysis, but was monophyletic when shorter SSU sequences were used.Barrmaelia melanotes, Poronia punctata, Hyponectria buxi, andMonographella nivalis are members of Xylariomycetidae, but we could not determine whetherMonographella should be included in Hyponectriaceae. The new family Papulosaceae is erected forPapulosa on molecular and morphological bases, but the exact systematic position ofPapulosa within subclass Sordariomycetidae is still uncertain, since the genus did not cluster consistently with any of the included taxa. Phyllachorales are not closely related to Diaporthales, as previously suggested.     

Phylogeny of Hypselodoris (Nudibranchia: Chromodorididae) with a review of the monophyletic clade of Indo-Pacific species, including descriptions of twelve new species

This work provides an account of the systematics and phylogeny of Hypselodoris . Aspects of the morphology of 42 species are described and the systematic status of an additional 11 species is discussed. Twelve new species are described: Hypselodoris alboterminata, H. bertschi, H. bollandi, H. fucata, H. iacula, H. insulana, H. krakatoa, H. paulinae, H. reidi, H. rudmani, H. violabranchia and H. zephyra. A phylogenetic analysis supports the monophyly of Hypselodoris and Risbecia . Two distinct clades of Hypselodoris are present. One contains species from the Atlantic and eastern Pacific while the other contains species limited to the Indo-Pacific tropics and adjacent temperate regions. Species from the Atlantic and eastern Pacific are bluish in body colour and have a plesiomorphically large receptaculum seminis while Indo-Pacific taxa are variably coloured and all have a minute receptaculum seminis. The distribution and size of mantle glands provides a wealth of morphological characters. With few exceptions, mantle glands vary in closely related species and are important for distinguishing members of smaller clades. Mantle gland distribution is therefore useful in identifying preserved material that is difficult to identify to species in the absence of the pigment of living specimens. Similar colour patterns found in sympatric species of Hypselodoris appear to be a result of both common descent and convergence between less closely related lineages. Biogeographic distributions of sister taxa provide several examples of vicariance. Examination of these cases shows that no single vicariant pattern is present, but vicariance appears to occur at the margins of the Indo-Pacific rather than centrally. Some vicariance occurs even within archipelagos such as the Hawaiian Islands. These cases largely refute the generality of the hypothesis of Springer (1982), that Pacific Plate and Australasian Plate endemic sister taxa should predominate.     

The complex phylogeography of the Indo‐Malayan Alophoixus bulbuls with the description of a putative new ring species complex

The Indo‐Malayan bioregion has provided some of the most spectacular discoveries of new vertebrate species (e.g. saola, khanyou, bare‐faced bulbul) over the last 25 years. Yet, very little is known about the processes that led to the current biodiversity in this region. We reconstructed the phylogeographic history of a group of closely related passerines, the Alophoixus bulbuls. These birds are continuously distributed in Indo‐Malaya around the Thailand lowlands such that their distribution resembles a ring. Our analyses revealed a single colonization event of the mainland from Sundaland with sequential divergence of taxa from southwest to northeast characterized by significant gene flow between parapatric taxa, and reduced or ancient gene flow involving the two taxa at the extremities of the ring. We detected evidence of population expansion in two subspecies, including one that was involved in the closing of the ring. Hence, our analyses indicate that the diversification pattern of Alophoixus bulbuls fits a ring species model driven by geographic isolation. To our knowledge, the Alophoixus bulbuls represent the first case of a putative broken ring species complex in Indo‐Malaya. We also discuss the implications of our results on our understanding of the biogeography in Indo‐Malaya.