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1.
Aim Remote oceanic islands often provide good illustrations of adaptive radiations, but phylogenetic studies have also demonstrated unexpected multiple colonization events for a given archipelago. In this study we investigate the relationships among endemic populations of the Marquesas reed‐warbler, Acrocephalus mendanae Tristram, 1883, which have colonized nearly all islands of this remote Polynesian archipelago, and which exhibit a very uniform plumage pattern. We study the phylogeny and morphology of all subspecies in the Marquesas, providing an examination of the position of the Marquesas lineages in relation to reed‐warblers distributed across multiple Polynesian archipelagos. Location This study focused on all the main islands of the Marquesas archipelago, along with samples from other Polynesian archipelagos (Society, Tuamotu, Austral, Cook, Kiribati) and Australia. Methods We used mitochondrial DNA markers (cytochrome b and ND2 genes) to develop a phylogeny of the main eastern Polynesian taxa. All subspecies for the Marquesas were investigated, including multiple individuals per island. Phylogenetic analyses using maximum‐likelihood and Bayesian approaches were employed to infer relationships among A. mendanae populations and between the main Polynesian archipelagos. Morphometric analyses based on 110 specimens from museum collections were performed on external characters to investigate the differences between islands, and these results were compared to the phylogeny. Results Our data indicate that the Marquesas reed‐warbler is in fact a polyphyletic taxon including two independent lineages: the northern Marquesas reed‐warbler, closely related to the Tuamotu reed‐warbler, and the southern Marquesas reed‐warbler, sister taxon to that endemic to the Kiribati. Analyses of morphological characters show that the size and shape features of the Marquesas reed‐warblers exhibit high plasticity linked to adaptation to ecological factors, particularly habitat richness (the diversity of vegetation structure that provides suitable resources and habitat for reed‐warblers, simplified here as the number of indigenous plant species). Main conclusions Our results suggest that reed‐warblers have successfully colonized the Marquesas archipelago, one of the most remote groups of islands in the Pacific Ocean, at least twice. Both events occurred more or less simultaneously at ca. 0.6 Ma, and are more recent than the islands' formation. We outline the taxonomic consequences of our phylogeny and discuss the supertramp strategy of reed‐warblers in the Pacific.  相似文献   

2.
Aim Patterns of genetic variation within forest species are poorly documented in island ecosystems. The distribution of molecular variation for Santalum insulare, an endangered tree species endemic to the islands of eastern Polynesia, was analysed using chloroplast microsatellite markers. The aims were to quantify the genetic diversity; to assess the genetic structure; and to analyse the geographical distribution of the diversity within and between archipelagoes. The ultimate goal was to pre‐define evolutionary significant units (ESUs) for conservation and restoration programmes of this species, which constitutes a natural resource on small, isolated islands. Location Eleven populations, each representative of one island, covering most of the natural occurrence of S. insulare were sampled: five populations from the Marquesas Archipelago; three from the Society Archipelago; and three from the Cook–Austral Archipelago. These South Pacific islands are known for their high degree of plant endemism, and for their human occupation by Polynesian migrations. The extensive exploitation of sandalwood by Europeans nearly 200 years ago for its fragrant heartwood, used overseas in incense, carving and essential oil production for perfume, has dramatically reduced the population size of this species. Methods We used chloroplast microsatellites, which provide useful information in phylogeographical forest tree analyses. They are maternally inherited in most angiosperms and present high polymorphism. Among the 499 individuals sampled, 345 were genotyped successfully. Classical models of population genetics were used to assess diversity parameters and phylogenetic relationships between populations. Results Four microsatellite primers showed 16 alleles and their combinations provided 17 chlorotypes, of which four exhibited a frequency > 10% in the total population. The gene diversity index was high for the total population (He = 0.82) and varied among archipelagoes from He = 0.40 to 0.67. Genetic structure is characterized by high levels of differentiation between archipelagoes (36% of total variation) and between islands, but differentiation between islands varied according to archipelago. The relationship between genetic and geographical distance confirms the low gene flow between archipelagoes. The minimum spanning tree of chlorotypes exhibits three clusters corresponding to the geographical distribution in the three main archipelagoes. Main conclusions The high level of diversity within the species was explained by an ancient presence on and around the hotspot traces currently occupied by young islands. Diversity in the species has enabled survival in a range of habitats. Relationships between islands show that the Cook–Austral chlorotype cluster constitutes a link between the Marquesas and the Society Islands. This can be explained by the evolution of the island systems over millions of years, and extinction of intermediary populations on the Tuamotu Islands following subsidence there. Based on the unrooted neighbour‐joining tree and on the genetic structure, we propose four ESUs to guide the conservation and population restoration of Polynesian Sandalwood: the Society Archipelago; the Marquesas Archipelago; Raivavae Island; and Rapa Island.  相似文献   

3.
The Aclopinae is a small subfamily within the family Scarabaeidae. It currently comprises five extant genera with 28 species, and eight fossil genera with 25 species. The systematic position of Aclopinae within the family Scarabaeidae is uncertain, particularly because representative species of Aclopinae have been absent in previous phylogenetic studies. Here we performed phylogenetic analyses using morphological and molecular data to investigate the phylogenetic position of fossil and extant Aclopinae. For this objective, we expanded and revised a former morphological data matrix (composed of 68 characters) including all extant genera of Aclopinae. We complemented our morphological investigations with a molecular phylogenetic analysis based on four genes of several extant taxa of Aclopinae and a wide sample of diverse Scarabaeoidea. Our phylogenetic analyses show that all the type species of the fossil genera formerly included within Aclopinae do not belong within the extant Aclopinae clade and support both the exclusion of those fossil taxa and the monophyly of the extant genera of Aclopinae: Aclopus Erichson, Desertaclopus Ocampo & Mondaca, Gracilaclopus Ocampo & Mondaca, Neophanaeognatha Allsopp and Phanaeognatha Hope. Our results also show that the fossil taxa Prophaenognatha robusta Bai et al. and Ceafornotensis archratiras Woolley are closely related to Ochodaeidae, while the remaining type species of fossils formerly included in Aclopinae (Cretaclopus longipes (Ponomarenko), Holcorobeus vittatus Nikritin, Juraclopus rodhendorfi Nikolajev, Mesaclopus mongolicus (Nikolajev), and Mongolrobeus zherikhini Nikolajev) belong to a distinct lineage closely related to Diphyllostomatidae. Based on these results, the subfamily Aclopinae appears monophyletic and sister to the ‘pleurostict’ lineage. Consequently, we propose the following changes to the current classification of the fossil taxa: Holcorobeus monreali (Gómez‐Pallerola) belongs to Carabidae (incertae sedis) as proposed by the original author, and we place Ceafornotensis Woolley, Cretaclopus Nikolajev, Holcorobeus Nikritin, Juraclopus Nikolajev, Mesaclopus Nikolajev, Mongolrobeus Nikolajev and Prophaenognatha Bai et al. in Scarabaeoidea (incertae sedis). Furthermore, we provide an identification key to, and diagnoses of, the genera, illustrations of diagnostic characters and checklists of their included species. The evolutionary perspective presented provides new insights into the evolution of the pleurostict condition in Scarabaeoidea and the biogeography of this group, which is now regarded as Gondwanan, probably evolving during the Cretaceous and not from the upper Jurassic as previously assumed.  相似文献   

4.
Aim Deciphering the complex colonization history of island archipelagos is greatly facilitated by comprehensive phylogenies. In this study we investigate the phylogeny and biogeography of the insular reed‐warblers (genus Acrocephalus) of the tropical Pacific Ocean, from Australia to eastern Polynesia. Location Oceania. Methods We used sequences of mitochondrial DNA (cytochrome b, ND2 and ATP8 genes) to infer the colonization patterns of reed‐warblers endemic to Pacific islands and Australia. We sampled all known taxa of Acrocephalus in the Pacific except A. luscinius nijoi, for which no sample was available. Most taxa were represented by toe‐pad samples from museum specimens collected in the 19th and 20th centuries. With a few exceptions, several specimens per taxon were sequenced independently in two institutions (Smithsonian Institution and Natural History Museum of Geneva). Results Our data indicate that Pacific reed‐warblers do not form a monophyletic group, because A. luscinius luscinius from Guam falls outside the main Pacific radiation. The remaining Pacific taxa are divided into two clades: one clade includes all the reed‐warblers from Micronesia (except Guam) and Australia, and two Polynesian taxa from the Line Islands and the southern Marquesas; the other clade includes all remaining Polynesian taxa. The taxa endemic to three archipelagos (Mariana, Marquesas and Society islands) are polyphyletic, suggesting several independent colonizations. Main conclusions Our results provide evidence for a complex pattern of colonization of the Pacific by reed‐warblers. Calibration analyses suggest that reed‐warbler lineages are much younger than the ages of the islands they occupy. Several remote archipelagos were colonized independently more than once. Consequently, we infer that the colonization of reed‐warblers in the Pacific did not follow a regular, stepping‐stone‐like pattern. The phylogeny also suggests a previously undetected case of reverse colonization (from island to continent) for the Australian lineage and indicates that A. luscinius, as currently defined, is not monophyletic. We discuss the supertramp strategy of reed‐warblers in the Pacific and show that, although Pacific reed‐warblers meet some of the supertramp criteria in their aptitude for colonizing remote archipelagos, their life history characteristics do not fit the model.  相似文献   

5.
6.
In order to classify and taxonomically describe the first two fossil Othiini (Coleoptera: Staphylinidae: Staphylininae) species from three well‐preserved specimens in Cretaceous Burmese amber, a phylogenetic analysis was conducted, combining extant and extinct taxa. A dataset of 76 morphological characters scored for 33 recent species across the subfamilies Staphylininae and Paederinae was analysed using maximum parsimony and Bayesian inference methods. The many differing phylogenetic hypotheses for higher‐level relationships in the large rove beetle subfamilies Staphylininae and Paederinae were summarized and their hitherto known fossil record was reviewed. Based on the analyses, the new extinct genus Vetatrecus gen.n. is described with two new species: V. adelfiae sp.n. and V. secretum sp.n. Both species share character states that easily distinguish them from all recent Othiini and demonstrate a missing morphological link between subfamilies Staphylininae and Paederinae. This is the first morphology‐based evidence for the paraphyly of Staphylininae with respect to Paederinae, suggested earlier by two independent molecular‐based phylogenies of recent taxa. Our newly discovered stem lineage of Othiini stresses the importance of fossils in phylogenetic analyses conducted with the aim of improving the natural classification of extant species. It also suggests that the definitions of Staphylininae and Paederinae, long‐established family‐group taxa, may have to be reconsidered. This published work has been registered in ZooBank, http://zoobank.org/urn:lsid:zoobank.org:pub:817F39C4-F36B-4FD9-96CD-5F8FB064C39E .  相似文献   

7.
An increase in studies in the Hajar Mountains from the southeastern Arabian Peninsula has revealed a high richness of endemic evolutionary lineages with many cryptic taxa. Omanosaura is the only lacertid lizard genus endemic to the Hajar Mountains, with two species O. cyanura and O. jayakari distributed throughout this mountain range. The phylogenetic relationships and genetic diversity between and within these species have been poorly studied. In this study, we collected mitochondrial (12S, cytb, and nd4) and nuclear (cmos and mc1r) sequences for 25 specimens of Omanosaura, including 15 individuals of O. jayakari and 10 of O. cyanura. We performed phylogenetic analyses based on network reconstruction, maximum likelihood and Bayesian inference to estimate the relationships and intraspecific genetic diversity of these species. We estimated the time of divergence between the two species in the Miocene, around 8.5 million years ago. Omanosaura jayakari shows little genetic diversity, while O. cyanura presents two differentiated lineages. These are reciprocally monophyletic at mitochondrial and nuclear genes and present a high genetic distance between them. These two lineages are associated with the geographic features of the Hajar Mountains, with one lineage distributed in the northernmost part of the Hajar Mountains and the other in the rest of the western Hajars, the Jebel Akhdar, and the eastern Hajars. This geographic relationship has been recovered previously in other reptile taxa and is generally associated with high levels of local genetic diversity. Our results suggest the existence of cryptic diversity within O. cyanura and support a general biogeographic pattern of high diversity and endemism in the northern Hajar Mountains that certainly deserves additional research in the future.  相似文献   

8.
We performed a phylogenetic analysis focused on the hydrophiloid family Helophoridae (Coleoptera: Polyphaga) in order to test the phylogenetic position of selected Mesozoic fossils assigned to the Hydrophiloidea. The analysis is based on 92 characters of larvae and adults, and includes all extant subgenera of Helophorus and representatives of all other extant hydrophiloid families. Based on this analysis, we provide additional evidence for the monophyly of the helophorid lineage containing the families Helophoridae, Georissidae and Epimetopidae, as well as the first hypothesis on the phylogenetic relationships within Helophorus, revealing three main clades: Lihelophorus, Rhopalohelophorus and the clade of sculptured small subgenera; the subgenera Helophorus s.str., Gephelophorus, Trichohelophorus and Transithelophorus are recognized as paraphyletic or polyphyletic. Inclusion of fossil species in the analysis reveals the Mesozoic genera Hydrophilopsia Ponomarenko, Laetopsia Fiká?ek et al. (adult forms) and Cretotaenia Ponomarenko (larval form) as basal extinct clades of the helophorid lineage, the former genus Mesosperchus Ponomarenko as containing probable stem taxa of Helophorus and the former genus Mesohelophorus Ponomarenko as a member of the Helophorus clade containing extant sculptured subgenera. The extant subgenus Thaumhelophorus syn.nov. is synonymized with Rhopalohelophorus. Our results show that the family Helophoridae may be dated back to the late Jurassic (c. 150 Ma) and the extant clades of Helophorus back to the Early Cretaceous (c. 136 Ma). The basal groups of Helophorus and the supposed basal extinct lineages of the helophorid lineages are shown to be aquatic as adults. A single origin of trichobothria and ventral hydrophobic pubescence in the common ancestor of the Hydrophiloidea is hypothesized, indicating ancestral aquatic habits in the adult stage for the whole Hydrophiloidea.  相似文献   

9.
Archaeognatha (Machilida plus †Monura), with ~450 extant species worldwide, represent a key lineage for the understanding of insect evolution. In a recently published phylogenetic analysis on Archaeognatha, based on a total-evidence approach, a Machilidae key fossil (Gigamachilis triassicus) from the Middle Triassic Lagerstätte of Monte San Giorgio and a representative of †Monura (Dasyleptus triassicus) from the same fossiliferous site, were not considered. In the present study, the phylogenetic analyses performed by Zhang et al. (2018) using maximum parsimony and Bayesian inference were repeated including these two key taxa; in addition, Tricholepidion gertschi and Lepisma saccharina were included as representatives of Zygentoma. In the total-evidence Bayesian analysis, †Monura was found to be paraphyletic, whereas in the maximum parsimony analysis, performed only on morphological characters, they were monophyletic. Moreover, the attribution of G. triassicus to Machilidae is now confirmed by these analyses, indicating that members of the extant group of Machilidae were already present in the Middle Triassic, at least ~100 Myr before the previous estimate.  相似文献   

10.
We sequenced reduced representation libraries by means of Illumina technology to generate over 1.5 Mb of orthologous sequence from a representative of each of the four extant gibbon genera (Nomascus, Hylobates, Symphalangus, and Hoolock). We used these data to assess the evolutionary relationships between the genera by evaluating the likelihoods of all possible bifurcating trees involving the four taxa. Our analyses provide weak support for a tree with Nomascus and Hylobates as sister taxa and with Hoolock and Symphalangus as sister taxa, though bootstrap resampling suggests that other phylogenetic scenarios are also possible. This uncertainty is due to short internal branch lengths and extensive incomplete lineage sorting across taxa. The true phylogenetic relationships among gibbon genera will likely require a more extensive whole-genome sequence analysis.  相似文献   

11.
The Ryukyu Archipelago, located at the southwestern part of Japan, is known as a group of continental islands and harbours many endemic taxa, supposedly reflecting its fairly long isolation from the Eurasian continent, Taiwan and the Japanese main islands. Microhyla okinavensis has been known as an endemic member of the terrestrial fauna of this archipelago. Molecular phylogenetic analyses using samples from nearly all island populations of the species and representative samples of other east Asian congeneric species revealed that M. okinavensis consists of four distinct subclades, of which the Amami, Okinawa and Miyako subclades, though exhibiting distinct genetic differentiations from each other, formed a monophyletic group (clade A). The remaining Yaeyama subclade was exclusively sister to M. mixtura from inland China, forming another monophyletic group (clade B), rendering M. okinavensis in the current definition paraphyletic. These results, as well as estimated dates of divergence from related taxa, indicate that M. okinavensis actually includes more than one distinct species. The results indicate that M. okinavensis and M. mixtura are relict species with disjunct distributions which had been most probably caused by invasion of M. fissipes in intervening areas.  相似文献   

12.
13.
Anguimorpha is a clade of limbed and limbless squamates with ca. 196 extant species and a known fossil record spanning the past 130 million years. Morphology‐based and molecule‐based phylogenetic analyses disagree on several key points. The analyses differ consistently in the placements of monstersaurs (e.g. Gila Monsters), shinisaurs (Crocodile Lizards), the anguid Anniella (American Legless Lizards), carusioids (Knobby Lizards), and the major clades within Varanus (Monitor Lizards). Given different data sources with such different phylogenetic hypotheses, Anguimorpha is an excellent candidate for a combined phylogenetic analysis. We constructed a data matrix consisting of 175 fossil and extant anguimorphs, and 2281 parsimony‐informative characters (315 morphological characters and 1969 molecular characters). We analysed these data using the computer program TNT using the “new technology search” with the ratchet. Our result is novel and shows similarities with both morphological and molecular trees, but is identical to neither. We find that a global combined evidence analysis (GCA) does not recover a holophyletic Varanoidea, but omission of fossil taxa reveals cryptic molecular support for that group. We describe these results and others from global morphological analysis, extant‐only morphological analysis, molecular data‐only analyses, combined evidence analysis of extant taxa, and GCA. © The Willi Hennig Society 2010.  相似文献   

14.
15.
The genus Nuphar consists of yellow-flowered waterlilies and is widely distributed in north-temperate bodies of water. Despite regular taxonomic evaluation of these plants, no explicit phylogenetic hypotheses have been proposed for the genus. We investigated phylogenetic relationships in Nuphar using morphology and sequences of the chloroplast gene matK and of the internal transcribed spacer (ITS) regions of nuclear ribosomal DNA. Two major lineages within Nuphar are consistently resolved with the morphological and molecular data sets. One lineage comprises New World taxa and the other represents a primarily Old World lineage. Relationships within the major lineages were poorly resolved by morphology and ITS, yet certain relationships were elucidated by all analyses. Most notable is the strong support for a monophyletic lineage of dwarf taxa and the alliance of the North American N. microphylla with the Eurasian taxa. Minor discordance between the independent cladograms is accounted for by hybridization. The common taxonomic practice of uniting all North American and Eurasian taxa under one species is not supported phylogenetically.  相似文献   

16.
A total evidence phylogenetic analysis was performed for 14 extant and 18 fossil caniform genera using a data matrix of 5.6 kbp of concatenated sequence data from six independent loci and 80 morphological characters from the cranium and dentition. Maximum parsimony analysis recovered a single most parsimonious cladogram (MPC). The topology of the extant taxa in the MPC agreed with previous molecular phylogenies. Phylogenetic positions for fossil taxa indicate that several taxa previously described as early members of extant families (e.g., Bathygale and Plesictis) are likely stem taxa at the base of the Arctoidea. Taxa in the “Paleomustelidae” were found to be paraphyletic, but a monophyletic Oligobuninae was recovered within this set of taxa. This clade was closely related to the extant genera Gulo and Martes, therefore, nested within the extant radiation of the family Mustelidae. This analysis provides a resolution to several discrepancies between phylogenies considering either fossil taxa or extant taxa separately, and provides a framework for incorporating fossil and extant taxa into comprehensive combined evidence analyses.  相似文献   

17.
On two small islands of the Tuscan Archipelago, two new endemic species of the Saxifraga granulata group, namely S. caprariae and S. montis-christi, were recently described on a morphological basis. This led us to investigate these species using a molecular approach involving the analysis of ITS and trnL-F regions. Our aims were: to highlight their phylogenetic traits; to confirm or reject the hypothesis that they are more closely related to S. corsica than to S. granulata; and to verify their phylogenetic position in the context of Saxifraga L. ser. Saxifraga. We considered all the species belonging to the ser. Saxifraga and some other species of sect. Saxifraga – a total of 19 species. We generated 10 new DNA sequences, six for ITS and four for trnL-trnF. We produced separate Bayesian and Maximum likelihood trees for both ITS and trnL-trnF regions and we analysed the genetic distances among the new endemics and the more closely related species. The phylogenetic analyses showed that S. caprariae and S. montis-christi are relatively well separated from S. granulata and more related to S. corsica. This supports the taxonomic treatment previously proposed. We showed that the results of our phylogenetic analysis are in agreement with our biogeographic knowledge of the Tuscan Archipelago and the neighbouring territories and emphasize the conservation relevance of these findings.  相似文献   

18.
19.
Ectothermy is a primitive state; therefore, a shared common ancestor of crocodiles, dinosaurs, and birds was at some point ectothermic. Birds, the extant descendants of the dinosaurs, are endothermic. Neither the metabolic transition within this lineage nor the place the dinosaurs held along the ectothermic-endothermic continuum is defined. This paper presents a conceptual model for the evolution of endothermy in the theropod-bird lineage. It is recognized that other animals (some fish, insects, etc.) are functionally endothermic. However, endothermy in other clades is beyond the scope of this paper, and we address the onset of endothermy in only the theropod/bird clade. The model begins with simple changes in a single gene of a common ancestor, and it includes a series of concomitant physiological and morphological changes, beginning perhaps as early as the first archosaurian common ancestor of dinosaurs and crocodiles. These changes continued to accumulate within the theropod-avian lineage, were maintained and refined through selective forces, and culminated in extant birds. Metabolic convergence or homoplasy is evident in the inherent differences between the endothermy of mammals and the endothermy of extant birds. The strength and usefulness of this model lie in the phylogenetic, genetic, evolutionary, and adaptive plausibility of each of the suggested developmental steps toward endothermy. The model, although conceptual in nature, relies on an extensive knowledge base developed by numerous workers in each of these areas. In addition, the model integrates known genetic, metabolic, and developmental aspects of extant taxa that phylogenetically bracket theropod dinosaurs for comparison with information derived from the fossil record of related extinct taxa.  相似文献   

20.
Oliver, P.M., Richards, S.J. & Sistrom, M. (2012). Phylogeny and systematics of Melanesia’s most diverse gecko lineage (Cyrtodactylus, Gekkonidae, Squamata). —Zoologica Scripta, 41, 437–454. The systematics and biogeographical history of the diverse fauna of New Guinea and surrounding islands (Melanesia) remain poorly known. We present a phylogeny for 16 of the 21 recognised Melanesian bent‐toed geckos in the genus Cyrtodactylus based on mitochondrial sequence data. These analyses reveal two divergent lineages of Cyrtodactylus within Melanesia. One includes a single recognised species with clear affinities to sampled taxa from Asia. The other comprises a relatively diverse radiation (likely 30+ species), not closely related to sampled extralimital taxa and centred on the Melanesian region (including Australia). Many taxa within this second lineage are endemic to islands surrounding New Guinea, and dispersal and speciation on peripheral islands appears to have played an important role in the accumulation of species diversity within this clade. In contrast, little diversity is centred upon montane areas, although we do identify at least one lineage closely associated with hill and lower montane forest that probably dates to at least the late Miocene. Our phylogenetic analyses also reveal numerous divergent lineages that require taxonomic attention, including at least two widespread taxa that are likely to be composite, additional specimens of Cyrtodactylus capreoloides (until recently known only from the holotype) and several divergent and completely novel lineages, two of which we introduce herein: Cyrtodactylus arcanus sp. n. and Cyrtodactylus medioclivus sp. n.  相似文献   

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