首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 812 毫秒
1.
The Oceanian plant genus Spiraeanthemum (Cunoniaceae) has a centre of diversity in New Caledonia, where it is represented by seven species. Its diversification was investigated using two low‐copy nuclear genes, ncpGS and GapC, and phylogenetic analyses were based on maximum parsimony, maximum likelihood and recombination networks. We detected several cases of gene recombination in both datasets, and these have obscured the history within the genus. For S. ellipticum and S. pubescens, accessions from southern populations on ultramafic soils were genetically distinct from accessions from northern populations on non‐ultramafic soils. Given that no obvious morphological characters distinguish northern and southern populations in either taxon, both may be considered as examples of cryptic species. Incongruence between gene trees and species' delimitation may be explained by the parallel evolution of similar morphology, differential lineage sorting leading to differential fixation of alleles or different introgression patterns in the north and south leading to allele displacement. In New Caledonia, some species with broad ecological preferences may thus be artificial concepts. This suggests that they should be treated more critically in monographs and that the species' richness of the New Caledonian flora may be underestimated. Problems associated with the typification of S. ellipticum and evidence of hybridization events in the history of Spiraeanthemum are also discussed. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 161 , 137–152.  相似文献   

2.
Aim A New Caledonian insect group was studied in a world‐wide phylogenetic context to test: (1) whether local or regional island clades are older than 37 Ma, the postulated re‐emergence time of New Caledonia; (2) whether these clades show evidence for local radiations or multiple colonizations; and (3) whether there is evidence for relict taxa with long branches in phylogenetic trees that relate New Caledonian species to geographically distant taxa. Location New Caledonia, south‐west Pacific. Methods We sampled 43 cricket species representing all tribes of the subfamily Eneopterinae and 15 of the 17 described genera, focusing on taxa distributed in the South Pacific and around New Caledonia. One nuclear and three mitochondrial genes were analysed using Bayesian and parsimony methods. Phylogenetic divergence times were estimated using a relaxed clock method and several calibration criteria. Results The analyses indicate that, under the most conservative dating scenario, New Caledonian eneopterines are 5–16 million years old. The largest group in the Pacific region dates to 18–29 Ma. New Caledonia has been colonized in two phases: the first around 10.6 Ma, with the subsequent diversification of the endemic genus Agnotecous, and the second with more recent events around 1–4 Ma. The distribution of the sister group of Agnotecous and the lack of phylogenetic long branches in the genus refute an assumption of major extinction events in this clade and the hypothesis of local relicts. Main conclusions Our phylogenetic studies invalidate a simple scenario of local persistence of this group in New Caledonia since 80 Ma, either by survival on the New Caledonian island since its rift from Australia, or, if one accepts the submergence of New Caledonia, by local island‐hopping among other subaerial islands, now drowned, in the region during periods of New Caledonian submergence.  相似文献   

3.
Aim To test whether environmental diversification played a role in the diversification of the New Caledonian Hydropsychinae caddisflies. Location New Caledonia, south‐west Pacific. Methods The phylogeny of the New Caledonian Hydropsychinae caddisflies was hypothesized using parsimony and Bayesian methods on molecular characters. The Bayesian analysis was the basis for a comparative analysis of the correlation between phylogeny and three environmental factors: geological substrate (ultrabasic, non‐ultrabasic), elevation and precipitation. Phylogenetic divergence times were estimated using a relaxed clock method, and environmental factors were mapped onto a lineage‐through‐time plot to investigate the timing of environmental diversification in relation to species radiation. The correlation between rainfall and elevation was tested using independent contrasts, and the gamma statistic was calculated to infer the diversification pattern of the group. Results The diversification of extant Orthopsyche–Caledopsyche species began in the Middle–Late Oligocene, when much of the island of New Caledonia was covered by ultrabasic substrate and mountain forming was prevalent. Most lineages originated in the Middle–Late Miocene, a period associated with long‐term climate oscillation. Optimization of environmental factors on the phylogeny demonstrated that the New Caledonian Hydropsychinae group adapted to ultrabasic substrate early in its evolutionary history. The clade living mostly on ultrabasic substrate was far more species‐rich than the clade living mostly on non‐ultrabasic substrate. Elevation and rainfall were significantly correlated with each other. The lineage‐through‐time plot revealed that the main environmental diversification preceded species diversification. A constant speciation through time was rejected, and the negative gamma indicates that most of the diversification occurred early in the history of the clade. According to the inferred phylogeny, the genus Orthopsyche McFarlane is a synonym under Caledopsyche Kimmins, and Abacaria caledona Oláh & Barnard should also be included in Caledopsyche. Main conclusions The age of the radiation does not support a vicariance origin of New Caledonian Hydropsychinae caddisflies. Environmental diversification pre‐dates lineage diversification, and thus environmental heterogeneity potentially played a role in the diversification of the group, by providing a variety of fragmented habitats to disperse into, promoting speciation. The negative gamma indicates that the speciation rate slowed as niches started to fill.  相似文献   

4.
Aim The distributions of many New Caledonian taxa were reviewed in order to ascertain the main biogeographical connections with other areas. Location Global. Methods Panbiogeographical analysis. Results Twenty‐four areas of endemism (tracks) involving New Caledonia and different areas of Gondwana, Tethys and the central Pacific were retrieved. Most are supported by taxa of lower and higher plants, and lower and higher animals. Main conclusions Although parts of New Caledonia were attached to Gondwana for some time in the mid‐Cretaceous, most of the New Caledonian terranes formed as oceanic island arcs and sections of sea floor bearing seamounts. The flora and fauna have evolved and survived for tens of millions of years as metapopulations on ephemeral islands. Later, the biotas were juxtaposed and fused during terrane accretion. This process, together with the rifting of Gondwana, explains the biogeographical affinities of New Caledonia with parts of Gondwana, Tethys and the Pacific.  相似文献   

5.
The flora of New Caledonia encompasses more than 3000 plant species and an endemism of almost 80%. New Caledonia is even considered as one of the 34 ‘hot spots’ for biodiversity. Considering the current global loss of biodiversity and the fact that several drugs and pesticides become obsolete, there is an urgent need to increase sampling and research on new natural products. In this context, here, we reviewed the chemical knowledge available on New Caledonian native flora from economical perspectives. We expect that a better knowledge of the economic potential of plant chemistry will encourage the plantation of native plants for the development of a sustainable economy which will participate in the conservation of biodiversity. This review is divided into three parts, and the third part which is presented here summarizes the scientific literature related to the chemistry of endemic santalales, caryophyllales, and asterids. We show that the high rate of endemism is correlated with the originality of phytochemicals encountered in New Caledonian plants. A total of 176 original natural compounds have been identified from these plants, whereas many species have not been investigated so far. We also discuss the economic potential of plants and molecules with consideration of their medicinal and industrial perspectives. This review finally highlights several groups, such as Sapotaceae, that are unexplored in New Caledonia despite the high chemical interest in them. These plants are considered to have priority in future chemical investigations.  相似文献   

6.
Contemporary taxonomic work on New Caledonian Eumolpinae (Chrysomelidae) has revealed their high species richness in this Western Pacific biodiversity hotspot. To estimate total species richness in this community, we used rapid DNA‐based biodiversity assessment tools, exploring mtDNA diversity and phylogenetic structure in a sample of 840 specimens across the main island. Concordance of morphospecies delimitation with units delimited by phenetic and phylogenetic algorithms revealed some 98–110 species in our sample, twice as many as currently described. Sample‐based rarefaction curves and species estimators using these species counts doubled this figure (up to 210 species), a realistic estimate considering taxonomic coverage, local endemism, and characteristics of sampling design, amongst others. New Caledonia, compared with larger tropical islands, stands out as a hotspot for Eumolpinae biodiversity. Molecular dating using either chrysomelid specific rates or tree calibration using palaeogeographical data dated the root of the ingroup tree (not necessarily a monophyletic radiation) at 38.5 Mya, implying colonizations after the Cretaceous breakage of Gondwana. Our data are compatible with the slowdown in diversification rates through time and are also consistent with recent faunal origins, possibly reflecting niche occupancy after an initial rapid diversification. Environmental factors (e.g. soil characteristics) seemingly played a role in this diversification process. © 2013 The Linnean Society of London  相似文献   

7.
The flora of New Caledonia encompasses more than 3000 plant species and almost 80% are endemic. New Caledonia is considered as a ‘hot spot’ for biodiversity. With the current global loss of biodiversity and the fact that several drugs and pesticides become obsolete, there is an urgent need to increase sampling and research on new natural products. In this context, we review the chemical knowledge available on New Caledonian native flora from economical perspectives. We expect that a better knowledge of the economic potential of plant chemistry will encourage the plantation of native plants for the development of a sustainable economy which will participate in the conservation of biodiversity. In the second part of this review, we focus on the results exposed in 60 scientific articles and describe the identification of 225 original compounds from basal angiosperms and eudicot rosids. We discuss the economic potential of plants and molecules from medicinal and industrial perspectives. This review also highlights several plants and groups, such as Amborella sp., Piperaceae, or Phyllanthaceae, that are unexplored in New Caledonia despite their high chemical interest. Those plants are considered to have priority in future chemical investigations.  相似文献   

8.
A new species in the previously monotypic, endemic New Caledonian genus Gastrolepis (Stemonuraceae) is described. Gastrolepis alticola differs from G. austrocaledonica by its shorter and thicker petioles, strongly coriaceous leaves with revolute margins, shorter inflorescences, and pubescent corollas. The new species is further distinguished by its ecology, occurring only in high‐altitude maquis on two massifs in southern New Caledonia, Mt. Kouakoué and the Montagne des Sources. Gastrolepis alticola is assigned a preliminary conservation status of ‘Endangered’ using the World Conservation Union (IUCN) Red List criteria. Comparison of the IUCN threat status for the 19 species endemic to this distinctive, restricted vegetation type reveals a striking lack of consistency and underscores the need for a reassessment of the entire New Caledonian flora. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 157 , 775–783.  相似文献   

9.
The patterns of local endemism in New Caledonia were analysed in two endemic genera of Tingidae (Insecta, Heteroptera), Cephalidiosus and Nobarnus , through a phylogenetic analysis and species' distribution modelling. The aim was to determine the possible causes of diversification and endemism in New Caledonia. Our results show that environmental conditions are probably important for the distribution of the genus Cephalidiosus , in conjunction with other factors such as resource (host plant) distribution, but suggest that the same environmental conditions have not influenced the speciation processes and diversification in the genus.  © 2009 The Linnean Society of London, Biological Journal of the Linnean Society , 2009, 97 , 177–184.  相似文献   

10.
New Caledonia is a tropical hotspot of biodiversity with high rates of regional and local endemism. Despite offering an ideal setting to study the evolution of endemism, New Caledonia has received little attention compared with the other nearby hotspots, particularly New Zealand. Most studies of the Neocaledonian endemism have been carried out at the regional level, comparing the various groups and species present in New Caledonia but absent in neighboring territories. In addition, remarkably high short‐range endemism has been documented among plants, lizard and invertebrates, although these have usually been done, lacking a phylogenetic perspective. Most studies of Neocaledonian endemism have referred to the geological Gondwanan antiquity of the island and its metalliferous soils derived from ultramafic rocks. Very old clades are thought to have been maintained in refugia and diversified on the metalliferous soils. The present study documents the pattern of diversification and establishment of short‐range endemism in a phylogenetic context using the Neocaledonian cockroach genus Lauraesilpha. Mitochondrial and nuclear genes were sequenced to reconstruct phylogenetic relationships among the species of this genus. These relationships, in the light of the species distribution, do not support the hypothesis that species diversified via an adaptive radiation on metalliferous soils and are not consistent with areas of highest rainfall. Species of Lauraesilpha have similar altitudinal ranges and ecological habits and are short‐range endemics on mountains. What our analysis did reveal was that closely related species are found on nearby or contiguous mountains, and thus these formations probably played the key role establishing short‐range endemism (in association with recent climatic changes). © The Willi Hennig Society 2008.  相似文献   

11.
The flora of New Caledonia encompasses more than 3,000 species and almost 80% of them are endemic. New Caledonia is considered as a ‘hot spot’ for biodiversity. With the current global loss of biodiversity, and the fact that several drugs and pesticides are becoming obsolete, there is an urgent need to increase sampling and research on new natural products. In this context, we review the chemical information available on New Caledonian native flora from economical perspectives. We expect that a better knowledge of the economic potential will encourage the plantation of native plants for the development of a sustainable economy which will participate in the conservation of biodiversity. In the first part of this review, we discuss the results reported in 18 scientific articles on the chemicals isolated from 23 endemic conifers of New Caledonia. Several bioactive and original products, such as neocallitropsene or libocedrins, have been isolated from these conifers. This review also highlights several groups, such as Podocarpus spp., that are unexplored in New Caledonia despite the fact that they have been described in other countries to contain a wide range of original bioactive compounds. Those plants are considered as priority for future chemical investigations.  相似文献   

12.
We use approximately 1900bp of mitochondrial (ND2) and nuclear (c-mos and Rag-1) DNA sequence data to recover phylogenetic relationships among 58 species and 26 genera of Eugongylus group scincid lizards from New Caledonia, Lord Howe Island, New Zealand, Australia and New Guinea. Taxon sampling for New Caledonian forms was nearly complete. We find that the endemic skink genera occurring on New Caledonia, New Zealand and Lord Howe Island, which make up the Gondwanan continental block Tasmantis, form a monophyletic group. Within this group New Zealand and New Zealand+Lord Howe Island form monophyletic clades. These clades are nested within the radiation of skinks in New Caledonia. All of the New Caledonian genera are monophyletic, except Lioscincus. The Australian and New Guinean species form a largely unresolved polytomy with the Tasmantis clade. New Caledonian representatives of the more widespread genera Emoia and Cryptoblepharus are more closely related to the non-Tasmantis taxa than to the endemic New Caledonian genera. Using ND2 sequences and the calibration estimated for the agamid Laudakia, we estimate that the diversification of the Tasmantis lineage began at least 12.7 million years ago. However, using combined ND2 and c-mos data and the calibration estimated for pygopod lizards suggests the lineage is 35.4-40.74 million years old. Our results support the hypothesis that skinks colonized Tasmantis by over-water dispersal initially to New Caledonia, then to Lord Howe Island, and finally to New Zealand.  相似文献   

13.
Tropical rainforests have been thought to have low prevalence and diversity of ectomycorrhizal symbioses. However, to date, tropical regions have been poorly sampled for ectomycorrhizal fungi. Here, we investigated ectomycorrhizal fungal community diversity and the role of host plants in shaping this diversity in three main ultramafic rainforests in New Caledonia, an archipelago renowned for its exceptional plant diversity and recognized as a biodiversity hotspot. Sampling of ectomycorrhizal root tips and fruit bodies in Nothofagus aequilateralis-dominated, Arillastrum gummiferum-dominated and mixed rainforests showed high fungal diversity with, in total, 28 lineages and 311 operational taxonomic units (OTUs), of which 95% might be endemic. We also found that host preference and host density influenced ectomycorrhizal community composition and contributed to the high fungal diversity of New Caledonian rainforests. Finally, the /cortinarius lineage dominated the below- and above-ground communities, which suggests that this lineage plays a central role in ultramafic ecosystems functioning.  相似文献   

14.
New Caledonia is a global biodiversity hotspot. Hypotheses for its biotic richness suggest either that the island is a ‘museum’ for an old Gondwana biota or alternatively it has developed following relatively recent long distance dispersal and in situ radiation. The conifer genus Araucaria (Araucariaceae) comprises 19 species globally with 13 endemic to this island. With a typically Gondwanan distribution, Araucaria is particularly well suited to testing alternative biogeographic hypotheses concerning the origins of New Caledonian biota. We derived phylogenetic estimates using 11 plastid and rDNA ITS2 sequence data for a complete sampling of Araucaria (including multiple accessions of each of the 13 New Caledonian Araucaria species). In addition, we developed a dataset comprising 4 plastid regions for a wider taxon sample to facilitate fossil based molecular dating. Following statistical analyses to identify a credible and internally consistent set of fossil constraints, divergence times estimated using a Bayesian relaxed clock approach were contrasted with geological scenarios to explore the biogeographic history of Araucaria. The phylogenetic data resolve relationships within Araucariaceae and among the main lineages in Araucaria, but provide limited resolution within the monophyletic New Caledonian species group. Divergence time estimates suggest a Late Cretaceous-Cenozoic radiation of extant Araucaria and a Neogene radiation of the New Caledonian lineage. A molecular timescale for the evolution of Araucariaceae supports a relatively recent radiation, and suggests that earlier (pre-Cenozoic) fossil types assigned to Araucaria may have affinities elsewhere in Araucariaceae. While additional data will be required to adequately resolve relationships among the New Caledonian species, their recent origin is consistent with overwater dispersal following Eocene emersion of New Caledonia but is too old to support a single dispersal from Australia to Norfolk Island for the radiation of the Pacific Araucaria sect. Eutacta clade.  相似文献   

15.
The evolutionary history of the Mexican sierras has been shaped by various geological and climatic events over the past several million years. The relative impacts of these historical events on diversification in highland taxa, however, remain largely uncertain owing to a paucity of studies on broadly‐distributed montane species. We investigated the origins of genetic diversification in widely‐distributed endemic alligator lizards in the genus Barisia to help develop a better understanding of the complex processes structuring biological diversity in the Mexican highlands. We estimated lineage divergence dates and the diversification rate from mitochondrial DNA sequences, and combined divergence dates with reconstructions of ancestral geographical ranges to track lineage diversification across geography through time. Based on our results, we inferred ten geographically structured, well supported mitochondrial lineages within Barisia. Diversification of a widely‐distributed ancestor appears tied to the formation of the Trans‐Mexican Volcanic Belt across central Mexico during the Miocene and Pliocene. The formation of filter barriers such as major river drainages may have later subdivided lineages. The results of the present study provide additional support for the increasing number of studies that suggest Neogene events heavily impacted genetic diversification in widespread montane taxa. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 105 , 382–394.  相似文献   

16.
Parallel evolutionary radiations in adjacent locations have been documented in many systems, but typically at limited geographical scales. Here, we compare patterns of evolutionary radiation at the global scale in iguanian lizards, the dominant clade of lizards. We generated a new time‐calibrated phylogeny including 153 iguanian species (based on mitochondrial and nuclear data) and obtained data on morphology and microhabitats. We then compared patterns of species diversification, morphological disparity, and ecomorphological relationships in the predominantly Old World and New World clades (Acrodonta and Pleurodonta, respectively), focusing on the early portions of these radiations. Acrodonts show relatively constant rates of species diversification and disparity over time. In contrast, pleurodonts show an early burst of species diversification and less‐than‐expected morphological disparity early in their history, and slowing diversification and increasing disparity more recently. Analyses including all species (with MEDUSA) suggest accelerated diversification rates in certain clades within both Acrodonta and Pleurodonta, which strongly influences present‐day diversity patterns. We also find substantial differences in ecomorphological relationships between these clades. Our results demonstrate that sister clades in different global regions can undergo very different patterns of evolutionary radiation over similar time frames. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, ●● , ●●–●●.  相似文献   

17.
The biota of New Caledonia is one of the most unusual in the world. It displays high diversity and endemism, many peculiar absences, and far‐flung biogeographic affinities. For example, New Caledonia is the only place on Earth with both main clades of flowering plants – the endemic Amborella and ‘all the rest’, and it also has the highest concentration of diversity in conifers. The discovery of Amborella's phylogenetic position led to a surge of interest in New Caledonian biogeography, and new studies are appearing at a rapid rate. This paper reviews work on the topic (mainly molecular studies) published since 2013. One current debate is focused on whether any biota survived the marine transgressions of the Paleocene and Eocene. Total submersion would imply that the entire fauna was derived by long‐distance dispersal from continental areas since the Eocene, but only if no other islands (now submerged) were emergent. A review of the literature suggests there is little actual evidence in geology for complete submersion. An alternative explanation for New Caledonia's diversity is that the archipelago acted as a refugium, and that the biota avoided the extinctions that occurred in Australia. However, this is contradicted by the many groups that are anomalously absent or depauperate in New Caledonia, although represented there by a sister group. The anomalous absences, together with the unusual levels of endemism, can both be explained by vicariance at breaks in and around New Caledonia. New Caledonia has always been situated at or near a plate boundary, and its complex geological history includes the addition of new terranes (by accretion), orogeny, and rifting. New Caledonia comprises ‘basement’ terranes that were part of Gondwana, as well as island arc and forearc terranes that accreted to the basement after it separated from Gondwana. The regional tectonic history helps explain the regional biogeography, as well as distribution patterns within New Caledonia. These include endemics on the basement terranes (for example, the basal angiosperm, Amborella), disjunctions at the West Caledonian fault zone, and great biotic differences between Grande Terre and the Loyalty Islands.  相似文献   

18.
A previously unknown Annonaceae species from the South Pacific island of New Caledonia is described as Goniothalamus dumontetii . This is the first Goniothalamus species reported from the island, and the easternmost record for the genus. It is easily distinguished from its congeners by the shape of the monocarp (flattened elongate with lateral triangular projections), which reflects the shape of the seeds (flattened rhombohedral). The conservation status of the species is evaluated as endangered (EN) using World Conservation Union (IUCN) red list categories, as it is known from only one relatively small population. The interpretation of geological and molecular data suggests that Goniothalamus dispersed to New Caledonia relatively recently, and does not represent a relict of the break-up of Gondwana.  © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society , 2007, 155 , 497–503.  相似文献   

19.
New Caledonia is well known as a hot spot of biodiversity whose origin as a land mass can be traced back to the Gondwanan supercontinent. The local flora and fauna, in addition to being remarkably rich and endemic, comprise many supposedly relictual groups. Does the New Caledonian biota date back to Gondwanan times, building up its richness and endemism over 100 Myr or does it result from recent diversifications after Tertiary geological catastrophic events? Here we use a molecular phylogenetic approach to answer this question with the study of the Neocaledonian cockroach genus Angustonicus belonging to the subfamily Tryonicinae from Australia and New Caledonia. Both geological and molecular dating show that the diversification of this group is less than two million years old, whatever the date of its origin itself. This dating is not consistent with hypotheses of Gondwanan richness and endemism in New Caledonian biota. In other terms, local richness and endemism at the specific level are not necessarily related to an old Gondwanan origin of the Neocaledonian groups. © The Willi Hennig Society 2005.  相似文献   

20.
The South Pacific archipelago of Fiji is characterized by a predominantly Indo‐Malesian flora and fauna. We provide a first systematic study on Fiji's tateid gastropods – previously classified as Hydrobiidae – describing 18 new species, combining morphological, anatomical, and molecular data. The molecular phylogeny of tateid gastropods based on 16S rRNA and cytochrome c oxidase subunit I (COI) showed that the species from Fiji were closer related to New Zealand than to Australian or New Caledonian taxa, which is rather exceptional. Performing an ancestral range reconstruction we inferred the colonization history across the two main islands. The radiation had its origin in southern Viti Levu, with a subsequent dispersal over the western and central parts of the island. The chronology of the radiation over eastern Viti Levu and Vanua Levu remained unresolved because of incomplete lineage sorting, a phenomenon typical for young radiations. © 2014 The Linnean Society of London  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号