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1.
Recent studies suggest that species' life histories and ecology can be used to forecast future extinction risk. Threatened species often share similar traits such that if a trait predisposing a species to decline or extinction is evolutionarily conserved, then close relatives of threatened species are themselves likely to be at risk. The phylogenetic distribution of current threat has been argued to provide insight into the species that could be threatened in the future when trait data are not available. Conservation criteria are typically based on multiple indices that capture different symptoms of threat including population trends and range contraction. However, there is no reason to assume consistent phylogenetic distributions of different symptoms. I construct a molecular phylogeny of 249 species of British birds (more than 93% of the breeding and wintering species) and use this to show that the species that are threatened due to population declines are phylogenetically more closely related than expected by chance alone. However, species that are listed for other reasons, including range contraction, are distributed randomly with respect to phylogeny. I suggest that while phylogeny can be informative with respect to identifying clades that are susceptible to some measures of extinction risk, such patterns are likely to be idiosyncratic with respect to symptom and taxa.  相似文献   

2.
Summary Presented here is a record of a piciform bird from a late Oligocene fissure filling from Germany. This is the earliest known fossil record of a modern-type piciform bird and the only one from deposits earlier than Miocene. The specimen, an isolated tarsometatarsus, is similar in size and proportions to the tarsometatarsus of the recent Cardinal-Woodpecker (Dendropicos fuscescens, Picidae). However, owing to its fragmented state a reliable assignment to any of the recent piciform families is not possible.
Der älteste Nachweis eines modernen Spechtvogels aus dem späten Oligozän Deutschlands
Zusammenfassung Ein Nachweis eines Spechtvogels wird aus einer spätoligozänen Spaltenfüllung Deutschlands beschrieben. Es ist der bisher älteste Nachweis eines modernen Spechtvogels und der einzige aus vor-miozänen Ablagerungen. Das Exemplar, ein isolierter Tarsometatarsus, ähnelt in Größe und Proportionen dem Tarsometatarsus des rezenten Kardinalspechts (Dendropicos fuscescens, Picidae). Aufgrund seiner fragmentarischen Erhaltung ist jedoch keine zuverlässige Zuordnung zu einer der rezenten Familien spechtartiger Vögel möglich.
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3.
The osteology of the early Eocene (about 50 mya) avian taxon Pseudasturidae Mayr, 1998 is revised and its phylogenetic affinities are analysed. Members of the Pseudasturidae are known from abundant and excellently preserved skeletal material, both complete skeletons on slabs as well as isolated, three-dimensional bones. Although this taxon is thus among the best represented of all small early Tertiary birds, its systematic affinities were unknown so far. Derived osteological characters which are visible in newly recognized specimens from the Lower Eocene London Clay of England most convincingly support classification of the Pseudasturidae into the Psittaciformes (parrots). Both, in overall morphology and in terms of derived characters, the tarsometatarsus of the Pseudasturidae closely resembles that of the Eocene Quercypsittidae, which were assigned to the Psittaciformes by Mourer-Chauviré (1992 ). The Pseudasturidae are considered to be stem-group representatives of the Psittaciformes and the sister taxon of all other known psittaciform birds. The Eocene taxon lacks the specialized bill morphology of crown-group Psittaciformes of the Psittacidae. Several other osteological differences between the Pseudasturidae and the Psittacidae probably are also functionally correlated with the specialized feeding technique of the latter.  © 2002 The Linnean Society of London, Zoological Journal of the Linnean Society , 2002, 136 , 715–729.  相似文献   

4.
Tinamous, one of the earliest diverging living avian lineages, consists of a Neotropical clade of palaeognathous birds with a fossil record limited to the early Miocene–Quaternary of southern South America. Here, we conduct a comprehensive, morphology‐based phylogenetic study of the interrelationships among extinct and living species of tinamous. Morphological data of fossil species are included in a matrix of 157 osteological and myological characters of 56 terminal taxa. The monophyly of most recognized genera is supported by the results of the analysis. The cladistic analysis also recovers the traditional subdivision between those tinamous specialized for open areas (Nothurinae) and those inhabiting forested environments (Tinaminae). Temporal calibration of the resultant phylogeny indicates that such a basal divergence had already taken place in the early Miocene, some 17 million years ago. The placement of the fossil species within the open‐area (Nothurinae) and the forest‐dwelling (Tinaminae) tinamous is also consistent with the palaeoenvironmental conditions inferred from the associated fauna. © 2014 The Linnean Society of London  相似文献   

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7.
Birds are important pollinators, but the evolutionary history of ornithophily (bird pollination) is poorly known. Here, we report a skeleton of the avian taxon Pumiliornis from the middle Eocene of Messel in Germany with preserved stomach contents containing numerous pollen grains of an eudicotyledonous angiosperm. The skeletal morphology of Pumiliornis is in agreement with this bird having been a, presumably nectarivorous, flower-visitor. It represents the earliest and first direct fossil evidence of flower-visiting by birds and indicates a minimum age of 47 million years for the origin of bird–flower interactions. As Pumiliornis does not belong to any of the modern groups of flower-visiting birds, the origin of ornithophily in some angiosperm lineages may have predated that of their extant avian pollinators.  相似文献   

8.
Gobekko cretacicus, a Cretaceous lizard from the Gobi Desert of Mongolia, is a key fossil for understanding gecko phylogeny. We revisit this fossil using high‐resolution X‐ray computed tomography. The application of this imaging method reveals new information about sutures, bone shape, and structural details of the palate and basicranium. These data were used to assess the phylogenetic affinities of Gobekko in the context of an existing squamate data set. The effects of character ordering, search strategy, and the addition of another putative gekkonomorph (Hoburogekko suchanovi) on inferred gekkonomorph relationships were explored. Available specimens of G. cretacicus are skeletally mature but have unfused nasals, frontals, and parietals, and (possibly) a persistent basicranial fenestra. Some putative gekkonomorphs are not consistently supported as closer to crown clade gekkotans than to autarchoglossans. In a strict consensus both Gobekko and Hoburogekko form a polytomy with extant geckos. Some of the adult character states of Gobekko are observable in embryos of extant species. The evolution of tubular frontals and dentaries in gekkotans may be structurally related to the loss of the postorbital and supratemporal bars in this lineage. The complete lack of a parietal foramen, and presumably a light‐sensitive parietal eye, in this clade is of interest and could indicate an early origin of nocturnality in geckos. © 2013 The Linnean Society of London  相似文献   

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10.
A recent molecular analysis strongly supported sister group relationship between flamingos (Phoenicopteridae) and grebes (Podicipedidae), a hypothesis which has not been suggested before. Flamingos are long-legged filter-feeders whereas grebes are morphologically quite divergent foot-propelled diving birds, and sister group relationship between these two taxa would thus provide an interesting example of evolution of different feeding strategies in birds. To test monophyly of a clade including grebes and flamingos, I performed a cladistic analysis of 70 morphological characters which were scored for 17 taxa. Parsimony analysis of these data supported monophyly of the taxon (Podicipedidae + Phoenicopteridae) and the clade received high bootstrap support. Previously overlooked morphological, oological and parasitological evidence is recorded which supports this hypothesis, and which makes the taxon (Podicipedidae + Phoenicopteridae) one of the best supported higher-level clades within modern birds. The phylogenetic significance of some fossil flamingo-like birds is discussed. The Middle Eocene taxon Juncitarsus is most likely the sister taxon of the clade (Podicipedidae + (Palaelodidae + Phoenicopteridae)) although resolution of its exact systematic position awaits revision of the fossil material. Contrary to previous assumptions, it is more parsimonious to assume that flamingos evolved from a highly aquatic ancestor than from a shorebird-like ancestor.  © 2004 The Linnean Society of London, Zoological Journal of the Linnean Society , 2004, 140 , 157–169.  相似文献   

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Carotenoids are important as pigments for bright coloration of animals, and as physiologically active compounds with a wide array of health-related benefits. However, the causes of variation in carotenoid acquisition and physiology among species are poorly known. We measured the concentration of carotenoids in the blood of 80 wild bird species differing in diet, body size and the extent of carotenoid-based traits. Preliminary analyses showed that diet significantly explains interspecific variability in plasma carotenoids. However, dietary influences were apparently overridden by phylogenetic relationships among species, which explained most (65%) of this variability. This phylogenetic effect could be due partly to its covariation with diet, but may also be caused by interspecific differences in carotenoid absorption from food to the blood stream, mediated, for example by endothelial carriers or gut parasites. Carotenoid concentrations also decreased with body size (which may be explained by the allometric relationship between ingestion rate and body mass), and correlated positively with the extent of carotenoid-dependent coloration of plumage and bare parts. Therefore, the acquisition of carotenoids from the diet and their use for both health and display functions seem to be constrained by ecological and physiological aspects linked to the phylogeny and size of the species.  相似文献   

13.
More than 200 research papers on the molecular phylogeny and phylogenetic biogeography ofbryophytes have been published since the beginning of this millenium. These papers corroborated assumptions of a complex genetic structure of morphologically circumscribed bryophytes, and raised reservations against many morphologically justified species concepts, especially within the mosses. However, many molecular studies allowed for corrections and modifications of morphological classification schemes. Several studies reported that the phylogenetic structure of disjunctly distributed bryophyte species reflects their geographical ranges rather than morphological disparities. Molecular data led to new appraisals of distribution ranges and allowed for the reconstruction of refugia and migration routes. Intercontinental ranges of bryophytes are often caused by dispersal rather than geographical vicariance. Many distribution patterns of disjunct bryophytes are likely formed by processes such as short distance dispersal, rare long distance dispersal events, extinction, recolonization and diversification.  相似文献   

14.
Abstract

Sirenians have been extensively recorded from the Mediterranean and west European localities but there are only few finds to the east of it, from the area covered by the Paratethys. For the early Oligocene, to our knowledge, there are no published records of sirenians from inner seas of the Old World. Here we report a specimen of Dugongidae indet., consisting of two partial vertebrae and 12 fragments of ribs, collected in a manganese ore mine in Ukraine and dated as the earliest Oligocene (33–32 Ma). The specimens, as preserved, did not differ in morphology and size from ‘Halitherium schinzii’ and therefore can belong to Kaupitherium, at present the single early Oligocene genus recorded from Europe. However, its vertebral and rib anatomy is not specific for Kaupitherium, so we identify it only by family level. The marks of scavenging on a rib possibly are due to gastropod or bivalve mollusks. The sea, as suggested from biotic data, had a temperate or subtropical climate, relatively cold waters and high diversity of pelagic and deep-water habitats. Thus, the onset of the Oligocene was a period when sirenians could enter temperate inner Eurasian waters, a marginal area in their worldwide dispersal.  相似文献   

15.
The amphipod superfamily Crangonyctoidea is distributed exclusively in freshwater habitats worldwide and is characteristic of subterranean habitats. Two members of the family, Crangonyx islandicus and Crymostygius thingvallensis, are endemic to Iceland and were recently discovered in groundwater underneath lava fields. Crangonyx islandicus belongs to a well-known genus with representatives both in North America and in Eurasia. Crymostygius thingvallensis defines a new family, Crymostygidae. Considering the incongruences observed recently between molecular and morphological taxonomy within subterranean species, we aim to assess the taxonomical status of the two species using molecular data. Additionally, the study contributes to the phylogenetic relationships among several crangonyctoidean species and specifically among species from four genera of the family Crangonyctidae. Given the available data we consider how the two Icelandic species could have colonized Iceland, by comparing geographical origin of the species with the phylogeny. Regions of two nuclear (18S and 28S rRNA) and two mitochondrial genes (16S rRNA and COI) for 20 different species of three families of the Crangonyctoidea were sequenced. Four different methods were used to align the RNA gene sequences and phylogenetic trees were constructed using bayesian and maximum likelihood analysis. The Crangonyctidae monophyly is supported. Crangonyx islandicus appeared more closely related to species from the Nearctic region. Crymostygius thingvallensis is clearly divergent from the other species of Crangonyctoidea. Crangonyx and Synurella genera are clearly polyphyletic and showed a geographical association, being split into a Nearctic and a Palearctic group. This research confirms that the studied species of Crangonyctidae share a common ancestor, which was probably widespread in the Northern hemisphere well before the break up of Laurasia. The Icelandic species are of particular interest since Iceland emerged after the separation of Eurasia and North America, is geographically isolated and has repeatedly been covered by glaciers during the Ice Age. The close relation between Crangonyx islandicus and North American species supports the hypothesis of the Trans-Atlantic land bridge between Greenland and Iceland which might have persisted until 6 million years ago. The status of the family Crymostygidae is supported, whereas Crangonyx islandicus might represent a new genus. As commonly observed in subterranean animals, molecular and morphological taxonomy led to different conclusions, probably due to convergent evolution of morphological traits. Our molecular analysis suggests that the family Crangonyctidae needs taxonomic revisions.  相似文献   

16.
In this research, biostratigraphy, microfacies analysis and sequence stratigraphic framework of the Asmari Formation are discussed at Sepidar Anticline, Interior Fars sub-Basin. The strata are Rupelian to Chattian in age. According to the distribution of benthic foraminifera, two assemblage zones were recognised (I-) Nummulites vascus–Nummulites fichteli and (II-) Archaias asmaricus/hensoni–Miogypsinoides complanatus. Eight microfacies types which can be grouped into three depositional environments are recognised. Distribution of Oligocene foraminifera together with other constituents allowed the identification of three third-order sequences at Asmari Formation. Correlation of analysed sections through Interior Fars sub-Basin represents the development of a carbonate ramp with a deepening trend from SE to NW along the Rupelian/Chattian boundary.  相似文献   

17.
We describe the earliest temporally well‐constrained fossil that can be assigned to the Ardeidae (herons), from the lowermost Oligocene (32.0–33.0 million years ago) of Belgium. The specimen, a partial tarsometatarsus, belongs to a small species and is described as Proardea? deschutteri n. sp. It exhibits the characteristic tarsometatarsus morphology found in extant heron species, but a confident assignment to one of the ardeid subclades is not possible and even the assignment of the new fossil species to the crown group (the clade including the extant species) cannot be established. The fossil indicates a divergence of herons from their sister taxon by at least the earliest Oligocene, and current paleontological data suggest that herons arrived in Europe shortly after a major faunal turnover at the Eocene/Oligocene boundary. We consider that dispersal is the likely reason for the sudden appearance of herons in the earliest Oligocene of Europe but it is uncertain from where exactly this took place, with Asia and Africa being among the candidate areas.  相似文献   

18.
ALBRECHT MANEGOLD 《Ibis》2008,150(2):377-387
A passerine avifauna from the late Oligocene ( c. 26–25 mya) of Germany was characterized by a high diversity of conspicuously small birds ranging in size from the smallest known Oscines to moderately small forms. The avifauna comprised both Oscines and Suboscines. Other passerine fragments showed such an unexpected mosaic of characters that it was impossible to assign them with certainty to any subordinate clade within the Passeriformes. The isolated remains of oscine passerines are the earliest evidence of this taxon in the Northern Hemisphere. Coexistence of oscine and suboscine passerines during the late Oligocene is also documented for the first time in the Northern Hemisphere. These finds reduce a major gap in the passerine fossil record and allow new insights into the composition and natural history of ancient avifaunas.  相似文献   

19.
Eyeball structures such as the lens diameter (LD) and axial length are generally assumed to be highly correlated with optically meaningful parameters. However, these optical constraints on eyeball macroanatomy have never been tested explicitly. Tradeoffs between benefits of improved visual performance and cost of adaptation from an increase of tissue production predict that when eyeball size increases, optical parameters such as posterior nodal distance and maximum entrance pupil diameter should increase isometrically with eyeball axial length and LD, respectively. Here I show quantitatively that the interspecific allometry of the avian eye largely follows this predicted isometry. Additionally, I elaborate a method to estimate optically significant eyeball soft‐tissue dimensions from scleral ring and orbit morphology based on analyses of interspecific allometry in Aves. The stringent correlations between avian eyeball morphology and optical function render this system ideal for the analysis of form–function relationships and allow for an accurate estimate of optically significant eyeball soft‐tissue dimensions such as diameter, axial length, and LD in fossil species. J. Morphol. 2009. © 2009 Wiley‐Liss, Inc.  相似文献   

20.
A wide-range survey of cross-species microsatellite amplification in birds   总被引:23,自引:1,他引:22  
The possibility to perform cross-species microsatellite amplification in birds was surveyed by analysing sets of primers developed from the swallow and the pied flycatcher genomes on a panel of 48 different bird species. In total, 162 cases (species/marker combinations) of heterologous amplification were recorded. Ten amplification products were sequenced and all were found to be true homologues of the original loci. There was a significant and negative relationship between microsatellite performance and evolutionary distance between the original species and the tested species. As a rough indicator of expected cross-species microsatellite performance we estimate that 50% of markers will reveal polymorphism in a species with a DNA-DNA hybridization δTmH value of 5 separating it from the original species. This corresponds to a divergence time of = 11 million years before present for passerine birds. The established relationship between performance and evolutionary distance agrees very well with data obtained from some mammalian species. The proportion of polymorphic loci among those markers that amplified decreased with increasing genetic distance, suggesting that few long repeats are preserved during evolution. One of the swallow markers, HrU2, amplified a specific product in all species analysed and will thus allow access to nuclear sequence data over a broad range of species. The only predictor of cross-species performance was the amount of non-specific amplification seen in the original species. An analysis of 10 species from within the family Hirundinidae with the swallow primers consistently revealed extensive polymorphism with average probabilities of identical genotypes ranging from 6 times 10-4 to 6 times 10-7. There were distinct allele frequency differences between the Hirundinidae species and we envisage that microsatellite cross-species amplification will be a useful tool in phylogeny construction and in species identification.  相似文献   

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