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1.
The remarkable fauna of Australia evolved in isolation from other landmasses for millions of years, yet understanding the evolutionary history of endemic avian lineages on the continent is confounded by the ability of birds to disperse over geographical barriers even after vicariance events. The Plains‐wanderer Pedionomus torquatus (Charadriiformes) is an enigmatic, predominantly sedentary, quail‐like bird that occurs exclusively in sparse native grasslands of southeastern Australia. It is the only known species of its family (Pedionomidae), and its closest relatives are the South American seedsnipes (Thinocoridae). Here we describe a further representative of this lineage, Oligonomus milleri gen. et sp. nov., from the Late Oligocene of South Australia (26–24 Ma), which pre‐dates the earliest record of P. torquatus by c. 22 Ma and attests to the presence of this lineage during Australia's period of isolation (50–15 Ma). Based on the morphology of the coracoid and the palynological record, we propose that O. milleri and P. torquatus were ecologically disparate taxa and that, similar to coeval marsupials, O. milleri inhabited well‐wooded habitats, suggesting that the preference for grassland in the extant P. torquatus and thinocorids is likely to be convergent and not ancestral. The speciation event leading to the evolution of the extant Plains‐wanderer was probably triggered by the spread of grasslands across Australia in the Late Miocene–Pliocene, which this record pre‐dates. The presence of a pedionomid in the Late Oligocene of Australia strengthens the hypothesis of a Gondwanan divergence of the lineages giving rise to Thinocoridae and Pedionomidae.  相似文献   

2.
The Middle Jurassic was a key interval of mammalian evolutionary history that witnessed the diversification of the therian stem group. Great Britain has yielded a significant record of mammalian fossils from this interval, represented by numerous isolated jaws and teeth from the Bathonian of Oxfordshire and the Isle of Skye. This record captures a key period in early cladotherian evolution, with amphitheriids, peramurans and ‘stem zatherians’ displaying intermediate talonid morphologies that document the evolutionary assembly of tribosphenic molars. We present a mandible with near‐complete dentition from the late Bathonian (c. 167.4–166.5 Ma) Kilmaluag Formation, near Elgol, Skye, representing the amphitheriid Palaeoxonodon ooliticus, previously known only from isolated teeth. The specimen sheds new light on the taxonomic diversity of British Middle Jurassic stem therians, as the morphological variation within the preserved tooth row encompasses that previously ascribed to three distinct species within two genera: Palaeoxonodon ooliticus, P. freemani and Kennetheridium leesi. Thus, both P. freemani and K. leesi are subjective junior synonyms of P. ooliticus. The dental formula of P. ooliticus (i4:c1:p5:m5) is intermediate between the primitively larger postcanine count (p5:m6–7) of Amphitherium and the reduced number in peramurans and tribosphenidans (p5:m3). Phylogenetic analyses of P. ooliticus generally confirm a close affinity with Amphitherium, but highlight the lack of strong empirical support for hypothesized patterns of divergences among early cladotherians.  相似文献   

3.
A new monotypic subgenus, Premicrodispulus subgen. n., with the type species Premicrodispus reductus sp. n., and four new species of the nominative subgenus of the mite genus Premicrodispus, P. (Premicrodispus) paradoxus sp. n., P. (P.) heterocaudatus sp. n., P. (P.) obtusisetosus sp. n., and P. (P.) incisus sp. n., collected in soils of Turkmenistan are described. The subgenus Premicrodispulus subgen. n. differs from the nominative subgenus in the presence of 3 setae on genu I (seta l″ absent) and 1 seta on genu II (setae d and l″ absent). Premicrodispus (Premicrodispus) paradoxus sp. n. differs from all the species of the genus in the presence of solenidion on tarsus III. P. (P.) heterocaudatus sp. n. is most similar to P. longisetosus (Mahunka, 1970), but differs in the setae ps3 distinctly longer than ps 1 (in P. longisetosus, ps 3 and ps 1 are similar in length). P. (P.) obtusisetosus sp. n. is most similar to P. montanus Khaustov, 2006, but differs in obtuse setae c 1, e, and f (in P. montanus, these setae are pointed); P. (P.) incisus sp. n. is most closely related to P. longisetosus (Mahunka, 1970), but differs in the presence of distinct excavations on the posterior margin of tergites C and D (in P. longisetosus, excavations are absent).  相似文献   

4.
The well-preserved silicified fragment of a utricular envelope assigned to Sycidium aff. clathratum Peck, discovered in the earliest Famennian “incisus bed” of the Bohlen section near Saalfeld in Thuringia (Central Germany), is the first evidence of charophytes present in the West European Late Devonian. The occurrence of 16 longitudinal ridges is shared with the basal Mississippian S. clathratum. The specimen shows delicate structures of the external layer including ovoid elements at its basal end which are interpreted as casts of rudimentary bract cells and/or bracteoles, rarely observed in the fossil record of charophytes. S. aff. clathratum is among the rare Sycidiaceae that survived the terminal Frasnian Kellwasser Event. This single specimen was probably attached to a piece of wood and thereby transported into fully marine basinal environments that characterize the Famennian of the Bohlen section.  相似文献   

5.
Camera or genetic data are increasingly used to estimate wildlife abundance and density. We integrated video camera data with genetic data over 7 years to estimate annual age-structured apparent survival of American black bears (Ursus americanus). We identified 70 individuals through meticulous scrutiny of 7531 video captures, cross-referenced with 721 genetic captures from hair samples concurrently collected from stations in view of cameras. We used the Cormack–Jolly–Seber model in Program Mark to estimate annual age-structured apparent survival for yearling males, yearling females, 2+ year-old males, and 2+ year-old females. We manually calculated cub survival. We compared parameter estimates based on combined video and genetic data with those based on only genetic data. Combining video and genetic data provided a means to test video-based identification accuracy, which was highest for females (97%–100%). Annual apparent survival was highest for yearling females (φ = 0.92, SE = 0.07), followed by 2+ year-old females (φ = 0.88, SE = 0.05), 2+ year-old males (φ = 0.84, SE = 0.06), and yearling males (φ = 0.80, SE = 0.14). Annual cub survival (φ = 0.86, SE = 0.07) was likely biased because we could not account for mortality that occurred in-den through early spring. Annual apparent survival and recapture probabilities derived from only genetic data were lower than those derived from combined video and genetic data. Our finding that noninvasive data can be used to estimate annual age-structured apparent survival of a species with relatively indistinct traits is broadly relevant to wildlife research and conservation.  相似文献   

6.
Previous studies have indicated the occurrence of nine species of Palaemon in Brazil. However, the extensive variability in their diagnostic characters and the geographic distribution of some species raises doubts about the validity of some taxa, potentially indicating the occurrence of species not yet reported from Brazil or even not described. To solve taxonomic issues with Palaemon species in Brazil, we carried out a multigene analysis by using partial fragments of 16S and COI mitochondrial genes and the nuclear H3. Phylogenetic relationships were inferred by maximum likelihood and Bayesian inference. The external morphology corresponding to the terminal clades obtained in the molecular phylogram was analysed to identify diagnostic characters that allow the recognition of the groups and the correct taxa assignment. The combined analysis of molecular and morphological data confirms the existence of nine species of Palaemon in Brazil, five from the “Palaemon” lineage (P. mercedae and four Palaemon stensu strictoP. argentinus, P. octaviae—first record in Brazil, P. northropi and P. paivai) and four of the “Alaocaris” lineage (P. carteri, P. ivonicus, P. pandaliformis and P. yuna). The possibility of further cryptic speciation is also pointed out. In addition to confirming the validity of the nine species, the results indicate the need for taxonomic adjustments and corresponding changes in the geographic distribution of Palaemon species occurring in Brazil.  相似文献   

7.
Phytoplasmas belonging to the 16S rDNA subgroups IB and IC were found in five cyclamen (Cyclamen persicum L.) plants showing virescence and yellow stunted leaves and one plant showing phyllody, rolled and thickened leaves, respectively. Two cyclamens, representing the two syndromes, were chosen as source plants for transmission trials in which three leafhopper species, known as vectors of IB and IC subgroup phytoplasmas, were used to inoculate cyclamen and periwinkle [Catharanthus roseus (L.) G. Don] test plants. Out of 366 tested plants only one periwinkle exposed to Euscelis incisus was found harbouring a 16Sr‐IB phytoplasma. Out of 60 tested vector insects, only one adult of Macrosteles quadripunctulatus and two of E. incisus fed on 16Sr‐IB source cyclamen gave a positive amplification signal in nested PCR. This extremely low level of transmission to both cyclamen and the very susceptible periwinkle strongly suggests that cyclamen, commonly found infected in crops, is an unsuitable species for phytoplasma acquisition and can be regarded as a dead‐end host plant for phytoplasmas belonging to both IB and IC subgroups. Indications for glasshouse management are drawn from these findings. Among the leafhoppers investigated E. incisus falls most under suspicion since it feeds better than the others on cyclamen, was able to transmit the disease to one periwinkle plant, and IB phytoplasmas were detected in two individuals.  相似文献   

8.
Can remote underwater video be used to investigate the in-stream behaviour of small fishes and decapods? Diel activity of two threatened freshwater fishes (Macquaria australasica and Gadopsis bispinosus), a palaemonid prawn and an atyid shrimp, was established from remote underwater video in a pool of an upland stream in the current study. Decapods and large fishes (>5 cm TL) were nocturnal, whereas, small fishes (<5 cm TL) were diurnal. The suitability of using underwater video to quantify short-term (seconds) behavioural interaction among individuals was also demonstrated, with early-juvenile-phase Gadopsis bispinosus exhibiting interference competition on 35% of occasions when two or more individuals were observed. This study demonstrates that remote underwater video is useful for observing the in-stream behaviour of threatened freshwater fauna where other techniques are not viable, and presents sub-sampling of video as a means of reducing video processing time in assessing fish diel activity patterns.  相似文献   

9.
The phytoplankton species Gymnodinium catenatum is responsible for major worldwide losses in aquaculture due to shellfish toxicity. On the West coast of the Iberian Peninsula, toxic blooms have been reported since the mid-1970s. While the recent geographical spread of this species into Australasia has been attributed to human-mediated introduction, its origin in the Northeast Atlantic is still under debate. Gymnodinium catenatum forms a highly resistant resting stage (cyst) that can be preserved in coastal sediments, building-up an historical record of the species. Similar cyst types (termed microreticulate) are produced by other non-toxic Gymnodinium species that often co-occur with G. catenatum. We analysed the cyst record of microreticulate species in dated sediment cores from the West Iberian shelf covering the past ca. 150 years. Three distinct morphotypes were identified on the basis of cyst diameter and paracingulum reticulation. These were attributed to G. catenatum (35.6–53.3 μm), G. nolleri (23.1–36.4 μm), and G. microreticulatum (20.5–34.3 μm). Our results indicate that G. catenatum is new to the NE Atlantic, where it appeared by 1,889 ± 10, expanding northwards along the West Iberian coast. The earliest record is from the southernmost sample, while in the central Portuguese shelf the species appears in sediments dated to 1,933 ± 3, and in the North, off Oporto, in 1,951 ± 4. On the basis of the cyst record and toxic bloom reports, we reconstruct the invasive pathway of G. catenatum in the NE Atlantic. Although human-mediated introduction cannot be discarded, the available evidence points towards natural range expansion, possibly from NW Africa.  相似文献   

10.
The length–weight relationships (LWRs) were determined for two native cyprinid fishes: Poropuntius opisthopterus (Wu, 1977) and Raiamas christyi (Boulenger, 1920) collected from the upper reaches of Nujiang River (31°33′29″N; 92°55′58″E), Southwest of China. A total of 162 specimens were collected quarterly between March 2015 and November 2016. Fish were sampled by electrofishing in 12 wadable sites with maximum water depth 60–70 cm. The b values parameter in the length–weight relationship equations were calculated as 2.90 for P. opisthopterus and 3.45 for R. christyi. This study represents a new maximum standard length record for P. opisthopterus.  相似文献   

11.
A long-term record dating back to the 1960s indicates that Peridinium gatunense, an armored dinoflagellate, dominated the phytoplankton of Lake Kinneret (Sea of Galilee, Israel) until the mid-1990s, with a relatively stable spring bloom. However, since 1996, these blooms became irregular, failing to develop in 10 out of the past 16 years. During the later period, a significant correlation (R 2 = 0.605, P = 0.013) was found between annual peak P. gatunense biomass and riverine inflow volume. In-lake surveys showed that patches of high P. gatunense densities were associated with water enriched with fresher inflowing Jordan River water. Supplementing laboratory cultures of P. gatunense with Hula Valley water stimulated its growth relative to un-enriched controls. A likely explanation to the recent irregular blooms of this dinoflagellate is a hydrological modification that was made in the catchment in the mid-1990s, preventing Hula Valley water from reaching Lake Kinneret in most years—except for exceptionally wet years. We propose that until the mid-1990s, the Jordan River water enriched Lake Kinneret with a growth factor (a microelement and/or organic compound) originating in the Hula Valley, which in recent years has arrived in sufficient quantities to support a bloom only in high-rainfall years.  相似文献   

12.
Meiofaunal organisms are indirectly influenced by the activity of benthic macroinvertebrates within the sediment, which plays a role in modifying physical and chemical characteristics of the habitat. The association of meiofaunal organisms and macroburrows is well known in modern environments, but the record of this relationship in the geological record is still incipient. This study documents diminutive burrows (Helminthoidichnites tenuis) associated with the surface of macroburrows (Palaeophycus tubularis) in Early Permian deposits. The cylindrical shape and meandering to loop trajectory of the diminutive burrows indicate that they were produced by small free‐living meiofaunal nematodes. Apparently, P. tubularis (open burrow) constituted a favourable microhabitat for nematodes, providing the following: (1) protection against erosive processes and meiofauna predators; (2) oxygen access to more in‐depth layers within the sediment; (3) temperature stabilization; and (4) food supply due to mucus impregnation in the macroburrow walls by the Palaeophycus tracemaker. The association between H. tenuis and P. tubularis constitutes the first fossil record of a symbiotic relationship between meiofaunal nematodes and macrobenthic organisms (polychaetes). It also suggests that ecological strategies such as mutualism or commensalism, which are common between extant nematodes and macrobenthic invertebrates, were available in the behavioural programme of these organisms since the Early Permian.  相似文献   

13.
Upper Serpukhovian to lower Bashkirian conodonts studied from the lower and middle part of the Barcaliente Formation type section (NW Spain) are not abundant, but the sedimentary record seems unusually well represented. The first occurrence of Declinognathodus bernesgae occurs more than 140 m below the first occurrence of Dinaequalis, the taxon of the D. noduliferus species group appearing in the bed of the Global Standard Stratotype‐section and Point (GSSP) for the Mid‐Carboniferous Boundary (Arrow Canyon, Nevada). P1 elements transitional between D. bernesgae and Dinaequalis are described and considered relevant to the global correlation of the Mid‐Carboniferous Boundary. In addition, D. praenoduliferus, D. cf. noduliferus, D. lateralis, Idiognathoides asiaticus, I. corrugatus and Neognathodus sp. are described and illustrated from the Barcaliente Formation. A phylogeny is proposed for the early species of these genera on the basis of the morphological changes of the P1 element, where the rostral parapet and area, the surface roughness and the length and depth of the adcarinal troughs are diagnostic characters at the specific level, while caudal ornamentation is a secondary taxonomic character.  相似文献   

14.
The parasitic phaeophycean endophyte Herpodiscus durvillaeae (Lindauer) G. R. South has previously only been recorded from New Zealand, in association with a single host species, Durvillaea antarctica (Chamisso) Hariot (southern bull‐kelp). Here we use DNA sequence data from plastid and nuclear markers (chloroplast rbcL, ribosomal LSU, and a nuclear pseudogene copy of COI) to test for the presence of H. durvillaeae beyond the New Zealand region, and on host species other than D. antarctica. Analyses of samples from the Falkland Islands confirm the first record of H. durvillaeae from the Atlantic Ocean. We report that Falkland Islands H. durvillaeae are genetically indistinguishable from samples of this species from New Zealand's sub‐Antarctic Campbell Island, suggesting recent dispersal of the parasite across the Pacific Ocean, presumably by rafting with its buoyant macroalgal host. We also here record Hdurvillaeae from New Zealand endemics Durvillaea poha Fraser et al. and D. willana Lindauer.  相似文献   

15.
Analyses of pollen, macrofossils and microscopic charcoal in the sediment of a small sub-alpine lake (Karakol, Kyrgyzstan) provide new data to reconstruct the vegetation history of the Kungey Alatau spruce forest during the late-Holocene, i.e. the past 4,000 years. The pollen data suggest that Picea schrenkiana F. and M. was the dominant tree in this region from the beginning of the record. The pollen record of pronounced die-backs of the forests, along with lithostratigraphical evidence, points to possible climatic cooling (and/or drying) around 3,800 cal year b.p. and between 3,350 and 2,520 cal year b.p., with a culmination at 2,800–2,600 cal b.p., although stable climatic conditions are reported for this region for the past 3,000–4,000 years in previous studies. From 2,500 to 190 cal year b.p. high pollen values of P. schrenkiana suggest rather closed and dense forests under the environmental conditions of that time. A marked decline in spruce forests occurred with the onset of modern human activities in the region from 190 cal year b.p. These results show that the present forests are anthropogenically reduced and represent only about half of their potential natural extent. As P. schrenkiana is a species endemic to the western Tien Shan, it is most likely that its refugium was confined to this region. However, our palaeoecological record is too recent to address this hypothesis thoroughly.  相似文献   

16.
At present 14 species of Potentilla L. have been cytologically worked out from different geographical areas of Kashmir and Himachal Pradesh in the Western Himalayas. New chromosome numbers in nine species—Potentilla argyrophylla (n = 14), P. atrosanguinea (n = 7, 14), P. desertorum (n = 7), P. gerardiana (n = 14), P. indica (n = 14), P. micropetala (n = 14), P. nepalensis (n = 14), P. sibbaldia (n = 14) and P. thomsonii (n = 7)—have been reported on a worldwide basis for the first time. Additional chromosomal races of polyploid cytotypes for P. argyrophylla (n = 28) and P. desertorum (n = 14) along with a diploid cytotype for P. micropetala (n = 7) plus diploid cytotypes for the five species as P. fulgens (n = 7), P. gelida (n = 7), P. kleiniana (n = 7), P. sibbaldia (n = 7) and P. sundaica (n = 7) as well as a tetraploid cytotype for P. fruticosa (n = 14) all have been cytologically worked out from India for the first time. The course of meiosis varies from normal to abnormal in different populations of the majority of the species, such as P. argyrophylla, P. atrosanguinea, P. desertorum, P. fruticosa, P. fulgens, P. gelida, P. indica, P. nepalensis, P. sibbaldia and P. sundaica, except for normal meiosis observed in P. gerardiana, P. kleiniana, P. micropetala and P. thomsonii. The anomalous taxa are marked with meiotic abnormalities in the form of cytomixis, chromosomal stickiness, unoriented bivalents, formation of laggards and bridges resulting in abnormal microsporogenesis, and production of heterogenous-sized fertile pollen grains along with reduced pollen fertility. All the taxa with normal meiotic courses show nearly one hundred percent pollen fertility.  相似文献   

17.
18.
Animals can adapt their activity patterns throughout the circadian cycle. Prey may use moonlight as a predation risk cue and allocate their activity to lower risk periods. Here, we assessed moon transit influence on the activity allocation of nocturnal mammalian prey, in the presence of a predator (pumas, Puma concolor), during different moon phases, through camera trapping in Central Amazon. Thirty camera traps were installed 2 km apart from each other in each of our three study sites. Prey record distributions were assessed across the moon cycle, and their daily activity patterns were described in each moon phase. The record distributions of pacas (Cuniculus paca) (N = 262) and armadillos (Dasypus sp.) (N = 244) were concentrated in darker nights, contrasting with red brocket deer (Mazama americana) (N = 123) and pumas (N = 31), whose records were evenly distributed through the moon cycle. Yet, every prey was found to avoid the brighter times of the night regardless of the moon phase. These findings suggest prey can shift the temporal distribution of their activities under different moon phases when predators are present, perhaps in response to predation risk variations.  相似文献   

19.
We provide a taxonomic review of the extinct testudinid Testudo catalaunica, based on published and unpublished material from several Miocene (late Aragonian and early Vallesian) sites of the Vallès‐Penedès Basin (north‐east Iberian Peninsula). We show that Testudo catalaunica irregularis is a junior subjective synonym of T. catalaunica, and further provide an emended diagnosis of the latter based on newly reported material. Contrary to some recent suggestions, this emended diagnosis discounts an alternative attribution of T. catalaunica to Paleotestudo. The latter is merely recognized as a subgenus of Testudo, based on a cladistic analysis that assessed the phylogenetic position of all extant and most extinct species of Testudo currently recognized as valid (including T. catalaunica). Our phylogenetic analysis (which recovers the molecular phylogeny of extant Testudo s.l.) supports a taxonomic scheme in which the three extant subgenera of Testudo are represented in the fossil record. Testudo s.s. is retrieved as the sister taxon of Testudo (Agrionemys) + [Testudo (Paleotestudo) + Testudo (Chersine)]. The extinct Testudo (Paleotestudo) is therefore the sister taxon of the Testudo (Chersine) clade. The latter subgenus reveals as the most diverse clade of Testudo s.l. in the fossil record, with T. catalaunica Testudo steinheimensis constituting a subclade distinct from that including Testudo hermanni.  相似文献   

20.
Species of the genus Pleurodema are relatively small, plump frogs that mostly occur in strong‐seasonal and dry environments. The genus currently comprises 14 species distributed from Panama to southern Patagonia. Here we present a phylogenetic analysis of Pleurodema, including all described species and several outgroups. Our goals include testing its monophyly and the monophyly of the species groups that were historically proposed, and studying the evolution of some character systems, particularly macroglands and egg‐clutch structure; this last point also provided the chance for a discussion of foam nest evolution in anurans. Our dataset includes portions of the mitochondrial genes cytochromeb, 12S, 16S, and the intervening tRNAVal; the nuclear gene sequences include portions of rhodopsin exon 1 and seven in absentia homolog I. Our results support a clade composed of Pleurodema and including the monotypic Somuncuria Lynch, 1978 nested within it. The latter genus is therefore considered a junior synonym of Pleurodema and its sole species is added to this genus. Furthermore, our results indicate the non‐monophyly of several species groups proposed previously. We recognize four clades in Pleurodema: the P. bibroni clade (P. bibroni, P. cordobae and P. kriegi), the P. thaul clade (P. bufoninum, P. marmoratum, P. somuncurensis and P. thaul), the P. brachyops clade (P. alium, P. borellii, P. brachyops, P. cinereum, P. diplolister and P. tucumanum) and the P. nebulosum clade (P. guayapae and P. nebulosum). Our results further indicate the need for a taxonomic reassessment of P. borellii and P. cinereum (as did previous studies), P. guayapae and P. nebulosum, and the three species in the P. bibroni clade. Pleurodema shows a striking pattern of variation in presence/absence of lumbar glands. Our results indicate multiple losses or independent gains of this character associated with defensive displays. The reproductive modes of Pleurodema include four different egg‐clutch structures. The optimization of these indicates that there are at least two independent transformations from the plesiomorphic mode of foam nests to egg‐clutch structures involving gelatinous masses of different sorts (ovoid plates, masses, or strings). We hypothesize that these independent transformations could involve changes at the behavioural (the loss of foam beating behaviour by the parent) and/or structural level (transformations involving the pars convoluta dilata, the section of the oviduct where the foam‐making substance is secreted). Finally, our study of foam nest evolution in Pleurodema is extended to the other groups of anurans where foam‐nesting occurs, on the basis of available data and recent phylogenetic hypotheses. In the different hyloid groups where it occurs, foam‐nesting evolved from clutches laid in water. However, in all ranoids in which foam‐nesting occurs, it evolved from terrestrial clutches, with eggs laid hanging in vegetation, or, if the clutches are laid on a restricted volume of water, involving endotrophic development. © The Willi Hennig Society 2012.  相似文献   

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