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1.
A new species, Phoenicopsis anadyrensis Nosova, is described based on the leaf morphology and cuticle features from the Maastrichtian–Danian Rarytkin Formation, Chukotka, North-East of Russia. It is characterized by hypostomatic leaves with stomatal bands on the abaxial side, undulate anticlinal epidermal cell walls and papillae on the epidermal cells and on the subsidiary cells of the stomata. The new species is the youngest reliable representative of the genus Phoenicopsis. This record extends the stratigraphic range of Phoenicopsis from its previously known latest records in the early Campanian up to Maastrichtian–Danian. The persistence of the genus Phoenicopsis up to the Cretaceous–Paleogene boundary is most likely related with vicinity to mountain floras associated with Late Cretaceous and Paleogene volcanic uplands.  相似文献   

2.
The motacú palm (Attalea phalerata) is widespread in Bolivia and is an economically valuable species as a source of vegetable oil. In Bolivia it is utilized as construction material, food, medicine, cosmetic, and edible oil. Oil extracted from the kernel (60–70% of dry weight) is high in lauric and myristic oils and compares favorably with other tropical oil crops. The palms reach reproductive maturity in 7–10 years and potential oil production from cultivated stands is 1.1-2.4 tons/ha/yr.  相似文献   

3.
The Ediacaran–Fortunian ichnofauna from Central Brittany (NW France) is revised for the first time since the pioneering work by Lebesconte at the end of the 19th century. The study is based on fossils from the type-localities of the historical Brioverian taxa Montfortia (traces from Montfort-sur-Meu) and Neantia (wrinkle surfaces from Néant-sur-Yvel), and on two new outcrops from Saint-Gonlay. The ichnofossil assemblage includes Helminthoidichnites tenuis, Helminthopsis tenuis, Gordia marina, Palaeophycus tubularis, ?Neonereites uniserialis, and ?Spirodesmos archimedeus. Locally, the grazing traces are associated with wrinkle surfaces considered as microbially induced sedimentary structures (MISS). The sedimentological characteristics of these deposits correspond to a shelf marine environment. Both U-Pb datings on detrital zircon and ichnostratigraphic criteria tend toward an Ediacaran age of the fossiliferous deposits, but we cannot exclude the possibility of a Fortunian age at the present state of knowledge.  相似文献   

4.
Life stages of orthoclad species, Paracricotopus spinicornisn.sp., Parametriocnemus ornatocornis(Kieffer) and the immatures of Paraphaenocladius impensus albusalatusChaudhuri & Sinharay are described from India. A brief note on the ecology of the species is also given.  相似文献   

5.
The titanosaur sauropod Bonatitan reigi is redescribed. The material collected, originally interpreted as pertaining to two different individuals, is reorganised in five individuals, and the original type specimen is separated into three different individuals. One of the braincases is designated as a new type specimen. Some materials are described by the first time (sacral ribs, distal caudal, chevrons, metacarpals, astragalus and metatarsals), others reinterpreted as different bones (‘ulna’ and ‘radius’). The diagnosis of B. reigi is emended, removing some of the original characters (longitudinal groove located on the suture between the parietals that continues posteriorly over the supraoccipital to the foramen magnum) and adding some new (small paired pits on the frontals and posterior ridge of the metacarpal IV). The phylogenetic analysis does not support B. reigi as a member of the Saltasaurinae, but rather as a basal member of a broad clade of sauropods that in turn is recovered as the sister group of the Saltasauridae.  相似文献   

6.
7.
The Bankoualé Palm, Livistona carinensis is the only known species of Livistona occurring in Africa and is currently classified as vulnerable (IUCN 2004). This extreme outlier species of the genus is restricted to Yemen, Somalia and Djibouti, where all populations are in rapid decline. In Djibouti the palm is confined to three valley systems within the upland plateau of the Goda Massif. This study used microsatellite markers to investigate the genetic diversity and relationships within the species. At the species level L. carinensis contained very low genetic diversity. Most variation was due to the variation between the samples from Yemen and Somalia compared with those in Djibouti. The Djibouti populations were almost monomorphic across the nine loci tested. Interestingly, and despite the small sample sizes, the individuals from botanic gardens collections of the Yemen and Somalia populations were more genetically diverse than the Djibouti populations. This study indicates that the populations in Yemen and Somalia are highly significant for the conservation of the species genetic diversity. Given the lack of genetic diversity both within and among L. carinensis populations in Djibouti, plants could be cultivated for in-situ population enhancement from any seed that is available from within Djibouti with no significant genetic impacts of provenance mismatch. Clearly the populations from Djibouti, Somalia and Yemen are different genetic provenances raising some issues for the conservation and recovery of L. carinensis.  相似文献   

8.
The phylogeny of the Middle Jurassic Cardioceratidae is reconstructed on the basis of a study of their shell morphology and analysis of their stratigraphic distribution. The phylogenetic lineage CranocephalitesArctocephalitesArcticocerasParacadoceras is assigned to the subfamily Arctocephalitinae (Upper Bajocian–lowermost Callovian). The subfamily Cadoceratinae (Upper Bajocian–Callovian) also originating from Cranocephalites includes the phylogenetic lineage GreencephalitesCadocerasLongaeviceras; and lateral branches Chamoussetia and Platychamoussetia. The origin of the Early Callovian Eckhardites, also assigned to Cardioceratidae, is not established. The generic names Rondiceras and Cadochamoussetia are considered as junior synonyms of Cadoceras and Chamoussetia, respectively. The Early Callovian species Cadoceras bellabimba sp. nov. is described.  相似文献   

9.
A new species of the chromidotilapiine genus Thysochromis, is described from the Noumbi and Kouilou River drainages in the Republic of Congo. Based on the current investigation, Thysochromis is resolved as containing two geographically disjunct species, T. ansorgii from localities in the upper Guinean ichthyofaunal province (Ivory Coast, Ghana, Benin and Nigeria) and Thysochromis emili sp. nov. restricted to coastal regions of the Republic of Congo in the lower Guinean province.  相似文献   

10.
Extensively bored log-grounds with ichnospecies Teredolites longissimus and body fossils of the causative teredinid molluscs are recorded from the Early Eocene subsurface beds of the Cambay Shale Formation at Vastan lignite Mine in western India. Three sizes of T. longissimus observed in Vastan mostly represent animals in different stages of maturity or successive infestation of substrate. Orientation of a majority of small borings suggests that teredinid larvae preferred to initiate boring across the wood grain and subsequently turned to become parallel to grain exhibiting adult boring behavior. Variations in morphology of recovered shells indicate involvement of at least two teredinid taxa in constructing T. longissimus from Vastan—one is identified as Bankia isp. based on pallets and the other remains unidentified and may possibly represent another bankiine, Nototeredo. Evidences of traumatic as well as attritional mortality are noticeable. The xylic substrates having affinity with woods of a modern tree genus Aglaia (Meliaceae) were apparently transported from their natural habitat of an inland moist tropical forest to the coastal region where they were colonized by the teredinid bivalves. The profusely infested wood logs were buried in a near shore lagoon or a tidal flat setting, which is corroborated by the known biota (vertebrate, invertebrate as well as plants) as well as sedimentary facies of the Cambay Shale Formation in Vastan section.  相似文献   

11.
Altner  Melanie  Reichenbacher  Bettina 《Hydrobiologia》2021,848(16):3613-3637
Hydrobiologia - Fossil cichlids from East Africa offer unique insights into the evolutionary history and ancient diversity of the family on the African continent. Here we present three fossil...  相似文献   

12.
13.
Quarantine is often proposed and sometimes used to control the spread of infectious diseases through a human population. Yet there is usually little or no information on the effectiveness of attempting to quarantine humans that is not of an anecdotal or conjectural nature. This paper describes how a compartmental model for the geographic spread of infectious diseases can be used to address the potential effectiveness of human quarantine. The model is applied to data from the historical record in central Canada around the time of the 1918–19 influenza epidemic. Information on the daily mobility patterns of individuals engaged in the fur trade throughout the region prior to, during, and immediately after the epidemic are used to determine whether rates of travel were affected by informal quarantine policies imposed by community leaders. The model is then used to assess the impact of observed differences in travel on the spread of the epidemic. Results show that when mobility rates are very low, as in this region, quarantine practices must be highly effective before they alter disease patterns significantly. Simulation results suggest, though, that effectiveness varies depending on when the limitation on travel between communities is implemented and how long it lasts, and that a policy of introducing quarantine at the earliest possible time may not always lead to the greatest reduction in cases of a disease.  相似文献   

14.
Heteropternis raipurensis n. sp. is described from Barnawapara Wildlife Sanctuary (Raipur, Chhattisgarh, India), and compared to H. respondens (Walker, 1859). An identification key to Asian species of Heteropternis is provided.  相似文献   

15.
16.
We describe intergradations between the arthropod repichnial trace fossils Diplichnites gouldi (Gevers et al., 1971), Dendroidichnites Demathieu et al., 1992, and Monomorphichnus Crimes, 1970 with two distinct cubichnial traces, Gluckstadtella cooperi Savage, 1971 and Huilmuichnus santracruzensis new ichnogenus and ichnospecies. These compound ichnofossils are part of high ichnodiversity arthropod-dominated trace fossil associations from the Late Carboniferous Agua Escondida Formation of the San Rafael Basin (Argentina). The complex ichnotaxonomy of Diplichnites and the ichnospecies D. gouldi are discussed and some possible working solutions are proposed. The most likely producer of the compound trace fossils are the Pygocephalomorpha, a group of Late Paleozoic crustaceans that are recorded in nearby basins from Uruguay and Brazil. The compound trace fossils are used to infer a number of complex behaviors of pygocephalomorphs in a subaqueous setting, including caridoid (tail flip) or more primitive escape reactions, landing followed by resting and transient resting during normal walking. In addition, different gaits can be inferred from well-preserved D. gouldi, which can be correlated with contrasting trackway morphology.  相似文献   

17.
Polyamines (putrescine, spermidine and spermine) cause a marked increase in the activity of the loach Misgurnus fossilis DNA polymerase α on activated (gapped) DNA. The stimulatory effect increases in the order: putrescine, spermidine, spermine. Kinetic analysis shows that spermine does not change the affinity of the polymerase for dTTP, but it decreases the enzyme affinity for DNA. The apparent Km of the polymerase for activated DNA progressively increases from 14 to 1200 μM (nucleotide), if the concentration of spermine rises up to 2 mM, while Vmax reaches a maximum at 0.5 mM spermine and then drops at higher polyamine concentrations. Native calf thymus DNA and especially single-stranded DNA from phage M13 appear to be inhibitors of α-polymerase activity on gapped DNA. Dixon plots suggest simple competitive inhibition of the polymerase activity by single- or double-stranded DNA and absence of cooperativity in the interaction of the polymerase with DNA. Hill-plot analysis is compatible with the interpretation that there is only one DNA binding site on each DNA polymerase α molecule. Spermine, even at low concentrations, decreases sharply the affinity of the enzyme for double-stranded DNA, while the enzyme affinity for single-stranded DNA changes insignificantly. Another result of spermine action is the destabilization of the polymerase-DNA complex. The ratio of the ‘static affinity’ of the enzyme to its ‘kinetic affinity’ decreases 2.2-fold in the presence of 0.5 mM spermine. As a result, the sensitivity of DNA synthesis to 3′-deoxy-3′-aminothymidine 5′-triphosphate and to 1-β-d-arabinofuranosylcytidine 5′-triphosphate decreases in the presence of the polyamine. Both spermine effects, the decrease in the ‘nonproductive binding’ of the polymerase to double-stranded regions in DNA and the destabilization of the polymerase-DNA complex, presumably account for the increase in the activity of the loach α-polymerase on activated DNA.  相似文献   

18.
The present work is focused on the hipparionine remains from the late Miocene to early Pliocene deposits of the Haritalyangar areas, Himachal Pardesh, India. These remains are taxonomically ranked to five genera (Plesiohipparion, Proboscidipparion, Cormohipparion, Sivalhippus, and Eurygnathohippus) and seven species. The described taxa are predominantly known from China, Africa and the Indian subcontinent. Among these, Proboscidipparion is reported for the first time from the Siwaliks; the material assigned to Plesiohipparion sp. is a potential candidate for a new species. Hipparionines from this area have long been poorly known and are helpful to understand the palaeontological context of the Indian Siwalik mammalian fauna. The hipparionines suggest a wide variety of environmental conditions ranging from grasslands to forests.  相似文献   

19.
20.
We consider a predator–prey model system for spatially distributed species over patches. Each predator species has a unique preferred patch (shelter and reproduction site) and travel for chasing prey. Its individuals are split into resident from the preferred patch and travelers. Further there is at most one resident predator species per patch. Depending on the availability of local anthropized resources not related to local prey on the preferred patch, one distinguishes between well-fed and starving predators. We assume prey species do not disperse at the predator scale.In this study we are interested in the number of persistent stationary states for the resulting ordinary differential equations model system. There exists at most one persistent predator–prey stationary state when there is exactly one starving resident predators per patch provided all functional responses to predation are Lotka–Volterra like or when a single starving resident predators is available. Else multiple persistent predator–prey stationary state are likely to exist. A specific emphasis is put on toy-model systems with 2 or 3 patches. Slow–fast dynamical methodology is also used for locally asymptotically stable purposes.Numerical experiments suggest that several scalings may govern the dynamics at stabilization.  相似文献   

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