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1.
Bilal Sar? 《Geobios》2009,42(3):359
The Upper Cretaceous (Middle Cenomanian-Coniacian) successions of the Bey Da?lar? Carbonate Platform (Western Taurides, SW Turkey) are represented by rudist-bearing shallow-water limestones. Four rudist lithosomes are distinguished for the first time from the Eastern, Northern and Southern Areas of the Bey Da?lar? Autochthon. The oldest rudist assemblages dominated by caprinids are observed in the Eastern (Katran Da?) Area (caprinid lithosomes) and suggest a Middle-Late Cenomanian age. The uppermost part of the platform carbonates in the Northern Area is characterized by an association of hippuritid and radiolitid rudist bivalves dominated by Vaccinites praegiganteus (Toucas) (hippuritid lithosomes). The rudist fauna indicates the Late Turonian age, which is confirmed by the previously obtained 87Sr/86Sr values of well-preserved low-Mg calcite of Vaccinites praegiganteus (Toucas) shells. The rudist associations of the Southern (Susuzda?) Area are represented by two rudist formations. The lower lithosomes are mainly made up of hippuritids and radiolitids (hippuritid-radiolitid lithosomes). The stratigraphical distributions of the species of the assemblage indicate a Santonian-Early Campanian age. The rudist associations of the upper lithosomes are dominated by species of Joufia and Gorjanovicia (Joufia-Gorjanovicia lithosomes), which suggest a Late Campanian-Maastrichtian age. Identification of the rudist lithosomes yields information on the palaeobiogeographic distribution of the rudist species in the eastern Mediterranean region and also on the biostratigraphic frame of the Upper Cretaceous successions of the Bey Da?lar? Carbonate Platform.  相似文献   

2.
《Geobios》1988,21(6):693-707
The paper describes three taxa of rudists, namely Eoradiolites gilgitensis Douvillé? Horiopleura sp. and cf. Toucasia sp., from the Khalsi limestone of Indus Formation, Ladakh Himalaya exposed 2.5 kms East of Khalsi. The age and affinity of the rudist fauna have also been discussed.  相似文献   

3.
A new polyconitid rudist, Magallanesia canaliculata gen. et sp. nov., of probably late Albian age, is described from the Pulangbato area, central Cebu Island, the Philippines in the western Central Pacific and Takuyo‐Daini Seamount, now located in the Northwest Pacific. It is similar to Praecaprotina Yabe and Nagao, 1926, a Japanese–Central Pacific endemic genus of late Aptian – early Albian age, but differs in having canals that developed by partitioning of the large ectomyophoral cavity in the posterior part of the left valve. Its discovery strengthens the evidence for Pacific endemism in Albian times. Several other clades of canaliculate rudists flourished or evolved at the same time in different regions of the Tethyan Realm, suggesting the presence of common global biological and/or environmental factors stimulating the evolution of the canals despite such endemism. Furthermore, the finding of a canaliculate polyconitid provides evidence in favour of the evolutionary hypothesis of a polyconitid origin for the Late Cretaceous canaliculate rudist family Plagioptychidae Douvillé, 1888.  相似文献   

4.
Rudistid lithosomes cropping out near Castrojimeno, at the northern margin of the Central System in north-central Spain, provide detailed information on their composition and structure, on their development and succession, and about their relationship with the Coniacian sequence stratigraphy framework of the Iberian Basin. Most rudist assemblages are oligospecific, with a dominant species, or monospecific. The radiolitids Biradiolites angulosus, Praeradiolites requieni, and Radiolites sauvagesi and the hippuritids Hippurites incisus and Vaccinites giganteus were identified. Radiolitids demonstrate wide intraspecific morphological variability. The following Riding’s structural categories of organic reefs are represented: segment reefs, spaced and close cluster reefs, and close cluster/frame reefs. Bioclastic beds of reworked rudist fragments occur below or in between the rudist reefs. The vertical succession of all five types of rudistid lithosomes distinguished evidences a shallowing-upward trend. Rudistid lithosomes developed on the coastal margin during the superposition of the highstand sea-level stage of third- and fourth-order depositional sequences.  相似文献   

5.
The Upper Cretaceous rocks are widely distributed and well exposed in south Algeria and consist in beds rich in macrofauna. For the first time, twenty veneroid species (Bivalvia) are systematically described from the upper Cenomanian deposits of the Guir Basin. While three species were reported since long before [Granocardium desvauxi (Coquand), G. productum (J. de C. Sowerby) and Glossus aquilinus (Coquand)]; Lucina fallax Forbes, Crassatella (Rochella) tenuicostata (Seguenza), Protocardia hillana (J. Sowerby), G. productum (J. de C. Sowerby) var. byzacenica (Pervinquière), Arctica cordata (Sharpe), A. humei (Cox), A. inornata (d’Orbigny), A. picteti (Coquand), Tenea delettrei (Coquand), Paraesa faba (J. de C. Sowerby), Meretrix desvauxi (Coquand) were previously unknown from the Cretaceous of Algerian Sahara. Because of reduced degree of preservation, Sphaera cf. corrugata J. Sowerby, Maghrebella cf. forgemoli (Coquand), Maghrebella sp., Granocardium cf. carolinum (d’Orbigny), Protocardia sp. and Meretrix sp. are tentatively determined. The studied material, found in the lower part of the “Calcaires de Sidi Mohamed Ben Bouziane” Formation, evidences palaeobiogeographic affinities occurring over a wide geographical area: from North Africa, southern Europe to Middle East and India. The present study provides new information to the knowledge of the upper Cenomanian palaeobiology of the studied region.  相似文献   

6.
As part of a survey of the Mediterranean enchytraeids, large numbers of samples were collected from a wide range of habitats at 38 localities of Tunisia and Algeria in 1989. Twenty species were identified belonging to six genera. Five species are new records for Tunisia and 17 are new for Algeria. Most of the recorded species are widely distributed throughout Europe, or even cosmopolitan, but some have a more restricted range. Fridericia caprensis has a circummediterranean distribution, Fridericia sardorum seems to be endemic to the western Mediterranean and Fridericia berninii is known only from the Balearic Islands and Algeria. Enchytraeus minutus bisetosus n. ssp. is described. A critical revision of some species is also provided.  相似文献   

7.
Hennhöfer, D., Götz, S. & Mitchell, S.F. 2012: Palaeobiology of a Biradiolites mooretownensis rudist lithosome: seasonality, reproductive cyclicity and population dynamics. Lethaia, Vol. 45, pp. 450–461. During the Cretaceous, rudist bivalves were among the most important benthic carbonate producers on tropical to sub‐tropical carbonate platforms. Yet questions concerning the biology of rudist bouquets remain unanswered to a great extent. In this study a monospecific bouquet of the small radiolitid rudist Biradiolites mooretownensis has been evaluated from a palaeobiological angle. Three‐dimensional, high‐resolution, quantitative analysis provides a detailed evaluation of growth and reproduction in an in situ rudist association. A total of 1237 consecutive tomograms with a vertical spacing of 0.1 mm were produced of which 1150 have been digitally measured for total area, number of specimens, packing density, spat density, recruitment, survival time, mortality and accommodation space. The results show constant coverage of about 60%, a stable packing density of 3.2 specimens per cm2 and constant reproduction throughout the bouquet. Time series analysis (spectral analysis) using PAST statistical software shows cyclic spat density every 14.9 mm of vertical growth. Combined with the results of the δ18O isotope analysis (showing cyclicities of 14 mm) one reproduction cycle appears to be annual. 46.4% of all counted specimens died before 3 mm of vertical growth. More than 93% of the initial spat does not exceed 15 mm shell height or 1 year respectively. Two mortality peaks in the juvenile’s life at 4 and 10–15 mm shell height either represent important obstacles in the ontogenetic development of the species or reflect external influences. □ Biradiolites, grinding tomography, palaeobiology, population dynamics, reproduction, rudists, sclerochronology, seasonality.  相似文献   

8.
Prevalence of entomopathogenic fungi was studied in overwintering ground beetles (Col.: Carabidae) and rove beetles (Col.: Staphylinidae) collected from fields of lucerne, white cabbage and white cabbage undersown with white clover. In general infection levels in adult ground beetles and rove beetles were low (Carabidae: max. 7.6%,Staphylinidae: max. 7.0%). In comparison, prevalence of entomopathogenic fungi in carabid larvae was high (19–50%). At one study site an epizootic ofBeauveria bassiana was observed, infecting 67% of the staphylinidAnotylus rugosus and 37% of the staphylinidGyrohypnus angustatus. Beauveria bassiana was the predominant fungus isolated from ground beetles and rove beetles from all studied sites. Other fungal species included the hyphomycetesMetarhizium anisopliae, Paecilomyces farinosus andVerticillium lecanii as well asZoophthora radicans andZoophthora philonthi (Zygomycetes: Entomophthorales). Two individuals ofAnotylus rugosus were found to have a dual infection ofZoophthora philonthi andBeauveria bassiana.
Résumé La présence de champignons entomopathogènes a été recherchée chez des carabes (Col.: Carabidae) et des staphylins (Col.: Staphylinidae) récoltés dans des champs de luzerne, de chou et d'une culture mélangée chou-trèfle blanc. Chez les adultes, le taux d'infection dans les deux groupes d'insectes est en général très faible (Carabidae: max. 7,6%, Staphylinidae: max. 7%). Chez les larves de carabes par contre, le taux d'infection par les champignons est élevé (19–50%). Sur l'un des sites de l'étude, une épizootie àBeauveria bassiana a été observée, l'infection portant sur 67% des individus récoltés appartenant à l'espèceAnotylus rugosus et 37% desGyrohypnus angustatus. B. bassiana est le champignon prédominant isolé à partir des coléoptères de tous les sites étudiés. D'autres espèces fongiques ont été relevées: ce sont les hyphomycètesMetarhizium anisopliae, Paecilomyces farinosus etVerticillium lecanii ainsi queZoophthora radicans etZoophthora philonthi. Deux individus d'A. rugosus ont été retrouvés infectés à la fois parErynia etB. bassiana.
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9.
Summary In the area of Haidach (Northern Calcareous Alps, Austria), coral-rudist mounds, rudist biostromes, and bioclastic limestones and marls constitute an Upper Cretaceous shelf succession approximately 100 meters thick. The succession is part of the mixed siliciclasticcarbonate Gosau Group that was deposited at the northern margin of the Austroalpine microplate. In its lower part, the carbonate succession at Haidach comprises two stratal packages that each consists, from bottom to top, of a coral-rudist mound capped by a rudist biostrome which, in turn, is overlain by bioclastic limestones and, locally, marls. The coral-rudist mounds consist mainly of floatstones. The coral assemblage is dominated by Fungiina, Astreoina, Heterocoeniina andAgathelia asperella (stylinina). From the rudists, elevators (Vaccinites spp., radiolitids) and recumbents (Plagioptychus) are present. Calcareous sponges, sclerosponges, and octocorals are subordinate. The elevator rudists commonly are small; they settled on branched corals, coral heads, on rudists, and on biolastic debris. The rudists, in turn, provided settlement sites for corals. Predominantly plocoid and thamnasteroid coral growth forms indicate soft substrata and high sedimentation rates. The mounds were episodically smothered by carbonate mud. Many corals and rudists are coated by thick and diverse encrustations that indicate high nutrient level and/or turbid waters. The coral-rudist mounds are capped byVaccinites biostromes up to 5 m thick. The establishment of these biostromes may result from unfavourable environmental conditions for corals, coupled with the potential of the elevator rudists for effective substrate colonization. TheVaccinites biostromes are locally topped by a thin radiolitid biostrome. The biostromes, in turn, are overlain by bioclastic limestones; these are arranged in stratal packages that were deposited from carbonate sand bodies. Approximately midsection, an interval of marls with abundantPhelopteria is present. These marls were deposited in a quiet lagoonal area where meadows of sea grass or algae, coupled with an elevated nutrient level, triggered the mass occurrence ofPhelopteria. The upper part of the Haidach section consists of stratal packages that each is composed of a rudist biostrome overlain by bioclastic wackestones to packstones with diverse smaller benthic foraminifera and calcareous green algae. The biostromes are either built by radiolitids,Vaccinites, andPleurocora, or consist exclusively of radiolitids (mainlyRadiolites). Both the biostromes and the bioclastic limestones were deposited in a low-energy lagoonal environment that was punctuated by high-energy events.In situ-rudist fabrics typically have a matrix of mudstone to rudistclastic wackestone; other biogens (incl. smaller benthic foraminifera) are absent or very rare. The matrix of rudist fabrics that indicate episodic destruction by high-energy events contain a fossil assemblage similar to the vertically associated bioclastic limestones. Substrata colonized by rudists thus were unfavourable at least for smaller benthic foraminifera. The described succession was deposited on a gently inclined shelf segment, where coral-rudist mounds and hippuritid biostromes were separated by a belt of bioclastic sand bodies from a lagoon with radiolitid biostromes. The mounds document that corals and Late Cretaceous elevator rudists may co-occur in close association. On the scale of the entire succession, however, mainly as a result of the wide ecologic range of the rudists relative to corals, the coral-dominated mounds and the rudist biostromes are vertically separated.  相似文献   

10.
BackgroundPhlebotomine sand flies (Diptera: Psychodidae) are important vectors of various human and animal pathogens such as Bartonella bacilliformis, Phlebovirus, and parasitic protozoa of the genus Leishmania, causative agent of leishmaniases that account among most significant vector-borne diseases. The Maghreb countries Mauritania, Morocco, Algeria, Tunisia, and Libya occupy a vast area of North Africa and belong to most affected regions by these diseases. Locally varying climatic and ecological conditions support diverse sand fly fauna that includes many proven or suspected vectors. The aim of this review is to summarize often fragmented information and to provide an updated list of sand fly species of the Maghreb region with illustration of species-specific morphological features and maps of their reported distribution.Materials and methodsThe literature search focused on scholar databases to review information on the sand fly species distribution and their role in the disease transmissions in Mauritania, Morocco, Algeria, Tunisia, and Libya, surveying sources from the period between 1900 and 2020. Reported distribution of each species was collated using Google Earth, and distribution maps were drawn using ArcGIS software. Morphological illustrations were compiled from various published sources.Results and conclusionsIn total, 32 species of the genera Phlebotomus (Ph.) and Sergentomyia (Se.) were reported in the Maghreb region (15 from Libya, 18 from Tunisia, 23 from Morocco, 24 from Algeria, and 9 from Mauritania). Phlebotomus mariae and Se. africana subsp. asiatica were recorded only in Morocco, Ph. mascitti, Se. hirtus, and Se. tiberiadis only in Algeria, whereas Ph. duboscqi, Se. dubia, Se. africana africana, Se. lesleyae, Se. magna, and Se. freetownensis were reported only from Mauritania. Our review has updated and summarized the geographic distribution of 26 species reported so far in Morocco, Algeria, Tunisia, and Libya, excluding Mauritania from a detailed analysis due to the unavailability of accurate distribution data. In addition, morphological differences important for species identification are summarized with particular attention to closely related species such as Ph. papatasi and Ph. bergeroti, Ph. chabaudi, and Ph. riouxi, and Se. christophersi and Se. clydei.  相似文献   

11.
A survey of the hoverflies (Diptera: Syrphidae) of the region of Guelma, northeast Algeria, was carried out from August 2011 to July 2013. A total of 31 species was recorded with six (Scaeva mecogramma, Epistrophe melanostoma, Syrphus vitripennis, Brachypalpus valgus, Merodon calcaratus and M. chalybeus) new to Algeria. Of these, three species (E. melanostoma, M. calcaratus and M. chalybeus) are also new additions to the entomofauna of North Africa. The results complement those of a previous study covering Numidia and Tebessa and provide a more comprehensive view of the phenology and distribution of Syrphidae across northeast Algeria. An improved knowledge of the distribution of North African hoverflies will contribute to a better assessment of the status of each taxon and inform conservation efforts.  相似文献   

12.
Abstract: Pachytraga Paquier, 1900, the stratigraphically oldest genus of caprinine caprinid rudist, was previously known from only two chronospecies from a single lineage, that is the Hauterivian Ptubiconcha Astre, 1961 and the early Aptian Pparadoxa (Pictet and Campiche, 1869). Here, a new species, Pachytraga? tanakahitoshii, is erected on the basis of isolated left valves recovered from the Osaka and Sanchu areas, south‐west Japan. This species has a moderate shell size (antero‐posterior commissural diameter c. 30 mm), and its left valve is characterized by at least one possibly autapomorphic character (narrow anterior myophore, inclined inwards), as well as a mosaic of primitive (single longitudinal carina developed on the anterior side) and derived (simple marginal canals in the antero‐dorsal valve margin) characters of Mediterranean and Middle East Tethyan Pachytraga. The Japanese Pachytraga? represents the first probable record of this genus outside the Mediterranean/Middle Eastern Tethyan province, and its early Barremian age partly fills the ‘gap’ in its previously known stratigraphical record, although the evolutionary relationship of the Japanese form with Mediterranean and Middle East Tethyan Pachytraga remains unsolved. However, the discovery of early Barremian Pachytraga? in Japan indicates that the evolutionary history of the genus is more complex than previously thought and should thus be discussed in a broader palaeogeographical context that must now include the Pacific.  相似文献   

13.
The identification of migration dates and wintering zones for migratory birds are key elements for the understanding of the Afro-Palearctic migration system. From 2015 to 2022, a large-scale survey of Turtle Doves Streptopelia turtur, a vulnerable species, was established in Northwest Africa, including Morocco, Algeria, and Tunisia. We monitored migration dates and wintering individuals using the line-transect method. We found that Turtle Doves arrived in the last week of March and left the North African region in mid-October. Compared with Morocco, Doves arrived significantly earlier in Algeria and Tunisia. Moreover, Doves were discovered wintering on nine Northwest African sites, from October to February, where individuals feed in groups. We found that the occurrence probability of wintering Turtle Doves decreased significantly with increasing temperature and rainfall. Birds wintered most often close to wetlands since the overwintering probability decreased with the increasing distance from the recording area to the nearest water body. These are the first and only detailed findings on the migration phenology of the globally vulnerable Turtle Dove in north western Africa.  相似文献   

14.
Summary Species ofScelionidae, parasiting in eggs ofLymantria dispar (L.) are mentioned and the results of use of these parasites are added. A new egg-parasite of gipsy moth —Hadronotus lymantriae n.sp. — is described. A key to Scelionid egg-parasites living inLymantria dispar (L.) is given. Attention is drawn to the fact thatH. bernardi Manev. is a nomen nudum. Finally, the author discusses the phylogenetical and taxonomical internal relations inHadronotus Foerst.
Résumé L'auteur mentionne les différentes espèces de Scélionides parasites des œufs deLymantria dispar (L.) et rappelle les résultats obtenus par l'utilisation de ces parasites. Un nouveau parasite des œufs de ce Bombyx,Hadronotus lymantriae n. sp., est décrit. Il est montré en outre queH. bernardi Manev. doit être considérénomen nudum. Enfin l'auteur discute les relations phylogéniques et taxonomiques des espèces du genreHadronotus Foerst.
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15.
Shell disintegration and taphonomic loss in rudist biostromes   总被引:1,自引:0,他引:1  
Radiolitid biostromes in the Upper Cretaceous of Austria and Italy record a marked taphonomic loss controlled mainly by the composition of the biocoenosis, by the density of rudist colonization, by the style of radiolitid shell disintegration and by early diagenetic processes. Radiolitid shells consisted of a calcitic ostracum and an originally aragonitic hypostracum. The attached valve of most radiolitids was built of (1) an outermost ostracal layer of delicate calcite lamellae, (2) a thick layer of ‘boxwork ostracum’ built of radial funnel plates and cell walls, (3) a thin, inner ‘ostracal layer 3’ of thick-walled boxwork, and (4) the hypostracum that formed the innermost shell layer. The attached valve disintegrated by spalling of radial funnel plates of layer 2, and by selective removal of the boxwork ostracum. In the free valve, the ostracum consisted of two layers: (a) an inner, lid-shaped layer of dense calcite, and (b) an outer layer composed of calcite lamellae. The free valve disintegrated by spalling into ostracal and hypostracal portions, by spalling of the ostracum into layers a and b, and by disintegration of layer b into packages of calcite lamellae and individual lamellae. The specific style of disintegration of the radiolitids was aided or induced by discontinuities in shell structure. Lamellar fragments from the ostracum of the upper valve and from the radial funnel plates of the lower valve locally are abundant in free-valve-funnel-plate floatstones that comprise the matrix of or occur in lenses within radiolitid biostromes. In biostromes with an open parautochthonous fabric, selective removal of the boxwork ostracum of the attached valve occurred by mechanical spalling and, most probably, by early diagenetic dissolution. Complete removal of the boxwork ostracum yielded thin, relict shells composed of the ‘ostracal layer 3’ and the hypostracum. During early diagenesis, the hypostracum was replaced by blocky calcite spar, or was dissolved and became filled by internal sediments. The combination of both selective removal of boxwork ostracum and early diagenetic dissolution of aragonite locally resulted in the formation of ghost biostromes that entirely or largely consist of faint relics of radiolitids. The syndepositional formation of radiolitid shell relics and the presence of radiolitid ghost biostromes produced by bios-tratinomic and early diagenetic processes show that rudist biostromes can undergo marked taphonomic loss during fossilization. The presence of ghost biostromes with a burrowed, open parautochthonous rudist fabric indicates that the final preservation of a rudist biostrome was directly influenced by the characteristics of the biocoenosis, including unpreserved burrowing taxa. Rudist biostromes may be of markedly different taphonomy as a result of the taxonomic composition of the entire assemblage and the density of colonization by the rudists.  相似文献   

16.
Genetic variation within the North African toad Bufo mauritanicus was estimated by sequencing partial 12S rRNA and 16S rRNA mitochondrial regions from widespread populations in Morocco, Algeria and Tunisia. Unlike many other wide ranging species from this area, B. mauritanicus demonstrated very low levels of intraspecific variation. The minimal intraspecific genetic variation may be due to a relatively recent, possibly post-glacial, expansion into its current range. Further phylogeographic studies of other North African species are needed to assess if this is a common biogeographical phenomenon. Phylogenetic analyses support immunological data that B. mauritanicus is part of a clade of predominantly sub-Saharan Bufo, recently assigned to a new genus Amietophrynus. Two different lineages within this clade, B. mauritanicus and the B. pardalis group, appear to have reverted from 20 chromosomes to the more typical 22 chromosomes found in most other Bufonids. However, the alternative hypothesis that the Bufo species with 20 chromosomes form a monophyletic lineage cannot be rejected.  相似文献   

17.
Mauremys leprosa, distributed in Iberia and North‐west Africa, contains two major clades of mtDNA haplotypes. Clade A occurs in Portugal, Spain and Morocco north of the Atlas Mountains. Clade B occurs south of the Atlas Mountains in Morocco and north of the Atlas Mountains in eastern Algeria and Tunisia. However, we recorded a single individual containing a clade B haplotype in Morocco from north of the Atlas Mountains. This could indicate gene flow between both clades. The phylogenetically most distinct clade A haplotypes are confined to Morocco, suggesting both clades originated in North Africa. Extensive diversity within clade A in south‐western Iberia argues for a glacial refuge located there. Other regions of the Iberian Peninsula, displaying distinctly lower haplotype diversities, were recolonized from within south‐western Iberia. Most populations in Portugal, Spain and northern Morocco contain the most common clade A haplotype, indicating dispersal from the south‐western Iberian refuge, gene flow across the Strait of Gibraltar, and reinvasion of Morocco by terrapins originating in south‐western Iberia. This hypothesis is consistent with demographic analyses, suggesting rapid clade A population increase while clade B is represented by stationary, fragmented populations. We recommend the eight, morphologically weakly diagnosable, subspecies of M. leprosa be reduced to two, reflecting major mtDNA clades: Mauremys l. leprosa (Iberian Peninsula and northern Morocco) and M. l. saharica (southern Morocco, eastern Algeria and Tunisia). Peripheral populations could play an important role in evolution of M. leprosa because we found endemic haplotypes in populations along the northern and southern range borders. Previous investigations in another western Palearctic freshwater turtle (Emys orbicularis) discovered similar differentiation of peripheral populations, and phylogeographies of Emys orbicularis and Mauremys rivulata underline the barrier status of mountain chains, in contrast to sea straits, suggesting common patterns for western Palearctic freshwater turtles.  相似文献   

18.
Rhynchosauria was an important clade of herbivorous archosauromorph reptiles during the Triassic, with a worldwide distribution. We describe a new genus and species of early rhynchosaur, E ohyosaurus wolvaardti gen. et sp. nov. , from the early Middle Triassic (early Anisian) Cynognathus Assemblage Zone (Subzone B) of the Karoo Supergroup, South Africa. Eohyosaurus wolvaardti is known from a single skull, and is recovered as the sister taxon of Rhynchosauridae in a new phylogenetic analysis. Cynognathus Subzone B has previously yielded the stratigraphically oldest well‐understood rhynchosaur species, Mesosuchus browni and Howesia browni. Eohyosaurus wolvaardti increases the rhynchosaur diversity within this stratigraphical horizon to three species. Intriguingly, all currently confirmed rhynchosaur occurrences from the Early Triassic to earliest Middle Triassic are from South Africa. This may suggest a relatively restricted palaeogeographical distribution for early rhynchosaurs, followed by a global dispersal of rhynchosaurids during the Middle Triassic. © 2015 The Linnean Society of London  相似文献   

19.
Aim To investigate the impact of past environmental changes on Cedrus atlantica and its current genetic diversity, and to predict its future distribution. Location Morocco, Algeria and Tunisia. Methods Eleven fossil pollen records from these three countries were used to locate putative glacial refugia and to reconstruct past climate changes. A mechanistic vegetation distribution model was used to simulate the distribution of C. atlantica in the year 2100. In addition, a genetic survey was carried out on modern Moroccan C. atlantica. Results Pollen records indicate that Cedrus was present during the last glacial period, probably in scattered refugia, in Tunisia, Algeria and Morocco. In the Tunisian and Algerian sites, cedar expanded during the late glacial and the early Holocene, then disappeared after c. 8000 yr bp . Reconstructed mean annual precipitation and January temperature show that the last glacial period in Morocco was cooler by 10–15°C and drier by c. 300–400 mm year?1 than the climate today. Modern chloroplast microsatellites of 15 C. atlantica populations in Morocco confirm the presence of multiple refugia and indicate that cedar recolonized the Moroccan mountains fairly recently. Model simulation indicates that by the year 2100 the potential distribution of C. atlantica will be much restricted with a potential survival area located in the High Atlas. Main conclusions Environmental changes in northern Africa since the last glacial period have had an impact on the geographical distribution of C. atlantica and on its modern genetic diversity. It is possible that by the end of this century C. atlantica may be unable to survive in its present‐day locations. To preserve the species, we suggest that seedlings from modern C. atlantica populations located in the High Atlas mountains, where a high genetic diversity is found, be transplanted into the western High Atlas.  相似文献   

20.
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