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1.
New remains of Eremotherium were recovered from the Pacific coast of Ecuador’s Manabi province. The Machalilla fossiliferous locality records the northernmost presence of Eremotherium along the Pacific coast of South America. Most of the fossil remains belong to the same individual, mainly its posterior half, but other individuals are represented. Among the better-preserved specimens are skull fragments, most of the hind limb bones and a number of trunk and caudal centra. These remains were compared with samples collected during the 20th century along the southern coastal regions of Ecuador and northern Peru. Many characters of the long bones and tarsals testify to a possibly different lineage despite the closeness of other Eremotherium populations. Some metric and morphological aspects suggest a different space-temporal southern Caribbean provenance. Other Eremotherium specimens, coming from other Ecuadorian localities, were studied and compared with classic Eremotherium samples. Interesting morpho-functional aspects are pointed out with regard to the tail and its importance in the bipedal stance.  相似文献   

2.
The taxonomy and stratigraphic location of new remains of an ancient whale (Basilosaurus) discovered on the western coast of the Tsymlyansk water reservoir are considered. The Kharkov Formation deposits containing these remains are described, and their age is substantiated. The Basilosaurus remains discovered in the Lower Don area indicate that in the Late Eocene the ocean covered the southern part of the Russian Platform almost entirely.  相似文献   

3.
We describe a large collection of fossil ‘waterfowl’ bones that are referable to the extinct clade Presbyornithidae (Anseriformes). All of these fossils were collected between 1971 and 1994 from Upper Paleocene and Lower Eocene sediments at the Tsagaan Khushuu site in the Gobi Desert of southern Mongolia. The collection includes specimens referred to a new small species within the genus Presbyornis Wetmore, 1926 as well as large numbers of bones that we place in the genus Presbyornis. On this basis of the Tsagaan Khushuu collection we suggest that several species of Presbyornis likely coexisted in this region; indeed, the presence of large numbers of middle‐sized, morphologically consistent but probably ecologically disparate species at the Tsagaan Khushuu site is consistent with the range of variation seen, for example, in taxa of extant dabbling ducks (Anatini). Although the anatomy and phylogenetic position of Presbyornithidae (in particular Presbyornis) are well known, this material from Mongolia further demonstrates the prevalence of these birds in aquatic and semi‐aquatic habitats by the earliest Paleogene. Because presbyornithids are also well documented from the late Cretaceous, their palaeoecology and morphological diversity provides a clue to selective avian survivorship across the Cretaceous‐Paleogene (K‐Pg) boundary. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

4.
An isotopic investigation of upper Pleistocene mammal bones and teeth from Scladina cave (Sclayn, Belgium) demonstrated the very good quality of collagen preservation. A preliminary screening of the samples used the amount of nitrogen in whole bone and dentine in order to estimate the preserved amount of collagen before starting the extraction process. The isotopic abundances of fossil specimens from still-extant species are consistent with their trophic position. Moreover, the15N isotopic abundance is higher in dentine than in bone in bears and hyenas, a phenomenon already observed in modern specimens. These results demonstrate that the isotopic compositions of samples from Scladina cave can be interpreted in ecological terms. Mammoths exhibit a high15N isotopic abundance relative to other herbivores, as was the case in Siberian and Alaskan samples. These results suggest distinctive dietary adaptations in herbivores living in the mammoth steppe. Cave bears are clearly isotopically different from coeval brown bears, suggesting an ecological separation between species, with a pure vegetarian diet for cave bear and an omnivorous diet for brown bear.  相似文献   

5.
Univariate and multivariate statistics were applied to analyse the morphometrical variability of 4920 upper cheek teeth (P4, M1 and M2) of cave bears from 123 geographical sites (180 samples) of different Pliocene – Pleistocene ages. The analysed specimens included those belonging to the big cave bears Ursus kudarensis, U. deningeri, U. spelaeus (three subspecies) and U. kanivetz (including U. ingressus), as well as the small cave bear U. rossicus. The information‐theoretical parameters (Shannon entropy and orderliness (Von Foerster, 1960: On self‐organizing systems and their environments. In Self‐Organizing Systems, 31–50. Pergamon Press, London) were used to estimate tooth diversity in different teeth, different taxa and in selected local chrono‐populations. Multivariate allometry coefficients (Klingenberg, 1996: Multivariate allometry. In Advances in Morphometrics, 23‐49. Plenum Press, New York) were used to describe the relationships of different ‘parts’ of a tooth and to compare allometric patterns amongst species or selected local samples. A multivariate analysis showed a significant overlap of the size/shape parameter ranges in deningeroid and spelaeoid bears within morphological spaces. Within the cave bear lineage, the Deninger's bear has the greatest morphological diversity index (entropy) of all the teeth overall, and the lowest diversity is observed in the final taxon of this lineage – U. kanivetz (=ingressus). The P4 and M2 diversity showed multidirectional correlations with elevation above sea level amongst several ‘local’ populations of Late Pleistocene cave bears. The morphological disparities between the studied taxa are in close agreement with the distances in the available schemes of genetic differentiation based on ancient mitochondrial DNA. The split of U. kudarensis and U. deningeri has a good bootstrap support, which corresponds to the hypothesis about their parallel evolution. The small cave bear U. rossicus is placed between U. arctos and U. deningeri. The phylogenetic signal is more pronounced in the variability of teeth in comparison with other skeletal remains of cave bears (cranium, mandible, or metapodial bones).  相似文献   

6.
X-ray tomography is used to analyse the grain size and sedimentary fabric of two tsunami deposits in the Marquesas Islands (French Polynesia, Pacific Ocean) which are particularly exposed to trans-Pacific tsunamis. One site is located on the southern coast of Nuku Hiva Island (Hooumi) and the other one is on the southern coast of Hiva Oa Island (Tahauku). Results are compared with other techniques such as two-dimensional image analysis on bulk samples (particle analyser) and anisotropy of magnetic susceptibility. The sedimentary fabric is characterized through three-dimensional stacks of horizontal slices (following a vertical step of 2·5 mm along the cores), while grain-size distribution is estimated from two-dimensional vertical slices (following a step of 2 mm). Four types of fabric are distinguished: (a) moderate to high angle (15 to 75°); (b) bimodal low-angle (<15°); (c) low to high angle with at least two different orientations; and (d) dispersed fabric. The fabric geometry in a tsunami deposit is not only controlled by the characteristics of the flow itself (current strength, flow regime, etc.) but also sediment concentration, deposition rate and grain-size distribution. There is a notable correlation between unimodal high-angle fabric – type (a) – and finely-skewed grain-size distribution. The two tsunami deposits studied represent two different scenarios of inundation. As demonstrated here, X-ray tomography is an essential method for characterizing past tsunamis from their deposits. The method can be applied to many other types of sediments and sedimentary rocks.  相似文献   

7.
The small, burrowing, edwardsiid sea anemone Nematostella vectensis is widely distributed in estuaries and bays. Most typically it occurs in pools in marshes though it may occur subtidally as well. We have compiled records of its occurrence in North America from Nova Scotia to Georgia along the shores of the Atlantic Ocean, from Florida to Louisiana in the Gulf of Mexico and from California to Washington on the Pacific coast. To date we have found no records of its presence in Alabama or Texas, though it is present in all other of the contiguous coastal states of the United States. The species also occurs in England. We have obtained living specimens from many locations and have crossed females from England, Maryland, Georgia, California, Oregon, and Washington with males from Nova Scotia, Maryland, Georgia, and Oregon. These 24 crosses all yielded viable first-generation anemones that in turn produced second-generation animals. We accept this as proof that this widely distributed anemone is a single species. We have obtained living N. vectensis from 11 areas. Of these, only samples from Maine, Maryland, Georgia, and Oregon contained both sexes. The sample from Nova Scotia was all male and our samples from England, New Hampshire, California, and Washington were all female. We hypothesize that the unisexual samples were from clones resulting from asexual reproduction in this species. *** DIRECT SUPPORT *** A01BY066 00015  相似文献   

8.
A Late Eocene foraminiferal fauna of free specimens is recorded from Cascade Seamount, a feature of volcanic origin, whose age and fauna were previously studied only in thin section. The fauna is of Late Eocene (P15) age because of the presence of Globigerapsis index, Globigerapsis rubriformis, Subbotina linaperta, Subbotina angiporoides and Chiloguembelina cubensis. Many typical Eocene indicators, such as Hantkenina, Pseudohastigerina and key globorotaliids, are absent. The age is a little older than that estimated for previous samples from the seamount. The fauna is dominated (78%) by benthic species, especially species of Cibicides that have greater affinities with New Zealand faunas than with coeval southern Australian faunas. The sediment and its fauna accumulated near the lower limits of wave activity, off the coast of a volcano that probably stood at least 400 m above sea level. The location has subsided nearly 1000 m over the past 40 million years to its present water depth of 1000 m, suggesting that the entire East Tasman Plateau was approximately 1000 m above its current depth at the time. Conditions were cool temperate and the fauna lacks any warm water indices, consistent with a palaeolatitude of 55–60°S, but also with cool waters at a time of oscillating conditions in southern Australia and also in Antarctica. There is essentially no infauna and the waters were highly oxygenated in the turbulent zone.  相似文献   

9.
Bone remains and a trackway of Pantheraichnus bottropensis nov. ichg. ichnsp. of the Late Pleistocene lion Panthera leo spelaea (Goldfuss, 1810) have been recovered from Bottrop and other open air sites in northern Germany. Some of these bones are from open air hyena den sites. A relative high proportion of lion bones (20%) exhibit bite, chew or nibble marks, or bone crushing and nibbling caused by a large carnivore. Repeated patterns of similar bone damage have been compared to bone remains found at hyena dens in gypsum karst areas and cave sites in northern Germany. Ice Age spotted hyenas have been the main antagonists and the main scavengers on lion carcasses. The remains appear to have been imported often by hyenas into their communal dens, supporting the theory of strong hyena-lion antagonism, similar to the well documented antagonism between modern African lions and spotted hyenas. Most of the lion bones from the open air hyena den at Bottrop are probably a result of such antagonism, as are the rare remains of these carnivores found within large hyena prey bone accumulations along the Pleistocene rivers. The Emscher River terrace also has the largest quantity of hyena remains from open air river terrace sites in northern Germany. Their cub remains, and incomplete chewed prey bones from mammoths and woolly rhinoceroses, typical of hyena activity, underline the character of these sites as cub-raising and communal dens, where their prey was accumulated along the riverbanks in a similar manner to modern African hyenas.  相似文献   

10.
The late Quaternary stratigraphy and geochronology of San Mateo and Las Flores Creeks indicates that both streams, which drain into the Pacific Ocean along the southern California coast, had a synchronous landscape history. Both San Mateo and Las Flores Creeks cut deep valleys during the late Pleistocene in response to the worldwide drop in sea level. A long period of aggradation followed as sea level rose to its present position during the late Pleistocene and Holocene. Around 500 years ago, the channels of both streams downcut into their respective floodplains creating a prominent terrace (T-2). This was followed by renewed deposition and later channel incision which created a second terrace (T-1). These channel changes are probably the result of a complex response of the fluvial system to major flooding during the late Holocene. The geologic history of these drainages provides a framework that can be used to assess the buried archaeological record along the coast and evaluate regional prehistoric settlement patterns. Based on this study, the post-4000 B.P. valley floor archaeological record along the southern California coast will be more complete and accessible, resulting in a better understanding of the spatial distribution of sites. On the other hand, the pre-4000 B.P. valley floor record lies deeply buried and inaccessible to researchers, which results in a distortion of settlement patterns before 4000 B.P. Finally, examination of post-4000 B.P. sites in the alluvium of San Mateo and Las Flores creeks yielded a pattern of large sites that were occupied extensively for multiple seasons and had considerable evidence of marine exploitation. These findings are contrary to models of cultural development along this portion of the southern California coast. © 1999 John Wiley & Sons, Inc.  相似文献   

11.
A previously uncollected fauna of ammonites, bivalves, and other molluscs, associated with radiolarian microfossils, has been newly recognized near Lawn Hill on the east coast of central Queen Charlotte Islands, British Columbia. The regional biostratigraphic zonation indicates that the Lawn Hill fauna is correlative with the Nostoceras hornbyense zonule of the Pachydiscus suciaensis ammonite biozone, recognized in the Nanaimo Group of southeast Vancouver Island. The Nostoceras hornbyense Zone (new) is herein proposed for strata of Pacific coast Canada containing the zonal index. Several molluscan taxa present in the Lawn Hill section are new to British Columbia and the ammonite fauna suggests that the Nostoceras hornbyense Zone is late Campanian in age, supported by radiolarian taxa present in the section. Strata sampled in the Lawn Hill section preserve reversed-polarity magnetization, considered likely correlative with Chron 32r. The presence of the Nostoceras hornbyense Zone on Queen Charlotte Islands is the first recognition of this zone in Canada north of central Vancouver Island and represents the youngest Cretaceous known in this region. Campanian radiolarians identified from the Lawn Hill section are also the first recognized from the Pacific coast of Canada.  相似文献   

12.
This paper presents the study and palaeoecological analysis of fossil fish vertebrae of the Arbreda Cave (Serinyà, Girona), probably the most significant Catalan palaeolithic site. Morphological and radiographical studies were used to identify vertebrae to genus and, whenever possible, to species level. The taxa identified are: Anguilla anguilla, Barbussp., Leuciscussp., Rutilus sp., Salmo salar, Salmo trutta and Salmo sp. Species distribution at various archaeological levels provided palaeoecological data. There is a high proportion of Salmo trutta remains in the Upper Gravettian level and a sudden decrease of fossil fish bones in the Solutrean level with shouldered points. This decrease coincides with the period of lower temperatures of the Late Pleniglacial. Finally, the post-glacial terra rossa level is characterised by the absence of Salmo trutta remains. The presence of Salmo salar in Mediterranean sites has often been discussed. However, the dating of remains of this Atlantic species found in the Arbreda Cave makes it likely that these specimens were caught in Atlantic rivers on the northern Pyrennean slope and then transported to the area studied. © 1997 John Wiley and Sons, Ltd.  相似文献   

13.
Tsunamis have proven to represent a significant hazard around the globe and there is increased awareness about their occurrence. The Pacific coast in southern México is no exception, because there is firm evidence of the effects of past large tsunamis. Here we present results from computer-aided modeling of the March 28, 1787-“San Sixto” earthquake and tsunami, and focus on the regions of Acapulco, Corralero, Jamiltepec, and Tehuantepec, located along the Guerrero-Oaxaca coast. The theoretical waveforms suggest wave heights in excess of 4 m and 18 m at specific locations in Acapulco and Corralero, respectively, and wave heights of at least 2 m at locations in Jamiltepec and Tehuantepec. From our modeling results and based on historical documents and the topography of the area, we conclude that these wave heights would have been sufficient to cause inundations that in the case of Acapulco were restricted to several meters inland, but in other areas like Corralero reached at least 6 km inland. Our results are consistent with published and unpublished damage reports that attest to the hazards associated with great earthquakes and tsunamis along the subduction zone in Mexico  相似文献   

14.
Tree-ring records from western juniper (Juniperus occidentalis var. occidentalis Hook.) growing throughout the interior Pacific Northwest identify extreme climatic pointer years (CPYs) (i.e., severe single-year droughts) from 1500–1998. Widespread and extreme CPYs were concentrated in the 16th and early part of the 17th centuries and did not occur again until the early 20th century. The 217-yr absence of extreme CPYs may have occurred during an extended period of low variance in the Pacific Decadal Oscillation. We mapped climatic boundaries for the interior Pacific Northwest based on the location of sites with similar precipitation variability indices. Three regions, the Northwest (based on chronologies from nine sites), the Southwest (four sites), and the East (five sites) were identified. Our results suggest that western juniper radial growth indices have substantial interannual variability within the northwestern range of the species (central Oregon), particularly when compared with western juniper growing in its eastern range (eastern Oregon, southeastern Idaho, and northern Nevada) and southwestern range (southern Oregon and northeast California). We suspect that the substantial differences in the variability of western juniper radial growth indices are linked to the influence of ENSO events on winter/spring precipitation amounts.  相似文献   

15.
In the summer of 1960, mammoth bones were discovered by a dragline operator in southern Wyoming at the Union Pacific (U.P.) Mammoth site. Although subsequent archaeological work during 1960 and 1961 identified artifacts in association with the mammoth remains, many authors have since questioned the nature of that association. Also, little has been published about the site other than a brief article in National Geographic Magazine in 1962. In this paper, we present additional information on the U.P. Mammoth site including stratigraphic profiles from the first author's geoarchaeological work in 1961, stratigraphic and spatial location of bones and artifacts derived from the original field notes, and new radiocarbon dates. Although the precise stratigraphic provenance for many artifacts and skeletal elements remains unclear, a compelling argument can be made for spatial and stratigraphic association of the mammoth remains with the artifact assemblage suggesting some kind of human interaction with the animal.  相似文献   

16.
Intestinal samples from the one-month-old Siberian mammoth calf ‘Lyuba’ were studied using light microscopy and ancient DNA to reconstruct its palaeo-environment and diet. The palynological record indicates a ‘mammoth steppe’. At least some pollen of arboreal taxa was reworked, and thus the presence of trees on the landscape is uncertain. In addition to visual comparison of 11 microfossil spectra, a PCA analysis contributed to diet reconstruction. This yielded two clusters: one of samples from the small intestine and the other of large-intestine samples, indicating compositional differences in food remains along the intestinal tract, possibly reflecting different episodes of ingestion. Based on observed morphological damage we conclude that the cyperaceous plant remains and some remains of dwarf willows were originally eaten by a mature mammoth, most likely Lyuba’s mother. The mammoth calf probably unintentionally swallowed well-preserved mosses and mineral particles while eating fecal material deposited on a soil surface covered with mosses. Coprophagy may have been a common habit for mammoths, and we therefore propose that fecal material should not be used to infer season of death of mammoths. DNA sequences of trnL and rbcL genes amplified from ancient DNA extracted from intestinal samples confirmed and supplemented plant identifications based on microfossils and macro-remains. Results from different extraction methods and barcoding markers complemented each other and show the value of longer protocols in addition to fast and commercially available extraction kits.  相似文献   

17.
Along the south coast of Ireland, a shelly diamict facies, the Irish Sea Till, has been variously ascribed to subglacial deposition by a grounded Irish Sea glacier or to glacimarine sedimentation by suspension settling and iceberg rafting. Observations are presented here from five sites along the south coast to directly address this question. At these sites, sedimentary evidence is preserved for the onshore advance of a grounded Irish Sea glacier, which glacitectonically disturbed and eroded pre‐existing sediments and redeposited them as deformation till. Recession of this Irish Sea glacier resulted in the damming of ice‐marginal lakes in embayments along the south coast, into which glacilacustrine sedimentation then took place. These lake sediments were subsequently glacitectonised and reworked by overriding glacier ice of inland origin, which deposited deformation till on top of the succession. There is no evidence for deposition of the Irish Sea diamicts by glacimarine sedimentation at these sites. The widespread development of subglacial deforming bed conditions reflected the abundance of fine‐grained marine and lacustrine sediments available for subglacial erosion and reworking. Stratigraphical and chronological data suggest that the advance of a grounded Irish Sea glacier along the south coast occurred during the last glaciation, and this is regionally consistent with marine geological data from the Celtic Sea. These observations demonstrate extension of glacier ice far beyond its traditional limits in the Celtic Sea and on‐land in southern Ireland during the last glaciation, and remove the stratigraphical basis for chronological differentiation of surficial glacial drifts, and thus the Munsterian Glaciation, in southern Ireland. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   

18.
We describe isolated shark teeth collected from levels of the Calafate Formation at the SE coast of the Argentino Lake, Calafate city, Santa Cruz province, Argentina (Atlantic Ocean), and from the Algarrobo coast at the Valparaíso Region in central Chile (Pacific Ocean). The teeth belong to a new species of the echinorhiniform genus Echinorhinus. Echinorhinus maremagnum n. sp. was a taxon distributed in both the southwestern Atlantic and the southeastern Pacific. This new taxon constitutes the oldest record of echinorhiniforms from South America and one of the few Mesozoic records at a worldwide scale.  相似文献   

19.
Geochemical works were conducted on anthropogenically effective lithologic unit exposing along the Susanoglu coast in Mersin, Turkey. For this purpose, beach sand sediments from 33 stations were collected and heavy metal and oxide concentrations were analyzed. To determine the source of heavy metals (natural and anthropogenic), simple and multivariate statistical analyses were applied. According to factor analysis, three factors were determined. The first factor consists of SiO2, Al2O3, Na2O, K2O, TiO2, Cr, Ni, Cu and Mo and total variance is explained with 27.502% and expressed as “natural process factor”. These elements (Cr, Ni, Cu, Mo) are closely associated with geogenic materials and came from same sources of ultrabasic rocks (ophiolite). The second factor consists of CaO, MgO, TiO2, MnO, Ni, Pb, Zn and W and total variance is explained with 21.505% and expressed as “anthropogenic factor”. These elements (Pb, Zn, Cd, V, W) are anthropogenic and are mainly due to the effluent or industrial input/activities and came from different sources of pollution in the study area. The third factor consists of Pb, Cd and Sb and total variance is explained with 9.748% and expressed as “intermediate factor”. The factor analysis and the cluster analysis are in support of each other. Cr, Ni, Co, Cd, Hg and Mo concentrations are greater than Turkish acceptable values and they show toxic effect. Al, Cu, Pb, Cd and Mo concentrations in beach sand deposits in the Susanoglu coast are found as 1.44, 1.26, 1.21, 1.02 and 1.04 mg/kg and higher than those in Kızkalesi beach sands. However, all other heavy metal contents are determined in low concentrations.  相似文献   

20.
Canary rockfish are one of the commercially important rockfish species along the US Pacific coast. Yet little is known about their life history and stock structure. In this study 120 canary rockfish otoliths were collected from waters off the Washington and Oregon coast and subjected to stable O and C isotope (δ18O and δ13C) analyses. One powder sample was taken from the nucleus of each otolith, and the other from the 5th annual ring. Data from otolith nuclei can provide information on the natal sources and spawning stock separations, while data from age-1 to age-5 may indicate changes in fish habitat. Overall the δ18O values in otoliths of canary rockfish ranged from −0.2‰ to +1.7‰, whereas δ13C values of the same samples ranged from −5.4‰ to −1.4‰. The isotopic data and correlation of δ18O versus δ13C did not show clear separation between Washington and Oregon samples, similar to those for a previous study on yelloweye rockfish from the same region. These results suggest that canary rockfish may belong to a single spawning stock or population along the Washington and Oregon coast.  相似文献   

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