scholarly journals The forelimb of †Cyonasua sp. (Procyonidae, Carnivora): ecomorphological interpretation in the context of carnivorans

2015 ◽  
Vol 106 (4) ◽  
pp. 325-335 ◽  
Author(s):  
J. Tarquini ◽  
N. Toledo ◽  
C. C. Morgan ◽  
L. H. Soibelzon
Keyword(s):  
Elbow Joint ◽  
Principal Component ◽  
Substrate Preference ◽  
Early Pleistocene ◽  
Pectoral Girdle ◽  
Linear Measurements ◽  
Late Pliocene ◽  
Morphological Adaptations ◽  
Locomotory Mode ◽  
Palaeoenvironmental Conditions

ABSTRACTThe procyonid †Cyonasua is endemic to South America and recorded from the Late Miocene to the Early Pleistocene. This paper studies the forelimb of †Cyonasua sp. (late Pliocene of Miramar, Argentina), using an ecomorphological approach to infer morphological adaptations linked to substrate preference and locomotory mode, as well as to grasping and digging ability. Twenty linear measurements of forelimb and pectoral girdle were taken from †Cyonasua sp. and a sample of 87 specimens of extant carnivoran families (Procyonidae, Mustelidae, Ursidae, Viverridae, Canidae and Felidae). Raw values were transformed to minimise the effect of size. Morphological variation was explored by principal component analysis (PCA); substrate preference and locomotory mode were further analysed by multivariate analysis of variance (MAV) and discriminant analysis (DA); grasping and digging ability were analysed by DA. In the PCA morphospace, †Cyonasua sp. occupied a unique position, close to extant procyonids. DA classified it as non-specialised digger with poor grasping ability. The results lead to the interpretation of †Cyonasua sp. as having a moderately stabilised elbow joint with poor pronation–supination, although some climbing skills cannot be ruled out. Thus, †Cyonasua sp. could have had generalised habits, in agreement with reconstructed palaeoenvironmental conditions.

scholarly journals Millennial-scale climate change and oceanic processes in the Late Pliocene and Early Pleistocene

2001 ◽  
Vol 16 (5) ◽  
pp. 535-543 ◽  
Author(s):  
Katherine Mc Intyre ◽  
Margaret L. Delaney ◽  
A. Christina Ravelo
Keyword(s):  
Climate Change ◽  
Early Pleistocene ◽  
Late Pliocene ◽  
Millennial Scale

scholarly journals Khorbas: a Lower Palaeolithic site on Qeshm Island in the Persian Gulf

Antiquity ◽  
2017 ◽  
Vol 91 (358) ◽  
Author(s):  
Sirvan Mohammadi Ghasrian
Keyword(s):  
Persian Gulf ◽  
Early Pleistocene ◽  
Fars Province ◽  
Potential Importance ◽  
Zagros Mountains ◽  
The West ◽  
Qeshm Island ◽  
Late Pliocene ◽  
The Persian Gulf ◽  
Lower Palaeolithic

Despite the potential importance of southern Iran, and the Persian Gulf area in particular, for discussions on the dispersal of early hominins from Africa into Eurasia during the late Pliocene and early Pleistocene (Bar-Yosef & Belfer-Cohen 2001; Rose 2010), this area has remained almost unexplored until recently. Historically, Palaeolithic survey and excavations in Iran have mainly concentrated in western regions, especially the Zagros Mountains. As a result of recent studies, however, evidence for Palaeolithic sites in the southern regions of Iran, from Fars province to Qeshm Island, has greatly increased (Dashtizade 2009, 2010). Even with this improvement, no sites of Lower Palaeolithic date have yet been reported from the southern coastal areas on one of the proposed early hominin routes into Eurasia. As a result, it has been suggested that the few Lower Palaeolithic sites reported from other parts of Iran, especially in the west (e.g. Biglari & Shidrang 2006), were not populated from the south.

scholarly journals Contribution of changes in opal productivity and nutrient distribution in the coastal upwelling systems to Late Pliocene/Early Pleistocene climate cooling

2012 ◽  
Vol 8 (5) ◽  
pp. 1435-1445 ◽  
Author(s):  
J. Etourneau ◽  
C. Ehlert ◽  
M. Frank ◽  
P. Martinez ◽  
R. Schneider
Keyword(s):  
Southern Ocean ◽  
Coastal Upwelling ◽  
Atmospheric Co2 ◽  
Early Pleistocene ◽  
Silicon Isotope ◽  
Time Interval ◽  
Nutrient Distribution ◽  
Biogenic Opal ◽  
Late Pliocene ◽  
Polar Ocean

Abstract. The global Late Pliocene/Early Pleistocene cooling (~3.0–2.0 million years ago – Ma) concurred with extremely high diatom and biogenic opal production in most of the major coastal upwelling regions. This phenomenon was particularly pronounced in the Benguela upwelling system (BUS), off Namibia, where it is known as the Matuyama Diatom Maximum (MDM). Our study focuses on a new diatom silicon isotope (δ30Si) record covering the MDM in the BUS. Unexpectedly, the variations in δ30Si signal follow biogenic opal content, whereby the highest δ30Si values correspond to the highest biogenic opal content. We interpret the higher δ30Si values during the MDM as a result of a stronger degree of silicate utilisation in the surface waters caused by high productivity of mat-forming diatom species. This was most likely promoted by weak upwelling intensity dominating the BUS during the Late Pliocene/Early Pleistocene cooling combined with a large silicate supply derived from a strong Southern Ocean nutrient leakage responding to the expansion of Antarctic ice cover and the resulting stratification of the polar ocean 3.0–2.7 Ma ago. A similar scenario is hypothesized for other major coastal upwelling systems (e.g. off California) during this time interval, suggesting that the efficiency of the biological carbon pump was probably sufficiently enhanced in these regions during the MDM to have significantly increased the transport of atmospheric CO2 to the deep ocean. In addition, the coeval extension of the area of surface water stratification in both the Southern Ocean and the North Pacific, which decreased CO2 release to the atmosphere, led to further enhanced atmospheric CO2 drawn-down and thus contributed significantly to Late Pliocene/Early Pleistocene cooling.

scholarly journals Angular and linear measurements of adult flexible flatfoot via weight-bearing CT scans and 3D bone reconstruction tools

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Maurizio Ortolani ◽  
Alberto Leardini ◽  
Chiara Pavani ◽  
Silvia Scicolone ◽  
Mauro Girolami ◽  
...  
Keyword(s):  
Reference Frames ◽  
Weight Bearing ◽  
Principal Component ◽  
Longitudinal Axis ◽  
3D Models ◽  
Shape Reconstruction ◽  
Skeletal Structure ◽  
Foot Deformities ◽  
Foot And Ankle ◽  
Linear Measurements

AbstractAcquired adult flatfoot is a frequent deformity which implies multiple, complex and combined 3D modifications of the foot skeletal structure. The difficult thorough evaluation of the degree of severity pre-op and the corresponding assessment post-op can now be overcome by cone-beam (CBCT) technology, which can provide access to the 3D skeletal structure in weight-bearing. This study aims to report flatfoot deformities originally in 3D and in weight-bearing, with measurements taken using two different bone segmentation techniques. 21 such patients, with indication for surgical corrections, underwent CBCT (Carestream, US) while standing on one leg. From these scans, 3D models of each bone of the foot were reconstructed by using two different state-of-the-art segmentation tools: a semi-automatic (Mimics Innovation Suite, Materialise, Belgium), and an automatic (Bonelogic Ortho Foot and Ankle, Disior, Finland). From both reconstructed models, Principal Component Analysis was used to define anatomical reference frames, and original foot and ankle angles and other parameters were calculated mostly based on the longitudinal axis of the bones, in anatomical plane projections and in 3D. Both bone model reconstructions revealed a considerable valgus of the calcareous, plantarflexion and internal rotation of the talus, and typical Meary’s angles in the lateral and transverse plane projections. The mean difference from these angles between semi-automatic and automatic segmentations was larger than 3.5 degrees for only 3 of the 32 measurements, and a large number of these differences were not statistically significant. CBCT and the present techniques for bone shape reconstruction finally provide a novel and valuable 3D assessment of complex foot deformities in weight-bearing, eliminating previous limitations associated to unloaded feet and bidimensional measures. Corresponding measurements on the bone models from the two segmentation tools compared well. Other more representative measurements can be defined in the future using CBCT and these techniques.

scholarly journals Late Pliocene Cordilleran Ice Sheet development with warm northeast Pacific sea surface temperatures

2020 ◽  
Vol 16 (1) ◽  
pp. 299-313 ◽  
Author(s):  
Maria Luisa Sánchez-Montes ◽  
Erin L. McClymont ◽  
Jeremy M. Lloyd ◽  
Juliane Müller ◽  
Ellen A. Cowan ◽  
...  
Keyword(s):  
Ocean Circulation ◽  
Ice Sheet ◽  
Gulf Of Alaska ◽  
Sea Surface ◽  
Early Pleistocene ◽  
Late Pliocene ◽  
Subarctic Pacific ◽  
Cordilleran Ice Sheet ◽  
Forcing Mechanisms ◽  
Atmospheric Co2 Concentrations

Abstract. The initiation and evolution of the Cordilleran Ice Sheet are relatively poorly constrained. International Ocean Discovery Program (IODP) Expedition 341 recovered marine sediments at Site U1417 in the Gulf of Alaska (GOA). Here we present alkenone-derived sea surface temperature (SST) analyses alongside ice-rafted debris (IRD), terrigenous, and marine organic matter inputs to the GOA through the late Pliocene and early Pleistocene. The first IRD contribution from tidewater glaciers in southwest Alaska is recorded at 2.9 Ma, indicating that the Cordilleran Ice Sheet extent increased in the late Pliocene. A higher occurrence of IRD and higher sedimentation rates in the GOA during the early Pleistocene, at 2.5 Ma, occur in synchrony with SSTs warming on the order of 1 ∘C relative to the Pliocene. All records show a high degree of variability in the early Pleistocene, indicating highly efficient ocean–climate–ice interactions through warm SST–ocean evaporation–orographic precipitation–ice growth mechanisms. A climatic shift towards ocean circulation in the subarctic Pacific similar to the pattern observed during negative Pacific Decadal Oscillation (PDO) conditions today occurs with the development of more extensive Cordilleran glaciation and may have played a role through increased moisture supply to the subarctic Pacific. The drop in atmospheric CO2 concentrations since 2.8 Ma is suggested as one of the main forcing mechanisms driving the Cordilleran glaciation.

Davis Creek silt, an Early Pleistocene or Late Pliocene deposit in the Cypress Hills of Saskatchewan

1989 ◽  
Vol 26 (1) ◽  
pp. 192-198 ◽  
Author(s):  
W. J. Vreeken ◽  
R. W. Klassen ◽  
R. W. Barendregt
Keyword(s):  
Volcanic Ash ◽  
Magnetic Polarity ◽  
Polarity Reversal ◽  
Early Pleistocene ◽  
The South ◽  
Glacial Deposits ◽  
Late Pliocene ◽  
Late Wisconsinan ◽  
Weathering Zone ◽  
Magnetic Polarity Reversal

Davis Creek silt is the informal name for a previously unreported loess and its reworked detritus encountered at several locations to the south of the east and centre blocks of the Cypress Hills. This unit intervenes between a pediment with an estimated age of 10 Ma and Late Wisconsinan glacial deposits. Because the unit has reversed magnetization, it is older than 788 ka, the astronomical age of the Matuyama–Brunhes magnetic polarity reversal. The unit also contains an undated volcanic ash from the Pearlette ash family that could represent the Mesa Falls (1.27 Ma) or the Huckleberry Ridge (2.02 Ma) ash bed. Davis Creek silt overlies an oxidized weathering zone and contains large secondary carbonate nodules near its truncated top that were, in places, reworked into a lag deposit or stone line before accumulation of the glacial overburden. At one location Davis Creek silt is separated from this overburden by a unit of cryoturbated gravelly loam with remnants of a reddish-yellow paleosolic B horizon.

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