VERTEBRATE TAPHONOMY OF TWO UPPER MIOCENE BONEBEDS IN WESTERN PROTO-AMAZONIA (SOLIMÕES FORMATION, BRAZIL): INSIGHTS FROM MACROVERTEBRATE AND MICROVERTEBRATE FOSSILS

Palaios ◽  
2021 ◽  
Vol 36 (8) ◽  
pp. 269-282
Author(s):  
FELLIPE P. MUNIZ ◽  
MARCOS CÉSAR BISSARO-JÚNIOR ◽  
EDSON GUILHERME ◽  
JONAS PEREIRA DE SOUZA FILHO ◽  
FRANCISCO RICARDO NEGRI ◽  
...  
Keyword(s):  
Aquatic Environment ◽  
Local Community ◽  
Depositional Environments ◽  
Moderate Level ◽  
Time Averaging ◽  
Sedimentation Environment ◽  
Collecting Methods ◽  
Taphonomic Analysis ◽  
Paleoecological Reconstructions ◽  
Vertebrate Taphonomy

ABSTRACT The Niterói and Talismã sites comprise two of the most important fossiliferous deposits of the Neogene in Brazil. After 30 years of research, these sites have revealed rich assemblages of vertebrates and provided a glimpse of the Amazonian fauna and environment during the Miocene. Despite this, detailed studies that attempt to explain the genesis of these bonebeds are still scarce and hamper more robust paleoenvironmental and paleoecological reconstructions. Here we provide the first in-depth taphonomic analysis for both locations. Sedimentological and taphonomic evidence suggest that the depositional environments of Niterói and Talismã were similarly represented by shallow and calm waters in lacustrine/swampy contexts. We propose that the accumulation of bones and teeth is the result of attritional (day-to-day) mortality of organisms of the local community in a low sedimentation environment. The thanatocoenosis was exposed to biostratinomic processes for longer periods of time, which explains the high disarticulation, disassociation, fragmentation and loss of skeletal elements. The almost absence of weathering indicates that the aquatic environment slowed down the organic degradation of bioclasts, while the rarity of abrasion shows a limited influence of hydraulic flows in transporting and remobilizing bioclasts. Thus, both sites preserve mostly autochthonous to parautochthonous bioclasts, with a moderate level of time-averaging. Our results corroborate the hypothesis that lentic environments can present remarkable preservational conditions for the formation of attritional accumulations of vertebrate remains. Moreover, we show how the different collecting methods affect the description of preservational features and taphonomic interpretations of both fossil assemblages.

ECOLOGICAL AND TAPHONOMIC FIDELITY IN FOSSIL CRINOID ACCUMULATIONS

Palaios ◽  
2019 ◽  
Vol 34 (11) ◽  
pp. 575-583 ◽  
Author(s):  
DAVID L. MEYER ◽  
WILLIAM I. AUSICH
Keyword(s):  
Depositional Environments ◽  
Biological Processes ◽  
Post Mortem ◽  
Eastern Flank ◽  
South Central ◽  
Middle Mississippian ◽  
Symmetrical Distribution ◽  
Close Proximity ◽  
Marine Facies ◽  
Taphonomic Analysis

ABSTRACT Among fossiliferous marine facies, deposits rich in stalked echinoderms, particularly encrinites, have long been suspected to be susceptible to taphonomic biases because intact calyxes are under-represented or masked by disarticulated skeletal debris. In the middle Mississippian Fort Payne Formation of south-central Kentucky, penecontemporaneous crinoid-rich facies are exposed in close proximity along the shores of Lake Cumberland. Crinoidal packstone buildups preserve a broad preservational spectrum, with articulated crinoid calyxes with arms and columns attached, intact calyxes, holdfasts, and long articulated columns, in a matrix of entirely disarticulated crinoidal fragments. Along a 250 m transect across the flanks and crest of this buildup, identification of 563 specimens of crinoids and blastoids revealed a symmetrical distribution of taxa in which the crest was dominated by disparid and camerate crinoids and the flanks were dominated by camerates. Taphonomic analysis of the same transect showed that intact crinoid calyxes with or without attached arms and column occurred across the entire buildup, but nearly complete specimens with attached arms and column were most common on the western flank and less common on the crest and eastern flank. Taxonomic and taphonomic distributions demonstrate a primary ecologic zonation across the buildup with only localized post-mortem dispersal of crinoids. This is the first demonstration of primary ecologic zonation of a crinoid community preserved within a single lithofacies. Depending on depositional and taphonomic circumstances, crinoids are preserved intact close to their living site; understanding these physical and biological processes provides a significant feedback in reconstructing these ancient depositional environments.

VERTEBRATE TAPHONOMY, PALEONTOLOGY, SEDIMENTOLOGY, AND PALYNOLOGY OF A FOSSILIFEROUS LATE DEVONIAN FLUVIAL SUCCESSION, CATSKILL FORMATION, NORTH-CENTRAL PENNSYLVANIA, USA

Palaios ◽  
2020 ◽  
Vol 35 (11) ◽  
pp. 470-494
Author(s):  
DAVID R. BROUSSARD ◽  
CAYLA J. TREASTER ◽  
JEFFREY M. TROP ◽  
EDWARD B. DAESCHLER ◽  
PIERRE A. ZIPPI ◽  
...  
Keyword(s):  
Depositional Environments ◽  
Late Devonian ◽  
North Central ◽  
Central Pennsylvania ◽  
Bone Fragments ◽  
Bivalve Shell ◽  
Floodplain Deposits ◽  
Stratigraphic Succession ◽  
Channel Bar ◽  
Vertebrate Taphonomy

ABSTRACT The fluvial facies of the Catskill Formation record important ecological events that occurred during Late Devonian time. A well-exposed section between the towns of Blossburg and Covington, in north-central Pennsylvania, contains abundant macrofossils and sedimentary features, making it well-suited for linking Upper Devonian fossil occurrences with depositional environments and sedimentary processes. Strata consist of two distinct fluvial facies: floodplain lithofacies consist of mudrocks, with evidence of pedogenic overprinting and sharp-based sandstones interpreted as crevasse splays; channel-bar lithofacies consist of single- and multi-storied cross-stratified lenticular sandstone bodies interpreted as fluvial channel-bar complexes. Macrofossils occur in 22 discrete horizons spanning > 240 m of stratigraphic succession that include Archanodon bivalve shell impressions, two genera of “placoderms” (Bothriolepis, Phyllolepis), an unidentified acanthodian, and several taxa of sarcopterygian fishes, including lungfish (Dipnoi indet.), Holoptychius, Langlieria, and Sauripterus. Most vertebrate macrofossils are preserved as disarticulated, abraded plates, scales, and bone fragments in sandstone channel-bar deposits. Articulated, unabraded remains are preserved in proximal floodplain deposits. Miospores recovered from Catskill Formation fossil sites in the Blossburg-Covington section belong to the COR subzone of the VCo (Diducites versabilis-Grandispora cornuta) palynological zone, indicating deposition ca. 362 to 361.8 Ma during the late Famennian stage of the Late Devonian. Catskill Formation fluvial strata exposed tens of kilometers to the south and west yield latest Famennian palynomorphs. These broadly contemporaneous continental depositional environments supported Late Devonian vertebrate evolution, including the fin-to-limb transition in tetrapodomorphs, and the possible euryhalinity of vertebrates occupying marine-to-nonmarine transitional habitats.

scholarly journals Taphonomic analysis of saurischian dinosaurs from the Plottier Formation (Upper Cretaceous), Mendoza, Argentina

2019 ◽  
Vol 46 (2) ◽  
pp. 345 ◽  
Author(s):  
Elena Previtera
Keyword(s):  
Upper Cretaceous ◽  
Holistic Approach ◽  
Depositional Environments ◽  
Continental Deposits ◽  
Wide Range ◽  
History Of ◽  
Fossil Assemblages ◽  
Vertebrate Assemblage ◽  
Taphonomic Analysis ◽  
Fluvial Environments

The uppermost Cretaceous continental deposits of the Neuquén Basin (west-central Argentina) have yielded a high diversity vertebrate assemblage, including numerous dinosaur species. The Neuquén Group is the richest unit in remains of dinosaur of the basin and comprises the Río Limay, the Río Neuquén and the Río Colorado subgroups. In this group, there is abundance of isolated, disarticulated or partially articulated sauropods and theropods. However, little is known about the taphonomic history of fossil assemblages. In this study, dinosaur remains from the Plottier Formation (late Coniacian-early Santonian) found in the Cerro Guillermo area in southern Mendoza are examined. The investigation of fossil occurrences within the study area revealed the existence of different taphonomic modes, from isolated bones until partially articulated skeletons preserved in deposits of floodplain and fluvial channel settings. SEM-EDS analysis showed the substitution of hydroxyapatite by francolite in the bone microstructure. The presence of fluorine-in one of the cases-suggested a link between the elemental composition and depositional environments: floodplain and fluvial channel. The survey of the vertebrate accumulation types and their sedimentary context allowed documenting a wide range of processes responsible for their genesis, operating within a meandering fluvial environment. This contribution represents a holistic approach about taphonomic history of Cretaceous dinosaurs for assessing the differential preservation of fossil assemblages in fluvial environments.

Time-averaging and postmortem skeletal survival in benthic fossil assemblages: quantitative comparisons among Holocene environments

Paleobiology ◽  
1997 ◽  
Vol 23 (2) ◽  
pp. 207-229 ◽  
Author(s):  
Keith H. Meldahl ◽  
Karl W. Flessa ◽  
Alan H. Cutler
Keyword(s):  
Time Resolution ◽  
Gulf Of California ◽  
Tectonic Setting ◽  
Depositional Environments ◽  
Sediment Surface ◽  
Time Averaging ◽  
Benthic Assemblages ◽  
Shallow Marine ◽  
Carbonate Sedimentation ◽  
Fossil Assemblages

We used radiocarbon ages on dead Holocene shells of the venerid bivalveChionespp. to investigate how time-averaging and taphonomy in shallow marine benthic assemblages vary with sedimentary and tectonic setting. We compared shells collected from the sediment surface in five depositional environments from two regions of the Gulf of California, Mexico: Bahía Concepción, a young faulted rift basin with high rates of terrigenous and carbonate sedimentation; and Bahía la Choya, an intertidal system along a sediment-starved shelf. Frequency distributions of shell ages in all environments form a hollow curve, with a mode at young ages and a long tail toward older ages. This pattern suggests that shells are added to the taphonomically active zone (TAZ) at roughly constant rates (via continuous shell deaths), and removed from the TAZ at random, either through destruction or by achieving final burial. Shell half-lives (the amount of time to remove half the shells from the TAZ) provide a comparative measure of time-averaging. Time-averaging varies with sedimentary and tectonic setting. The lowest amounts of time-averaging (shell half-lives of 90 to 165 years) occur in Bahía Concepción, where rapid rates of terrigenous sedimentation (on fan-deltas) and carbonate sedimentation (in pocket bays) bury shells rapidly. Time-averaging is higher in the sediment-starved environments of Bahía la Choya (shell half-lives of 285 to 550 years). The highest amounts of time-averaging occur the inner tidal flats of Bahía la Choya (shell half-life of 550 years). Here the conjunction of low sedimentation rates with low rates of shell destruction (due to periodic tidal emergence) permits shells to persist in the TAZ for very long time spans.There is no systematic relationship between a shell's age and its taphonomic condition (taphonomic grade) in any environment, probably because of the complex and random nature of burial-exhumation in the TAZ. Agevariancetends to increase with increasing taphonomic alteration: highly altered shells range in age from young to several thousand years old, while less altered shells are mostly young. The correspondence between time-averaging and the taphonomic condition of entire shell assemblages is also weak, but might be resolved with further study.These results provide quantitative data on time-averaging in benthic assemblages as a function of sedimentary and tectonic setting, and suggest some guidelines for facies appropriate for particular studies. Shallow marine rift basins like Bahía Concepción can potentially contain within-horizon fossil assemblages representing time spans of only a few hundred years—time resolution often beyond reach in paleontology. In contrast, sediment-starved shelf habitats like Bahía la Choya are unlikely to yield assemblages with time resolution finer than several thousands of years.

Benthic foraminiferal zonation in deep-water carbonate platform margin environments, northern Little Bahama Bank

1988 ◽  
Vol 62 (01) ◽  
pp. 1-8 ◽  
Author(s):  
Ronald E. Martin
Keyword(s):  
Deep Water ◽  
Benthic Foraminifera ◽  
Carbonate Platform ◽  
Sedimentary Facies ◽  
Depositional Environments ◽  
Near Surface ◽  
Sediment Gravity Flows ◽  
Gravity Flows ◽  
Platform Margin ◽  
Water Carbonate

The utility of benthic foraminifera in bathymetric interpretation of clastic depositional environments is well established. In contrast, bathymetric distribution of benthic foraminifera in deep-water carbonate environments has been largely neglected. Approximately 260 species and morphotypes of benthic foraminifera were identified from 12 piston core tops and grab samples collected along two traverses 25 km apart across the northern windward margin of Little Bahama Bank at depths of 275-1,135 m. Certain species and operational taxonomic groups of benthic foraminifera correspond to major near-surface sedimentary facies of the windward margin of Little Bahama Bank and serve as reliable depth indicators. Globocassidulina subglobosa, Cibicides rugosus, and Cibicides wuellerstorfi are all reliable depth indicators, being most abundant at depths >1,000 m, and are found in lower slope periplatform aprons, which are primarily comprised of sediment gravity flows. Reef-dwelling peneroplids and soritids (suborder Miliolina) and rotaliines (suborder Rotaliina) are most abundant at depths <300 m, reflecting downslope bottom transport in proximity to bank-margin reefs. Small miliolines, rosalinids, and discorbids are abundant in periplatform ooze at depths <300 m and are winnowed from the carbonate platform. Increased variation in assemblage diversity below 900 m reflects mixing of shallow- and deep-water species by sediment gravity flows.

Electron Microscopy in the Study of Natural Phytoplankton Assemblages

1985 ◽  
Vol 43 ◽  
pp. 620-623
Author(s):  
Linda Sicko-Goad
Keyword(s):  
Electron Microscopy ◽  
Aquatic Environment ◽  
Size Range ◽  
Physical Parameters ◽  
Specific Information ◽  
Phytoplankton Assemblages ◽  
Phytoplankton Productivity ◽  
Ecosystem Effects ◽  
Time Of Year ◽  
Species Specific

Although the use of electron microscopy and its varied methodologies is not usually associated with ecological studies, the types of species specific information that can be generated by these techniques are often quite useful in predicting long-term ecosystem effects. The utility of these techniques is especially apparent when one considers both the size range of particles found in the aquatic environment and the complexity of the phytoplankton assemblages.The size range and character of organisms found in the aquatic environment are dependent upon a variety of physical parameters that include sampling depth, location, and time of year. In the winter months, all the Laurentian Great Lakes are uniformly mixed and homothermous in the range of 1.1 to 1.7°C. During this time phytoplankton productivity is quite low.

Lycopene alleviates sulfamethoxazole-induced hepatotoxicity in grass carp (Ctenopharyngodon idellus) via suppression of oxidative stress, inflammation and apoptosis

2020 ◽  
Vol 11 (10) ◽  
pp. 8547-8559
Author(s):  
Hongjing Zhao ◽  
Yu Wang ◽  
Mengyao Mu ◽  
Menghao Guo ◽  
Hongxian Yu ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Secondary Metabolites ◽  
Human Health ◽  
Grass Carp ◽  
Aquatic Environment ◽  
Ctenopharyngodon Idellus

Antibiotics are used worldwide to treat diseases in humans and other animals; most of them and their secondary metabolites are discharged into the aquatic environment, posing a serious threat to human health.

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