Acetate peels are replicas of etched surfaces embedded in sheets of cellulose acetate. These replicas are usually so detailed that the fine structure of shells and various sedimentary rocks can be easily studied under a light microscope. Because these peels can be quickly and easily produced, the procedure is now commonly used in most geologic laboratories.

The term palynomorph generally includes the spores of lower vascular plants (isospores/homospores, and megaspores), prepollen, the pollen of gymnosperms and angiosperms, dinoflagellates, acritarchs, fungal spores, and algal remains. Chitinozoans, scolecodonts, and foraminiferal inner tests also are concentrated by palynological processing techniques, and some palynologists therefore include them as palynomorphs. These processes isolate any silt-sized or sand-sized acid-resistant organic-walled particles, however, and also will concentrate foraminiferal inner tests leaf cuticle, vascular debris from plants, chitinous insect parts, etc., which usually are not considered palynomorphs. All of the above are recovered, definition notwithstanding.

There are at present two techniques that use X-rays to show internal structures, both are in common use in medicine. The first technique is essentially a photographic method (for extensive description see Quinn and Sigl, 1980). The second (Cat scan or Computer Tomography) computes a section from many pictures taken by a thin, fan shaped X-ray beam. X-rays are a form of electromagnetic radiation with a wave length 10,000 times smaller, and energy 10,000 times greater, than visible light. They are generated in a high-vacuum tube where electrons are produced by a heated cathode and are shot at high electromotive force (30 to over 100 kilovolts) at the anode where most of the energy is converted to heat; only a small fraction is given off as X-radiation.

Archeological interest in predation ranges from studies of the earliest evidence for human meat-eating, to attempts to understand the fossil record's ambiguity about the meaning of associated animal bones and human artifacts. A number of quantitative measures are used to find the meaningful patterns in archeological assemblages, and taphonomic research has also provided analogs and comparative standards for interpreting human behavior based on the evidence for predation. The most important methods, approaches, and interests are discussed here, using case studies to illustrate the way archeologists have thought about the record of humans as predators.

The extinct Paleozoic coral groups Rugosa and Tabulata suffer from confused systematics because of extreme morphological variation, pervasive homoplasy, and relatively simple skeletal morphology. Morphological variation occurs within individuals or colonies, between individuals within a population, and between populations. Variation at each level may have both genetic and ecologic components. Homoplasy is very abundant and extended sequences of parallel or convergent character transformations have led to the recognition of “recurrent evolutionary trends” in many lineages.

Morphological variation causes much difficulty in the recognition and characterization of coral species and homoplasy is problematic for phylogeny reconstruction. Improved coral systematics require a more holistic approach to both taxonomy and phylogeny analysis, including: 1) population-based species concepts, as opposed to typological approaches; 2) use of more quantitative techniques in species discrimination and description; 3) more attention to subtle morphological elements, such as microstructure; 4) description of ecological settings (depositional environments) to aid in analysis of behavior and to help unravel ecophenotypic plasticity; and 5) use of stratigraphic and geographic distribution data in phylogeny analysis, because skeletal morphology is inadequate by itself.

Plants can become incorporated into the sediments of virtually any environment, from the oozes of abyssal plains to the silts and sands of delta fronts to brecciated mudflows of volcanic origin. However there is a much narrower range of sedimentary environments in which identifiable plant remains are found in abundance. Generally speaking these are the very shallow or subaerial portions of deltas and estuaries, the channels and floodplains of fluvial systems, lakes of all sizes, ash-falls, and mass-flow deposits such as mudflows. For the purposes of this paper peat swamps are considered as unusual subtypes of deltaic and fluvial environments in which clastic input is low relative to organic accumulation.

Since Dolf Seilacher coined the term Konservat-Lagerstätten in 1970, these deposits have migrated from the margins to the mainstream of paleontological research. With greater understanding of the controls on their occurrence, new examples of exceptional preservation continue to be discovered. They provide critical data for phylogenies and stratigraphic ranges. Together with molecular data, they calibrate the history of many infrequently preserved taxa. Ostracods, tiny crustaceans with a biomineralized carapace, illustrate the importance of recent discoveries in Konservat-Lagerstätten. The rare examples with fossilized appendages are preserved in a diversity of ways, organically or through authigenic mineralization. They confirm that ostracods were present at least by the late Ordovician, provide evidence of relationships obscured by the morphology of the routinely preserved valves, and extend the stratigraphic range of particular groups. They reveal extraordinary features of the soft-tissue anatomy of ostracods, including reproductive morphology and strategy. While other taxa would provide equally compelling examples of research progress, it is clear that the concept of exceptional preservation is expanding. Future discoveries and new analytical methods will match the reconstruction of coloration in feathered dinosaurs, for example, for unexpected novelty.

Quantitative phylogenetic inference estimates the probability of observed character distributions given trees and rates. Most available programs for doing this assume (tacitly or explicitly) that the sampled taxa are contemporaneous. However, paleontologists usually sample taxa over a clade's history. Thus, we must estimate the probability of observed character-state distributions over time given trees and rates. When we include information about sampling intensity, then we really are estimating the probability of the observed record given trees and rates. Some additional problems that should be issues for neontologists, but which are much more obvious concerns for paleontologists include: 1) ancestor-descendant relationships; 2) punctuated versus continuous morphological change; and, 3) the effects of extinction and speciation rates on prior probabilities of trees. Future goals of paleosystematists include incorporating these and other “nuisance” parameters so that, ultimately, our tests of phylogeny are really tests of evolutionary histories.

Plant fossil assemblages are biased samples of the capacity of the once living source vegetation to produce litter (leaves, flowers, pollen, spores, fruits, seeds, twigs, branches, trunks, roots etc.). The “image” that the depositional system “sees” of the vegetation is in terms of isolated plant organs (or parts of organs) that are produced in greater or lesser quantities depending on the organ type. For instance throughout the life of a tree hundreds of thousands of leaves, many millions of pollen grains but only one trunk are produced. Only very rarely do plant fossil assemblages consist of entire or nearly entire plants. Instead assemblages consist of a mixture of organs in various states of completeness derived from a number of different taxa (each of which produces different organs in different relative amounts) growing at various distances from the depositional site.

The edrioasteroids (seat stars) are a small but diverse group of Paleozoic (Lower Cambrian through Pennsylvanian) echinoderms known to include five morphologically distinct types of thecal construction. Domal and clavate thecae predominate, although some are globoid and others axially elongate. Adult thecal diameters range from 6 – 7 mm to approximately 9 cm, but 15 – 30 mm is the norm. Edrioasteroids are not common fossils, although when proper conditions for preservation existed, entire populations were often fossilized so that hundreds or even thousands of specimens can be recovered through excavation. Apparently, preservation depended upon catastrophic kills, most of which seem to have resulted from storm-deposited mud deeply burying the entire substrate surface area.

Radiolaria are marine holoplanktonic animal-like protists belonging to the Superclass Actinopodea of the Subphylum Sarcodina. When biologists speak of radiolarians they usually mean the subgroup Acantharia that are common in nearshore waters and are sometimes involved in plankton blooms. When paleontologists speak of radiolarians they usually mean the subgroups preserved in the fossil record; the Polycystina (or polycystine) encompassing Spumellaria and Nassellaria, which possess solid opaline skeletal structures, and the Phaeodaria (or phaeodarians), which possess hollow skeletal structures of an admixture of silica and organic matter.

Studying the paleoecology of the extinct chambered cephalopods is somewhat analogous to studying a distant landscape through the wrong end of a powerful telescope: we can see very small views of what must have been great panoramic vistas. Two factors have lead to this situation. First, the extant cephalopods still utilizing the phragmocone system of density reduction are at very low standing diversity, while most of the more interesting taxa, such as ammonites and belemnites, are completely extinct. Our functional interpretations of various shell morphologies thus depend heavily on generalizations based on a small number of sometimes distantly related taxa, such as Nautilus and Sepia. Secondly, studies of fossil associations and their relationships to various facies are clouded by the possibility of extensive post-mortal drift of the cephalopod shells. Because of this, we cannot ever be sure that we are studying cephalopod biocoenoses. In spite of these constraints, however, the past two decades have witnessed a great research effort into the study of cephalopod paleoecology. Debate over various issues has been sometimes clamorous, a sign of a healthy and vigorous utilization of the scientific method by many interested students of the fossil record.

Tracemaking organisms are common and diverse components of the fauna and flora of tropical, shallow-marine and coastal carbonate environments. In the shallow subtidal zone, the burrowing activity of callianassid shrimp commonly is the dominant process in the modification of original depositional fabrics (Tudhope and Scoffin, 1984; Tedesco and Wanless, 1991). Both borers and burrowers have great potential to leave their mark in tropical carbonate sediments and rocks and to become part of the fossil record.

It is difficult to overestimate the importance of arthropods in the history of life. In terms of diversity and abundance, modern arthropods embody the ultimate success of the metazoa. Their prominence stems from an innovative, durable body plan, allowing mobility and adaptability for almost any environment in the earth's biosphere. Arthropods have been able to exploit an enormous range of lifestyles, becoming a conspicuous biotic component of many marine and terrestrial settings.

The Wenlockian lichid trilobite Arctinurus boltoni has been regarded as a classic example of a “snow-shoe” type adaptation. That is, the broad flat doublure has been interpreted as a resting surface, with well-developed terrace ridges serving as either sensory or frictional devices. New data from the Rochester Shale of western New York State indicate that this interpretation is incorrect The discovery of the small, calcareous worm tube Cornulites on complete, articulated specimens of Arctinurus indicates that these trilobites seldom rested their doublure on the sediment surface. Apertures of all specimens of Cornulites are oriented posteriorly, suggesting a rheophilic response to persistent water circulation patterns beneath the trilobite. The presence of suspension feeding organisms on the doublure also indicates that the water currents beneath the trilobite were free of suspended mud, so that Arctinurus may not have processed sediment in search of food.

Large specimens of Arctinurus also have numerous epibionts on the dorsal shield, including cyclostome bryozoans, brachiopods (Stegerhynchus) and Cornulites. The presence of these suspension feeders indicates that Arctinurus did not burrow or even partially cover itself with mud. The large number of epibionts on adult specimens of Arctinurus, including several age classes for Stegerhynchus, indicates that molting stopped or at least slowed greatly once a certain size was attained, and that these trilobites may have had fairly long life spans.