Greeetings All,
This posting is a modified version that I originally posted a little over a year ago on rd.net and Cali made this a sticky just before the great dying, but the edits are minor,and neither add or subtract from the first edition in a meaningful manner. I have removed Cali's comments to more focus this on the science and not the dubunking. If the moderation feels this is an inappropriate sub forum I have no issues with movement to the correct place.

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Paleontology is a multi-faceted field and each face requires independent testing. Geology, comparative anatomy, paleobotany, pathology, geochemistry, hydrology, morphology, geochronology, and paleo-biodiversity all must be addressed with testing.


Geology:

When one collects a specimen, let's say a hadrosaur femur, one must establish the geologic framework in which this bone is found. Is this a product of in situ burial or postmortem transportation? In order to determine this one must examine the formation carefully and test the conclusions. If the bone is found in what appear to be a high energy deposit, such as fine grained sandstone, one could assume this to be the case but assumptions are not acceptable. The underlying and capping layers must be examined to assure the facts are the facts. If the sandstone has inclusions of botanical matter the high energy assumption could be wrong and imply an overbank situation. If the specimen has microscopic abrasion markings there is evidence of postmortem transportation, but not proof. Comparing this individual specimen to others displaying similar markings and the depositional environment thereof is part of the testing. This is a simplification of the procedures but without this testing all one has is a dinosaur bone, which is scientifically worthless.


Comparative Anatomy:

Returning to this same hadrosaur femur, how do we know this is a hadrosaur femur at all? We look at the vast number of other specimens and test the physical characteristics by precise measurements. We look at the muscle attachment scars, joint angles, wall thickness, marrow features and other factors and determine the possibility of species relationship. This testing procedure is required to establish this relationship. Without this testing we again have nothing more than a dinosaur bone.


Paleo-Botany:

When we excavate the hadrosaur femur we must retrieve samples of any plant matter in close proximity. We then test these associated samples for chronological matching. If we find that the plant matter is from a species known to be post Cretaceous in nature we can be confident in stating that the bone has been reworked (eroded from older deposits and replaced within younger deposits). However if the plant matter is known to be of a nature consistent with the time frame wherein hadrosaurs were extant we can establish an accurate chronological setting. Without this testing all we have is a dinosaur bone and no further knowledge.


Pathology:

Let us consider the possibility that this hadrosaur femur doesn't meet the morphometric data points and has unexplained oddities. This bone still meets other data points to establish that it is a hadrosaur, but these abnormalities present problems. Since vet care was non existent and we know many animals survived being injured these oddities are more common than many realize. We examine these oddities and test these against modern examples of injuries and let the data reveal the causes for these oddities. If a bone has fractured and healed, for example, we can see where the bone grew imperfectly. If this bone suffered from an infection we can see the pitting and other trace information. Without the testing all we have is an odd looking dinosaur bone.


Geochemistry:

The hadrosaur bone is extremely well preserved we must determine why. Many dinosaur fossils are not well preserved and we ask why for these as well. If there is a high level of silicate replacement of the organic bone material we can discover why. How? We test the bone and surrounding matrix for the composition of the chemical nature which transform the bone into a fossil. In contrast we can test for the reason why the bone was not replaced by silicates. There are other chemical agents which contribute or subtract from the fossilization process and these can all be revealed by careful testing. Without this testing all we have is either a great looking rock hard dinosaur bone or a crumbling mess that drive prep workers insane.


Hydrology:

In association with the other tested conditions mentioned above we must address the influence of water on the hadrosaur bone. Assuming we have established by previous testing that the specimen has been transported prior to deposit we must test to establish how much energy was involved. Dr. Horner established that one of the bone beds he examined was a result of a massive, but localized, flood event. Those exclusive (no other species represented) hadrosaur bones displayed sharp fractures and strange orientations that could only result from the energy present in such a localized flood event. Slow moving water does not lead to such depositional factors. Also the inclusion of inorganic matter, such as boulders, can reveal the energy of a flood event. Without testing for these conditions all we know is that the dinosaur bone was deposited in the matrix. Again, just a dinosaur bone.

Morphology:

How do we know this is a hadrosaur femur, and how do we know if this is an adult, juvenile, hatchling, or a new species? We test the bone for data points that have been established by prior work. In conjunction with comparative anatomy we test to see if the data points are correct and if not why. Dwarfism and other considerations must be addressed. A fully adult dwarf hadrosaur would display some adult characteristics and some juvenile characteristics. A new species of small hadrosaur would present a consistent set of data points across the age range of a life cycle, as would a larger species. Without this testing we have nothing but an odd dinosaur bone.

Geochronology:

So we have established that this is a hadrosaur bone and the environment in which it lived, died and was deposited. Now we must test to establish the geologic time for these events. We do radiometric testing to establish this in association with the paleo-botany and by other means. If the geochronological data matches for the species of known hadrosaurs we can safely conclude the species or family identity. If, however, the dating reveals the specimen falls outside the known time frame wherein the known speciation of hadrosaurs exists we must ask why? Without testing we have nothing but a hadrosaur bone which may or may not be a representation of a new species and of unknown age.

Paleo-biodiversity:

When we recover this hadrosaur bone we also find a shed tooth of a large predatory dinosaur and a few smaller predator teeth. We can test to determine the species of these teeth to cross check the time frame. We know the difference between Tyrannosaur teeth and those of Albertosaur, and those of Dromeosaurs, Troodon and Sauronitholetes and the difference between these. We know, by testing, that these teeth represent a sample of the other dinosaurs present when the hadrosaur bone was deposited. These tests determine the predator-prey ratios and in association with other herbivores we test for the diversity of the fauna of a local environment. One revealing aspect of this testing is the overall decline in dinosaur species, but not numbers, towards the end of the Cretaceous. Without testing for the biodiversity of the environment all we have is a bone and some teeth.

So, when claims are made that there is no testing done in paleontology just go ahead and laugh. It displays a level of ignorance so elevated that it cannot easily be measured. Actually I know of no accurate means by which we could measure such.

RS

This post is a related follow-up to the above, also previously a part of the rd.net archive.

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Details of field work in vertebrate paleontology:

One summer we had a volunteer on a dig crew that was a little ignorant of the methodology we employed when recovering vertebrate fossils. I think in this case we had located the left front leg of a Triceratops horidus from the radius down (maybe there were couple phalanges missing I can't remember). This semi articulated set of fossils was not all visible in an exposed state, and unfortunately this was the extent of that particular find.

When we started laying out a grid and taking measurements before we even started digging this person got the strangest look on his face, and stood in silence watching. When we began a stratigraphic site examination and still weren't actually digging to uncover the bones he couldn't stand it any more. A string of questions followed, which we answered as we continued our preparatory work.

We explained that we were laying out the grid so that we would be able to reconstruct the depositional data at a later date. We showed him that we could determine if the fossils were deposited to their current position as a result of water transport and if so what sort of actions had taken place to leave the fossils in their present positions. The grid, we explained, would allow us to construct a map that would allow us to better understand what had happened so long ago, and document the whole affair. We went into detail to show him that if there was a great deal of this particular triceratops would could not currently see we would be able to determine if, or how much, scattering has taken place, and maybe the reasons for that scattering.

We didn't have to spend near as much time explaining the stratigraphics, as we actually had him help with that. When he saw the layering with diverse types of sediments and how we we recording these layers from well above to well below the horizon in which the fossils had been found he had a "light bulb" moment. We showed him how there had been multiple ash falls and overbank flooding and the distinction each layer exhibited. We did out best to show how we could tell by the clastic characteristics what forces had worked to leave this data. In the process of collecting this data we stuck a layer of heavily lignitic material that clearly represented a long stable period in which a great deal of organic matter had been laid down without disturbances. In this layer we located several thin coal seams with embedded tiny amber nuggets. This volunteer then became much more interested in the sedimentology than recovering the bones.

The entire point being that without the associated data one collects as a fossil is recovered all one has is a dinosaur bone. A dinosaur bone, alone, only tells us that a dinosaur died and here's the bone. However when one collects every scrap of information that is available we can tell if the dinosaur was fossilized where it fell, if scavengers spread the remains out or carried off portions thereof, if the bones were transported to their final resting place by a flood and how intense this flood may have been, and a great many other data points. Far too many lay persons think all there is to collecting fossils is to dig 'em out of the ground. Of all the fossils I saw recovered none of the data points suggested anything other than deposition by natural causes.

RS

Again, this posting is a part of the series once posted on that other bastion of rational thought.
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In an earlier post I placed the following questions as a challenge to a fellow member that seemed to think his field of study surpasses all others and those without his exposure and learning were somehow a part of the "great unwashed". Since said poster feels this challenge was "silly" I feel it is my responsibility to provide answers to those which may be curious.

theropod asked;
1. What methods should one employ to ensure the long term preservation of an Edmonotosaurus annectens femur with advanced pyrite disease?

Pyrite disease is a nearly unstoppable degenerative condition wherein a fossil will eventually be consumed by replacement of the fossil material with pyrite crystals. While it is possible, with extremely tightly controlled storage, to slow, or limit, the advancement of this condition no means exists to completely halt the progression of loss. The best method to deal with this situation is to make a mold of the fossil and cast a replica. This condition is far too common in some depositional settings such as the Hell Creek formation, and those working with these fossils are fully aware of this fact.

theropod asked;
2. When one is confronted with a series of dinosaur fossils that are jumbled and cross bedded in close proximity to one another, and the matrix is a soft mudstone, what methods should one use to assure a limitation of damage during recovery?

When faced with such a situation the worker, or team of workers, should form a plan of action to ensure that the fossils do not become destabilized as a result of removing too much of the matrix in the field. Undermining the fossils by removing too much matrix can lead to collapsing trauma. Supporting material, such as wooden slats or steel bars, can be applied to individual fossils in a manner to add strength and form "bridging" structures. Judicial application of consolidants in conjunction with the supporting material will help limit recovery damage. A separating layer of material is applied between the fossils and the jacketing material so that the jacket does not adhere to the fossil and make final prep work a nightmare. When the jackets are formed, usually plaster or fiberglass impregnated burlap or other suitable material, on the upper surfaces of the fossils lifting hooks can be formed. These "strong points" will later serve as a means by which the fossils can be manipulated for transportation. Such jackets of multiple fossils can become quite large and unwieldy and consideration for final transport should be taken.

When the upper side of the jackets have hardened, and the fossils can be safely undercut to form a pedestal, the mass of fossils may have additional reinforcing material driven or otherwise placed beneath the fossils and matrix prior to being turned and the jacketing material fully encapsulating the fossils.

theropod asked;
3. Under what conditions is the use of acid reduction appropriate in the preparation of a fossil specimen, how does one make such a determination, and how does one determine the correct chemistry to employ?

Sometimes the matrix encasing a fossil is far too hard to remove by mechanical means and not damage, or destroy, the fossil. Limestone, siderite, fine grained sandstones and other natural material make up the fossils encasing matrix. If testing reveals that this matrix is too hard to be removed safely the acid reduction method should be considered. In the field the worker(s) should collect samples of the matrix which is free of fossils for the lab worker(s) to use as test material. If the matrix is limestone, for example, the lab worker(s) may choose a solution of sufficient strength as to dissolve the matrix yet not erode the fossil. Even then this method requires a very careful application of the acid divided by neutralization and drying periods where protective coatings can be applied to the fossil prior to repeating the acid bath.

The lab worker(s) should save the residue from the dissolved matrix for later examination should a study of the Palynology be undertaken.

theropod asked;
4. How does one determine if a shed theropod tooth was lost externally during feeding or has been swallowed while feeding and past through the digestive tract of the owner?

Of all these questions this is the most simple to answer. The teeth of all dinosaurs were shed on a regular basis, much like sharks. The teeth that were lost while feeding will remain, under normal conditions, very well preserved while the teeth that have been swallowed will have digestive juices acting to erode them. The digested teeth will have pitting and other scaring characteristics which can only come about as a result of exposure to the highly aggressive digestive juices. Most theropods of any size also consumed bone in the act of feeding and their digestive tract was evolved to deal with this to extract the nutrients contained therein. A tooth, while much harder than normal bone, will still suffer degrading erosion from exposure to the digestion process.

RS

This is the final (for now) segment regarding dinosaur paleontology from our former home.
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I made a statement last evening (2/9/10) that I would present an essay on the evolutionary pathways which lead to the emergence of dinosaurs. Hopefully I will be able to show, with the assistance of peer reviewed literature, that dinosaurs did not magically appear in the fossil record. It seems there are some people that hold to the view that because the fossil record is incomplete this implies that the fossil we do find are not indicative of a valid evolutionary pathway. Nothing could be further from the truth, and is not possibly based on anything but conjecture. This conjecture, as colorful as any imaginative writing in history, does not reflect the facts, and only serves to confuse the lay person. It is my intent to provide hard evidence that at no point was magic, or supernatural causes, involved the rise of dinosaurs.

The fossil record is a fragile set of data points based on the remains of once living creatures. The act of fossilization is neither perfect nor assured for all creatures that die. Once an organism has become a fossil there are no guarantees that natural forces will remain constant so that the fossil will be retained across an extended stable temporal setting. Plate tectonics subduct great masses of fossil bearing strata on a continuous basis, and destroy any fossils contained therein. Erosion of strata is also constant and greatly contributes to removing fossils from the geologic column via mechanical reduction and disruption. Even when the fossils are not lost due the effects of erosion but rather redeposited the "founding condition" information is lost and with it a great deal of vital data. Other strata which contain fossils are buried so deeply that any efforts to study them is either cost prohibitive or physically impossible to access. In some cases forests have overgrown fossil bearing strata and make field work a fools errand. This leaves us with the study of what fossil bearing strata remains. Obviously the older a given depositional setting is the more challenging it becomes to recover the fossils, because of the forces cited earlier, as we examine progressively older deposits. These challenges to paleontology have been well understood and in fact studied carefully so as to gain a predictive prospective prior to starting field work.

Many people unfamiliar with the methodology paleontologists employ have a misconception that all we do is dig up bones and make assumptions. Nothing could be further from the facts. Paleontology is as much a "true" science as any other scientific endeavor with more attention paid to comparative anatomy than most medical practitioners. Minute details of a femoral articulation, for example, across several species allows for construction of a cladistic analysis that focuses on the differences and similarities. These studies have allowed us another avenue to better understand how the forces of evolution influenced the fossils we recover.

Before there were any creatures that can be classified as true dinosaurs there had to have been progenitors, according to the theory of evolution. This is true for the first dinosaurs as it is for all creatures. According to our current understanding of the pathway from which dinosaurs emerged this event happened sometime over 230 million years ago. Note that I attempted to use references with the most recent work I could locate so as to present our most up-to-date understanding of the subject.

Please consider the following publication which was published only a few months ago.

Biological Reviews
Volume 85 Issue 1, Pages 55 - 110

Published Online: 6 Nov 2009
DOI: 10.1111/j.1469-185X.2009.00094.x
Journal compilation © 2010 Cambridge Philosophical Society

"The origin and early evolution of dinosaurs"

Max C. Langer, Martin D. Ezcurra, Jonathas S. Bittencourt and Fernando E. Novas


ABSTRACT

The oldest unequivocal records of Dinosauria were unearthed from Late Triassic rocks (approximately 230 Ma) accumulated over extensional rift basins in southwestern Pangea. The better known of these are Herrerasaurus ischigualastensis, Pisanosaurus mertii, Eoraptor lunensis, and Panphagia protos from the Ischigualasto Formation, Argentina, and Staurikosaurus pricei and Saturnalia tupiniquim from the Santa Maria Formation, Brazil. No uncontroversial dinosaur body fossils are known from older strata, but the Middle Triassic origin of the lineage may be inferred from both the footprint record and its sister-group relation to Ladinian basal dinosauromorphs. These include the typical Marasuchus lilloensis, more basal forms such as Lagerpeton and Dromomeron, as well as silesaurids: a possibly monophyletic group composed of Mid-Late Triassic forms that may represent immediate sister taxa to dinosaurs. The first phylogenetic definition to fit the current understanding of Dinosauria as a node-based taxon solely composed of mutually exclusive Saurischia and Ornithischia was given as "all descendants of the most recent common ancestor of birds and Triceratops". Recent cladistic analyses of early dinosaurs agree that Pisanosaurus mertii is a basal ornithischian; that Herrerasaurus ischigualastensis and Staurikosaurus pricei belong in a monophyletic Herrerasauridae; that herrerasaurids, Eoraptor lunensis, and Guaibasaurus candelariensis are saurischians; that Saurischia includes two main groups, Sauropodomorpha and Theropoda; and that Saturnalia tupiniquim is a basal member of the sauropodomorph lineage. On the contrary, several aspects of basal dinosaur phylogeny remain controversial, including the position of herrerasaurids, E. lunensis, and G. candelariensis as basal theropods or basal saurischians, and the affinity and/or validity of more fragmentary taxa such as Agnosphitys cromhallensis, Alwalkeria maleriensis, Chindesaurus bryansmalli, Saltopus elginensis, and Spondylosoma absconditum. The identification of dinosaur apomorphies is jeopardized by the incompleteness of skeletal remains attributed to most basal dinosauromorphs, the skulls and forelimbs of which are particularly poorly known. Nonetheless, Dinosauria can be diagnosed by a suite of derived traits, most of which are related to the anatomy of the pelvic girdle and limb. Some of these are connected to the acquisition of a fully erect bipedal gait, which has been traditionally suggested to represent a key adaptation that allowed, or even promoted, dinosaur radiation during Late Triassic times. Yet, contrary to the classical "competitive" models, dinosaurs did not gradually replace other terrestrial tetrapods over the Late Triassic. In fact, the radiation of the group comprises at least three landmark moments, separated by controversial (Carnian-Norian, Triassic-Jurassic) extinction events. These are mainly characterized by early diversification in Carnian times, a Norian increase in diversity and (especially) abundance, and the occupation of new niches from the Early Jurassic onwards. Dinosaurs arose from fully bipedal ancestors, the diet of which may have been carnivorous or omnivorous. Whereas the oldest dinosaurs were geographically restricted to south Pangea, including rare ornithischians and more abundant basal members of the saurischian lineage, the group achieved a nearly global distribution by the latest Triassic, especially with the radiation of saurischian groups such as "prosauropods" and coelophysoids.

In the above paper we can see that those examining the evidence have valid reason to suggest that while every single fossil required to establish an evolutionary pathway have not been found leading to true dinosaurs the fossils we do have show just such a relationship. This evidence is based on sound scientific principles, such as the cladistic analysis. In order to refute these findings one needs to show how there cannot be, or never was, any relationship between the dinosaurs and the creatures that are so closely resembling them. Such refutation will require the same diligence and careful examination as was performed in the gathering of data presented above. Without sound data in objection we are left with opinion, which is not a valid method to overturn our current understanding. Considering the lateral supporting evidence, for creatures outside of the dinosaurs, that evolution acts across populations of organisms we would also have to refute all the other instances of speciation we have in support of evolution by common descent.

Of course there are many questions remaining in regarding the issue of just how the dinosaurs emerged. The entire point is that science is an continuous process and paleontology is no different. Those of us that understand the principles of the scientific method can comprehend the problems facing such research. Considering how far back in time we are searching for answers it becomes clear that great accomplishments have been made in this area.

Consider the following:

"Dinosaurian Precursors from the Middle Triassic of Argentina: Lagerpeton Chanarensis"
Paul C. Sereno and Andrea B. Arcucci
Journal of Vertebrate Paleontology, Vol. 13, No. 4 (Jan. 14, 1994), pp. 385-399

Abstract
We describe the holotype and referred material of the unusual Middle Triassic dinosaur precursor, Lagerpeton chanarensis. The autapomorphies of Lagerpeton chanarensis include the convex and fluted puboischial flange, hook-shaped femoral head, elongate femoral fourth trochanter, fused astragalocalcaneum, tall posterior ascending process on the astragalus, and functionally didactyl pes. Among ornithodirans, Lagerpeton chanarensis is more closely related to dinosaurs than are pterosaurs. We list tarsal and pedal synapomorphies shared by Lagerpeton chanarensis and other dinosauromorphs that are absent in pterosaurs and crurotarsal archosaurs. These include an increase in the relative size of the central metatarsals and subparallel orientation of pedal digit V. There is no evidence that Lagerpeton and other small-bodied dinosauromorphs in the Los Chañares fauna, namely "Lagosuchus" lilloensis, comprise a monophyletic group. The digitigrade pes and the elongate and erect hind-limbs of basal pterosaurs and dinosauromorphs suggest that an obligatory bipedal posture had evolved in early ornithodirans. In extant vertebrates, obligatory bipedal posture is often associated with either cursorial or saltatory locomotor habits. Although these two locomotor patterns are difficult to distinguish on skeletal traits alone, the anteriorly inclined dorsal neural spines, small pelvic girdle, fused proximal tarsals, and very narrow didactyl pes in Lagerpeton chanarensis suggest that it may have been a saltator.

In this paper the authors make note of a species that displays a set of characteristics which very closely approximates the set of skeletal features displayed within dinosaurs. Of particular importance is the puboischial/hip joint morphology. This area is one of a set of diagnostic features that determines a dinosaur as a dinosaur. This feature sets dinosaurs apart form lizards and a great many creatures that shared their world. Quite interestingly is the focus on the bipedal stance observed in Lagerpeton chanarensis in particular and in the Lagosuchus in general which shows this was not a "one time" freak.

Let's look at one final paper:

Science 20 July 2007:
Vol. 317. no. 5836, pp. 358 - 361
DOI: 10.1126/science.1143325

"A Late Triassic Dinosauromorph Assemblage from New Mexico and the Rise of Dinosaurs"

Randall B. Irmis, Sterling J. Nesbitt, Kevin Padian, Nathan D. Smith, Alan H. Turner, Daniel Woody, Alex Downs

ABSTRACT

It has generally been thought that the first dinosaurs quickly replaced more archaic Late Triassic faunas, either by outcompeting them or when the more archaic faunas suddenly became extinct. Fossils from the Hayden Quarry, in the Upper Triassic Chinle Formation of New Mexico, and an analysis of other regional Upper Triassic assemblages instead imply that the transition was gradual. Some dinosaur relatives preserved in this Chinle assemblage belong to groups previously known only from the Middle and lowermost Upper Triassic outside North America. Thus, the transition may have extended for 15 to 20 million years and was probably diachronous at different paleolatitudes.

Here the authors make note of a temporal span in which the transitional evolution of dinosaurs occurred. Note that they examined the data from several depositional settings. Their work suggest very strongly that the rise of dinosaurs was not sudden nor was this transition taking place at the same rate at all locations. This alone destroys any notion of a special creation for the dinosaurs. The fact that dinosaur ancestors remained extant during this transition also tells us that, in accordance with our understanding of evolution, replacement of species is not required for new and novel life forms to arise. In this case the question, "If dinosaurs came from Lagerpeton chanarensis why were there still Lagerpeton chanarensis after dinosaurs evolved?"

I feel the matter of the evolutionary transitional steps leading to true dinosaurs, while not complete, have been shown to be supported by the evidence. It is not a matter of faith, or assumption, that more specimens and a finer detail of the fossil record will emrge. Paleontology is not a static effort and with each new discovery we learn more about the forces of evolution acting in the past. At no point is there any suggestion from the evidence that dinosaurs suddenly appear in the fossil record, and indeed ancestral fossils have been found. The association of how these ancestors of dinosaurs relate has been shown. Some of those ancestral organisms were not immediately replaced within the biosphere and the rate of dinosaur diversification following their emergence is well documented. Both major branches of the dinosaurs were well established by the end of the Triassic, and they did not show up in the fossil record by some act of magic.

RS

For those interested in a more technical reporting of this matter see the link below. This paper deals more with the post emergence evolutionary forces than the other references cited above, but is still relevant and well worth the read.

"The first 50 Myr of dinosaur evolution: macroevolutionary pattern and morphological disparity"
(FULL PAPER)