Category Archives: Paleontology

What X-Rays and Absorptions Really Tell Us About Fossilization – #365papers – 2018 – 24

Stathopoulou, Psycharis, Chryssikos, Gionis, and Theodorou, 2008, Bone diagnesis: New data from infrared spectroscopy and X-ray diffraction: Palaeogeography, Palaeoclimatology, Palaeoecology, v. 266, p. 168-174.

What’s it about?

The authors here use two different methods to gain a sense of the changes in the shapes and sizes of crystals of the bone mineral bioapatite due to the process of fossilization. They also consider the various differences in composition (i.e. how much fluorine, hydroxyl, or carbonate) is present in the bioapatite. While this is done nominally to look at the effects of fossilization, it appears to be better at fingerprinting different localities.Continue reading “What X-Rays and Absorptions Really Tell Us About Fossilization – #365papers – 2018 – 24”

Why Can’t We Just Measure Alteration of Bone Due To Fossilization? – #365papers – 2018 – 23

Trueman, Privat, and Field, 2008, Why do crystallinity values fail to predict the extent of diagenetic alteration of bone mineral? Palaeogeography, Palaeoclimatology, Palaeoecology, v. 266, p. 160-167.

What’s it about?

Bones are composed of little crystals of the mineral referred to as bioapatite with organic materials (collagen, blood vessels, and cells that regulate the growth of bioapatite, etc) spread throughout. When an animal dies, the organic materials decay and the bioapatite crystals change their shape and size. There are methods by which we can readily measure the shape and size of the crystals, which, presumably, would tell us just how altered the bones are due to the fossilization process. This would then let us know how accurate any geochemical analyses we do with the bone are.

Only that the shape and size of bone crystals doesn’t actually work as a good measure of the alteration due to fossilization. Continue reading “Why Can’t We Just Measure Alteration of Bone Due To Fossilization? – #365papers – 2018 – 23”

The Shape of Feathers Doesn’t Tell You How Well Birds Fly – #365papers – 2018 – 21

Wang, Nudds, Palmer, and Dyke, 2017, Primary feather vane asymmetry should not be used to predict the flight capabilities of feathered fossils: Science Bulletin, v. 62, p. 1227-1228.

What’s it about?

In modern bird, the primary flight feathers are asymmetrical. That is, if you compare the width of the feather on one side of the thick quill that goes the length of the feather with the width of the feather on the other side of the quill, they’re usually not the same. This asymmetry makes the feather capable of lift (like an airplane wing). This asymmetry is then interpreted to go hand-in-hand with birds being capable of flapping flight. From this, it is often thought that birds that lack asymmetrical feathers could not fly very well, if at all.Continue reading “The Shape of Feathers Doesn’t Tell You How Well Birds Fly – #365papers – 2018 – 21”

Carbon from Bone Mineral and Bone Collagen Tells Us Who’s Eating Whom – #365papers – 2018 – 20

Clementz, Fox-Dobbs, Wheatly, Koch, and Doak, 2009, Revisiting old bones: coupled carbon isotope analysis of bioapatite and collagen as an ecological and palaeoecological tool: Geological Journal, v. 44, p. 605-620.

What’s it about?

“Trophic level” is a term scientists use to describe where an organism lies in the food chain (or food web). Animals of high trophic level are the carnivores, and organisms low in tropic level are the primary producers, like algae, or other plants. In the middle are the herbivores (primary consumers) that eat the primary producers. This paper is a discussion of another means by which one can interpret trophic level of animals, particularly those for which we only have fossil evidence.Continue reading “Carbon from Bone Mineral and Bone Collagen Tells Us Who’s Eating Whom – #365papers – 2018 – 20”

The Beginning of Bone Fossilization – #UREES270 – 2018

Instructor Assigned Paper 1 – Jan 19

Keenan and Engel, 2017, Early diagenesis and recrystallization of bone: Geochimica et Cosmochimica Acta, v. 196, p. 209-223.

What’s it about?

In order to have the science of vertebrate paleontology, we have to have the fossilization of bones. The authors use experimental methods to examine what happens early in the process of fossilization and understand the role of bacteria in the preservation of bone.Continue reading “The Beginning of Bone Fossilization – #UREES270 – 2018”

Life History of Carnivores: Comparing Across Size and Ecology – #365papers – 2018 – 19

Gittleman, 1986, Carnivore life history patterns: Allometric, phylogenetic, and ecological patterns: The American Naturalist, v. 127, p. 744-771

What’s it about?

This paper is an effort to summarize the similarities of life history among all mammals. Life history includes things like age of maturity, the time between litters, and the overall size of the animals.Continue reading “Life History of Carnivores: Comparing Across Size and Ecology – #365papers – 2018 – 19”

Better Specimens, Better Techniques, Better Understanding of the Sauropodomorpha – #365papers – 2018 – 17

Chapelle and Choiniere, 2018, A revised cranial description of Massospondylus carinatus Owen (Dinosauria: Sauropodomorpha) based on computed tomographic scans and a review of cranial characters for basal Sauropodomorpha: PeerJ, v. 6, e4224

What’s it about?

Using CT scanning techniques, the authors were able to pull apart all the bones of a sauropodomorph dinosaur called Massospondylus. The sauropodomorphs are a group of dinosaurs that include all the sauropods (the ‘long necks’ if you’re a fan of The Land Before Time), and their more primitive ancestors.

By examining all the bones of the skull one at a time, the authors were able to better understand the actual relationships between Massospondylus and other primitive sauropodomorphs. Continue reading “Better Specimens, Better Techniques, Better Understanding of the Sauropodomorpha – #365papers – 2018 – 17”

Isotopes and Interpretations: Are We Getting it Right? – #365papers – 2018 – 15

Kohn and McKay, 2012, Paleoecology of late Pleistocene-Holocene faunas of eastern and central Wyoming, USA, with implications for LGM climate models: Palaeogeography, Palaeoclimatology, Palaeoecology, v. 326-328, 42-53.

What’s it about?

Here, the authors compare values of carbon and oxygen isotopes from multiple species (herbivores and carnivores) from a single site to understand how these isotopes reflect environmental variables like annual precipitation and temperature, and how all the animals interacted with each other and the environment. Understandings gathered from the isotopic results were compared to what is known from modern, living animals and to the results from climate models.Continue reading “Isotopes and Interpretations: Are We Getting it Right? – #365papers – 2018 – 15”

Color Vision in Cretaceous Birds – #365papers – 2018 – 14

Tanaka, Zhou, Zhang, Siveter, and Parker, 2017, Rods and cones in an enantiornithine bird eye from the Early Cretaceous Jehol Biota: Heliyon, v. 3, e00479

What’s it about?

A fossilized bird (as yet unidentified except to know it’s an enantiornithine bird) was found to have well-preserved structures in its eye, especially a fossilized retina. Using various methods (including scanning electron microscopy and specialized light microscope techniques) the authors were able to not only identify rods and cones in the retina, but were also able to determine that this bird was able to see in color.Continue reading “Color Vision in Cretaceous Birds – #365papers – 2018 – 14”

When the Structure of Bones Tell You How Animals Breathed – #365papers – 2018 – 13

Lambertz, Bertozzo, and Sander, 2018, Bone histological correlates for air sacs and their implications for understanding the origin of the dinosaurian respiratory system: Biology Letters, v. 14, 20170514

What’s it about?

Modern birds are known for having a system of air sacs throughout their bones, allowing birds to circulate air through their bodies in one direction (rather than air simply going in and out of the lungs as breathing works in mammals). This unidirectional flow of air allows birds to maximize the amount of oxygen extracted from the air they breathe.

In birds, the air sacs are openings in bones that are all connected to the lungs. There are air sacs in vertebrae and wing bones among other places. Many other animals have hollow places in bones that are not associated with air sacs. These openings served to lighten the weight of the bones.

The authors show that there are structures in the bone surrounding the open spaces that distinguish air sacs from other openings.Continue reading “When the Structure of Bones Tell You How Animals Breathed – #365papers – 2018 – 13”