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

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

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

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

When Does a Puppy’s Teeth Come In? – #365papers – 2018 – 18

Slaughter, Pine, and Pine, 1974, Eruption of cheek teeth in Insectivora and Carnivora: Journal of Mammalogy, v. 55, p. 115-125

What’s it about?

This paper explores the order in which teeth come in for two major mammal groups: the insectivores and the carnivores. In early terrestrial vertebrates, teeth come in from front to back, or from the snout to the back of the jaw. In some mammals this is still the case, but not all. Continue reading

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

How Do Populations of Giant Snails Cope Annual Changes? – #365papers – 2017 – 136

#365papers for May 16, 2017

Miranda and Fontenelle, 2015, Population dynamics of Megalobulimus paranaguensis (Gastropoda: Pulmonata) the the southeast coast of Brazil: Zoologia, v. 32, p. 463-468.

What’s it about?

This study used techniques described in yesterday’s paper to examine the annual changes in activity of a population of Megalobulimus paranaguensis snails in southeast Brazil. There are specific periods of time when more snails are active and when they are reproducing, based upon the environmental conditions such as evaportranspiration and precipitation. These snails are more active during the winter months and are dormant during the summer. Continue reading

Assigning an Age to a Giant Snail – #365papers – 2017 – 135

#365papers for May 15, 2017

Fontenelle and Miranda, 2012, The use of outer lip in age estimation of Megalobulimus paranaguensis (Gastropoda, Pulmonata): Strombus, v 19, p. 15-22.

What’s it about?

Megalobulimus is a giant snail that lives in South America. Using the thickness of the outer lip of the shell (where the snail sticks out of its shell), it’s possible to estimate the age of the snail. Continue reading

Using Giant Snails to Understand Past Atmospheric Carbon – #365papers – 2017 – 130

#365papers for May 10, 2017

Macario, Alves, Carvalho, Oliveira, Ramsey, Chivall, Souza, Simone and Cavallari, 2016, The use of the terrestrial snails of the genera Megalobulimus and Thaumastus as representatives of the atmospheric carbon reservoir: Nature Scientific Reports, v. 6, 27395.

What’s it about?

Snails. It turns out that snails record evidence of their environment in their shells. The authors here show how shells from these two giant snails can be used to examine the concentration of carbon dioxide in the atmosphere. Continue reading