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

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

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

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

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

When You Don’t Know That You Don’t Know – #365papers – 2018 – 16

Not only do these people reach erroneous conclusions and make unfortunate choices, but their incompetence robs them of the metacognitive ability to realize it.” — Kruger and Dunning, 1999

Kruger and Dunning, 1999, Unskilled and unaware of it: How difficulties in recognizing one’s own incompetence lead to inflated self-assessments: Journal of Personality and Social Psychology, v. 77, p. 1121-1134.

What’s it about?

This paper is the basis of what is now called the Dunning-Kruger Effect. This is the phenomenon where people tend to grossly overestimate their abilities, especially when they are objectively incompetent at a particular task. Conversely, people of high competence tend to underestimate their ability. 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

Carnivore Guilds: Are They the Same Everywhere? – #365papers – 2018 – 11

Croft, Engelman, Dolgushina, Wesley, 2017, Diversity and disparity of sparassodonts (Metatheria) reveal non-analogue nature of ancient South American mammalian carnivore guilds: Proceedings of the Royal Society B, v. 285, 20172012.

What’s it about?

The phrase ‘carnivore guild’ refers to the ecological roles of carnivores (animals that feed on other vertebrates) in a particular region. In most modern areas where many carnivorous mammals co-exist, some are hypercarnivores (like cats), some are mesocarnivores (like dogs), and some are hypocarnivores (like armadillos). These last two groups (meso- and hypocarnivores) would be more loosely categorized as omnivores, with hypocarnivores only very rarely consuming other vertebrates, despite having the capability of doing so more often.

In this paper, the authors compare modern mammalian carnivore guilds with the extinct marsupial carnivore guild of ancient South America, to see if the general proportions of hyper-, meso-, and hypocarnivores are about the same. They find that the South American carnivore guild is substantially different from modern guilds. Continue reading

Can We Prove That Some Mammals ‘Hid Out’ During Glacial Times? – #365papers – 2018 – 9

Ntie, Davis, Hils, Mickala, Thomassen, Morgan, Vanthomme, Gonder, and Anthony, 2017, Evaluating the role of Pleistocene refugia, rivers and environmental variation in the diversification of central African duikers (genera Cephalophus and Philantomba): BMC Evolutionary Biology, v. 17.

What’s it about?

Researchers have suggested that during glacial times, tropical forests receded into restricted regions, wherein tropical forest animals were able to survive. After the glaciers receded, the forests spread again and the forest animals dispersed across the landscape. These restricted forested regions are called refugia. Because of the extended separation of the refugia, it is thought that animals and plants within would evolve and become distinct from those in other refugia.

This paper looks at a group of tiny deer called duikers. These deer live only in the thick forests of Africa. Through the study of fossil and modern DNA from duikers, these scientists studied the regional and subtle differences in DNA to attempt to prove or disprove the hypothesis that refugia existed in central Africa. Continue reading