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

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

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

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

Inside the Heads of Extinct Marine Reptiles – #365papers – 2018 – 12

Voeten, Reich, Araujo, and Scheyer, 2018, Synchrotron microtomography of a Nothosaurus marchicus skull informs on nothosaurian physiology and neurosensory adaptations in early Sauropterygia: PlosONE, v 13, e0188509

What’s it about?

This paper is about the use of syncrotron radiation to make images of the inside of the fossilized skull of a marine reptile. Using contrasts in density, the authors were able to distinguish between bones of the skull and originally empty places where the brain, nerves, and blood vessels would have gone. Continue reading