Encrusting Competition: How to Win the Battle of the Substrate – #365papers – 2017 – 55

#365papers for February, 24, 2017

Taylor, 2016, Competition between encrusters on marine hard substrates and its fossil record: Palaeontology, v 59, p. 481-497

What’s it about?

Some animals live by growing directly on other hard surfaces, forming a living surface ‘crust.’ This paper describes how such encrusting organisms interact and compete with each other over the surfaces upon which they’re growing. Continue reading

Old Horse Gives Up Its DNA – #365papers – 2017 – 54

#365papers for February 23, 2017

Orlando and 55 others, 2017, Recalibrating Equus evolution using the genome sequence of an early Middle Pleistocene horse: Nature, v. 499, p. 74-81.

What’s it about?

This paper discusses the results and implications of DNA analysis of a ~700 thousand-year-old horse fossil found in the Yukon Territory of Canada. This is the oldest horse fossil ever found with DNA. The results were compared with DNA from several modern horse breeds, donkeys, and Przewalski’s horse, the only non-domesticated horse breed. Continue reading

The Tully Monster. Is it our cousin or not? – #365papers – 2017 – 53

#365papers for February 22, 2017

Sallan, Giles, Sansom, Clarke, Johanson, Sansom, and Janvier, 2017, The ‘Tully Monster’ is not a vertebrate: Characters, convergence and taphonomy in Palaeozoic problematic animals: Palaeontology, p. 1-9.

What’s it about?

Tully Monsters have always been a bit of a mystery as they lack the important hard parts that are most often diagnostic for fossil species. Recently, there has been lots of discussion about vertebrate affinities for the Tully Monster. This paper provides evidence that the interpretation of vertebrate features might be in error. Continue reading

How Not to be Biased Against Pterosaurs – #365papers – 2017 – 52

#365papers for February 21, 2017

Dean, Mannion, and Butler, 2016, Preservational bias controls the fossil record of pterosaurs: Palaeontology, v. 59, p. 225-247.

What’s it about?

This paper discusses diversity (the number and kinds of species present at any one time) in pterosaurs – the flying reptiles – and how what we think the diversity was might be a product of bias in the rock record. We know that the fossil record is incomplete, but just how incomplete is it? Continue reading

After the Mother of All Extinctions, an Unexpected Triassic Fauna – #365papers – 2017 – 51

#365papers for February 20, 2017

Brayard, Krumenacker, Botting, Jenks, Bylund, Fara, Vennin, Olivier, Goudemand, Saucede, Charbonnier, Romano, Doguzhaeva, Thuy, Hautmann, Stephen, Thomazo, and Escarguel, 2017, Unexpected early Triassic marine ecosystem and the rise of the modern evolutionary fauna: Science Advances, v. 3, e1602159.

What’s it about?

This paper describes the fossils from four of early Triassic localities that have been correlated to be the same age. It is mostly descriptive of the fossils found. Continue reading

The Clean SWEEP of the Rocky Mountains – #365papers – 2017 – 50

#365papers for February 19, 2017

Chamberlain, Mix, Mulch, Hren, Kent-Corson, Davis, Horton, and Graham, 2012, The Cenozoic climatic and topographic evolution of the western North American cordillera: American Journal of Science, v. 312, p. 213-262.

What’s it about?

This paper uses a compilation of new and previously published oxygen stable isotope data from all over the Rocky Mountain region to understand the timing and uplift pattern of the Rocky Mountains. It seems that the Rocky Mountains first rose to the north, then grew southward. Continue reading

Climate Models and Eocene Isotopes, or How to Make My Head Hurt – #365papers – 2017 – 49

#365papers for February 18, 2017

Feng, Poulsen, Werner, Chamberlain, Mix, and Mulch, 2013, Early Cenozoic evolution of topography, climate, and stable isotopes in precipitation in the North American cordillera: American Journal of Science, v. 313, p. 613-648.

What’s it about?

Isotopes of oxygen and hydrogen in precipitation vary based on multiple factors, including how far from water vapor sources (usually the ocean) the precipitation is taking place, and whether or not there are mountains present, which can deflect and change patterns and amounts of precipitation. Because of this, we can use isotopes of oxygen from rocks and fossils, which reflect ancient precipitation, and understand the pattern and timing of uplifts of mountains.

This paper goes a step further, by using mathematical models to predict what oxygen isotopes of precipitation should have looked like based on a few ideas of how the Rocky Mountains may have come up. Continue reading

Two Papers, Two Authors, One Year, Same Result, But… – #365papers – 2017 – 48

#365papers for February 17, 2017

Bender, M.M., 1971, Variations in the 13C/12C ratios of plants in relation to the pathway of photosynthetic carbon dioxide fixation: Phytochemistry, v. 10, p. 1239-1244.

Smith, B.N. and Epstein, S., 1971, Two categories of 13C/12C ratios for higher plants: Plant Physiology: v. 47, p. 380-384.

Two papers, one topic.

What are these about?

Both of these papers are important first steps in our understanding of how stable isotopes can be used to understand plant physiology. Continue reading

Analyzing Salty Waters with Laser Spectroscopy – #365papers – 2017 – 47

#365papers for February 16, 2017

Skrzypek and Ford, 2014, Stable Isotope Analysis of Saline Water Samples on a Cavity Ring-down Spectroscopy Instrument: Environmental Science & Technology, v. 48, p. 2827-2834.

What’s it about?

This is a methods paper about how to analyze saline (salty) waters with the new laser-based isotope analyzers. It discusses several solutions to the problems that can arise when dealing with salty waters. Continue reading

Paleogene Mountains, Rivers, Lakes,… and Isotopes – #365papers – 2017 – 46

#365papers for February 15, 2017

Davis, Mulch, Carroll, Horton, and chamberlain, 2009, Paleogene landscape evolution of the central North American Cordillera: Developing topography and hydrology in the Laramide foreland: Geological Society of America Bulletin, v. 121, p. 100-116.

What’s it about?

This paper uses isotopes of oxygen, carbon, and strontium from multiple areas along the east edge and middle of the Rocky Mountains to explore the timing of the uplift of the Rockies, and to understand how the new mountains affected climate locally. Continue reading