Tempo (Rate) and Mode (Style) of Evolution Are Not Related – #365papers – 2017 – 56

#365papers for February 25, 2017

Voje, 2016, Tempo does not correlate with mode in the fossil record: Evolution, v. 70, p. 2678-2689.

What’s it about?

Tempo describes the rate of evolution. Is change happening quickly, or is it very very slow? This is distict from mode, which describes the pattern of evolution. Is there a direction to the change, all individuals growing bigger than their predecessors, for example? Is there no apparent change over time? Is there change, but it seems to be going back and forth, where sometimes descendants are bigger and sometimes they’re smaller?

This paper shows that there is no relationship between tempo and mode. Continue reading

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 Рthe flying reptiles Рand 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

Doctoral Day! – Mammals of the Torrejonian-Tiffanian (Paleocene) Transition – #365papers – 2017 – 45

#365papers for February 14, 2017

Higgins, 2003, A Wyoming succession of Paleocene mammal-bearing localities bracketing the boundary between the Torrejonian and Tiffanian North American Land Mammal “Ages”: Rocky Mountain Geology, v. 38.

What’s it about?

This paper discusses the nature of the boundary between two adjacent North American Land Mammal “Ages” (NALMAs). NALMAs are defined by the presence or absence of certain mammal species and are usually quite different in species composition. The 136 localities studied here bracket the Torrejonian-Tiffanian boundary, so we can examine the transition more closely. Continue reading

The Last Glacial Maximum in Wyoming. A Story From Tooth Enamel – #365papers – 2017 – 44

#365papers for February 13, 2017

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

What’s it about?

This paper uses measurements of stable isotopes of carbon and oxygen from tooth enamel to interpret past mean annual precipitation and other climatic variables for two caves in Wyoming. Continue reading

How Do the Early Processes of Fossilization Affect the Chemistry of Bones and Teeth? – #365papers – 2017 – 41

#365papers for February 10, 2017

Tutken, Vennemann, and Pfretzschner, 2008, Early diagenesis of bone and tooth apatite in fluvial and marine settings: Constraints from combined oxygen isotope, nitrogen and REE analysis: Palaeogeography, Palaeoclimatology, Palaeoecology, v. 266, p. 254-268.

What’s it about?

This paper discusses how we can determine how altered a geochemical signal in a fossil bone or tooth might be, comparing bones and teeth that fossilized in both freshwater (river) and marine (ocean) environments. The authors used collagen content, nitrogen content, and the abundance of Rare Earth Elements (REEs) to attempt to estimate alteration. Continue reading

How Can Paleobiology Help Conservation Efforts? – #365papers – 2017 – 40

#365papers for February 9, 2017

Barnosky et al, 2017, Merging paleobiology with conservation biology to guide the future of terrestrial ecosystems: Science, v. 355, eaah4787.

What’s it about?

This paper discusses the kinds of decisions that must be made by conservation biologists when trying to save species and ecosystems. These decisions depend on the overall goals of conservation: the maintain and restore current ecosystems, to save species, or to maximize biodiversity for example. These decisions can be informed by paleobiology. Continue reading