Oxygenating the Oceans in the Early Cambrian – #365papers – 2018 – 8

Zhang, Chang, Khan, Feng, Denelian, Clausen, Tribovillard, and Steiner, 2017, The link between metazoan diversity and paleo-oxygneation in the early Cambrian: An integrated palaeontological and geochemical record from the eastern Three Gorges Region of South China: Palaeogeography, Palaeoclimatology, Palaeoecology.

What’s it about?

The Cambrian is the period of Earth’s history in which many of the modern groups of multicelluar organisms appeared in the fossil record for the first time. Some have argues that this also when these groups first appeared (the so-called “Cambrian Explosion”), but that’s not necessarily the case and is a good topic for another blog post. Rocks in South China provide a good record of this period of time and the authors show that the amount of oxygen in the ocean (and therefore in the atmosphere) fluctuated frequently during this important period of time. Continue reading

Comparing Modern and Fossil Diving Birds – #365papers – 2018 – 7

Bell, Wu, and Chiappe, in press, Morphometric comparison of the Hesperornithiformes and modern diving birds: Palaeogeography, Palaeoclimatology, Palaeoecology.

What’s it about?

The Hesperornithiformes are toothed birds that lived during the Cretaceous period. They are not directly related to modern birds, but clearly were birds that lived near water and foraged by diving, similar to modern cormorants, loons, grebes, and some ducks. In the past, some scientists have considered hesperornithiforms most similar to grebes and loons, but this paper shows that cormorants are a better modern analogue. Continue reading

Geochemistry Shows Oldest “Fossils” Really Are Fossils – #365papers – 2018 – 6

Schopf, Kitajima, Spicuzza, Kudryavtsev, Valley, 2018, SIMS analyses of the oldest known assemblage of microfossils document their taxon-correlated carbon isotope compositions: Proceedings of the National Academy of Sciences, v. 115, p. 53-58.

What’s it about?

The best evidence for the origins of life on this planet are geochemical signatures in rocks representing the metabolism of living organisms. Here, the authors show that the geochemical (isotopic) signatures directly correlate with what have been interpreted at the body fossils of primitive life forms, mostly bacteria. Continue reading

Finding Family for Extinct Seals – #365papers – 2018 – 5

Boessenecker and Churchill, 2018, The last of the desmatophocid seals: a new species of Allodesmus from the Upper Miocene of Washington, USA, and a revision of the taxonomy of Desmatophocidae, Zoological Journal of the Linnean Society.

What’s it about?

This paper first describes a new species of seal and then goes on to show where that seal, and the family it is in (the Desmatopocidae), fit within the evolutionary sequence of modern seals. Continue reading

Understanding Variation in Body Shape and Size in Extinct and Unusual Mammals – #365papers – 4

Gaudin and Lyon, 2017, Cranial osteology of the pampathere Holmesina floridanus (Xenarthra: Cingulata; Blanca NALMA), including a description of an isolated petrosal bone: PeerJ 5:e4022; DOI 10.7717/peerj.4022

What’s it about?

This paper is a detailed description of several fossil skulls of the Holmesina floridanus, a pampathere that once lived in Florida. These skulls are then compared with other species of Holmesina from North and South America, and to skulls of other pampatheres. Continue reading

The genetic origins of ‘handedness’ in humans – #365papers – 3

Ocklenburg, Schmitz, Moinfar, Moser, Klose, Lor, Kunz, Tegenthoff, Faustmann, Francks, Epplen, Kumsta, Gunturkun, 2017, Epigenetic regulation of lateralized fetal spinal gene expression underlies hemispheric asymmetries, eLIFE, e22784

What’s it about?

Most people are right handed. Researchers have wondered why. This paper discusses the state-of-the-art in studying the development of preferred hand-use during early development of human embryos. It turns out that much of ‘handedness’ may come from gene expression in the spinal cord and not so much in the brain. Continue reading

The Archaeopteryx that was neither Archaeopteryx nor Pterodactylus – #365papers – 2018 – 2

Foth and Rauhut, 2017, Re-evalutation of the Haarlem Archeopteryx and the radiation of maniraptoran theropod dinosaurs: BMC Evolutionary Biology, v. 17, 236.

What’s it about?

Archeopteryx is a fossil theropod that is known only from limestones of Bavaria, Germany. The Haarlem specimen is incomplete. Initially, it was thought to be a pterosaur, then was later discovered to be a dinosaur and assigned to the genus Archaeopteryx. The authors here show that though it is a dinosaur, it is actually not Archeopteryx and name a new genus, Ostromia. Continue reading

Carboniferous Glaciers of Chad – #365papers – 2018 – 1

Le Heron, 2018, An exhumed Paleozoic glacial landscape in Chad: Geology, v. 46, p. 91-94.

What’s it about?

Rocks of early Carboniferous age (mid-Mississippian, about 340 million years ago) in Chad show evidence of the passage of glaciers. Today, this part of the world is largely desert. This paper discusses the evidence for ancient glaciers and shows that they are not modern features of the wind. Continue reading

Friday Headlines: September 8, 2017

Friday Headlines, September 8, 2017

THE LATEST IN THE GEOSCIENCES

Today’s round-up:

Irma on my mind…

Hurricane Irma is bearing down on the state of Florida. Today’s headlines are about how we know what we know about hurricanes well before they make landfall.

  • Doppler Radar – How does it work?
  • Satellite Precipitation Measurements – How is this possible?
  • Forecast Tracks – How do they do that?

Continue reading