Paleocene Mammals from Brazil – #365papers – 2018 – 67

de Paula Couto, 1952, Fossil Mammals from the Beginning of the Cenozoic in Brazil, Condylarthra, Litopterna, Xenungulata, and Astrapotheres: Bulletin of the American Museum of Natural History, v. 99, 355-394.

What’s it about?

This paper is a listing, with descriptions, of most of the Paleocene mammals of Brazil at the time of its writing (1952). Several new species, genera, families, and even orders are named, in many cases by the author, Carlos de Paula Couto. Continue reading

Why is Irritator so Irritating? – #365papers – 2018 – 66

Martill, Cruickshank, Frey, Small, and Clarke, 1996, A new crested maniraptoran dinosaur from the Santana Formation (Lower Cretaceous) of Brazil: Journal of the Geological Society, London, v. 153, p. 5-8.

What’s it about?

This paper is the description of a new species (and Genus and Family) of dinosaur, grouped with the tetanuran theropods, a subgroup of carnivorous dinosaurs along the lineage leading to modern birds.

The type specimen was collected from the Santana Formation in Brazil, the same unit that gave us Santanaraptor. Continue reading

A Lost Titan – #365papers – 2018 – 65

Kellner and Azevedo, 1999, A new sauropod dinosaur (Titanosauria) the the Late Cretaceous of Brazil, in Tomida, Rich, and Vickers-Rich, eds., Proceedings of the Second Gondwanan Dinosaur Symposium: National Science Museum Monographs, no. 15, p. 111-142.

What’s it about?

This paper is a detailed description of Gondwanatitan foustoi, a new species of titanosaur (a sauropod) from Brazil. This new species is based upon specimen number MN 4111-V at the Museu Nacional. The material includes several vertebrae, part of a shoulder blade, parts of the hips, upper arm and lower leg bones, and some ribs. Continue reading

The Dinosaurs of the Santana Formation, Brazil – #365papers – 2018 – 64

Naish, Martill, and Frey, 2004, Ecology, systematics and biogeographical relationships of dinosaurs, including a new theropod, from the Santana Formation (?Albian, Early Cretaceous) of Brazil: Historical Biology, v. 16, p. 1-14.

What’s it about?

The Santana Formation of the Araripe Basin of northeastern Brazil has yielded many important fossils, including some dinosaurs. Notably, Santanaraptor, described in an earlier post, is one of many dinosaurs known from the Santana Formation. It is interesting, however, that almost all the dinosaurs known from the Santana Formation are predatory dinosaurs. Continue reading

On Fossil Eggshells – #365papers – 2018 – 63

Montanari, 2018, Cracking the egg: the use of modern and fossil eggs for ecological, environmental and biological interpretation: Royal Society Open Science, v. 5, 180006.

What’s it about?

Most people think of bones or shells as the most important mineralized remains of fossil animals. Vertebrates, particularly land-dwelling vertebrates, produce a third important (though often overlooked) mineralized remnant: Egg shells. Continue reading

Infrared Light and the Quality of Fossil Preservation – #365papers – 2018 – 62

Beasley, Bartelink, Taylor, and Miller, 2014, Comparison of transmission FTIR, ATR, and DRIFT spectra: implications for assessment of bone bioapatite diagenesis: Journal of ARchaeological Science, v. 46, p. 16-22.

What’s it about?

One of the challenges of studying the chemistry of fossil bones and teeth is being confident that the chemistry of the fossils is unaltered from its original state (that is, the bones and teeth still faithfully record the chemistry of the living animal they came from). During the process of fossilization, the mineral and chemical structure of bones and teeth are altered from what they were in life, a process called diagenesis. Continue reading

Long Distance Prospecting – #365papers – 2018 – 61

Conroy, Emerson, Anemone, and Townsend, 2012, Let your fingers do the walking: A simple spectral signature model for “remote” fossil prospecting: Journal of Human Evolution, v. 63, p. 79-84.

What’s it about?

The authors demonstrate the utility of satellite imagery combined with surface observations and GIS software to make predictions about where fossil localities may be located. Continue reading

When Two Species Merge into One – #365papers – 2018 – 60

Kearns, Restani, Szabo, Schoder-Nielsen, Kim, Richardson, Marzluff, Fleisher, Johnsen, and Omland, 2018, Genomic evidence of speciation reversals in ravens: Nature Communications, v. 9, 906

What’s it about?

The authors describe how what were once two distinct lineages of ravens (the Californian and the holarctic) have merged into what we now refer to as the common raven in the western United States. Using evidence from mitochondrial DNA, the authors show that not only is the common raven the result of the fusion of two lineages, but that the Chihuahuan raven, that lives alongside the common raven, is a descendant of the Californian raven. Continue reading

Bringing Up Baby (Mountains) in Western North America – #365papers – 2018 – 59

Yonkee and Weil, 2015, Tectonic evolution of the Sevier and Laramide belts within the North American Cordillera orogenic system: Earth-Science Reviews: v. 150, p. 531-593

What’s it about?

This paper is a wonderful, yet highly technical, summary of the tectonic events leading to the Rocky Mountains as we know them today. Continue reading

Pharyngeal Denticles and the Placoderms – #365papers – 2018 – 58

Johanson and Smith, 2005, Origin and evolution of gnathostome dentitions: a question of teeth and pharyngeal denticles in placoderms: Biological Reviews, v. 80, p. 303-345

What’s it about?

This paper presents a detailed discussion of tooth development in fishes. In particular, the authors review the state of knowledge of tooth development in placoderms, among the first of the jawed fishes and now extinct. They also make observations about denticles, tooth-like bumps, on the gill arches of many fishes, including jawless forms, and how the development of these relate the development of teeth and external scales in early fishes. With these details, the authors propose a hypothesis for the origins and development of teeth in placoderms and in modern fishes. Continue reading