Author Archives: paleololigo

#365papers for April 2, 2017

Carr, Varricchio, Sedlmayr, Roberts, and Moore, 2017, A new tyrannosaur with evidence for anagenesis and crocodile-like facial sensory system: Nature Scientific Reports. DOI:10.1038/srep44942.

What’s it about?

This paper describes a new member of the Subfamily Tyrannosaurinae from the late Cretaceous of Montana. Two important things came from this study:

1. The different species of tyrannosaurids that occur at different times may be the result of evolution along a single lineage, a process called anagenesis
2. The structure of the skull suggests that the face of this tyrannosaurid was highly sensitive to touch.

Continue reading “Feelings. Tyrannosaurid feelings – #365papers – 2017 – 92”

#365papers for March 31, 2017

Wood, Ivantsov, and Zhuravlev, 2017, First macrobiota biomineralization was environmentally triggered: Proceedings of the Royal Society B, v 284: 201700059

What’s it about?

It’s skeletons that we mostly see in the fossil record. The fossil record prior to the advent of mineralized skeletons (bones and shells, for example) is pretty sparse. Here, the authors show some very early organisms with skeletons (from around 550 million years ago) that have similar counterparts that lack the skeletons. Skeletons appear to have developed during times of environmental change, when minerals naturally grew around the bodies of the originally soft-bodied animals. Later, organisms took charge of this mineral growth to build the complex skeletons that we see in modern animals and plants.Continue reading “When the Environment Changed, Animals Made Skeletons – #365papers – 2017 – 90”

#365papers for March 30, 2017

Bailleul and Holliday, 2017, Joint histology in Alligator mississippiensis challenges the identification of synovial joints in fossil archosaurs and inferences of cranial kinesis: Proceedings of the Royal Society B, v. 284: 20170038

What’s it about?

In the past, when paleontologists have observed joints between bones, especially in the skull, that possess smooth surfaces, an assumption as been made that these joints are flexible. Flexible joints in the skull result in cranial kinesis, where the head can be deformed as exemplified by modern snakes as they consume prey much larger than their own heads. The authors show, through study of modern alligator skulls, that smooth joint surfaces don’t necessarily mean that a joint was movable, and that detailed study of the structure of the bone itself is needed to know if a joint could bend or not.Continue reading “Not All Joints Are Flexible – #365papers – 2017 – 89”

#365papers for March 29, 2017

Mallon, 2017, Recognizing sexual dimorphism in the fossil record: Lessons from nonavian dinosaurs: Paleobiology, DOI:10.1017/pab.2016.51

What’s it about?

In paleontology, we define species by what they look like. This can be problematic if males and females of one species look markedly different from one another. Some authors have claimed to see sexual dimorphism, the difference in shape between males and females in a species, based on size. Here, the author shows that it is essentially impossible with the fossil record to make such determinations.Continue reading “Telling the Boys from the Girls in Fossils – #365papers – 2017 – 88”

#365papers for March 28, 2017

Getty, Aucoin, Fox, Judge, Hardy, and Bush, 2017, Perennial lakes as an environmental contol on theropod movement in the Jurassic of the Hartford Basin: Geosciences, v. 7, doi:10.3390/geosciences7010013

What’s it about?

This is a paper about dinosaur tracks. Specifically, it discusses how dinosaur tracks, when they all seem to go in the same direction, are used as evidence that dinosaurs traveled in herds. Here, they show that the reason why the dinosaurs were all going the same way has to do with a lake near by, and not that the dinosaurs were all traveling together.Continue reading “When Water Stopped the Dinosaurs – #365papers – 2017 – 87”