Isostylomys: A Rodent of Unusual Size – #365papers – 2017 – 107

#365papers for April 17, 2017

Rinderknecht, Bostelmann, annd Ubilla, 2017, Making a giant rodent: cranial anatomy and ontogenetic development in the genus Isostylomys (Mammalia, Hystricognathi, Dinomyidae): Journal of Systematic Palaeontology, DOI: 10.1080/14772019.2017.1285360.

What’s it about?

Isostylomys is (was) a giant rodent from the Miocene of Uruguay. By giant, I mean larger than the largest rodent today. I mean huge.

The authors here discuss the status of the genus and its relationships with other rodents. Importantly, they show how it is very possible that some species of South American large rodents might be juvenile forms of giant rodents like Isostylomys. Continue reading

The Shortest-Necked of the Long-Necked Elasmosaurs – #365papers – 2017 – 108

#365papers for April 18, 2017

Serratos, Druckenmiller, and Benson, 2017, A new elasmosaurid (Sauropterygia, Plesiosauria) from the Bearpaw Shale (Late Cretaceous, Maastrichtian) of Montana demonstrates multiple evolutionary reduction of neck length within Elasmosauridae: Journal of Vertebrate Paleontology e1278608.

What’s it about?

Elasmosaurids were marine reptiles that are considered a sub-group of the plesiosaurs. Distinctive features of elasmosaurids are their very long necks and small heads. Here, a new species of elasmosaurid is described that had a relatively short neck and was also fairly small. Continue reading

What Really Is Ichthyosaurus? – #365papers – 2017 – 106

#365papers for April 16, 2017

Massare and Lomax, 2017, A taxonomic reassessment of Ichthyosaurus communis and I. intermedius and a revised diagnosis for the genus: Journal of Systematic Paleontology. DOI: 10.1080/14772019.2017.1291116.

What’s it about?

Ichthyosaurus is (or was) a type of marine reptile that looked sort of dolphin-like.

Ichthyosaurus communis from the Natural History Museum in London. Credit Gehdoghedo CC 3.0 By SA

Ichthyosaurus communis life reconstruction.
Credit: Nobu Tamura CC BY 3.0

Here, the authors work to distinguish between three common species of Ichthyosaurus, I. communis, I. intermedius, and I. breviceps. The authors also present a better definition for the genus Ichthyosaurus. Continue reading

Body Size, Metabolic Rate, and Body Temperature in Giant Sloth Evolution – #365papers – 2017 – 105

#365papers for April 15, 2017

Toldeo, Bargo, Vizcaino, Iuliis, and Pujos, 2017, Evolution of body size in anteaters and sloths (Xenarthra, Pilosa): phylogeny, metabolism, diet and substrate preferences: Earth and Environmental Science Transaction of the Royal Society of Edinburgh, v. 106, p. 289-301.

What’s it about?

Modern sloths are tiny, tree-dwelling herbivores that dangle below the branches and move very, very slowly. However, in the past, there were enormous sloths that ranged across the landscape.

This paper discusses both anteaters and sloths, the modern components of which have adaptations for eating diets of low nutrition. The fossil record of both closely related groups are studied, and the relationships between great size and inferred metabolic rate and diets are considered. Continue reading

M is for Macrotarsius – #AtoZChallenge – 2017 – Uintan Mammals

M is for Macrotarsius

Macrotarsius is a fossil primate closely related to and similar in appearance to modern tarsiers.

Philippine Tarsier (Carlito syrichta), one of the smallest primates. This one is about 5 inches long with a tail longer than its body. Photo taken in Bohol, Philippines. Credit: mtoz CC 2.0 By SA

Modern tarsiers are unique in the structure of their back foot, specifically the ankle bones (the tarsals), hence their common name of ‘tarsier.’

 

 

L is for Leptotragulus – #AtoZChallenge – 2017 – Uintan Mammals

L is for Leptotragulus

Leptotragulus was a hoofed mammal that would have roughly looked like a deer, but were more closely related to camels and llamas. They were a member of a group called the Protoceratidae, that were unique in having horns on their snouts.

Here is a relative of Leptotragulus, Synthetoceras:

Synthetoceras tricornatus. Credit: Nobu Tamura CC 3.0 By

 

Who (or What) is Procerberus – #365papers – 2017 – 104

#365papers for April 14, 2017

Clemens, 2017, Procerberus (Cimolestidae, Mammalia) from the latest Cretaceous and earliest Paleocene of the northern western interior, USA: Paleobios, v. 34.

What’s it about?

Procerberus is a genus of mammal that lived mostly just after the extinction of the dinosaurs. There is some confusion about the distinctions among the several species of Procerberus and the relationship of this genus to other groups of mammals. This paper is about sorting that all out. Continue reading

Air Sacs and Uniquely Hollow Bones in a New Sauropod – #365papers – 2017 – 103

#365papers for April 13, 2017

Ibiricu, Lamanna, Martinez, Casal, Cerda, Martinez, and Salgado, 2017, A novel form of postrcranial skeletal pneumaticity in a sauropod dinosaur: Implications for the paleobiology of Rebbachisauridae: Acta Palaeontologica Polonica.

What’s it about?

In birds, dinosaurs, and some other archosaurs (includes crocodilians) there are often hollow spaces in bones that are connected to the respiratory system. The hollowness of bones is called pneumaticity. The authors here describe the bones of a recently described species Katepensaurus goicoecheai. Katepensaurus shows a style of pneumaticity that is not seen in any other dinosaurs. Continue reading