Baenid turtles
My master's research focused on the evolution of baenid turtles, with an emphasis on the assemblage preserved in the Cretaceous Kaiparowits Formation of southern Utah. Baenids were the most abundant and diverse pond and river turtles of the Late Cretaceous in North America, though they went extinct around 20 million years after the non-avian dinosaurs disappeared. I found that the baenid assemblage of Utah was twice as diverse as that of Alberta at the same snapshot in geologic time, ~76 million years ago. This is interesting because it has always been assumed that a reduced gradient in temperature between the equator and poles would have permitted 'cold-blooded' animals to range over broad latitudinal (north-south) ranges. That was not the case with baenids, and hints that ecosystems during greenhouse climates were more complex than previously thought.
Through my research on baenids, I discovered three new species: Arvinachelys goldeni, Neurankylus hutchisoni, and Neurankylus utahensis. Arvinachelys is unique in that it is the only turtle known that possessed two bony external nares (nasal openings), whereas all other turtles have only a single external naris with only a fleshy partition between the nostrils. The other two turtles were giants, with Neurankylus hutchisoni possessing a domed shell that was nearly 1 meter (3 feet) in length! Based on its size and shell shape, it may have been the giant tortoise of the Late Cretaceous.
Publications:
Lively, J.R. 2016. Baenid turtles from the Kaiparowits Formation (Upper Cretaceous: Campanian) of southern Utah. Journal of Systematic Palaeontology 14(11): 891-918. DOI:10.1080/14772019.2015.1120788. [published online 15 December 2015]
Lively, J. R. 2015. A new species of baenid turtle from the Kaiparowits Formation (Upper Cretaceous, Campanian) of southern Utah. Journal of Vertebrate Paleontology 35(6): e1009084. 16 pp. DOI: 10.1080/02724634.2015.1009084.*
*Media coverage of this project can be found here.
Ongoing projects:
My master's research focused on the evolution of baenid turtles, with an emphasis on the assemblage preserved in the Cretaceous Kaiparowits Formation of southern Utah. Baenids were the most abundant and diverse pond and river turtles of the Late Cretaceous in North America, though they went extinct around 20 million years after the non-avian dinosaurs disappeared. I found that the baenid assemblage of Utah was twice as diverse as that of Alberta at the same snapshot in geologic time, ~76 million years ago. This is interesting because it has always been assumed that a reduced gradient in temperature between the equator and poles would have permitted 'cold-blooded' animals to range over broad latitudinal (north-south) ranges. That was not the case with baenids, and hints that ecosystems during greenhouse climates were more complex than previously thought.
Through my research on baenids, I discovered three new species: Arvinachelys goldeni, Neurankylus hutchisoni, and Neurankylus utahensis. Arvinachelys is unique in that it is the only turtle known that possessed two bony external nares (nasal openings), whereas all other turtles have only a single external naris with only a fleshy partition between the nostrils. The other two turtles were giants, with Neurankylus hutchisoni possessing a domed shell that was nearly 1 meter (3 feet) in length! Based on its size and shell shape, it may have been the giant tortoise of the Late Cretaceous.
Publications:
Lively, J.R. 2016. Baenid turtles from the Kaiparowits Formation (Upper Cretaceous: Campanian) of southern Utah. Journal of Systematic Palaeontology 14(11): 891-918. DOI:10.1080/14772019.2015.1120788. [published online 15 December 2015]
Lively, J. R. 2015. A new species of baenid turtle from the Kaiparowits Formation (Upper Cretaceous, Campanian) of southern Utah. Journal of Vertebrate Paleontology 35(6): e1009084. 16 pp. DOI: 10.1080/02724634.2015.1009084.*
*Media coverage of this project can be found here.
Ongoing projects:
- One hundred years without a head: the first skull-shell association of Thescelus.
- The evolutionary biogeography of Late Cretaceous Baenidae.