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Université de Fribourg

Cranial osteology of the early cretaceous turtle Pleurosternon bullockii (paracryptodira: pleurosternidae)

Evers, Serjoscha W. ; Rollot, Yann ; Joyce, Walter G.

In: PeerJ, 2020, vol. 8, p. e9454

Pleurosternon bullockii is a turtle from the Early Cretaceous of Europe known from numerous postcranial remains. Only one skull has so far been referred to the species. Pleurosternon bullockii belongs to a group of turtles called pleurosternids, which is thought to include several poorly known taxa from the Late Jurassic and Early Cretaceous of Europe and North America. Pleurosternids and...

Université de Fribourg

The last surviving Thalassochelydia — A new turtle cranium from the Early Cretaceous of the Purbeck Group (Dorset, UK)

Anquetin, Jérémy ; André, Charlotte

In: PaleorXiv, 2020, p. 7pa5c

Background. The mostly Berriasian (Early Cretaceous) Purbeck Group of southern England has produced a rich turtle fauna dominated by the freshwater paracryptodires Pleurosternon bullockii and Dorsetochelys typocardium. Each of these species is known by numerous relatively complete shells and by a single cranium. The two other turtles found in the Purbeck Group (Hylaeochelys belli, a species of...

Université de Fribourg

A new species of baenid turtle from the Early Cretaceous Lakota Formation of South Dakota

Joyce, Walter G. ; Rollot, Yann ; Cifelli, Richard L.

In: Fossil Record, 2020, vol. 23, no. 1, p. 1–13

Baenidae is a clade of paracryptodiran turtles known from the late Early Cretaceous to Eocene of North America. The proposed sister-group relationship of Baenidae to Pleurosternidae, a group of turtles known from sediments dated as early as the Late Jurassic, suggests a ghost lineage that crosses the early Early Cretaceous. We here document a new species of paracryptodiran turtle, Lakotemys...

Université de Fribourg

A review of the fossil record of nonbaenid turtles of the clade Paracryptodira

Joyce, Walter G. ; Anquetin, Jérémy

In: Bulletin of the Peabody Museum of Natural History, 2019, vol. 60, no. 2, p. 129–155

The fossil record of nonbaenid paracryptodires ranges from the Late Jurassic (Kimmeridgian) to the Paleocene of North America and Europe only. Earlier remains may be present as early as the Middle Jurassic (Bathonian). Only a single dispersal event is documented between the two continents after their breakup during the Cretaceous in the form of the appearance of the Compsemys lineage in the ...

Université de Fribourg

Estimating the phylogeny of geoemydid turtles (Cryptodira) from landmark data: an assessment of different methods

Ascarrunz​, Eduardo ; Claude, Julien ; Joyce, Walter G.

In: PeerJ, 2019, vol. 7, p. e7476

Background: In the last 20 years, a general picture of the evolutionary relationships between geoemydid turtles (ca. 70 species distributed over the Northern hemisphere) has emerged from the analysis of molecular data. However, there is a paucity of good traditional morphological characters that correlate with the phylogeny, which are essential for the robust integration of fossil and...

Université de Fribourg

Comparative analysis of the shape and size of the middle ear cavity of turtles reveals no correlation with habitat ecology

Foth, Christian ; Evers, Serjoscha W. ; Joyce, Walter G. ; Volpato, Virginie S. ; Benson, Roger B. J.

In: Journal of Anatomy, 2019, no. 0, p. -

The middle ear of turtles differs from other reptiles in being separated into two distinct compartments. Several ideas have been proposed as to why the middle ear is compartmentalized in turtles, most suggesting a relationship with underwater hearing. Extant turtle species span fully marine to strictly terrestrial habitats, and ecomorphological hypotheses of turtle hearing predict that this...

Université de Fribourg

Novel insights into the morphology of Plesiochelys bigleri from the early Kimmeridgian of Northwestern Switzerland

Raselli, Irena ; Anquetin, Jérémy

In: PLOS ONE, 2019, vol. 14, no. 5, p. e0214629

Plesiochelyidae were relatively large coastal marine turtles, which inhabited the epicontinental seas of Western Europe during the Late Jurassic. Their fossil record can be tracked in Germany, Switzerland, the United Kingdom, France, Spain and Portugal. The Jura Mountains, in northwestern Switzerland, have been the main source for the study of this group, mostly thanks to the rich and famous...

Université de Fribourg

A description of the skull of eubaena cephalica (hay, 1904) and new insights into the cranial circulation and innervation of baenid turtles

Rollot, Yann ; Lyson, Tyler R. ; Joyce, Walter G.

In: Journal of Vertebrate Paleontology, 2018, vol. 38, no. 3, p. e1474886

The internal carotid system has played an important role in the systematics of fossil turtles, including baenids. A new, almost perfectly preserved specimen of Eubaena cephalica provides an opportunity to explore for the first time the cranial circulation and innervation of this taxon using CT (computed tomography) scans. We here document that the skull possesses a well-developed, branching...

Consortium of Swiss Academic Libraries

From Cycle Rooted Spanning Forests to the Critical Ising Model: an Explicit Construction

de Tilière, Béatrice

In: Communications in Mathematical Physics, 2013, vol. 319, no. 1, p. 69-110