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Université de Fribourg

Dental anomaly in a middle Miocene fossil of the genus Spermophilinus (Rodentia, Sciuridae) from southern Germany

Prieto, Jérôme ; Rummel, Michael ; Peláez-Campomanes, Pablo ; Vasilyan, Davit

In: Fossil Imprint, 2020, vol. 76, no. 1, p. 174-180

The maxillary presented in this work has been excavated in the middle Miocene karst filling Petersbuch 136 (Germany, Bavaria) and shows the oldest evidence of dental anomaly in a sciurid. The aberrant morphology, probably hyperdontia or no replacement of roots of deciduous teeth, affects the area of the P3, a tooth that is generally not well documented in the Spermophilinus record.

Université de Fribourg

Shining a light on species delimitation in the tree genus Engelhardia Leschenault ex Blume (Juglandaceae)

Zhang, Can-Yu ; Low, Shook Ling ; Song, Yi-Gang ; Nuraina ; Kozlowski, Gregor ; Do, Truong Van ; Li, Lang ; Zhou, Shi-Shun ; Tan, Yun-Hong ; Cao, Guan-Long ; Zhou, Zhuo ; Meng, Hong-Hu ; Li, Jie

In: Molecular Phylogenetics and Evolution, 2020, vol. 152, p. 106918

Enhanced efficacy in species delimitation is critically important in biology given the pending biodiversity crisis under global warming and anthropogenic activity. In particular, delineation of traditional classifications in view of the complexity of species requires an integrative approach to effectively define species boundaries, and this is a major focus of systematic biology. Here, we...

Université de Fribourg

Neuroanatomy of the spinosaurid Irritator challengeri (Dinosauria: Theropoda) indicates potential adaptations for piscivory

Schade, Marco ; Rauhut, Oliver W. M. ; Evers, Serjoscha W.

In: Scientific Reports, 2020, vol. 10, no. 1, p. 9259

Spinosauridae, a theropod group characterized by elongated snouts, conical teeth, enlarged forelimbs, and often elongated neural spines, show evidence for semiaquatic adaptations and piscivory. It is currently debated if these animals represent terrestrial carnivores with adaptations for a piscivorous diet, or if they largely lived and foraged in aquatic habitats. The holotype of Irritator...

Université de Fribourg

On the genus defect of positive braid knots

Liechti, Livio

In: Algebraic & Geometric Topology, 2020, vol. 20, no. 1, p. 403–428

We show that the difference between the Seifert genus and the topological 4–genus of a prime positive braid knot is bounded from below by an affine function of the minimal number of strands among positive braid representatives of the knot. We deduce that among prime positive braid knots, the property of having such a genus difference less than any fixed constant is characterised by finitely...

Université de Fribourg

The fossil record of the genus Varanus from the Southern Caucasus (Armenia, Georgia)

Vasilyan, Davit ; Bukhsianidze, Maia

In: PeerJ, 2020, p. e8322

The Southern Caucasus, with its special geographic position and complex topography, is a well-known biodiversity hotspot. However, the formation of this hotspot remains largely unstudied. To reveal this, a thorough study of the fossil record of the region is necessary. In the present paper, we describe for the first time fossil monitor lizards (Varanus sp.) from two late Miocene localities from...

Université de Fribourg

Early Agenian rhinocerotids from Wischberg (Canton Bern, Switzerland) and clarification of the systematics of the genus Diaceratherium

Jame​, Claire ; Tissier​​, Jérémy ; Maridet, Olivier ; Becker, Damien

In: PeerJ, 2019, vol. 7, p. e7517

Background: Wischberg is a Swiss locality in Bern Canton which has yielded numerous vertebrates remains from the earliest Miocene (= MN1). It has a very rich faunal diversity, one of the richest in Switzerland for this age. Among all the mammals reported in the original faunal list 70 years ago, three rhinocerotid species were identified. The material consists of two fragmentary skulls,...

Université de Fribourg

Species delimitation in the East Asian species of the relict tree genus Zelkova (Ulmaceae): A complex history of diversification and admixture among species

Naciri, Yamama ; Christe, Camille ; Bétrisey, Sébastien ; Song, Yi-Gang ; Deng, Min ; Garfì, Giuseppe ; Kozlowski, Gregor

In: Molecular Phylogenetics and Evolution, 2019, vol. 134, p. 172–185

Zelkova species, trees of the elm family (Ulmaceae), are part of the Cenozoic relict flora. In western Eurasia, the genus comprises three species that are restricted to disjunct areas (Z. sicula on Sicily, Z. abelicea on Crete and Z. carpinifolia in Transcaucasia). The situation is different in East Asia, where three species (Z. serrata, Z. schneideriana and Z. sinica) have at least partly...

Université de Fribourg

3D morphology of pharyngeal dentition of the genus Capoeta (Cyprinidae): Implications for taxonomy and phylogeny

Ayvazyan, Anna ; Vasilyan, Davit ; Böhme, Madelaine

In: Journal of Zoological Systematics and Evolutionary Research, 2019, vol. 57, no. 1, p. 179–190

Capoeta is a herbivorous cyprinid fish genus, widely distributed in water bodies of Western Asia. Recent species show a distinct biogeographic pattern with endemic distribution in large fluvial drainage basins. As other cyprinids, the species of this genus are characterized by the presence of the pharyngeal bone with pharyngeal teeth. Despite this, the detailed morphology of the pharyngeal...

Université de Fribourg

The genus Amphistegina (benthic foraminifera): distribution along the southern Tunisian coast

Kateb, Akram El ; Stalder, Claudio ; Stainbank, Stephanie ; Fentimen, Robin ; Spezzaferri, Silvia

In: BioInvasions Records, 2018, vol. 7, no. 4, p. 391–398

The benthic foraminiferal genus Amphistegina is currently expanding its range in the Mediterranean Sea after being introduced through the Suez Canal from the Red Sea. Over the previous decade, Amphistegina spp. has colonized the eastern part of the Mediterranean Sea including the Egyptian and Libyan coasts, but the present southern limit in the Mediterranean Sea is along the southern Tunisian...

Université de Fribourg

Eocene Western European endemic genus Thaumastosaurus: new insights into the question “Are the Ranidae known prior to the Oligocene?”

Vasilyan, Davit

In: PeerJ, 2018, vol. 6, p. e5511

Background Amphibians, due to their ecophysiological peculiarities, have a physiology dependent on environmental conditions and sensitively respond to their changes. Here, the oldest record of the genus Thaumastosaurus is described, whose fossil record known exclusively from Western Europe is discussed in the scope of the climatic changes of 33.5–40.5 Ma. Results In the present paper, the...