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Université de Fribourg

Enigmatic dinosaur precursors bridge the gap to the origin of Pterosauria

Ezcurra, Martín D. ; Nesbitt, Sterling J. ; Bronzati, Mario ; Vecchia, Fabio Marco Dalla ; Agnolin, Federico L. ; Benson, Roger B. J. ; Egli, Federico Brissón ; Cabreira, Sergio F. ; Evers, Serjoscha W. ; Gentil, Adriel R. ; Irmis, Randall B. ; Martinelli, Agustín G. ; Novas, Fernando E. ; Silva, Lúcio Roberto da ; Smith, Nathan D. ; Stocker, Michelle R. ; Turner, Alan H. ; Langer, Max C.

In: Nature, 2020, vol. 588, no. 2020-7838, p. 445–449

Pterosaurs were the first vertebrates to evolve powered flight1 and comprised one of the main evolutionary radiations in terrestrial ecosystems of the Mesozoic era (approximately 252–66 million years ago), but their origin has remained an unresolved enigma in palaeontology since the nineteenth century2,3,4. These flying reptiles have been hypothesized to be the close relatives of a wide...

Université de Fribourg

Fossil amphibians and reptiles from the Neogene locality of Maramena (Greece), the most diverse European herpetofauna at the Miocene/Pliocene transition boundary

Georgalis, Georgios L. ; Villa, Andrea ; Ivanov, Martin ; Vasilyan, Davit ; Delfino, Massimo

In: Palaeontologia Electronica, 2019, p. -

We herein describe the fossil amphibians and reptiles from the Neogene (latest Miocene or earliest Pliocene; MN 13/14) locality of Maramena, in northern Greece. The herpetofauna is shown to be extremely diverse, comprising at least 30 different taxa. Amphibians include at least six urodelan (Cryptobranchidae indet., Salamandrina sp., Lissotriton sp. [Lissotriton vulgaris group], Lissotriton sp.,...

Université de Fribourg

Mechanisms of vision in the fruit fly

Andres-Bragado, Lucia de ; Sprecher, Simon G.

In: Current Opinion in Insect Science, 2019, vol. 36, p. 25–32

Vision is essential to maximize the efficiency of daily tasks such as feeding, avoiding predators or finding mating partners. An advantageous model is Drosophila melanogaster, since it offers tools that allow genetic and neuronal manipulation with high spatial and temporal resolution, which can be combined with behavioral, anatomical and physiological assays. Recent advances have expanded our...

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

Early Miocene herpetofaunas from the Greek localities of Aliveri and Karydia – bridging a gap in the knowledge of amphibians and reptiles from the early Neogene of southeastern Europe

Georgalis, Georgios L. ; Villa, Andrea ; Ivanov, Martin ; Roussiakis, Socrates ; Skandalos, Panagiotis ; Delfino, Massimo

In: Historical Biology, 2019, vol. 31, no. 8, p. 1045–1064

We here describe new remains of amphibians and reptiles from the early Miocene (MN 4) of two different Greek localities, Aliveri and Karydia. The newly described material consists of urodelans, alytids, indeterminate anurans, turtles, crocodylians, lacertids, indeterminate scincomorphs, anguids, colubrids, viperids, and indeterminate snakes. The presence of the frog Latonia cf. gigantea in...

Université de Fribourg

Adaptation to developmental diet influences the response to selection on age at reproduction in the fruit fly

May, Christina M. ; Heuvel, Joost van den ; Doroszuk, Agnieszka ; Hoedjes, Katja M. ; Flatt, Thomas ; Zwaan, Bas J.

In: Journal of Evolutionary Biology, 2019, vol. 32, no. 5, p. 425–437

Experimental evolution (EE) is a powerful tool for addressing how environmental factors influence life‐history evolution. While in nature different selection pressures experienced across the lifespan shape life histories, EE studies typically apply selection pressures one at a time. Here, we assess the consequences of adaptation to three different developmental diets in combination with...

Université de Fribourg

The adaptive significance of chromosomal inversion polymorphisms in Drosophila melanogaster

Kapun, Martin ; Flatt, Thomas

In: Molecular Ecology, 2019, vol. 28, no. 6, p. 1263–1282

Chromosomal inversions, structural mutations that reverse a segment of a chromosome, cause suppression of recombination in the heterozygous state. Several studies have shown that inversion polymorphisms can form clines or fluctuate predictably in frequency over seasonal time spans. These observations prompted the hypothesis that chromosomal rearrangements might be subject to spatially and/or ...

Université de Fribourg

dSir2 and Dmp53 interact to mediate aspects of CR‐dependent life span extension in D. melanogaster

Bauer, Johannes H. ; Morris, Siti Nur Sarah ; Chang, Chenguyi ; Flatt, Thomas ; Wood, Jason G. ; Helfand, Stephen L.

In: Aging, 2009, vol. 1, no. 1, p. 38-48

Calorie Restriction (CR) is a well established method of extending life span in a variety of organisms. In the fruit fly D. melanogaster, CR is mediated at least in part by activation of dSir2. In mammalian systems, one of the critical targets of Sir2 is the tumor suppressor p53. This deacetylation of p53 by Sir2 leads to inhibition of p53's transcriptional activity. We have recently shown...

Université de Fribourg

Paying the costs of reproduction

Flatt, Thomas

In: eLife, 2015, vol. 4, p. e09556

When a female fly mates it produces a hormone that increases the size of its midgut and enhances fat metabolism in order to provide the energy needed for reproduction.

Université de Fribourg

Comparing thyroid and insect hormone signaling

Flatt, Thomas ; Moroz, Leonid L. ; Tatar, Marc ; Heyland, Andreas

In: Integrative and Comparative Biology, 2006, vol. 46, no. 6, p. 777-794

Transitions between different states of development, physiology, and life history are typically mediated by hormones. In insects, metamorphosis and reproductive maturation are regulated by an interaction between the sesquiterpenoid juvenile hormone (JH) and the steroid 20-hydroxy-ecdysone (20E). In vertebrates and some marine invertebrates, the lipophilic thyroid hormones (THs) affect...