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LAB WATCH Hippos Boast New Ancestor BY EMMANUELLE CRANE Left to right: evolution of a molar of Anthracotherium; Epirigenys; and primitive hippoppotamus. 9 SPRING 2015 N° 37 mariejulie.dalbe@ens-lyon.fr to peel the adhesive at constant speed, constant angle, and with a cons- tant length of free tape, the researchers found three ways in which the strip separates from its substrate: stable separation, whereby the tape peels at constant speed; stick-slip separation; and bistable state, where stick-slip and stable separations alternate. Each of these dynamics occurs only at certain angles and separation speeds. Of industrial interest is stable separation, which the study shows to happen not only at low speeds and large angles, but also at high speeds and large angles. To elucidate the screech of peeling tape, Dalbe and colleagues are already investigating the connection between the noise produced and the stick-slip instability. The results should be of great interest to the many industries that work with adhesive tape. ii In a context of massive commoditization, the rose trade has indeed become international. South America and East Africa are home to most of the world’s largest rose farms, whose only focus is profitability. Their flowers ultimately flood the florist shops in the northern hemisphere, which leads to the marketing of only two types of cultivars, says Veith. Mass distribution could therefore cause loss of diversity in commercial varieties. To reverse this trend, some growers have decided to help bring old, highly scented roses back into fashion. And most breeders, aware that scent is important to customers, are seeking to return fragrance to the types of roses currently available. Meanwhile, they also experiment with extraordinary scents, including parsley, aniseed, and more surprisingly, red wine. ii bveith@u-paris10.fr jean.claude.caissard@univ-st-etienne.fr Paleontology Family ancestry is always somewhat of a mystery, regardless of the species, but this is especially true in the case of hippopotamuses. Yet a joint French-Kenyan team has now solved the enigma. Researchers at ISEM1 and IPHEP,2 working in collaboration with the National Museums of Kenya, recently discovered a fossil that bridges the evolutionary gap between hippos and the common ancestor they share with cetaceans. This finding, published last February,3 also shows that the ancestors of hippos were among the most ancient mammals to colonize the African continent some 35 million years ago, long before large carnivores, giraffes, and bovids. Geneticists, using DNA comparisons, had highlighted the close relationship between hippos and cetaceans back in the 1990s and 2000s, but there were no fossils documenting hippo ancestry. The fossil species recently discovered in Lokone (Kenya) confirms an evolutionary scenario congruent with genetic data. Epirigenys Iokonensis (“epiri” means “hippo” in the Turkana language) forms a transition between hippos and a lineage of anthracotheres, a now extinct ungulate family. The interdisciplinary collaboration between geneticists and paleontologists is proving fruitful. While the fossils enabled paleontologists to determine precise dates and trace the evolutionary process, geneticists demonstrate wellestablished relationships between living organisms. “Now we want to understand whether hippo ancestors had an aquatic life or a purely terrestrial one,” says CNRS researcher Jean-Renaud Boisserie of the IPHEP. This would bring scientists closer to understanding the evolution of the group. The next step for the team is to go back in time some 40-55 million years, prior to the emergence of anthracotheres. “New discoveries of fossils will be decisive to shed light on the common origin of hippos and cetaceans,” Boisserie concludes. ii jean.renaud.boisserie@univ-poitiers.fr 1. Institut des sciences de l’évolution de Montpellier (Université de Montpellier-II / CNRS / IRD). 2. Institut de paléoprimatologie et paléontologie humaine: évolution et paléoenvironnements (Université de Poitiers / CNRS). 3. F. Lihoreau et al., “ Hippos stem from the longest sequence of terrestrial cetardiodactyl evolution in Africa,” Nature, 2015. 6:6264. © J.-R. BOISSERIE/LPRP 40 million years ago 28 million years ago 10 million years ago © M.-J. DALBE/ILM, UNIV. LYON


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