Moderately sized plesiosaurs, they reached roughly 11-15 feet in length. They had small, narrow heads, with long teeth adapted for catching fish. They probably swam with an undulating movement, using their rear paddles in a flying motion and their front paddles for stabilisation and to control the angle and direction they swam in. Fossils have been found containing gastroliths, which they would have swallowed to regulate their buoyancy- using the weight of the stones to counteract the air in their lungs.
“Plesiosaurus” is also a wastebasket taxon, meaning all sorts of fossil specimens have been assigned this name (Iguanodon and Megalosaurus were, and still are, wastebasket taxons, thanks to 19th Century paleontologists.)
“Scientists are exploring dripping passages by the light of headlamps, mapping out an ecosystem from 307 million years ago, just before the world’s first great forests were wiped out by global warming. This vast prehistoric landscape may shed new light on climate change today.
Dating from the Pennsylvanian period of the Carboniferous era, the forest lies entombed in a series of eight active mines. They burrow through the rich seams of the Springfield Coal, a nationally important energy resource that underlies much of Illinois and two neighboring states and has been heavily mined for decades.”
Thus 38% of the variation in trace metal is explained by the variation in reduced carbon. White indicates areas where the correlation is high and in this case shows how the Cu zoning is strongly controlled by scale pattern in the skin.
Does this fossil show the first trace of biomineralization?
Researchers in the Canadian Yukon have uncovered three different species of algae, each showing signs of having a hard, mineralized exterior. The fossils date back to 750 million years ago, which is about the same time that independent research teams previously estimated biomineralization occurred. The process is significant, because it was the first step towards developing skeletons. Although life survived for nearly 3 billion years without skeletons, the Cambrian explosion ushered in a wave of biodiversity, and skeletons have arisen around two dozen different times in animals.
Early Eocene land bridges allowed numerous plant and animal species to cross between Europe and North America via the Arctic. While many species suited to prevailing cool Arctic climates would have been able to cross throughout much of this period, others would have found dispersal opportunities only during limited intervals when their requirements for higher temperatures were met. Here, we present Titanomyrma lubei gen. et sp. nov. from Wyoming, USA, a new giant (greater than 5 cm long) formiciine ant from the early Eocene (approx. 49.5 Ma) Green River Formation. We show that the extinct ant subfamily Formiciinae is only known from localities with an estimated mean annual temperature of about 20°C or greater, consistent with the tropical ranges of almost all of the largest living ant species. This is, to our knowledge, the first known formiciine of gigantic size in the Western Hemisphere and the first reported cross-Arctic dispersal by a thermophilic insect group. This implies intercontinental migration during one or more brief high-temperature episodes (hyperthermals) sometime between the latest Palaeocene establishment of intercontinental land connections and the presence of giant formiciines in Europe and North America by the early middle Eocene.