Posts tagged: prehistoric
and was inordinately interested in symbolist poetry, but i could never really get what this shit was trying to get at, so our conversations were always kind of… what?
(illustration by Dmitry Bogdanov)
oh my god
Mounted specimen on display at the Zurich Natural History Museum.
When: Late-Eocene to Early Oligocene (~38 to 30 million years ago)
Where: North America
What: Hoplophoneus is a saber-toothed carnivore which is well known from the several deposits in the Western states and provinces of the USA and Canada. This animal is not a felid, but a member of the group Nimravidae. One day I will probably be a true saber-toothed cat on here, but today is not that day! Hoplophoneus is a lot closer to true saber-toothed tigers than Thylacosmilus is, today’s fossil is a placental mammal, and has been closely linked to the order Carnivora, which is the order that includes cats. Exactly how closely linked has been a matter of debate for some time, pretty much since the first nimravid fossils were found in the late 1800s. At first nimravids, including Hoplophoneus, were thought to be felids. They were never thought to be sister taxa to the much later occurring saber-toothed forms however, so they have always represented another event of convergent acquisition of extremely enlarged canines.
Hoplophoneus and kin were kept as felids for several decades, but their placement was then called into question when relationships within Carnivora were re-examined using cladistic methodology. Since the 1970s they have been, at various times, true felids, non felids in feliformia, in caniformia, or outside of Carnivora all together! The most recent studies, the first to look at all parts of the skeleton, have placed Hoplophoneus and the rest of the nimravids outside of Carnivora, as the sister taxon to the rest of the group. They are neither caniforms (dog like carnivorans) or feliforms (cat like carnivorans).
This placement means that the leopard sized Hoplophoneus is an even more stunning example of convergent evolution than was first though. Not only are its enlarged canines convergent with some felids, but so are many other features of its anatomy. However, there are many differences as well, and these features are what place nimravids outside of Carnivora. Most of the differences are really specific anatomical features, most of which found in the ear region and the postcranial skeleton, but one easy one to see is the size of the brain. If you look at the reconstruction above the body looks very cat-like, but the head is quite different. According to one friend ‘Its not a cat, its a weasel-cat! sabertooth… thing.’
Human Origins Traced to Worm Fossil In Canada?
by PhysOrg staff
Paleontologists have traced the origins of humans and other vertebrates to a worm that swam in the oceans half a billion years ago, said a study published Monday (3/5/12).
A new analysis of fossils unearthed in the Canadian Rockies determined that the extinct Pikaia gracilens is the most primitive known member of the chordate family, which today includes fish, amphibians, birds, reptiles and mammals. The research published in the British scientific journal Biological Reviews identified a notochord or rod that would become part of the backbone in vertebrates, and skeletal muscle tissue called myomeres in 114 fossil specimens of the creature.
They also found a vascular system… “The discovery of myomeres is the smoking gun that we have long been seeking,” said the study’s lead author, Simon Conway Morris of the Cambridge University. “Now with myomeres, a nerve chord, a notochord and a vascular system all identified, this study clearly places Pikaia as the planet’s most primitive chordate. “So, next time we put the family photograph on the mantle-piece, there in the background will be Pikaia.”
The first specimens of Pikaia were collected by early explorers of the Burgess Shale in 1911. But the animals were overlooked as an ancestor of earthworms or eels. It was not until the 1970s that Morris suggested the five-centimeter (two inch) long, sideways-flattened, somewhat eel-like animal that likely swam by moving its body in a series of side-to-side curves could be the earliest known member of the chordate family…
(read more: PhysOrg) (images: Cambridge Univ.)
More information: Pikaia gracilens, Walcott, a stem-group chordate from the Middle Cambrian of British Columbia, Article first published online: 4 MAR 2012. DOI: 10.1111/j.1469-185X.2012.00220.x
Euhelopus is a genus of sauropod dinosaur that lived during the Early Cretaceous period, between 130 - 112 million years ago. It lived in what is now Shandong Province in China. A large herbivore, it weighed approximately 15 - 20 tons and attained an adult length of 15m (50 ft). Unlike most other sauropods, Euhelopus had longer fore legs than hind legs…
Anatosuchus (“duck crocodile”, for the broad, duck-like snout) is an extinct genus of notosuchian crocodylomorph discovered in Gadoufaoua, Niger, and described by a team of palaeontologists led by the American Paul Sereno in 2003, in the Journal of Vertebrate Paleontology.As the specific name indicates, A. minor was a very small crocodylomorph, with an adult body length estimated at around 70 centimeters. It had a very broad, duck-like snout…
(read more: Wikipedia)
Dicynodontia is a taxon of anomodont therapsids or mammal-like reptiles with beginnings in the mid-Permian, which were dominant from Late Permian through the Triassic, with a few surviving into the Early Cretaceous. Dicynodonts were small to large herbivorous animals with two tusks, hence their name, which means ‘two dog tooth’. They are also the most successful and diverse of the non-mammalian therapsids, with over 70 genera known, varying from rat- to ox-sized…
(read more: Wikipedia)
find out more: http://rhamphotheca.tumblr.com/tagged/dicynodont
Velociraptor’s Last Meal Reavealed
by Jeanna Bryner
A lightweight Velociraptor dinosaur may have chowed down on the carcass of a much larger flying reptile not long before meeting his own demise some 75 million years ago.
The evidence comes from a pterosaur bone discovered in the gut of the skeletal remains of what was likely a Velociraptor mongoliensis that lived in what is now the Gobi Desert in Mongolia. The fossil, the first pterosaur bone to be found inside dinosaur guts, was discovered in 1994 but not fully analyzed and detailed in a scientific publication until now.
Velociraptor was known to have fearsome sickle-shaped talons on the second toe of each foot; it kept these talons off the ground like foldable switchblades. Past research has shown these theropod dinosaurs used their talons to slash live prey and hook them to keep them from escaping.
The new study, which says the pterosaur may have been dead before the predator found it, adds to research suggesting the fierce carnivores wouldn’t turn their back on a free meal, either. A study published in 2010 reported the discovery of a Velociraptor frozen in time, scavenging the corpse of a larger dinosaur…
(read more: Live Science)
(top illustration by Brett Booth, bottom photo: David Hone)
I’m loving all these dinosaur illustrations
also personally I think velociraptors look even more ferocious with feathers
Uintatherium anceps (1890’s) by Charles Knight