Gentle dino giant had fleshy cock's comb

Monday, December 30, 2013

The discovery of a comb atop Edmontosaurus is a first (Source: Artwork by Julius Csotonyi/Bell, Fanti, Currie, Arbour, Current Biology)

Anna Salleh

A duck-billed dinosaur from North America had a fleshy cock's comb that it probably used to communicate with others of its species, say researchers.

The comb, found in a rare mummified specimen of Edmontosaurus regalis, is reported today in Current Biology.

"The discovery of the comb was a total surprise because there is no indication from any other dinosaur that these animals had such a structure," says palaeontologist and lead author Dr Phil Bell of the University of New England.

At 10-12 metres long and weighing up to 4 tonnes, Edmontosaurus regalis was one of the most common dinosaurs to live 70 million years ago.

"It was a big gentle herbivore," says Bell. "It would have filled the same ecological role as a kangaroo would, or a deer."

He says the animal's skull is long and low like a horse's skull, and the front end of its jaws have no teeth and is broad like a duck bill.

Scientists have known about Edmontosaurus for a century, and there are numerous complete skeletons, some even with skin, but the latest discovery was never expected, says Bell.

He says co-author Frederico Fanti discovered the new specimen while the two of them were prospecting in a river in Northern Alberta.

Back in the lab, Bell started to chip away at the surrounding earth and that's when he struck gold.

"I'd uncovered the skin on parts of the neck and I could see where the head was going, so I put my chisel in the rock where there shouldn't have been skin, and low and behold, there was," he says.

"It was a mistake but a lucky blow, in the end."

Bell says the findings suggested a three-dimensional cranial crest, or comb, made of soft tissue.

"There was a fleshy substance and wrinkles on the preserved skin so we know it was supple. It was probably a fatty tissue underneath," he says.

Communication device


Bell says some relatives of the dinosaur have been found to have a bony crest, which are extensions of the nasal passages and were used as resonators when the animals called out to each other.

He says the bony crests disappeared at the end of the Cretaceous when Edmontosaurus appeared.

Its fleshy crest was in the same place as the previous bony crests but had no connections to the nasal passage.

Bell says it's likely that Edmontosaurus, which travelled in herds for protection, used the crest to communicate.

"There's always some kind of hierarchy in a herd," he says. "We believe this crest was used to signal to mates or to confer its position within the herd hierarchy - 'he with the biggest crest wins' kind of thing."

Bell says this is supported by the fact that modern-day birds - from the rooster to the Andean condor - all have brightly coloured crests that are used to signal to each other.

It's all in the skin


While most scientists are interested in skeletons, Bell has devoted his career to looking at skin on dinosaurs.

"It's the skin and the flesh that really give you that true life picture," he says.

The preservation of soft tissues like this is made possible by a special "mummification" process that was common in the area he and colleagues were exploring, says Bell.

"Animals were dying but getting buried very rapidly, probably within a space of a couple of days after they died," he says.

And, says Bell, the sediment that "entombed" the dinosaurs was anaerobic and probably contained bacteria that precipitated out certain elements like manganese, iron and calcium from the water to help preserve the skin.

Bell says it is interesting the comb was found in a herbivore like Edmontosaurus which is not closely related to birds.

But, he says, there may well be combs on therapods that have yet to be discovered.

"This opens the possibility that we have all kinds of soft tissue structures that we've never seen," he says. "We're in for more surprises, I think."


Wednesday, December 18, 2013

Basilosauridae, the so-called zeuglodonts, referring to their complex, many-cusped teeth (the Greek zugotos means yoked or joined, and odous, of course, tooth). The most primitive archaeocete identified to date was Nalacetus, known mainly from isolated teeth. Pakicetus, another small, very early archaeocete, had eyes on top of its head, drank only fresh water (confirmed from oxygen isotope ratios in its tooth enamel), and was predominantly wolf- or hyena-like in appearance. The other families of archaeocetes had been largely supplanted by the zeuglodonts during the late Eocene. Probably the best-known zeuglodont was Basilosaurus, or the "king lizard" (from the Greek basileus for king and sauros for lizard). This animal could be almost 70 ft (21 m) long and weighed at least 11,000 lb (5,000 kg). Its small head in relation to the long body made it appear truly serpentine. The front appendages had been modified into short, broad paddles, but were still hinged at the elbow; and the rear appendages had atrophied to nothing more than stumps. 

Basilosaurids may have had dorsal fins and horizontal tail flukes, and they were likely hairless, or nearly so. In short, Basilosaurus was well along the path to becoming what cetologists now think of as a whale. The archaeocetes are replaced in the fossil record by odontocetes and mysticetes beginning in the Oligocene, about 38 mya. By approximately the middle of that epoch, the archaeocetes appear to have died out completely. The oldest known cetacean in the mysticete clade is Llanocetus denticrenatus, found in late Eocene rocks on the Antarctic Peninsula. 

This species' most characteristic feature was its series of lobed, widely spaced teeth, which were somewhat reminiscent of the teeth of the crabeater seal (Lobodon carcinophagus). Like the crabeater seal, L. denticrenatus was probably a filter feeder on krill-like invertebrates or possibly small schooling fish. At least four families of tooth-bearing mysticetes have been described from the Oligocene (24-38 mya). The transition leading to rudimentary baleen plates in the spaces between teeth probably occurred about 30 mya with the emergence of the Cetotheriidae, or primitive baleen-bearing mysticetes. It is a slight misconception to say that the presence of teeth is a diagnostic feature of Odontoceti, the so-called toothed whales, because all archaeocetes and some of the primitive fossil mysticetes also had teeth. Further, all of the modern baleenbearing mysticetes have teeth in the early fetal stages of their development. 

Odontocetes also radiated rapidly and widely during the Oligocene, by the end of which there were more than 13 families and 50 species of cetaceans in the world's oceans. This diversity was probably driven by changes in foraging opportunities related to breakup of the southern supercontinent of Gondwana, opening of the Southern Ocean, and the consequent polar cooling and sharpening of latitudinal temperature gradients. Several of the early odontocete lineages failed to survive beyond the Miocene (5-23 mya). The shark-toothed dolphins (Squalodontidae), with their sharp, triangular, serrated teeth, were likely active carnivores, while the very longbeaked Eurhinodelphinidae, with their overhanging upper jaws and many small, conical teeth, were more like the dolphins that cetologists know today. Both of these groups had vanished from the fossil record, and others had dwindled to mere remnants, by the end of the Miocene. 

The cetotheres radiated further during the Miocene (5-23 mya), with more than 20 genera in which the blowholes were positioned about as far back on the top of the head as they are in living mysticetes. Also, by the early Miocene, the two main branches of cetotheres were evident, one leading to the modern right whales (Balaenidae) and the other to the rorquals (Balaenopteridae) and gray whale (Eschrichtiidae). Gray whales do not appear in the fossil record until only about 100,000 years ago, and their ancestry is therefore particularly problematic. For their part, the odontocetes also experienced a major Miocene radiation. Beaked whale (Ziphiidae) fossils are common in marine sediments worldwide by 5-10 mya, and these include animals belonging to the modern genus Mesoplodon. Sperm whales in the family Physeteridae, similar in some important ways to the living species, were present by 22 mya.

Desolation of Smaug

Tuesday, December 17, 2013

In the film Smaug looks realistic, glows with inner fire when he's about to unleash his deadly breath and has a face so evil looking he's actually a little scary. The HOBBIT: THE DESOLATION OF SMAUG - is Smaug the greatest cg character since Gollum?

In the sixth and final War of Wrath in Beleriand, winged dragons first appear, the mightiest of which is Ancalagon the Black. At the climax of this war, Ancalagon is slain by Eärendil in a titanic battle ending with the dragon's cataclysmic fall upon the towers of Morgoth's realm. In the victory over their Enemy, the Valar destroy ``well-nigh all the dragons''; an earlier version of the ``Quenta Silmarillion'' published in The Shaping of Middle-earth says two escaped into the East. These were apparently male and female, for they are said to have bred in the dark places of the earth to afflict the world, ``as they do still.'' The Lord of the Rings' Appendix A mentions their multiplying and growing strong in the wastes of Ered Mithrin north of Mirkwood- yet another class of dragons called colddrakes, apparently lacking fire-which slay King Dain I and Fro' r his son and drive the Dwarves out. About two hundred years later, Smaug-the fiery dragon of The Hobbit-descends on the Lonely Mountain. 

The Hobbit has been seen as a dragon-slayer narrative of the Beowulf type rewritten as a comic children's story (Stein). Bilbo's adventures climax with the slaying of Smaug by Bard, a Man from Laketown, by an arrow-shot to a small unarmored spot on the dragon's underbelly-a motif borrowed from Germanic sources. A speaking dragon like Glaurung, Smaug is modeled on Fäfnir, whose dying speech prophesies Sigurd's doom. Despite its comic tone, Smaug's voice has the unsettling effect of malevolent threat masked in jocularity. Smaug and other dragons are presented as extremely old, a characteristic mentioned in Beowulf and probably based ultimately on the biblical dragon of the Apocalypse, the draconem serpentem antiquum qui est diabolus, ``the dragon, that old serpent, which is the Devil'' (Rev. 20:2). The narrator of The Silmarillion says ``long and slow is the life of the dragons.'' Also mentioned in The Hobbit are the ``Wild Were-worms of the Last Desert'' (H, I, 49) otherwise unexplained but seemingly a reference to the human-to-dragon transformation motif of Germanic tradition (cf. werewulf, ``man-wolf ''). 

Dragons as such do not appear in The Lord of the Rings. In the Shire, Ted Sandyman scoffs at them as relics of children's stories; Gandalf comments that dragon-fire could melt the Rings of Power, but no dragons left on earth are hot enough and not even Ancalagon the Black could have melted the One Ring. At the end of the book, Merry Brandybuck is awarded a Dwarf-made horn taken from the hoard of Scatha the Worm by Fram-a Man of Rohan, slayer of the dragon.