Xu Xing is a Chinese paleontologist who finds the most interesting things! This week's unveiling is the head and some bones from what is easily the biggest bird in all time---as big as a Tyrannosaur Rex! So I just had to draw my version of this bird. I assume it turned its head red when angry just like my turkeys like to do....
The dinosaur world's latest star had a toothless beak, waved feathered arms incapable of flight and may have hunted only plants. But if you met Gigantoraptor erlianensis in a Mongolian forest 70 million years ago, best to have given it a wide berth. At more than 16 feet tall and roughly 3,000 pounds, the beast could stand eyeball-to-eyeball with a tyrannosaur, Chinese researchers say.
The bones of what its discoverers call the world's largest birdlike dinosaur were revealed Wednesday in Beijing. The announcement came two years after the remains were dug from a mud hill near the Inner Mongolian city of Erlian.
Most theories suggest carnivorous dinosaurs shrank as they grew more birdlike. This latest find is about 35 times heavier than other similar feathered dinosaurs, called oviraptors, which rarely exceeded a body mass of 88 pounds.
"This could be the largest ever species to have feathers," says Xu Xing, the lead scientist behind the discovery, reported in the journal Nature.
After the death and destruction of the whole world of dinosaurs, when creatures recolonized the planet, the biggest of them all for a while were the 'terror birds' which ran around North America for a while. There is one of these guys in the Natural History Museum in Boston. It is taller than a human but it is dwarfed by this critter! The interesting thing here is, why do all animals end up giants?
And in this case, a giant which was walking about the place at the same time as other giants and it has no teeth! The others had huge teeth. How did it survive? Was its econiche hostile to these other predators? If it was feathered, was the climate too cold for the other giants who prefered warmer climes? Or was it too dry and prone to sudden floods? In general, huge birds like this such as the moa or ostrich live in dry climates which have colder nights.
So, was central China a savanna? This wonderful discovery opens many doors to rooms we can't even imagine. The simple straight-line evolutionary trees we learn are actually very thorny bushes with many side branches and individual leaves. All I know is, we barely have found maybe about 1% of the variety and continuity of the creatures who populated this planet over the last 300 million years!
Avian genomes are small and streamlined compared with those of other amniotes by virtue of having fewer repetitive elements and less non-coding DNA (a typical bird genome consists of about 1.45 billion base pairs; human genomes are another billion base pairs longer). This condition has been suggested to represent a key adaptation for flight in birds, by reducing the metabolic costs associated with having large genome and cell sizes.
However, the evolution of genome architecture in birds, or any other lineage, is difficult to study because genomic information is often absent for long-extinct relatives. Organ et al. (2007) found that bone-cell size correlates well with genome size in extant vertebrates, and used that relationship to estimate the genome sizes of 31 species of extinct dinosaur, including several species of extinct birds.
Their results indicate that the small genomes typically associated with avian flight evolved in the saurischian dinosaur lineage between 230 and 250 million years ago, long before this lineage gave rise to the first birds.
By comparison, ornithischian dinosaurs were inferred to have had much larger genomes, probably typical of ancestral Dinosauria. Using comparative genomic data, Organ et al. (2007) estimated that genome-wide interspersed mobile elements, a class of repetitive DNA, comprised 5–12% of the total genome size in the saurischian dinosaur lineage, but was 7–19% of total genome size in ornithischian dinosaurs, suggesting that repetitive elements became less active in the saurischian lineage.
These genomic characteristics should be added to the list of attributes previously considered avian, but now thought to have arisen in non-avian dinosaurs, such as feathers, pulmonary innovations, and parental care and nesting.
If this is so and the new discovery is a bird-like creature living 70 million years ago, then birds took to the air and then some evolved back to ground-only life and there is enough evolutionary time between in this history, over 100 million years. We know that animals evolve various things and then lose them again depending on what is needed for survival and the rearing of young.
This latest find fills us with wonder. Did the bone structure look like dinosaurs or birds? How dense were they? And did the creature have a wishbone? I do know that many birds with no teeth are quite capable of ripping up other animals. My turkeys used to tear apart mice and snakes, for example. And of course, the raptor birds can rip apart small animals and vultures tear up the carcasses of humans and elephants! I bet this latest creature that was discovered this week probably dined on carcasses. With all the giant dinosaurs roaming the planet, I'm sure there was plenty to eat.