Microraptor

Gliding Microraptor

Phylum : Chordata
Class : Reptilia
Order : Saurischia
Family : †Dromaeosauridae
Genus : †Microraptor

Length : 2ft (61cm)

Status : Extinct since the Early Cretaceous, 120 million years ago.

Microraptors were tiny, predatory dinosaurs that most likely fed on insects and small vertebrates, including small mammals. They are some of the smallest Dinosaurs ever discovered.

Around two dozen nearly complete specimens have been uncovered in China during the last decade or so, and what makes these Dinosaurs so remarkable is that we know for a fact that they had feathers. And not only that, but they basically had two full sets of wings, one set on the front arms, and the second on the hind legs. These feathers were similar to the flight feathers that we see on our modern birds, and because of them Microraptor was most likely able to glide. These long flight feathers are a contrast to several other Dinosaurs, where feathers were present, but only as a covering and not for flight.

There is debate within paleontology regarding the origin of birds. Did they evolve directly from dinosaurs, or did they evolve independently through an as yet undiscovered species? Feathered Dinosaurs like Microraptor can help us to one day solve that mystery.

Brontomerus mcintoshi

Brontomerus fights off an attacker!

Genus : Brontomerus
Species : mcintoshi

Length : 46ft (14m)
Weight : 13,500lbs (6,100kg)

Status : Extinct since the Early Cretaceous, approximately 110 million years ago

This animal came across my news radar this morning and I just had to cover it.This new species was actually first discovered in Utah in 1994, but wasn't fully evaluated until 2007. When scientists finally got a good look at it, the realized that this species had a really interesting feature.

Brontomerus mcintoshi has a bony plate that projects from the hip bone. This plate serves as an anchor for the dinosaur's leg muscles. It is between 31% and 55% longer than bone plates in other sauropods. This means that this new dinosaur had substantially powerful hind legs, the most muscular legs of any Sauropod! These legs were so powerful, in fact, that scientists gave it the name Brontomerus, which means "Thunder Thighs." (The species name, mcintoshi, is in honor of John McIntosh, a world authority on Sauropods.)

It is believed that the animals used their powerful legs to move across rough terrain, and that they also used them to kick and stomp at predators!

Bones from two individuals have so far been uncovered, an adult and a much smaller juvenile.

Iguanodon

Iguanodon

Phylum : Chordata
Class : Reptilia
Superorder : Dinosauria
Order : †Ornithischia
Family : †Iguanodontidae
Genus : †Iguanodon

Length : 33ft (10m)
Weight : 10,000lbs (4,500kg)

Status : Extinct for around 110 million years

"Iguanodon" refers to several different discovered species within the genus Iguanodon. Theses Dinosaurs are notable because they were actually discovered before the word Dinosaur even existed! Around 1820 English geologist Gideon Mantell discovered a tooth of one of these guys in Sussex, England. He thought the tooth looked like a large Iguana tooth and the name stuck. Mantell continued to do research on Iguanodons and other fossilized species until his death in 1852.

Mantell's Iguanodon
 Teeth Illustration

Iguanodons were herbivores that lived in what is now Europe, Asia, and North America. The various species lived in the early Cretaceous, around 140-110 million years ago. They had three fingers on each hand, along with a thumb that had a hooked claw that could be used for grasping food and for defense. Iguanodon mouths had teeth in the back but none in the front. This was so they could tear apart plant materials with their beak-like mouths and then chew.

Iguanodons could move on all fours, but also on just their hind legs, due to the fact that their front limbs were only about 3/4 the size of the back limbs. They most likely moved in packs, like many modern herbivores do, and they laid eggs.

Sarahsaurus

I might not have a whole lot to write about this particular Dinosaur, but that is because it is simply so new! Sarahsaurus, named after Sarah Butler, an Austin, TX philanthropist, was first discovered in 1997 and findings regarding it have just recently been published. Sarahsaurus lived in the early Jurassic around 190 million years ago.

(Image Source)

Sarahsaurus is so awesome because of what it tells us about the dispersion of dinosaurs across North and South America. The traditional view was that Dinosaurs were so dominant that they out-competed everything else around them. A new view is rising that Dinosaurs in the Americas were successful because they were opportunistic rather than dominant. There were no Dinosaurs in the area prior to the Triassic-Jurassic extinction, and then after the previous residents went extinct, Dinosaurs like Sarahsaurus moved in.

Sarahsaurus was a Sauropodomorph, a precursor to Sauropods like Apatosaurus. Like the Sauropods, Sarahsaurus had a long neck and a small head. It also interestingly had hands! They were about the size of human hands, but much, much more powerful. It is now thought that these Dinosaurs were something more than herbivores. Their strong hands and versatile teeth point to the fact that they may have been scavengers.

Velociraptor

In 1993, a film called Jurassic Park was released that thrust the Velociraptor into the forefront of our collective Dinosaur fascination. Unfortunately... its depiction was pretty darn wrong. Granted, that wasn't wholly the fault of the movie-makers, because one of the primary physical characteristics of the Velociraptor wasn't even discovered until several years after the film's release. But the other major discrepancy... yeah, that one is probably on them.

Image by Christopher Srnka

There are two species of Velociraptor, and both lived in what is now Central Asia. In 1998, a forelimb from one specimen was found that contained some interesting features. There are marks in the bone known as quill knobs. This revelation points to the fact that Velociraptors definitely had feathers. Velociraptors could not fly, but they probably used their feathers for maneuverability, display, and for temperature control. And guess what? They were probably warm blooded.

The other physical trait that the movie got wrong? The size. You see, Velociraptors probably weighed no more than 30lbs, and had a height of about 3 feet. They did at least have those large, terrifying claws, which they used to attack and kill their prey, and one of their favorite meals was the Protoceratops. Velociraptors lived during the late Cretaceous period.

Torosaurus

I haven't written about any Extinct animals since the Mother's Day Quagga, so I'm definitely overdue. Thus, I present the Torosaurus, a dinosaur which walked the earth during the late Cretaceous Period, around 70 million years ago. It also just so happens to be the very first dinosaur that you see when entering that particular wing at the Milwaukee Public Museum.

First discovered in 1889 in Wyoming, and then named in 1891, all Torosaurus fossils have been found in the western United States and Canada. The Torosaurus was a bird-hipped, herbivorous dinosaur that probably weighed around 4 tons. It used a beak like mouth to shear tough vegetation, and it also had the largest skull of any land animal yet discovered, with fossilized skulls measuring 8 feet in length. The skull also included a massive frill which had two large symmetrical openings, which possibly existed in order to cut off some weight. In addition, the Torosaurus had three large horns, two immediately above the eye socket, and one smaller one on the snout, all of which face forward.

Image from Texas Geology

The term Torosaurus encompasses an entire genus, conveniently named Torosaurus. Two species have been classified, though the true identity of the genus is under debate. So few fossil remains have been discovered that it is speculated that Torosauruses may actually be a different growth phase of the more abundant Triceratops. Recent studies into dinosaur growth have already eliminated a handful of species, and there are estimates that further research could eliminate 1/3 of all species entirely, as they are really just different growth stages of other species.