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Hypacrosaurus: Hypacrosaurus (meaning "under the top lizard") was a large, plant-eating, hollow-crested duck-billed dinosaur (a hadrosaur) similar to Corythosaurus. It had almost 40 rows of cheek teeth, a short toothless beak, and a row of
short spines coming out of its vertebrae, forming a small fin along its back. It had a hollow, bony crest on top of its long
head in the shape of a helmet flattened on the sides (like the crest of Corythosaurus but thicker). Hypacrosaurus' nostrils went up through
the crest. The crest may have been used to make sounds, as a cooling device, courtship displays, and/or as a sense-of-smell
enhancer. Males had larger crests than females and juveniles. It had a toothless beak and hundreds of cheek teeth that it
used to grind up its food. It walked on two legs, had shorter arms, and a long, heavy tail. It had no natural defenses. Hypacrosaurus
may have been a herding animal. It lived in humid forests and may have migrated from shorelines to higher ground to reproduce.
A nest that may have belonged to Hypacrosaurus was found in Devil's Coulee, near Alberta, Canada. The
nest had eight large, round eggs plus the bones of duckbill embryos, probably those of Hypacrosaurus. The cantaloupe-sized
eggs were laid in rows and were probably covered with sand and plant material. Hypacrosaurus was an herbivore, eating pine
needles, seeds, fruit, twigs, and magnolia leaves. Hypacrosaurus was an ornithopod, whose intelligence
(as measured by its relative brain to body weight, or EQ) was midway among the dinosaurs. Hypacrosaurus walked and ran on
two legs, and was a relatively fast dinosaur. It may have gone on all fours to forage for low-lying plants.
Hypsilophodon: Hypsilophodon
measured about 6.5 feet long and 2 feet tall, weighing about 150 pounds. Hypsilophodon had a beak made of horn, cheek pouches
and 28-30 self-sharpening cheek teeth in a small skull 4 3/4 inches (12 cm) long, by 2 inches (5 cm) wide. Hypsilophodon may
have had 2 rows of bony plates running down its back. Slender legs and a stiffened tail gave it speed and agility. It had
large eyes, strong jaws, five-fingered hands and four-toed feet (one toe on each foot had a hind claw). Hypsilophodon was
a very fast bipedal runner; its back legs were long. It had a stiffened tail that helped it balance when running. A bone bed of about 20 Hypsilophodon fossils were unearthed together on the Isle of Wight (an island off the coast
of southern England). This indicates that a herd of Hypsilophodon died together. They laid eggs and may have cared for their
young for at least a little while. This is evidenced by eggs found carefully placed in Hypsilophodontid nests. Hypsilophodon
was an ornithopod, whose intelligence (as measured by its relative brain to body weight, or EQ) was midway among the dinosaurs.
This horny beaked dinosaur was an herbivore (it ate only plants). It had 28-30 chisel-like teeth.
Iguanodon: Iguanodon was
a plant-eating dinosaur that had a conical spike on each thumb. Iguanodon was a dinosaur that had a horny, toothless beak
and tightly packed cheek teeth. On each hand, Iguanodon had four fingers plus a conical thumb spike on each hand (that was
perpendicular to the other fingers). The thumb spikes may have been used for defense or in obtaining food; it ranged from
2 to 6 inches long. Iguanodon had a flat, stiff tail and three-toed hind feet with hoof-like claws. Its legs were much larger
than its arms. Iguanodon was probably a herding animal, as evidenced by bone bed discoveries in Belgium. In these bone beds,
dozens of Iguanodon fossils were found together, suggesting that they congregated during their lives. Iguanodon was an herbivore,
a plant eater. It probably nipped cycads and other plants with its tough, toothed beak. It had no teeth in the front of its
mouth, but had strong teeth (about 2 inches long) in the side of its jaw (cheek teeth), which it used to grind up tough plant
material. Iguanodon was an ornithopod, whose intelligence (as measured by its relative brain to body weight, or EQ) was midway
among the dinosaurs. Iguanodon could run on two legs or walk on four; it was a relatively fast dinosaur. British paleontologist
David Norman showed that some mature Iguanodons were quadrupedal. Iguanodon may have traveled as fast as 15-20 km/hr.
Jobaria:
Jobaria is a sauropod, known as Africas Dinosaur Giant. There were twelve vertebrae in its neck, and it was six feet
wide at the breast.
Kentrosaurus: Kentrosaurus
is very similar to Stegosaurus, but there are actually many subtle differences between the two. As many as seven pairs
of spike extend from the tend of the tail to up over the hips, and sometimes on to the lower back. These seven pairs of spikes
seemingly evolved into plates; they changed shape over the length of the body until becoming platesnot spikeslike those of
Stegosaurus. Both the spikes and plates were paired, not staggered like this on Stegosaurus. The plates are
also much narrower than those belonging to Stegosaurus. A single spike pointed back from the shoulders, though early
drawings and rendering of Kentrosaurus have mistakenly put the spike along the hips. New discoveries and revelations
from the remains of these dinosaurs show that the spike extended from the shoulders over the forearms. It fed low to the ground.
A small beak at the front of its jaws tore off plant matter, and chopping teeth in the back of its mouth helped to chew it
up.
Lambeosaurus: Lambeosaurus
was a crested, duck-billed dinosaur. Its forward-leaning, hollow, bony crest was as big or bigger than the rest of its skull
and may have been used to produce sounds, enhance its sense of smell, and/or used in courtship displays. Lambeosaurus' nostrils
went up through the crest. Its snout was narrow and ended in a beak that was wide and blunt. Males may have had larger crests
than females. Lambeosaurus had pebbly-textured skin and may have had webbed fingers. Its sight and hearing were keen, but
it had no natural defenses. Lambeosaurus was the largest duckbilled dinosaur. Lambeosaurus was a herding animal that may have migrated from shorelines to
higher ground to reproduce. Lambeosaurus was an herbivore, eating pine needles,
the leaves of flowering trees, and twigs. Lambeosaurus was an ornithopod, whose
intelligence (as measured by its relative brain to body weight, or EQ) was midway among the dinosaurs. Lambeosaurus walked
and ran on two legs, and was a relatively fast dinosaur. It probably went on all fours to forage for plants.
Maiasaura: Maiasaura
gave way to an entire new field in paleontology, the study of dinosaur development. Discovered by John Horner and Robert Makela,
and named in 1979, it is now one of the most famous dinosaurs. The remains of Maiasaura provided information such as
how it cared for its young and the early development of dinosaurs, which is an interesting field of paleontology. At birth,
Maiasaura had a small, narrow head. With age, the head grew lower and wider from back to front. It had a broad, horny
beak, and stout, bony crests over the eyes adorned this creatures façade. These crests were probably used for display, or
for head-butting to protect territory or to woo a female Maiasaura. Sometimes up to 10,000 dinosaurs would congregate
in a single area to form a nesting ground to lay their eggs. The process of birth with Maiasauraand other Ornithischians
as well, probablyis as follows:
1.
Mother laid the eggs in a mound of circular- or spiral-situated dirt pattern.
2.
The mound was then covered with vegetation. The rotting vegetation would warm the eggs.
a.
Crocodiles do the exact same thing!
3.
The mother dinosaur would sit next to the nest, to ensure that the eggs would be safeguarded against lurking, egg-snatching
predators, and that no other dinosaurs would trample them.
a.
Often, nests would be congregated in a single area to form a nesting ground
4.
The eggs would hatch, baby dinosaurs emerging, and they would be cared for:
a.
When born, the hatchlings were too immature to leave the nest
i. Immature babies were brought food by the
adult dinosaurs
b.
The young probably lived in nests for one to two years
i. This period of staying in the nest could
be an indication of warm-bloodedness, but nothing is for sure
Massospondylus: Massospondylus
was an early herbivore about 13 feet long and 3 feet tall. It had a long neck, very long tail, a small head, peg-like teeth,
and large, five-fingered hands with a large thumb claw. Massospondylus may have been able to use its hand for grasping in
addition to walking. Its back legs were only a little bit larger than its front legs. It was a very common dinosaur.Massospondylus
was an herbivore, a plant eater. It swallowed pebbles and small stones to help in the digestion of the tough leaves and other
plant material that it ate. These gizzard stones (gastroliths) would help grind up the food in the stomach. Gastroliths have
been found in Massospondylus fossils. Massospondylus walked on four muscular legs and was a relatively fast runner. It may
have also run on two legs. Dinosaur speeds are estimated using their morphology (characteristics like leg length and estimated body mass) and fossilized trackways.
Massospondylus was a Sauropodomorpha, whose intelligence (as measured by its relative brain to body weight, or EQ) was the
lowest among the dinosaurs.
Megaraptor: Megaraptor
was a large, terrifying predator with two enormous, sickle-like toe claws. It was a huge, lightly built, fast-moving, agile,
bipedal (walked on two legs), bird-like dinosaur. It had a curved, flexible neck, and a big head with sharp, serrated teeth
in very powerful jaws. The second toe on each foot had a 14 inch (35 cm) sickle-like claw and the other toes had smaller claws.
When alive, this claw would have been sheathed in a horny, keratinous material much like our fingernails, making the claw
even bigger, longer and sharper. The tail was probably used for balance and fast turning. It may have had a relatively large
brain and large eyes. Megaraptor was among the smartest of the dinosaurs, as calculated from its brain:body weight ratio (or
EQ). This made them very deadly predators. Megaraptor
was a carnivore, a meat eater. It probably ate just about anything it could slash and tear apart. If it hunted in packs, Megaraptor
could probably kill any prey it desired.
Minmi: Minmi was a small armored dinosaur
(an ankylosaur) that walked on four legs and had a long tail. This plant-eater had some bony body armor on its body. Unlike
other ankylosaurids, Minmi had horizontal plates of bones that ran along the sides of its vertebrae (hence its species name).
Minmi had four short legs (the rear legs were larger than the front legs), a short neck, and a wide skull with a tiny brain.
Minmi was about 10 feet long and was roughly 3 feet tall to the top of the shoulder. Minmi was an herbivore (it ate only plants)
eating low-lying plant material like cycads, ferns, horse-tail rushes, etc. Minmi was an ankylosaur, whose intelligence (as
measured by its relative brain to body weight, or EQ) was low among the dinosaurs. Minmi probably moved relatively slowly
on four legs (as determined from fossilized tracks, its estimated mass, and its leg length).
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