Traits:
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A2.16 Diplodocus longus (double beam) (an extra lengthy
long necked dinosaur)
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Cells have DNA
Cells have a nucleus in them
Cells have mitochondria
Multicellular
Cells are held together with collagen.
Sexual reproduction
Early embryo forms as a hollow ball of cells called a blastula
This blastula opens into a tube “tail end first”
Has a head and is bilaterally symmetrical (you can draw one line down the middle)
Cells organize themselves into true tissues (muscle, nerves)
Cells organize themselves into true organs (heart, liver, stomach)
Has a hollow space between the gut and outer body wall where organs are (this space is
called a coelem—pronounced “see-lome”
Segmented body
Internal bony skeleton
Backbone, Spinal chord and braincase
Had jaws
Had lungs
Had paired appendages
Had four legs
Amniotic egg (able to lay its eggs out of water)
Two openings in the roof of the mouth (“palatal openings”)
Two openings in the side of the skull at the temple (“diapsid openings”)
Opening in the skull in front of eye socket (“antorbital fenestra”)
Has a hole in the hip socket allowing it to stand upright
Has grasping hands
Narrowing of the middle ear bone—only one middle ear bone (“slender stapes”)
A notch in the two bone just behind the eye opening (“notch in postorbital”)
Simple hinge-like ankle (requiring a more erect posture—no sprawling walk)
Long neck bones
Extra neck bones
Nostrils high, between eye sockets
Long neck and light limbs
Diplodocus was a long-necked, whip-tailed giant, measuring about 90 feet (27 m) long with a 26 foot (8 m) long neck
and a 45 foot (14 m) long tail, but its head was less than 2 feet long. It was among the longest land animals ever. Its
nostrils were at the top of its head and it had peg-like teeth, but only in the front of the jaws. Its front legs were shorter
than its back legs, and all had elephant-like, five-toed feet. One toe on each foot had a thumb claw, probably for protection. A fossilized Diplodocus skin
impression reveals that it had a row of spines running down its back.
Diplodocus was more lightly built than the other giant sauropods, and may have weighed only about 10-20 tons. Its backbone had extra bones underneath it,
which had bony protrusions running both forwards and backwards (anvil shaped), a "double beam", probably for support and extra mobility of its neck and tail. It
may have used its whip-like tail for protection. A recent Diplodocus skin impression was found, showing a row of spines running down the back.
It has been determined that Diplodocus (and the other diplodocid saropods, like Apatosaurus) could not hold their necks over about 17 feet (5.4 m) off the
ground (Parrish and Stevens,1999).
Gastralia (hanging belly ribs) are thin, fragile ribs that helped support and protect the internal organs (like the lungs) in the middle
area of the body. These ribs were not attached to the backbone; they were attached to the skin in the belly area.
Diplodocus was an herbivore (it ate only plants). It must have eaten a tremendous amount of plant material each day to sustain
itself. It swallowed leaves whole, without chewing them, and may have swallowed gastroliths (stones that remained in its stomach) to
help digest this tough plant material. It had blunt teeth, useful for stripping foliage.
Its main food was probably conifers, which were the dominant plant when the large sauropods lived. Secondary food sources may
have included gingkos, seed ferns, cycads, bennettitaleans, ferns, club mosses, and horsetails.
Diplodocus held its neck more-or-less horizontally (parallel to the ground). The long neck may have been used to poke into
forests to get foliage that was otherwise unavailable to the huge, lumbering varieties of sauropods who could not venture into forests
because of their size. Alternatively, the long neck may have enabled this sauropod to eat soft pteridophytes (horsetails, club mosses,
and ferns). These soft-leaved plants live in wet areas, where sauropods couldn't venture, but perhaps the sauropod could stand on firm ground and browse in
wetlands.
Diplodocus may have travelled in herds, migrating when the local food supply was depleted. Diplodocus probably hatched from eggs, like other sauropods.
Sauropod eggs have been found in a linear pattern and not in nests; presumably the eggs were laid as the animal was walking. It is thought that sauropods did
not take care of their eggs. Life spans may have been on the order of 100 years.
It used to be thought that the animals (like Diplodocus, Brachiosaurus and Apatosaurus) and Stegosaurus had a second brain. Paleontologists now think that
what they thought was a second brain was just an enlargement in the spinal cord in the hip area. This enlargement was larger than the animal's tiny brain.
Diplodocus was a sauropod, whose intelligence (as measured by its relative
brain to body weight, or EQ) was the among the lowest of the dinosaurs.
Diplodocus moved slowly on four column-like legs (as determined from
fossilized tracks and its leg length and estimated mass).
Diplodocus lived in the late Jurassic Period, from 155-145 million years ago.
The late Jurassic was the time of the enormous sauropods, including
Camarasaurus, Apatosaurus, and Brachiosaurus. Also present were
Stegosaurus, Tuojiangosaurus, Allosaurus, Supersaurus, Coelurosaur, and many
others.
The first Diplodocus fossil was found by Earl Douglass and Samuel W.
Williston in 1877 and was named by paleontologist Othniel C. Marsh in 1878.
Many Diplodocus fossils have been found in the Rocky Mountains of the western
USA (in Colorado, Montana, Utah, and Wyoming). Diplodocus means "Doublebeamed."