Appearances & Anatomy Flashcards
(82 cards)
1
Q
Paleontology
A
Study of all prehistoric life
2
Q
Fossil
A
Any preserved evidence left behind by a prehistoric organism
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Q
Adaptations
A
Traits that have evolved because they serve specific functions (i.e. bones)
4
Q
4 major functions of bones
A
- Passively resist gravity and maintain animal’s form.
- Provide a rigid framework for muscles to attach to.
- Provide protection (i.e. skull protects brain) & can be major components of horns and other weapons.
- Store mineral reserves for us to draw upon when mineral resources are scarce.
5
Q
Vertebrates
A
Animals w/ two specific skeletal adaptations: skulls and vertebrae.
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Q
Vertebrae
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Structures made primarily of bone and / or cartilage surrounding portions of the spinal cord.
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Q
Vertebral Column
A
Series of interlocking vertebrae
8
Q
Invertebrates
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Animals that lack vertebrae.
9
Q
Are there more invertebrates or vertebrates?
A
There have always been many more species of invertebrates, however there are more large animals who are vertebrates (particularly on land).
10
Q
Why are skulls important for paleontologists?
A
They can give great insight into a dinosaur’s life.
For example, the skull may have teeth or a beak, which can tell us what the dinosaur was adapted to eat.
11
Q
Brain Case
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Hollow chamber formed by multiple skull bones that houses the brain.
12
Q
What does the Brain Case tell us about a dino?
A
The size and shape can tell us the size and shape of the brain, giving an idea of the mental capabilities of the dino.
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Q
Nares
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The pair of openings in the skull for the nostrils
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Q
Orbits
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The pair of openings in the skull for the eyes.
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Q
Fenestrae
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Additional skull openings.
16
Q
What are the two fenestrae dinos have behind the orbits & what are their functions?
A
Laterotemporal Fenestrae - On the lateral sides of the skull
Supratemporal Fenestrae - On the top of the skull
Both provide extra room for large jaw muscles.
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Q
Antorbital Fenestrae
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Between the orbit and naris, their function is unclear.
May have made skulls lighter, may have housed large sinus cavities that warmed the air they breathed.
18
Q
Centrum
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Spool or disk-shaped body of a vertebra
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Q
Neural Arch
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Covers the neural canal (above the centrum)
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Q
Neural Canal
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Opening in each vertebra through which the spinal nerves run
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Q
Vertebral Processes
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Provide attachment surfaces for muscles and sometimes provide articulation surfaces for ribs
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Q
Transverse Processes
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A type of vertebral process that extends from the lateral sides of the vertebrae
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Q
Spinous Processes
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A type of vertebral process that extends upwards from the neural arch
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Q
Do vertebra in different regions of the vertebral column have all the same shapes for dinosaurs and mammals?
A
No. They will have differences based on the region as they serve different functions.
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Cervical Vertebrae
Vertebrae in the neck. Often have extra large openings for blood & nerve channels, and are adapted to support the weight of the head.
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Dorsal Vertebrae
Vertebrae in the back. Often have tall spinous processes and large rib articulation surfaces.
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Sacral Vertebrae
Vertebrae in the hips. Pelvic bones (which serve as anchors for leg muscles in terrestrial vertebrates) are fused to the sacral vertebrae. Sacral vertebrae are also fused with one another.
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Sacrum
Single solid bone structure formed by the fusion of the Sacral Vertebrae
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Caudal Vertebrae
Vertebrae in the tail.
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Chevrons
Bones underneath the Caudal Vertebrae.
They protect large blood and nerve channels and provide support for tail muscles.
31
Which types of vertebrae in dinosaurs may support ribs?
All (cervical, dorsal, sacral and caudal).
The largest ribs are those that connect to the dorsal vertebrae and form the ribcage. In dinosaurs, ALL dorsal vertebrae connect with ribs.
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Gastralia
AKA "belly ribs". Small ribs positioned across a dinosaur's underbelly, underneath the ribcage, which some dinosaurs had.
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Tetrapods
AKA "four feet". Animals that have evolved from an ancient ancestor with four feet and four limbs.
Most tetrapods still have 4 feet, however some now have hands instead of front feet (i.e. humans), and some have lost limbs altogether (i.e. snakes).
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Limb Girdles
Connect a tetrapod's limbs to the rest of the skeleton.
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Pectoral Girdle
AKA shoulder girdle. Connects the forelimbs to the rest of the skeleton.
Scapula (shoulder blade) is the largest bone in each side of the Pectoral Girdle.
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Pelvic Girdle
AKA hip bones. Connects the hindlimbs to the rest of the skeleton.
Each side is composed of three bones connected to each other: ilium, pubis, and the ischium.
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Ilium
Upper hip bone to which the sacral vertebrae are fused.
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Pubis
Hip bone found below the ilium & in front of the ischium (nearer the belly).
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Ischium
Hip bone found below the ilium & behind the pubis (nearer the tail).
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Acetabulum
The depression or the hole in the pelvic girdle into which the hind limb articulates.
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Humerus
Largest bone in the forelimb, between the elbow and the shoulder.
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Radius & Ulna
The two parallel bones between the elbow and the wrist, with the radius being the thinner of the two (in most cases).
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Carpals
Bones in the wrist.
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Metacarpals
Bones between the wrist and the fingers.
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Phalanges (forelimbs)
Finger bones.
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Femur
Largest bone in the hindlimbs, found between the hip and the knee.
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Fibula & Tibia
Two parallel bones between the knee and ankle. Tibia is our shin bone and the fibula is the thinner of the two.
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Phalanges (hindlimbs)
Bones in our toes.
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Metatarsals
Bones between our ankle and toes.
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What is the difference between how a human's and a dinosaurs feet touched the ground?
When humans stand and walk, our heels touch the ground.
When dinosaurs stood and walked, only their toes touched the ground. Their metatarsals were tilted upwards and contributed to the length of their legs. Helped them take longer steps and probably allowed many to run much faster.
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Saurischian
Group of dinosaurs that shared an evolutionary ancestor that had a pubis that extended downwards and forwards, towards the ribcage.
AKA "Lizard Hipped"
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Ornithischian
Group of dinosaurs that shared an evolutionary ancestor that had a both a special beak-forming bone in the lower jaw (called the predentary) and a pubis that extended downwards and backwards, towards the tail.
AKA "Bird Hipped"
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What are the two major types of Saurischian dinosaurs?
Sauropodomorphs & Theropods
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Sauropodomorphs
Large herbivores with elongated necks and relatively small heads.
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Prosauropods
Early group of sauropodomorphs, were the first group of large-bodied herbivorous dinosaurs to evolve.
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Sauropods
Later group of sauropodomorphs, attained a truly gigantic size (includes the largest animals to ever walk the earth).
They stood on four robust and column-like legs. Their vertebrae (particularly the cervical ones) were filled with complex air sacks which helped reduce weight. their teeth were usually simple and peg-like.
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Theropods
Bipedal saurischian dinosaurs that shared a carnivorous ancestor.
Many were carnivorous and had serrated blade-like teeth and sharp hooked claws. Some were herbivorous and a few lacked teeth altogether.
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What is the only non-completely extinct group of dinosaurs?
Theropods.
Birds are theropods.
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What adaptation(s) do Ornithischians have & what purpose(s) do they serve?
Their backwards extending pubis created more space in their ribcage, likely for extra-large digestive organs. Why? Plant matter is much harder to digest than meat -- most herbivores needed larger stomachs and intestines than carnivores. All known Ornithischians have been primarily herbivorous.
Their beaks are herbivorous adaptations that helped chop off large mouthfuls of vegetation.
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What are the five major groups of Ornithischians?
Ornithopods, Pachycephalosaurs, Ceratopsians, Stegosaurs, and Ankylosaurs.
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Ornithopods
Wide range of dinosaurs that lack armor and that either walked bipedally constantly or assumed a bipedal position when running.
Many were small antelope sized, some (like Iguanodonts) grew to be multi-ton giants.
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Iguanodonts
Large ornithopods with a spike shaped claw on each hand (i.e. Iguanodon).
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Hadrosaurs
Famous "Duck Billed" dinosaurs. Evolved late in the history of dinosaurs, but were highly successful.
Some hadrosaurs have elaborate boney crests. All hadrosaurs have strikingly large beaks in front of their mouths and dense, tightly packed rows of small teeth in the rear of their mouths which form large chewing surfaces collectively referred to as Dental Batteries.
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Pachycephalosaurs
Bipedal with short arms, unusually stout and strong tails, and armored skulls.
Some have thick, domed skull roofs and backwards pointing horns, thought to have rammed predators or butted heads in competitions for territory or mating rights. They have sharp conical teeth in the front of their mouths (behind their beaks), and leaf shaped teeth in the rear -- so they may have been omnivores.
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Ceratopsians
Another group that evolved late in the history of dinosaurs. They have large parrot-like beaks and skulls that are greatly expanded in the rear. In most, this expansion is taken to the extreme and a large boney frill, or neck shield, is present.
Many have horns and possess dental batteries. Most were quadrupedal and had short tails.
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Osteoderm
Bones that develop within the skin and are common component of animal armor.
"Osteo" = Bone, "Derm" = Skin
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Stegosaurs
Group of quadrupedal dinosaurs with rows of projecting osteoderm plates down their backs and long osteoderm spikes on their tails.
Their front limbs are much shorter than their hind limbs. Probably not fast runners, but could pivot quickly and rear up on their hind legs. Their heads are relatively small compared to their bodies, and their snouts are narrow.
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Ankylosaurs
Most heavily armored of all dinosaurs. Quadrupedal with short legs and wide ribcages. Most have short snouts and broader, rounded beaks.
Backs and skulls of most ankylosaurs are covered in spikey protective osteoderms. Some have large osteoderms on the ends of their tails, forming a mace or "tail clubs".
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Why is scaly skin more likely to be fossilized than would flesh?
Because scales are covered in keratin.
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Keratin
Tough but flexible material that also composes hair, feathers, fingernails, and the outside of claws, beaks and horns.
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What were the first mummified dinosaur specimens & what did their discovery reveal?
Hadrosaurs.
It was revealed that they were covered with scales and that scales in different regions of their bodies were shaped differently.
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What was the first specimen to be discovered with feathers?
A small theropod specimen of the carnivorous Sinosauropteryx was found in 1996.
The feathers were fossilized because the body was buried suddenly in fine volcanic ash.
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What is the largest known feathered dinosaur?
Yutyrannus, which had its feathers first reported in 2012.
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What are some known ornithischians with feather-like integuement?
Psittacosaurus - preserved unusual long, stiff, bristle-like structures on its tail.
Tianyulong - covered in long filaments across most of its body
Kulindadromeus - early and primitive ornithischian from Russia, preserves both simple, bristle-like filaments and branching feather-like structures as well.
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Melanosomes
Pigment cells within a feather.
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How might we deduce the color of a dinosaur's feathers?
Studies of modern birds have shown that their feather color is influenced by the shape & arrangement its melanosomes. These melanosomes can be observed in fossilized feathers as well.
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What shape & arrangements of melanosomes indicate what colours?
Black & Gray - long and narrow melanosomes.
Brown & Reddish - Short & wide melanosomes.
White - No melanosomes.
Iridescent or Glossy (i.e. crows) - narrow melanosomes that are aligned in the same direction.
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Do muscles generally fossilize? Why might understanding musculature of dinosaurs be important?
No, they seldom fossilize.
The musculature of dinosaurs allows us to understand how they moved.
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What else in a fossil might offer clues about musculature?
Bones. They provide attachment surfaces and a rigid frame work for muscles. Shapes of bones often correspond to particular muscle shapes, and muscles often leave behind scars on the surfaces of bones where they attached.
The overall pattern of muscle arrangement is largely the same across all tetrapods.
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Which specimen was found with preserved portions of the trachea and intestines, some muscles and keratinous sheaths on its claws?
Scipionyx
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