Midterm Flashcards
Paleotonlogy
The study of prehistoric life
Fossil
Any preserved evidence left behind by a prehistoric organism
Means ‘dug up’
Includes footprints, eggshells, coprolites, bones and skin/feather impressions
Adaptations
Traits that have evolved because they serve specific functions
Vertebrates
Animals that have skulls and vertebrae
Vertebrae
Structures made of bone and/or cartilage that surround a portion of the spinal nerve cord
Vertebrae interlock with each other in a series to form the vertebral column
Invertebrates
Animals that lack vertebrae
Brain Case
Hollow chamber formed by multiple skull bones that houses the brain
Nares
Pair of openings for the nostrils
Orbits
Pair of openings for the eyes
Fenestrae
Additional openings in the skull
Means “windows”
Laterotemporal Fenestrae
Fenestrae behind the orbits on the side of the skull
Provide extra room for large jaw muscles
Supratemporal Fenestrae
Fenestrae behind the orbits on the top of the skull
Provide extra room for large jaw muscles
Antorbital Fenestrae
Fenestrae in between the orbits and nares
Centrum
Disk-shaped body of a vertebra
Neural Arch
Part of a vertebra above the centrum that covers the neural canal
Neural Canal
The opening in each vertebrae through which the spinal nerves run
Vertebral Processes
Provide attachment surfaces for muscles and articulation surfaces for ribs
Transverse Processes
Types of vertebral processes that extend from the lateral sides of the vertebrae
Spinous Processes
Types of vertebral processes that extend upwards from the neural arch
Cervical Vertebrae
Vertebrae in the neck
Often have extra-large openings for blood and nerve channels
Are adapted to support the weight of an animals head
Dorsal Vertebrae
Vertebrae in the back
Often have tall spinous processes and large rib articulation surfaces
Sacral Vertebrae
Vertebrae in the hips
Fused to the pelvic bones and to one another
Sacrum
Single solid bone structure made up of fused sacral vertebrae
Caudal Vertebrae
Vertebrae in the tail
Chevrons
Bones underneath caudal vertebrae
Protect a large blood and nerve channel
Provide support for tail muscles
Gastralia
Small ribs positioned across a dinosaur’s underbelly
Also known as “belly ribs”
Tetrapods
Animals that evolved from an ancient ancestor with four feet and four limbs
Limb Girdles
Connects the limbs of a tetrapod to the rest of the skeleton
Pectoral Girdle
Connects the forelimbs to the rest of the skeleton
Also known as the “shoulder girdle”
Scapula
Largest bone in each side of the pectoral girdle
Also known as the “shoulder blade”
Pelvic Girdle
Connects the hindlimbs to the rest of the skeleton
Composed of three tightly connected bones
Ilium
The upper hip bone
Fused to the sacral vertebrae
Ischium
Hip bone positioned below the ilium and behind the pubis near the tail
Pubis
Hip bone positioned below the ilium and in front of the ischium near the belly
Acetabulum
Depression or hole in the pelvic girdle into which the hind limb articulates
Humerus
The bone between the shoulder and the elbow
Largest bone in the forelimb
Radius
A bone between the elbow and the wrist
Parallel to the ulna but thinner
Ulna
A bone between the elbow and the wrist
Parallel to the radius but thicker
Carpals
The bones in the wrist
Metacarpals
The bones between the wrist and the fingers
Phalanges
The bones in the fingers and the toes
Femur
The bone between the hip and the knee
The largest bone in the hindlimbs
Tibia
A bone between the knee and the ankle
Parallel to the fibula but thicker
Fibula
A bone between the knee and the ankle
Parallel to the tibia but thinner
Metatarsals
The bones between the ankle and the toes
Saurischians
Dinosaurs that share an evolutionary ancestor that had a pubis that extended downwards and forwards
Also known as “lizard hipped”
Ornithischians
Dinosaurs that share an evolutionary ancestor that had both a pubis that extended downwards and backwards and a special beak-forming bone in the lower jaw called the predentary
Also known as “bird hipped”
Sauropodomorphs
A group of saurischian dinosaurs characterized by elongated necks
Includes sauropods and prosauropods
Theropods
A group of bipedal saurischian dinosaurs that shared a carnivorous ancestor
The only group of dinosaurs that is not completely extinct
Prosauropods
An early group of sauropodomorphs
The first group of large-bodied herbivorous dinosaurs to evolve
Sauropods
A later group of sauropodomorphs
Includes the largest land animals to ever walk the earth
Ornithopods
A group of ornithischians
Lacked armour
Walked bipedally all the time or assumed a bipedal stance when running
Hadrosaurs
A group of large ornithopods characterized by large beaks in the front of their mouth and densely packed teeth in the back of their mouth
Also known as “duckbilled dinosaurs”
Iguanodonts
A group of large ornithopods characterized by a single spike-shaped claw on each hand
Pachycephalosaurs
A group of ornithischians
Armoured skulls
Bipedal
Ceratopsians
A group of ornithischians
Large parrot-like beaks
Skulls that are greatly expanded in the rear
Dental Batteries
Tightly packed rows of small teeth that form large chewing surfaces
Stegosaurs
A group of ornithischians
Quadrupedal
Plates on their backs and spikes on their tails
Osteoderms
Bones that develop within the skin
A common component of animal armour
Ankylosaurs
A group of ornithischians
Quadrupedal
Backs and skulls covered in spikes
“Tail club”
Most heavily armoured of all dinosaurs
Integument
Body covering
Keratin
A tough but flexible material
Covers the scales of dinosaurs
Composes hair, feathers, fingernails, and the outside of claws, beaks and horns
Sinosauropteryx
First feathered dinosaur discovered
Yutyrannus
The largest known feathered dinosaur
Psittacosaurus
Dinosaur with long stiff bristle-like structures on its tail
Kulindadromeus
Dinosaur with long stiff bristle-like structures and branching feather-like structures
Melanosomes
Pigment cells within a feather that determine the colour of the feather
Scipionyx
Dinosaur with a fossil that includes remains of the trachea and intestines
Taphonomy
The study of all natural processes that involve an organism after it dies
Bloat-and-float
A phenomenon where after death, decay causes a body to swell with putrid gases and be transported by weakly flowing water
Disarticulation
The separation of a skeleton into its various components
May occur as carnivores eat the carcass or because the specimen was transported by water
Plastic Deformation
When pressure causes the shape of a fossil to be permanently changed
Fluvial Deposits
River and stream deposits
Most common location to find dinosaur skeletons
Lacustrine Deposits
Lake deposits
More likely to preserve soft tissues like hair or feathers
Coastal Environments
Fossils that washed out to sea can be found here
Aeolian Deposits
Sediments representing ancient deserts
Uncommon to find fossils as there was not enough sediment to preserve the skeleton
Also known as wind-based deposits
Sedimentary Rocks
Rocks that form when mineral and organic particles accumulate and become either cemented or compacted together
Nearly all fossils are found in sedimentary rocks
Igneous Rocks
Rocks which form when magma cools
Metamorphic Rocks
Rocks that form when igneous or sedimentary rocks are changed by heat and pressure
Sedimentology
The study of how sedimentary rocks form
Mudstone
Sedimentary rocks that form from mud
Mudstone deposits are often indicative of a former lake bottom environment
Sandstone
Sedimentary rocks that form from sand
Sandstone deposits are often indicative of a former beach, river channel or ocean floor environment
Coal
Sedimentary rocks that form from the compressed remains of plants
Coal deposits are often indicative of a former swampy environment
Limestone
Sedimentary rocks that form from the shells and exoskeletons of small marine invertebrates
Limestone deposits are indicative of a former shallow marine environment
Preservation Styles
The different ways that fossils form
Permineralization
When the empty internal spaces of a bone are filled with minerals
Replacement
When the original bone gradually decays and minerals fill the space that the bone once occupied
Badlands
Arid environments where vegetation is sparse, erosion rates are high and large expanses of ancient sedimentary rocks are exposed
One of the best places to discover fossils
Overburden
Rock and earth the covers a fossil specimen and must be removed before the full extent of the specimen can be judged
Removed using shovels, pickaxes, jackhammers and bulldozers
Orientation
The orientation of a fossil can indicate whether the specimen transported by water and what direction the water was flowing
Abrasion
The abrasion of a fossil can indicate how far the specimen was transported by flowing water
Tooth Marks
Tooth marks on a fossil can indicate that carnivores fed on the specimen
Herbivores
Plant eaters
Thin, ridged leaf-shaped teeth for shearing and broad, flat teeth for grinding
Long legs and necks to browse high in trees
Carnivores
Meat eaters
Sharp pointed teeth for piercing
Sharp hooked claws for grasping prey
Serrations
Small sharp bumps on a tooth
Arranged in a line running from the top of the tooth to the bottom of the tooth
Used to slice through flesh
Frugivore
Fruit eater
May have sharp hooked beaks to tear apart the peels and husks of large fruits
Piscivore
Fish eater
Sharp conical teeth that lack serrations to hold on to slippery fish
Long jaws that are capable of snapping shut quickly
Insectivore
Insect eater
May have sharp piercing teeth for puncturing the exoskeleton (hard bodied insects) or weak jaws and reduced teeth (soft bodied insects)
Large spade-shaped claws and short powerful limbs for digging
Omnivores
Plant and meat eaters
May have unspecialized beaks and teeth or a variety of teeth with different shapes
Durophagy
Strong rounded teeth that can crack bones
Requires extremely powerful jaws
Resorption
The chemical process by which a dinosaur breaks down its own teeth and bone so that the minerals and nutrients that compose them can be reused
Cellulose
Compound that makes up plant cell walls
Cannot be digested by animals without the help of bacteria
Gastroliths
Small masses of stones inside a dinosaur’s rib cage
Part of a dinosaur’s gastric mill
Can also be used by aquatic organisms to help regulate buoyancy
Dromeosaurs
A group of theropod dinosaurs with thin tails supported by special rod-like projections of their caudal vertebrae and chevrons (e.g. Velociraptor)
Had serrated blade-like teeth and a large, retractable sickle-shaped claw on each foot
Spinosaurs
A group of theropod dinosaurs with skulls that ressemble those of crocodiles
Had conical teeth with sharp tips and no serrations
Thought to have been piscivores
Alvarezsaurs
A group of small theropod dinosaurs with short front limbs and compact hands
Had reduced teeth and strong front limbs
Thought to have been insectivores
Tyrannosaurs
A group of theropod dinosaurs with reduced front limbs and robust skulls
Had some serrated teeth for puncturing and cutting flesh but some blunt teeth
Had powerful jaws and a tremendous bite force
Thought to have been capable of durophagy
Scavenging
The consumption of an already dead animal by a carnivore that did not play a part in killing it
An opportunistic part of virtually every carnivore’s life
Cololites
Fossil gut contents
Can provide information on a dinosaur’s diet
Coprolites
Fossil poop
Can provide information on a dinosaur’s diet
Sprawling Stance
A stance where an animal’s humerus and femur project horizontally with knees and elbows strongly bent
Erect Stance
A stance where an animals humerus and femur project vertically such that all the limbs point straight down from their girdles
Cursorial Limbs
Limbs specially adapted for fast locomotion
Elongated lower leg bones to increase stride length
Digitigrade
Posture where animals stand on their toes
Unguligrade
Posture where animals stand on toenails that have been modified into hoofs
Plantigrade
Posture where animals stand on their toes, the flats of their feet and their heels simultaneously
Graviportal Limbs
Limbs specially adapted for supporting extreme body weight
Robust heavy limb bones and large feet with fleshy pads
Obligate Bipeds
Animals that almost always walk and run on two legs
Obligate Quadrupeds
Animals that almost always walk and run on four legs
Facultative Bipeds
Animals that walk on all four legs but rise on two legs to run
Facultative Quadrupeds
Animals that walk on two legs but descend to four legs to run
Caudofemoralis
Large muscle anchored to the ilium, caudal vertebrae and chevrons and connected by a tendon to the femur
Pulls backward on the hind leg to power walking and running
Trochanter
Prominence of bone found on the femur where the caudofemoralis muscle-ligament attaches
Ichnofossils
Fossils that record traces of biological activity
Trackways
An entire series of dinosaur footprints
Warm-blooded
Antiquated term for an endotherm
Cold-blooded
Antiquated term for an ectotherm
Endotherm
An animal that regulates its own body temperatures through metabolic processes
Ectotherm
An animal that adjusts its internal body temperature through behaviours that depend on temperature differences within its environment
Histology
The technique of slicing samples of bones into very thin sections such that the internal structure of the bone can be observed under magnification
Osteons
Bone cells arranged in a different pattern depending on whether an animal is an endotherm or an ectotherm
Gigantotherm
An animal that could be considered an ectotherm but whose large size allowed them to live an endotherms lifestyle
Cube Squared Law
As any shape increases in size the volume increases more quickly than the surface area
Amniotic Egg
Eggs with an encapsulating watertight membrane
Allowed amniotes to lay eggs in dry habitats and colonize new terrestrial environments
Amniotes
Animals that lay amniotic eggs
Lines of Arrested Growth
Rings inside of bones that arise due to seasonal differences in growth rates
Also known as LAGs
High Vascularity
Large number of blood vessels found in the bones of younger dinosaurs
Lamellar Bone
Texture found in the bones of younger dinosaurs
Remodelling
When old bone cells are replaced by new bone cells in more mature dinosaurs
Haversian Bone
The bone created by remodelling
Also known as secondary bone
External Fundamental System
A spaced series of LAGs that indicates a dinosaur is skeletally mature and has stopped growing
Non-Isometric Ontogenetic Changes
Changes in the relative proportions of animal as it grows that are not simply changes resulting from a general increase in size
Isometric Ontogenetic Changes
Changes in absolute size but not proportions
Sexual Dimorphism
Differences between the males and females of a species
Medullary Bone
Bone found in female dinosaurs that was used to store calcium in the months prior to eggshell development
Predator Satiation
Strategy used by sauropods and modern sea turtles to ensure some offspring reached maturity
Produces so many offspring that predators are not able to eat them all before they mature
Deterrents
Adaptations which discourage predators from choosing to attack
Finite Element Analysis
A technique used by paleontologists to evaluate hypotheses about the functions of various dinosaur adaptations by determining how stress is distributed throughout an object with a computer simulation
Ritualized Agonistic Combat
Competition that determines which of two individuals is the strongest without either combatant risking serious injury
Monospecific Bonebeds
Large accumulations of fossil bones that are all from multiple individuals of the same species
Common for hadrosaurs, ceratopsians and tyrannosaurs
Nonlethal Face Biting
A common agonistic behaviour among modern carnivores that tyrannosaurs may have engaged in
Shale
Sedimentary rocks that form from silt
Shale deposits are often indicative of a former lake bottom environment
