dino 101 lesson 1

paleontology

study of all prehistoric life

a paleontologists knowledge of prehistoric life comes primarily from ….?

fossils

fossil

any preserved evidence left behind by a prehistoric organism

• literally means “dug up”

• usually objects or structures found buried in ancient rock formations

what can dinosaur fossils include

• footprints

• eggshells

• coprolites (fossil poop)

• and sometimes skin and feather impressions

• bones (most common)

why do bones have a greater chance of preserving?

theyre made of minerals

T/F: modern birds are considered to be dinosaurs

true

why is it hard to determine the weight of dinosaurs

• fossils collect minerals

• other aspects of the dinosaur have decomposed

• air sacs in fossils

adaptations

traits that have evolved because they serve specific functions

what are the four major functions bones serve?

• resisting gravity and maintaining the animals form

• provide a ridged framework for muscle attachment

• provide protection and can be components of weapons (horns)

• store mineral reserves

are dinos vertebrates or invertebrates?

vertebrates

vertebrates

animals that have two special kinds of adaptations: skulls and vertebrae

vertebrae

structures made primarily of bone and/or cartilage that surround a portion of the spinal nerve cord

they interlock with each other in a series and form the vertebral column

what types of animas were the first vertebrates?

aquatic animals

invertebrates

animals that lack vertebrae

are there more invertebrates or vertebrates?

invertebrates

are vertebrates or invertebrates generally larger?

vertebrates

brain case

hollow chamber formed by multiple skull bones that houses the brain

• rear portion of the skull

• has many openings to allow nerves to pass through that connect to the brain

• size and shape indicate the size and shape of the brain it housed and can provide clues to the dinos mental capabilities

nares

pair of openings for the nostril

orbits

pair of openings for the eyes

fenestrae

additional skull openings in dinosaurs

laterotemporal fenestrae

the fenestrae on the lateral sides of the skull

• behind the orbit

supratemporal fenestrae

fenestrae on top of the skull

• behind orbits

what is the purpose of the laterotemporal fenestrae and the supratemporal fenestrae?

providing extra room for large jaw muscles

antorbital fenestrae

located between each orbit and naris

• function unclear

• may have helped them breathe or adaptations to make the skull lighter

centrum

spool/disk shaped body of a vertebra

neural arch

cover the neural canal

neural canal

opening in each vertebra through which the spinal nerves run

vertebral processes

provide attachment surfaces for muscles and sometimes provide articulation surfaces for ribs

two common types of vertebral processes

transverse processes: extend from the lateral sides of the vertebrae

spinous processes: extend upwards from the neural arch

cervical vertebrae

vertebrae in the neck

• often have extra large openings for blood and nerve channels and are adapted to support the weight of an animal’s head

dorsal vertebrae

vertebrae in the back

• often have tall spinous processes and large rib articulation surfaces

sacral vertebrae

vertebrae in the hips

• pelvic bones are fused to the sacral vertebrae

sacrum

the single solid bone formed when the sacral vertebrae fuse

• further increases strength of hips

caudal vertebrae

vertebrae in the tail

chevrons

protect a large blood and nerve channel and provide support for tail muscles

• underneath causal vertebrae

in dinos, _____, ________, _______, and ______ vertebrae may all support ribs

cervical, dorsal, sacral, caudal

what are the largest ribs in dinos?

those that connect to the dorsal vertebrae and form the ribcage

• in dinos all dorsal vertebrae connect with the ribs (in mammals the dorsal vertebrae close to the hips do not)

gastralia

small ribs positioned across a dino’s underbelly, underneath the ribcage

tetrapods

animals that evolved from an ancient ancestor with four feet and four limbs

• some have hands instead of feet (humans)

• some have no limbs at all (snakes)

• includes dinos, mammals, reptiles, and amphibians

limb girdles

connects limbs of tetrapods to the rest of the skeleton

pectoral girdle

where forelimbs connect

• aka shoulder girdle

scapula

largest bone in each side of the pectoral girdle

• aka shoulder blade

pelvic girdle

where hindlimbs connect

• aka hip bones

what are the three bones of the pelvic girdle

• ilium

• pubis

• ischium

these bones are tightly connected to one another

ilium

upper hip bone

sacral vertebrae fuse here

pubis

• below ilium

• positioned in front of the ischium (near belly)

ischium

• positioned behind the pubis, nearer the tail

acetabulum

depression or the hole in the pelvic girdle into which the hind limb articulates

humerus

bone between the shoulder and elbow

• largest bone in the forelimb

radius and ulna

parallel bones between the elbow and the wrist

• radius is the thinner one

carpals

bones in the wrist

metacarpals

bones between the wrist and fingers

phalanges

finger bones

femur

bone between the kip and knee

• largest bone in the hindlimb

fibula and tibia

two parallel bones between knee and ankle

• tibia forms the shin

• fibula is the one that’s usually broken (thinner)

tarsals

bones in ankles

metatarsals

bones between ankles and toes

phalanges

bones in the toes

T/F: patterns of bones are largely the same in all tetrapods

true

T/F: dinos only walked on their toes

true

• allowed them to take longer steps and run faster

what are the two major groups of dinosaurs

saurischians and ornithiscians

saurischians

dinos that share an evolutionary ancestor that had a pubis that extended downwards and forwards (towards the ribcage)

• "lizard hip”

ornithischians

dinos that share an evolutionary ancestor that had both a special beak-forming bone in the upper jaw (predentary) and a pubis that extended downwards and backwards, towards the tail

• “bird hip”

are birds saurischians or ornithischians

saurischians that have changes their hips from extending forward to extending backward

what are the two major groups of saurischians

• sauropodomorphs

• theropods

sauropodomorphs

large herbivores with elongated necks and relatively small heads

• prosauropods

• sauropods

prosauropods

an early group of sauropods and were the first group of large-bodied herbivorous dinos to evolve

sauropods

• later group of sauropodomorphs

• gigantic

• stood on four robust and column-like legs

• cervical vertebrae filled with air sacks to reduce weight

• simple and peg-like teeth

theropods

• bipedal

• shared a carnivore ancestor

most:

• carnivorous

• blade like teeth

• sharp hooked claws

some:

• herbivorous

• lack teeth

birds are a kind of therapod

ornithischians

• backward extending pubis

  • allows more space in the ribcage to better digest plants

• herbivorous

• have beaks (to eat plants better)

what are the 5 major groups of ornithischians

• ornithopod

• pachycephalosaurs

• ceratopsians

• stegosaurs

• ankylosaurs

ornithopods

• lack armour

• walked bipedally all the time or just wen running

• many were small but some were big

• iguanodonts

  • large ornithopods with a spike-shaped claw on each hand

• hadrosaurs

  • duck billed

  • boney crests

  • large beaks

  • dense, tightly packed teeth that form large chewing surfaces

    • dental batteries

pachycephalosaurs

• bipedal

• short arms

• unusually stout and strong tails

• armoured skulls

• thick dull domed skull roofs and backward pointing horns (fighting with each other)

• sharp conical teeth in the front of their mouths and leaf shaped teeth in the rear

• omnivores

ceratopsians

• large parrot-like beaks

• skulls that expanded into the rear (large boney frill or neck shield)

• quadrupedal and have short tails

• triceratops

  • large ceratopsian

stegosaurs

• group of quadrupedal dinos with rows of projecting osteoderm plates down their backs and long osteoderm spikes on their tails (and sometimes backs and shoulders)

• osteoderms: bones that develop within the skin (armour)

• front limbs ae shorter than hind limbs (not fast runners) but they could probably pivot quickly and could rear up and stand on their hind legs

• small heads

• narrow snouts

integument

dinos body covering

• difficult to know this because they decay rapidly

keratin

tough but flexible material that also composes hair, feathers, fingernails, and the outside of claws, beaks, and horns

• increases likelihood of fossilization

sinosauropteryx

• therapod dino whose feathers were preserved

  • dinos body was buried in ash from volcano

• how we know some small therapods had feathers

yutyrannus

largest known feathered dino

what are some examples of dinos suggesting that ornithiscians could have had feathers like therapods

• psittacosaurus

  • bristles on tail

• tianyulong

  • long filaments all over body

• kulindadromeus

  • feather- like structures on tail

melanosomes

pigment cells within a feather

• can be observed in some fossil feathers and give clues to dinos true colours

what do black and grey colours result from

long and narrow melanosomes

what do brown and reddish colours come from

short and wide melanosomes

what does white come from

no melanosomes

what does iridescence come from

narrow melanosomes aligned in the same direction

scipionyx

preserves the mineralized remains of the trachea