Paleo 200: Lesson 1, Appearances and Anatomy

What is paleontology

Study of all prehistoric life

Study of dinosaurs

Where does a paleontologists knowledge of prehistoric life comes from?

Fossils

Fossil

Any preserved evidence left behind by prehistoric organism

What does the word fossil mean?

Dug up

Types of dinosaur fossils

Skin

Eggshells

Coprolites

Feather impression

Footprints

Coprolites

Fossil poop

Which types of fossils are the rarest?

Skin and feather impressions

What are most fossils

Bones

What are bones made of

Partially of minerals

Do not decay as easily as flesh & soft tissue

What does bones not decaying easily mean for fossils

Have greater chance of being preserved

What are the smallest dinosaurs we know of?

Birds

What is a possible reason we may think dinosaurs are larger than intended?

Inflated by pop culture

E.g of inflation by pop culture

Velociraptor

Reality, size of dog/turkey not human

Example of small dinosaurs

Microraptor

Fruitadens

Both less than a meter long

Weighed less than a kg

What was then largest land dino

Sauropod

What is a fact about sauropods

Many of the long-necked sauropod dinosaurs were bigger than any land animal today

What are adaptations

Traits that ahve evolved bc they serve specific fxns

Are bones adaptations?

Yes, bones are adaptations that help animals survive by serving four major fxns

What techniques do we use to study dinos now?

Comparative biology

Genetic analysis

When did dinosaurs live?

Mesoszoic era

When was the mesozoic era

250 million years ago to 65 million years ago

Which of these animals are dinos?

a. dimetrodon

b. sauropod

c. tiktaalik

d. mammoth

b. sauropod

Not all extinct animals/reptiles are dino's

Why do dinos have diff hind limbs than mammals

Early dinos pulled their legs underneath their body

By doing so they re-oriented everything in their legs, hips, and feet

Who invented the term dinosaur?

Sir Richard Owen, 107 years ago

At this time there were no complete skeletons found

What did Owen discover

That the Ornithopod Iguanodon, thyreophoran hylaeosaurus and theropod Megalosaurus shared teeth that grew in sockets like crocodile & erect limbs like mammals & birds

Why do paleontologist look at skeletons?

How ecosystems have changed over tiem

Adaptations in each species

To understand how many species there were

Which of the sauropods was the heaviest

a. Argentinosaurus

b. Diplodacus

c. Girrafatitan

A. Argentinosaurus

Heaviest weighing 100 metric tons

Diplodocus was longest (25m)

Giraffatitan was tallest (12m)

Why is understanding the real size of dino hard?

Bc there is no living animal to measure and weigh

Also at most times fossilized skeletons are incomplete

What are the four major fxns of bones

1. Passively resist gravity and maintains an animals form

2. Provide ridged framework for muscle attachment

3. Provide protection and can also be major components of horns & other robust weapons

4. Store mineral reserves

Explain first fxn of bones

When you stand up straight, bones in your legs act as support columns

Leg bones support your weight without muscles actively flexing and expending energy

Explain fourth fxn of bones

When resource is scarce animal may gain access to stored minerals by reabsorbing some of its bone

What group of animals do dinosaurs belong to?

Vertebrates

Vertebrates

Animals that have two special kinds of skeletal adaptations

What are the two special skeletal adaptations vertebrates have?

Skulls

Vertebrae

What is a vertebrae (singular: vertebra)

Structures made primarily of bone and/or cartilage that surround portion of spinal cord

Vertebral column

Formed when vertebrae interlock w each other in a series

Example of vertebrates

Fish

Amphibians

Turtles

Snakes

Birds

Mammals

Who were the first vertebrates

Aquatic animals that evolved +500 million years ago

What are aniamls that lack vertebrae called?

Invertebrates

Example of invertebrates?

Insects

Spiders

Snails

Squids

Clams

Jellyfish

Worms

Are there more vertebrates or invertebrates

Since origin of animal life there has always been many more invertrebrate species

When are there more vertebrate species?

More numerous when it comes to species of large animals, especially on land

Why is this success of vertebrates seen on land?

Vertebral column's ability to passively support weight and to anchor enlarged muscles

What is the skull

Composed of many bones tightly locked tgther

What can the jaws of a skull tell a palaeontologist?

Dinosaurs eating habits

what does the rear portion of a skull contain?

Brain case

What is a brain case

Hollow chamber formed by multiple skull bones

Houses the brain

Are there holes in the brain case

Yes

Many small openings to allow nerves to pass through and connect to the brain

What does the size and shape of the brain case indicate

Clue for dino's mental capabilities

What do dino skulls ahve

Multiple pairs of large openings

Examples of skull openings

Nares

Orbits

Fenestrae

Nares (singular: naris)

Pair of opening for nostrils

Orbits

Pair of opening for eyes

Fenestrae

Skull openings

Where is the fenestrae in dino's (singular: fenestra)

Behind each orbit, dino's have two fenestrae (two pairs)

What are the two fenestrae

Laterotemporal fenestrae

Supratemporal fenestrae

Laterotemporal fenestrae

Fenestrae on lateral sides of skull

Supratemporal fenestrae

Fenestrae on top of skull

What do the laterotemporal and supratemporal fenestrae provide?

Extra room for large jaw muscles

How many fenestrae do dino's have in total

3

What is the third fenestrae

Antorbital fenestrae

What is the role of the antorbital fenestrae?

Adaptations to make skull lighter

May have also housed large sinus cavities that helped warm the air dino's breathed

Where does the vertebral column begin?

First vertebra in neck

Where does the vertebral column end?

Last vertebra in tail

What do nearly all vertebrae share?

Basic form

What does a vertebra have?

Spool/disk-shaped body called centrum

What is above the centrum?

Neural arch

What does the neural arch do?

Covers neural canal

What is the 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

What are the two common types of vertebral processes

Transverse

Spinous

Transverse processes

Extend from lateral sides of vertebrae

Spinous processes

Extend upwards from neural arch

What is to be noted throughout the vertebral column of anu animal?

Shapes of individual vertebrae very

Fish have little difff, dino's and mammals have big diff

What are vertebrae in the neck called?

Cervical vertebrae

What are cervical vertebrae known for?

Extra-large opening for blood and nerve channels

Adapted to support weight of animals head

Wht are bertebrae in the back called?

Dorsal vertebrae

What are dorsal vertebrae known for?

Often have tall spinous processes and large rib articulation surfaces

What are vertebrae in the hips called?

Sacral vertebrae

What are sacral vertebrae known for?

Fuse w pelvic bones to allow for powerful leg muscle

Also fuse with one another to form a single solid bone called the sacrum

What is the vertebrae for the tail called?

Caudal vertebrae

What is the caudal vertebrae known for?

Underneath caudal vertebrae are chevron (bones)

What do chevrons do?

Arch thar protects large blood and nerve channel

Provide support for tail muscle

What are the four types of vertebrae

Cervical

Dorsal

Sacral

Caudal

What is special about the four types of vertebrae in dino's

May all support ribs

however in tail, ribs are usually only present at the base and are tightly fused to dorsal vertebrae to form ribcage

What is diff btwn dinosaur dorsal vertebrae and mammals

For dino's all dorsal vertebrae connect w ribs

In mammals, dorsal vertebrae close to hips do not

What did some dino's have that mammals did not

Gastralia

Gastralia

Small ribs positioned across dino's underbelly underneath ribcage

What are tetrapod's

Special group of vertebrates including 4 diff groups

What are the 4 groups of tetrapod's

Amphibians

reptiles

Mammals

Dino's

Limb girdles

Connect tetrapod limbs to the rest of the skeleton

Pectoral/shoulder girdle

Forelimbs connect to

Scapula/shoulder blade

Largest bone in each side of pectoral girdle

Pelvic girdle/hip bones

Where the hindlimbs connect

What are the three bones that make up the pelvic girdle?

Ilium

Pubis

Ischium

Ilium

Upper hip bone

Sacral vertebrae are fused to ilium

Oubis

Below ilium

Positioned in front of ischium

Nearer to the belly

Ischium

Positioned behind pubis

Nearer to the tail

Acetabulum

Depression/hole in pelvic girdle into which the hind limb articulates

Humerus

Largest bone in forelimb

located btwn should and elbow