Lecture 16: Pterosaurs

Question 1

Flyers

Answer 1

Started relatively late, requires significant modifications (skeleton, muscles, and motor control/brain)

Question 2

Three levels of flight

Answer 2

Gliding/parachuting: body surface increases to provide resistance to air
Flying: powered
Soaring: take advantage of air movement

Question 3

When was air space conquered?

Answer 3

Devonian-395 million years ago. Animals and plants moved on land. First spores used air space for distribution and insects

Question 4

Why Fly?

Answer 4

Advantages: Larger distance in shorter time. (arctic tern- annual migration route of 30000 km) discovery of new areas. Discovery of new areas, inaccesible over land- colonization by air. Flyers can escape predators, predators can capture their prey.

Question 5

Flying fish

Answer 5

capable of flying 200m with speeds of up to 50km/h

Question 6

Flying frogs

Answer 6

Indonesia, membrane between toes

Question 7

Lizards and geckos

Answer 7

membranes along the side of body, Draco volans-flying lizard from southeast asia. Ribs extend beyond body, air born for about 15m

Question 8

Flying snake

Answer 8

from south east asia, india and siri lanka, flattens its body to increase air resitance

Question 9

mammals

Answer 9

Bats, flying squirrels, gliding possums and flying lemurs, fossil record goes back 60 million years

Question 10

Bats

Answer 10

flying mammals, fossil record of 60 million yrs, four greatly elongated fingers, flying reptiles have one finger, birds have feathers instead

Question 11

Birds

Answer 11

birds since late jurassic, archaeopteryx lithographica, solnhofen limestone, 140 mya ago

Question 12

pterosaurs

Answer 12

Flying reptile, appeared at the end of triassic, 213mya , took to the sky over 60 ma before birds

Question 13

What do flyers have in common?

Answer 13

wings, hollow bones for body weight, some fused joints to reduce flexibility for controlled movement, warm bloodedness for constant high levels of energy

Question 14

Poor fossil record of flyers

Answer 14

Due to hollow and fragile bones, poor fossilization potential, lithographic limestone of solnhofen offers preservation potential, chalks of Kansas

Question 15

Solnhofen- Germany,

Answer 15

140 mil years Europe was covered by a tropical sea tethyan sea, quiet lagoon sheltered by barrier

Question 16

Solnhofen

Answer 16

Quarried for 2000 years, used, used by Romans as building rock, lithography, splitting of rocks into thin slabs reveals fossil content

Question 17

Why was solnhofen ideal for fossilization?

Answer 17

Lagoon- hypersaline, carcasses fall in and settle down to the seafloor, lack of scavengers destroying carcasses, cover of very fine sediment preserving detail of fossil

Question 18

What is a pterosaur?

Answer 18

Word means winged lizard. survived over 140 million years, extinction 65 mil year ago, cretaceous/tertiary boundary, not a dinosaur!

Question 19

Pterosaurs

Answer 19

World wide distribution, early discovery in 18th century, white cliffs of dover, greensand deposits near oxford, solnhofen limestone, chalk deposits of Kansas

Question 20

Ornithodira created by gauthier

Answer 20

broad groups including: dinosaurs, pterosaurs, birds

Question 21

Origin of pterosaurs

Answer 21

the first ones already highly specialized flyers, missing link to more primitive forms, no fossil record of ancestors

Question 22

Possible ancestor

Answer 22

Scleromochlus, 220 million years old; Scotland, Skeletal modifications

Question 23

2 groups of pterosaurs

Answer 23

Rhamphorhynchoidea
- triassic to jurassic
-primitve
-retain tail, teeth
-smaller
Pterodactyloidea
-more advanced 
-longer skulls and necks
-fused backbones in shoulder region
-longer wrist bones
-shorter tail and 5. toe

Question 24

Features of Pterosaurs

Answer 24

Leathery bat-like wing, one greatly elongated finger, a joint at the base of finger so that the wing can be folded in when not flying, 4 joints in the finger, 3 or more short fingers for grasping prey, branches- bearing claws, large openings between nostril and eye, maybe to lighten skull, brains were large and bird like, sharp bill some with teeth on the jaw, teeth were sharp without serration suitable for capturing and killing

Question 25

Wing membrane

Answer 25

Superbly preserved specimens of Germany and Brazil, Preservation of wing membrane (consisting of several layers, outer layer is reinforced by thin fibers)

Question 26

Features of pterosaurs

Answer 26

breastbone is a large plate for bracing the wings and anchoring the massive flight muscles, no wishbone, hollow vertebrae at the front of body and connected to the lungs by pneumatic tubes, found also in birds and saurischian dinosaurs

Question 27

What do pneumatic tubes do?

Answer 27

they allow air into bones
-weight reduction, cooling system, oxygen reserve in warm blooded animals.
Long legs, with a foot of five toes

Question 28

Skull ornamentation

Answer 28

Pterodactyloid: complex and large
Rhamphorhynchoids: small no ornamentation

Question 29

Food

Answer 29

Either insect or fish eating there is evidence of this from their stomach content. Impressions of throat sacs (pelicans), later taxa without teeth, some had webbed feet

Question 30

On the ground

Answer 30

Bipeds or Quadrupeds? walking on all four limbs (hindfoot and wing)

Question 31

In the air

Answer 31

Smaller forms likely active flyers,

large forms- mixture of active flight and soaring

Question 32

Lifting into the air (2 hypotheses)

Answer 32

Arboreal hypothesis: Maybe tree climbers, but fossils found in desert conditions, sharp claws only found on hands, not feet.
Cursorial hypothesis: running on the ground and lifting up, long legs, walking on end of toes, similar hips, knees, foot joints than upright animals such as birds

Question 33

Pteranodon

Answer 33

17kg, 7m wingspan, good flyer, slow but able to maneuver and land softly, long bony headcrest, no teeth, long beak, late cretaceous

Question 34

Lifestyle

Answer 34

Triassic-dry, cretaceous-lush, on land, along ancient coastlines, taphonomic bias, hunting several 100km out to sea, egg lying maybe in colonies

Question 35

Fossil record

Answer 35

over 90 species of pterosaurs, birds have over 8000 species, poor fossil record, 20% alone found in solnhofen