Marine Reptiles

Question 1

What are marine reptiles?

Answer 1

Marine tetrapods (including marine reptiles) - 4 limbed vertebrate thats re-invaded the sea

Question 2

Secondary aquatic

Answer 2

originally went from sea to land to sea again

Question 3

Factors for being marine:

Answer 3

Feeding in the sea MOST IMPORTANT
Swimming in the sea PROBABLY
Because there are some that walk on the seafloor
vast majority was in the coastal seawater

Question 4

What are the major groups of (modern) marine reptiles?

Answer 4

Marine iguana
Sea snake
Sea turtles
Sea kraits

Question 5

Sea snake

Answer 5

Best adapted to water: gives birth in water, rarely leaves water

Question 6

Sea turtles

Answer 6

Only lay eggs on land

Question 7

Sea kraits

Answer 7

Eat in water, but nest and lay eggs on land

Question 8

OLD Marine reptile groups

Answer 8

Sauropterygians (biggest group) (1st)
Ichthyosaurs (2nd biggest)
Mosasaurs
Thalattosuchians - sea crocodiles
Sea turtles - only surviving mesozoic marine reptiles 
Thalattosaurs
Pleurosaurs

Question 9

OLD MAJOR Marine reptile groups

Answer 9

Sauropterygians (biggest group) (1st)
Ichthyosaurs (2nd biggest)
Mosasaurs

Question 10

Sauropterygians

Answer 10

(biggest group)
Started early triassic to end of cretaceous
(gave rise to) plesiosaurs

Question 11

Placodus

Answer 11

Sauropterygian
Flat body top to bottom
Shield on back
All shell eaters

Question 12

Elasmosauridae

Answer 12

Sauropterygian
plesiosaur (long back)
Started in early cretaceous but did the best in the late cretaceous
74 bones (in neck)

Question 13

liopleurodon

Answer 13

Sauropterygian
plesiosaur
Shorter neck: pilosauridae > liopleurodon (less than 74 bones in neck)

Question 14

Short neck plesiosaurs

Answer 14

MOST DANGEROUS
Gigantic skull
carnivores

Question 15

Ichthyopterygia

Answer 15

Started early triassic to end of cretaceous
Flat side to side
Lizards with sides
Cruisier in sea

Question 16

Eyes of Ichthyopterygia

Answer 16

GIGANTIC EYES: eyes has bone inside
had the largest eyes of all vertebrates
at least some of them were adapted to see in the deep sea

Question 17

Ophthalmosaurus

Answer 17

Ichthyopterygia
Had the biggest eye but the animal itself was small(er)
Used it to see in deep waters
BIGGEST EYE BALL: 23-26.4 cm/mm (?) eyeball size

Question 18

Parvipelvia

Answer 18

“fish shaped” ichthyosaurs

Question 19

Mosasuridea

Answer 19

From the Late Cretaceous and became extinct at the end of the Cretaceous
Lizards
Swimming in the sea, feeding in sea

Question 20

Basal to derived Mosasuridea

Answer 20

Opetiosaurus -> clidastes -> plotosaurus

Basal derived

Question 21

What change did Mosasuridea go through

Answer 21

Arms became flipper only

Question 22

How scary of predators were Mosasuridea

Answer 22

Worst neck predator besides plesiosaurs (short neck)

Question 23

Skull of Mosasuridea

Answer 23

Giant skull

Big sharp tip

Question 24

Tail of Mosasuridea

Answer 24

Tail means it did not go onto land (looks like a propeller)
tailbend, where the vertebral column kinks downward.

This allows the tip of the tail vertebral column to support the lower lobe of the tail fluke.

Question 25

What was the largest Mesozoic marine reptile?

Answer 25

Shonisaurus sikanniensis Ichthyopterygia > merriamosauria > shastasauridae 20-23 m BIGGEST ONE: ICHTHYOSAUR

Question 26

List of the largest Mesozoic marine reptiles?

Answer 26

``` Sea turtles Archelon 4 m Mosasuroidea > mosasuridae 12-15 m Short neck plesiosaurs 12-15 m Long neck plesiosaurs 12-15 m Shonisaurus sikanniensis Ichthyopterygia > merriamosauria > shastasauridae 20-23 m BIGGEST ONE: ICHTHYOSAUR ```

Question 27

How do modern marine tetrapods give birth?

Answer 27

Bottlenose dolphins giving birth Tail first birth to reduce suffocation Sea snake also tail first ( b/c doesn’t go on land) Marine tetrapods tend to give birth tail first in water, although some babies do come out headfirst occasionally and survive BUT NOT ON LAND Seals give birth on land head first

Question 28

How do modern reptiles give birth?

Answer 28

Archosaurs (crocs, turtles, and birds) all lay eggs Squamates, snakes, and lizards Blue tongue skink - head first birth Babies come out in a rolled fashion as in they come out in a membrane Chameleons giving birth Drops their baby really high up

Question 29

Types of birth (not reptiles)

Answer 29

Oviparity Lay eggs Viviparity Give birth “Ovoviviparity” Hatches egg in body Only for fishes and not reptiles

Question 30

Types of birth (reptiles)

Answer 30

Lecithotrophy Matrotrophy Partial placentotrophy (complete) Placentotrophy

Question 31

Lecithotrophy

Answer 31

Nutrients from yolk

Question 32

Matrotrophy

Answer 32

Nutrients from mother

Question 33

Partial placentotrophy

Answer 33

If you have an incomplete placenta or something similar, and if that allows the embryo to receive nutrients and remove wastes to some extent, then that is partial placentotrophy. Some lizards and sharks

Question 34

(complete) Placentotrophy

Answer 34

eating yolk but mothers supplies nutrients as well (related to both partial placentotrophy and matrotrophy) If you have a complete placenta, then you have complete Placentotrophy.

Question 35

Squamates giving birth

Answer 35

Squamates may give live birth or lay eggs

Question 36

Could two birth styles exist in one species?

Answer 36

Two birth styles could co-exist within a single species (skunk)

Question 37

How common is viviparity

Answer 37

Viviparity is common Evolved at least 100 times in squamates About 10% of squamates are viviparous

Question 38

How did Mesozoic marine reptiles give birth? (Mosasuridea)

Answer 38

Mosasuridea - squamates Carsosaurus Tiny curved boned in stomach Gave birth curved up

Question 39

How did Mesozoic marine reptiles give birth? (Sauropterygia)

Answer 39

``` Some fossils with embryo outside body Either thrown out or something happened Usually curved in embryo Can’t tell if curled up or headfirst Grew in stomach ```

Question 40

How did Mesozoic marine reptiles give birth? (Plesiosaurs)

Answer 40

Probably gave birth Grew within body Probably gave birth to 1 kid and nurtured for life b/c babies were larger

Question 41

How did Mesozoic marine reptiles give birth? (Ichthyopterygia)

Answer 41

Tail first but also found head first (in a primitive specimen though) Probably gave birth head first b/c ancestors were on land but slowly changed