1. 009a
Marine Reptiles

2. Phylum Chordata
Subphylum Vertebrata
3 Classes:
Class Reptilia
Class Aves (birds)
Class Mammalia

3. Reptiles, Birds, Mammals
Evolved from fish-like vertebrates
Moved from the water to the land
Developed 2 pairs of limbs for walking – tetrapods
Developed lungs to breathe
Challenge of land - need to avoid drying out

4. Lungfish – A Missing Link
Class Osteichthyes
Subclass Sarcopterygii (lobe-finned)
Breathe air through swim bladder
Pectoral and pelvic fins → “legs”

5. What About Amphibians? Lungfish – now only freshwater
Amphibians – some tolerate brackish water, none strictly marine
Extinct amphibians - ancestors to the reptiles
Extinct reptiles –
ancestors to the birds

6. Reptiles Better adapted to life on land than amphibians
Skin covered with scales, prevents water loss
Eggs – leathery shell, lay on land

7. Marine Reptiles Some reinvaded the oceans, but still breathe air:
Turtles (Order Chelonia)
Snakes (Order Squamata)
Iguanas (Order Squamata)
Crocodiles (Order Crocodilia)
Saltwater crocodile
Marine turtle
Marine Reptiles (Sea Snakes)
Marine Reptiles include sea snakes, saltwater crocodiles, marine iguanas and sea turtles. Sea snakes are a group of true snakes that have completely adapted their life-histories to live in the sea.
Sea snake
Marine iguana

8. Marine Reptiles
Ectotherms (“cold-blooded”), so mostly in warmer waters, seasonal in temperate waters
Cold stunning –
Turtles too far north when water temperature suddenly drops (<50°F)
Get lethargic, immobile, float to surface, wash up on beach
Fatal if not warmed

9. Marine Turtles (Honu)

10. History Found in fossil record 200 mya (Triassic)
Common in Cretaceous (130 mya)
Present day genera originated 60 (Eocene) and 10 mya (Pleistocene)
Not a very diverse group
Mostly tropical and subtropical

11. Taxonomy Class Reptilia
Order Chelonia- warm to temperate and boreal seas ex. leatherback, ridley's, kemps
Order Chelonia-
F. Cheloniidae- green, flatback, hawksbill,
loggerhead
F. Dermochelidae- leatherback
reduced shell, dermal bone scutes compose
shell
F. Emydidae- diamond back terrapin
Hawaii species- green, hawksbill, leatherback, Olive Ridley

12. Anatomy Dorsal shell = carapace Ventral shell = plastron
Head does not retract
carapace
plastron

13. Anatomy
Female
Male

14. Adaptation to salt water
Lacrimal glands

15. Green turtle Scientific Name: Chelonia mydas Diet: seagrass and algae
Size: ~500lbs
Conservation Status: threatened
Habitat: high energy ocean beaches, convergence zones in the pelagic habitat, benthic feeding grounds in relatively protected waters
Range: throughout world in all tropical and subtropical oceans

16. Kemp’s Ridley Scientific Name: Lepidochelys kempii
Diet: mollusks, crustaceans, jellyfish, fish, algae or seaweed, and sea urchins.
Size: 100lbs
Conservation Status: highly endangered
Habitat: shallow water benthic feeder
Range: Gulf of Mexico, Texas

17. Olive Ridley Scientific Name: Lepidochelys olivacea
Diet: jellyfish, tunicates, sea urchins, bryozoans, bivalves, snails, shrimp, crabs, rock lobsters, and sipunculid worms
Size: >100lbs
Conservation Status: highly endangered
Habitat: shallow marine waters
Range: Indo-Pacific, S. Atlantic
NOAA
NOAA

18. Hawksbill Scientific Name: Eretmochelys imbricata Diet: Shellfish
Size: cm ( in)
Conservation Status: Endangered
Habitat: coral reefs, rocky coasts
Range: Tropical Atlantic, Pacific and Indian Oceans; Caribbean

19. Loggerhead Scientific Name: Caretta caretta Diet: Crustaceans
Size: cm ( in), 300 lbs
Conservation Status: Vulnerable
Habitat: coasts, open sea
Range: Temperate and tropical areas of the Pacific, Indian and Atlantic Oceans
NOAA

20. Flatback Scientific Name: Natator depressus
Diet: sea cucumbers, soft corals, jellyfish
Size: < 1 m in length, 200 lbs
Conservation Status: vunerable
Habitat: near continental shelf, shallow, soft bottom sea beds
Range: northern part of Australia

21. Leatherback Leatherback Largest species (7 ft, 1200 lbs)
Family: Dermochelidae: Scientific Name: Dermochelys coriacea
Diet: sea jellies and salps
Size: lbs
Conservation Status: endangered
Habitat: pelagic water
Range: tropical seas, oceanic islands, Atlantic, Pacific, & Indian Ocean
Leatherback
Largest species (7 ft, 1200 lbs)
Global, widest distribution
Dive deep (up to 4000 ft)
“Warm-blooded” (counter-current circulation, fat)

22. Reproduction Mating- at sea
Migration- occurs in late spring; female is accompanied by male
Green sea turtles migrate as far as 800 miles from feeding area to nest in Northwestern Hawaiian Islands
Egg laying behavior- return to same beach (natal beach)

23. Front flippers dig pit, rear flippers carve out burrow
Kemps Ridley nesting
Usually nest at night
Front flippers dig pit, rear flippers carve out burrow

24. Egg tooth- used to chip away at shell
Group effort to get out of nest- emerge at night (safer) and head towards brightest light
Artificial lights- confuse hatchlings
Turtle nest
Cross section

25. Incidental Marine Turtle Catches

26. Marine Debris- plastic bags, soda can plastic rings, fishing line, oil and tar
Costal development and habitat degradation- noise, light, beach obstructions- affect nesting habitat

27. Fibropapilloma- virus in Green turtles
Affects ability to feed, see, move about, or breath
May be due to pollutants, blood parasites, or habitat change
Kaneohe Bay (1991)- >50% infected

28. Clutch size- about 100 eggs & covers pit with sand
Leatherback hatching
Kemps Ridley hatchlings
Clutch size- about 100 eggs & covers pit with sand
Egg incubation- 2 months depending upon species
Sex determined by temperature- males lower temp, females higher temp

29. Predators

30. Factors Affecting Green Sea Turtle Population
Hawaii nesting females
French Frigate Shoals in the Northwest Hawaiian chain
Hunters
Fisheries
Marine Debris
Coastal Development and Habitat Degradation
Fibropapilloma

31. Commercial Value Meat Eggs- nearly forbidden in all countries
with nesting beaches
Soup
Jewelry
Leather
Convention on International Trade in Endangered Species (CITES): turtle commerce prohibited in countries that signed agreement

32. Protection and Management
Law enforcement- in Hawaii, turtles protected under Endangered Species Act
Riding or harassing- $100,000 fine + prison time
Bringing turtle products into Hawaii- $20,000 + prison time

33. Protection and Management
Increase sea turtle populations:
Ranching- eggs or hatchlings from wild populations
Farming- originally from wild populations, for breeding stock

34. Protection and Management
Fishing regulations-
Shrimp Trawlers - incidental catch by commercial shrimp fish nets: drowned 10,000 turtles each year
Drift nets, gill nets
Turtle Excluder Device (TED)

35. Turtle
Excluder
Device

36. Sea Snakes Yellow- bellied sea snake Sea Snakes
Snakes are cold-blooded (poikilotherms). Consequently, their distributions are restricted to warm waters and sea snakes are only found in the Indo-Pacific region. There is concern that if a sea-level canal were constructed across Panama, they could become introduced to the Caribbean.
Sea snakes inhabit estuaries, coral reef areas and the open sea and they are often found in large schooling groups.
Normally, sea snakes are quite docile and donÕt pose a threat to humans. They have powerful venom which they use to incapacitate fishes or squid. Human fatalities have occurred and these are most common when the snakes wash up on beaches and humans handle the reptiles.
They have few natural predators other than sharks, saltwater crocodiles and eagles.
Yellow- bellied sea snake

37. Sea Snakes Diversity: Location: Habitat:
Laticodtidae- krates- 5 species (1 is fw in Solomon Islands)
Hydrophidae- 54 different species
All derived from Colubrid ancestor; colubrids evolved 40 mya; Laticotids evolved from colubrids 30 mya
Location:
Laticotids- live from east coast India to Japan and come to the tip of Cape York (Australia)
Hydrophiids- found from south tip of Africa to India to South East Asian Islands to Japan to north half of Australia
Habitat:
Primarily tropical; coastal estuaries, coral reefs, open sea; 33-36oC

38. Sea Snakes
Behavior: Often schooling in aggregations; Not aggressive but human fatalities have occurred
Prey: Feed on small fish or squid, which are killed with powerful venom
Predators (few): sharks, snapper, grouper, crabs, saltwater crocodiles, raptors; they descend to escape
Venom: 2-10 times as toxic as that of a cobras

39. Sea Snakes Adaptations to life in the sea
Osmoregulation: skin is impermeable to salts; salts eliminated by sublingual gland
Developing a flattened paddle-shaped tail and a laterally compressed body.
Reduced metabolic rate and increased tolerance for low oxygen levels
Lungs- greatly enlarged; hydrostatic organ
Gaseous exchange - lungs and the skin.
Developing salt excreting glands under the tongue.
2.Developing a flattened paddle-shaped tail and a laterally compressed body making it an efficient swimmer.
3.Reducing its metabolic rate. Sea snakes are capable of remaining submerged for up to 2 hours by decreasing its metabolic rate and developing an increased tolerance for low oxygen levels. After one breath at the surface, it can dive again. A sea snake also has valve-like flaps over its nostrils to stop water flowing into the lungs.
4.The lungs of sea snakes are greatly enlarged, extending to the base of the tail enabling a large volume of oxygen to be stored in the lungs.
5.Parts of the lung are believed to function as a hydrostatic organ regulating the snake's buoyancy.
6.Gaseous exchange occurs through both the lungs and the skin. Up to 22% of the oxygen is supplied from the sea water through the skin and all excess carbon dioxide is lost into the sea.

40. Sea Snakes Reproduction: Krates are oviparous and lay eggs on land
Hydrophiids are viviparous and produce young in the water
Not much known about breeding
However, olive sea snake breed in spring; seasonal courtship displays
Banded sea krates forming mating group
Olive Sea Snake

41. Saltwater crocodiles Largest living crocodilians: 6-7 m long
Eggs laid and incubated on land
Tropical and subtropical
Saltwater Crocodiles
Saltwater crocodiles are the largest of living crocodilians and adults can reach 6-7 m in length. These seagoing animals may travel thousands of miles in the ocean. They are wide-ranging and may move into freshwater areas as well. They havenÕt entirely left land and must return to lay their eggs which are incubated in a terrestrial nest. Their poikilothermic nature means that their distributions are limited to warm areas. Diets include fishes, invertebrates and vertebrates.

42. Marine Iguanas Endemic to Galapagos islands
Herbivorous: graze on seaweeds
Salt-glands on nose to eliminate excess salt
Recently observed feeding on land for first time
They return to land to escape predators.
Marine Iguanas
These are the only marine lizards and they are endemic to the Galapagos Islands off Ecuador. Marine iguanas have flattened tails that assist them in swimming and they have adapted to an aquatic life. Their primary diet are algae that encrust the rocks around the islands. Iguanas dive to feed on the algae and in the process, their bodies undergo substantial cooling. After diving and feeding bouts, they must warm themselves on land to raise their body temperature. During feeding they accumulate a lot of salt that is excreted via specialized salt-glands on their noses. Recently, iguanas have been observed feeding on terrestrial vegetation. The stresses of El Ni–os may have driven them to forage ashore.

43. How do marine turtles regulate salt in their body?
Inquiry
What is a natal beach?
What advantage is there in turtle hatchlings leaving in a group rather than individually?
Are the consequences for harassing a turtle adequate?
How does the fibropapilloma virus effect green sea turtles?
What is a TED?
How do marine turtles regulate salt in their body?