Marine Reptiles

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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

Lungfish – A Missing Link

• Class Osteichthyes• Subclass Sarcopterygii (lobe-finned)• Breathe air through swim bladder• Pectoral and pelvic fins → “legs”

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

Reptiles

• Better adapted to life on land than amphibians

• Skin covered with scales, prevents water loss

• Eggs – leathery shell, lay on land

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Marine turtle

Marine ReptilesMarine Reptiles

Marine iguana

Sea snake

Saltwater crocodile

Some reinvaded the oceans, but still breathe air:

• Turtles (Order Chelonia)• Snakes (Order Squamata)• Iguanas (Order Squamata)• Crocodiles (Order Crocodilia)

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

• 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

Order Chelonia- warm to temperate and boreal seas ex. leatherback, ridley's, kemps Order Chelonia-

F. Cheloniidae- green, flatback, hawksbill, loggerhead

F. Dermochelidae- leatherbackreduced shell, dermal bone scutes compose shell

F. Emydidae- diamond back terrapin

Class Reptilia

Hawaii species- green, hawksbill, leatherback, Olive Ridley

Anatomy• Dorsal shell = carapace• Ventral shell = plastron• Head does not retract

carapace

plastron

Anatomy

Female Male

Adaptation to salt water

Lacrimal glands

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

Green turtle

Kemp’s RidleyScientific Name: Lepidochelys kempiiDiet: 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

Olive Ridley

NOAA NOAA

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

Hawksbill

Scientific Name: Eretmochelys imbricataDiet: ShellfishSize: 76 - 91 cm (30 - 36 in) Conservation Status: Endangered Habitat: coral reefs, rocky coasts Range: Tropical Atlantic, Pacific and Indian Oceans; Caribbean

Loggerhead

NOAA

Scientific Name: Caretta carettaDiet: CrustaceansSize: 76 - 102 cm (30 - 40 in), 300 lbs Conservation Status: Vulnerable Habitat: coasts, open sea Range: Temperate and tropical areas of the Pacific, Indian and Atlantic Oceans

Flatback

Scientific Name: Natator depressusDiet: sea cucumbers, soft corals, jellyfish

Size: < 1 m in length, 200 lbsConservation Status: vunerable

Habitat: near continental shelf, shallow, soft bottom sea beds

Range: northern part of Australia

Leatherback

Family: Dermochelidae: Scientific Name: Dermochelys coriaceaDiet: sea jellies and salpsSize: 1500 lbsConservation Status: endangeredHabitat: pelagic waterRange: tropical seas, oceanic islands, Atlantic, Pacific, & Indian Ocean

Mating- at seaMigration- 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)

Kemps Ridley nesting

• Usually nest at night

• Front flippers dig pit, rear flippers carve out burrow

Turtle nestCross section

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

Incidental Marine Turtle Catches

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

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

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

Leatherback hatching Kemps Ridley hatchlings

Hawaii- 100-350 nesting femalesFrench Frigate Shoals in the Northwest Hawaiian chain

A.HuntersB.FisheriesC.Marine DebrisD.Coastal Development and Habitat

DegradationE. Fibropapilloma

• 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

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

Increase sea turtle populations:•Ranching- eggs or hatchlings from wild populations•Farming- originally from wild populations, for breeding stock

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)

Turtle Excluder Device

Sea SnakesSea Snakes

Yellow- bellied sea snake

Diversity:• 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

Sea SnakesSea 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

Sea SnakesSea 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.

Sea SnakesSea 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

Olive Sea Snake

Sea SnakesSea Snakes

Banded sea krates forming mating group

• Largest living crocodilians: 6-7 m long

• Eggs laid and incubated on land• Tropical and subtropical

Saltwater crocodiles

Marine IguanasMarine 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.

Inquiry1. What is a natal beach?2. What advantage is there in

turtle hatchlings leaving in a group rather than individually?

3. Are the consequences for harassing a turtle adequate?

4. How does the fibropapilloma virus effect green sea turtles?

5. What is a TED?

How do marine turtles regulate

salt in their body?