Download - Marine Reptiles
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
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
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)
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
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?