Marine Reptiles – Diversity

1. Marine Reptiles – Diversity • General Characteristics of Reptiles • Amniotic (shelled) eggs vs. fish-like eggs and larvae of amphibians; allows reproduction in dry habitats • Functional lungs with ribs; movement hinders respiration (same muscles used) • Diversity of Marine Reptiles • Many extinct forms (e.g., ichthyosaurs, pleisiosaurs) • Lizards: marine iguana of Galapagos Islands (eats seaweed and basks in sun after dives) • Sea snakes: most are kraits (same family as cobras) • Sea turtles: an ancient lineage • Crocodiles: marine crocodile of Indo-Pacific a dangerous predator (to 6m and 2 tons); inhabits mangroves and estuaries

2. Figure 5-99

3. Marine Reptiles – Sea Snakes • Indo-Pacific Distribution – some very abundant • Yellow-bellied sea snake: oceanic, wide distribution (most abundant reptile?) • Stoke’s sea snake: in 1932, millions of intertwined snakes reported near Strait of Malacca (3m wide by 100 km) • Adaptations and Characteristics • Paddle-shaped tail, nasal valves close during dives • Venomous: eat eels and small fishes • Most with short fangs; curious but passive with divers • Beaked sea snake: causes 90% of fatalities (one dose of venom could kill 53 people) • Banded krait: warning coloration (warns sharks or birds?) • Some lay eggs on shore, others bear live young in water

4. Figure 5-98 Yellow-bellied Sea Snake

5. Marine Reptiles – Sea Turtles • Diversity – all species considered endangered • Green sea turtle: most common; eats algae and sea grass; eggs and adults harvested for meat and soup; external tumors and diseases common • Loggerhead: Atlantic migrations; viral diseases; dives to 300m • Hawksbill: hooked beak; colorful shell harvested • Ridley: mass arrivals on nesting beaches; Kemp’s Ridley most endangered species in U.S. (led to turtle-exclusion devices in Gulf shrimp fisheries) • Leatherback: largest (to 1200 pounds); leathery skin over shell; feed mainly on jellies and salps • Behavior • Often with long migrations from feeding to nesting grounds (females return to nesting beach, use magnetic sense); hatchlings crawl towards moonlight and swim against direction of waves

6. Figures 5-95, 5-96, & 5-97

7. Marine Birds • Diversity • Oceanic forms: shearwaters, petrels, albatrosses • Coastal forms: shorebirds and marsh birds (sandpipers, stilts, egrets), waterfowl (ducks, geese, swans), grebes and loons, sea gulls and terns, cormorants, frigate birds, and pelicans • Penguins: as adept underwater as porpoises and tuna; fatty blubber, short limbs, dense (fur-like) feathers, heavy bones; predators include leopard seals and killer whales • Emperor Penguin: largest (to 4-ft tall and 100 lbs.), 18 min dives to 1400 ft., males incubate egg for 64 continuous days while female forages • Adaptations and Characteristics • Endothermic: insulation from feathers, air sacs provide efficient respiration (allows high metabolism) • Most with light-weight, hollow bones (some bones fused in wings) • Salt glands: excess salt excreted below eyes or with tube noses • Parental Care: all nest on land; regurgitation (ex. Wilson’s storm petrel feeds fat-rich oil after 48 hour feeding foray)

8. Figures 5-100 and 5-101

9. Marine Birds • Feeding Methods • Spearing: long-legged waders (herons, egrets) • Probing: with long bills, for food in mud (many shorebirds) • Picking/Sweeping: insects at surface (stilts, avocets) • Plunge Diving: pelicans (with pouch), terns • Dipping/Dabbling: ducks, petrels (plankton), albatrosses • Skimming: black skimmer (small fishes) • Underwater Pursuit: cormorants, grebes, penguins • Scavenging: giant petrel, fulmars (tubenoses) • Robbing (kleptoparasitism): frigate birds, bald eagle • Egg Specialists: skuas (eat penguin eggs) • Generalists: sea gulls (eat fish, squid, french fries …)