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This study explores the origins, diversity, and conservation of marine reptiles, focusing on marine turtles. Topics include limb modification, nesting habits, and the status of different species.
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Conservation and Ecology of Marine Reptiles MARE 490 Dr. Turner Summer 2010
Reptilian Origins Mammalia Aves Reptilia
Class Reptilia Order Chelonia – marine turtles Order Squamata – marine snakes and iguanas Order Crocodilia – saltwater crocodile
Class Reptilia 6,000 living species of reptiles (lizards, snakes, turtles, crocodiles) Dry skin covered with scales (prevent H20 loss) Air breathing Marine taxa include sea turtles, sea snakes, marine iguana, and saltwater crocodile
Marine Turtles Marine turtles tied to terrestrial environment for oviposition - process of laying eggs Other Aquatic Reptiles: iguanas, crocodilians, ichthyosaurs - tail undulation for locomotion
Marine Turtles Marine turtles: lost capacity of tail undulation Developed shortened, rigid body form & corselet (breastplate) Limbs required profound modification from terrestrial existence
Limb Modification Forelimbs modified into paddles: - elongate phalanges enmeshed in a continuous matrix of tough connective tissue Foreclaws reduced to three on each limb
Order Chelonii 2 Families: Cheloniidae & Dermochelyidae 7 or 8 species found throughout 3 tropical Oceans 3 species have restricted distribution: Flatback – northern Australia Kemp’s ridley – Gulf of Mexico, N. Atlantic Black sea turtle – eastern Pacific
Order Chelonii Turtles & tortoises – monophyletic group or clade “Pseudoturtle” Placochelys
Order Chelonii Cretaceous – 4 families: Toxichelyidae Protostegidae Cheloniidae Dermochelyidae
Order Chelonii - Extinct - Extant
Family Toxichelyidae Small/medium sized, broad-shelled marine turtles - diverged from Cheloniidae
Family Protostegidae A group of large to gigantic turtles - Rhinochelys sp. Parallels with dermochelyidae
Order Chelonii - Extinct - Extant
Family Cheloniidae Shell covered in horny scutes Variable in number Typically 5 pairs on carapace; 6 of plastron
Family Dermochelyidae Reduction in bones of the carapace & plastron No scutes
Cheloniid Diversity At one point – 31 genera 5 extant: Chelonia sp. Eretmochelys sp. Lepidochelys sp. Caretta sp. Natator sp.
Genus Chelonia Description: 4 pairs of lateral, non-overlapping scutes 2 extant species: Chelonia mydas Chelonia agassizii
Genus Chelonia Chelonia mydas:4-pairs lateral scutes, 1 pair prefrontal scales, non-overlapping scutes, round head, serrated jaw; to 230kg, shell 125cm
Family Cheloniidae Chelonia mydas – green sea turtle Herbivore Fibrilopapilloma – 49-92% Nest French Frigate Shoals ≈1,000 females
Family Cheloniidae Chelonia mydas – green sea turtle
Major Nesting Areas C. mydas
Genus Chelonia Chelonia agassizii: 4-pairs lateral scutes, 1 pair prefrontal scales, non-overlapping scutes, round head, serrated jaw; to 230kg, shell 125cm Black pigmentation Restricted to E. Pacific
Family Cheloniidae Chelonia agassizii – black sea turtle 4 pairs of non-overlapping lateral scutes Pacific coast of S. America
Family Cheloniidae Chelonia agassizii – black sea turtle
Major Nesting Areas C. agassizii
Genus Eretmochelys Description: 4 pairs of lateral, overlapping scutes 1 extant species: Eretmocheyls imbricata
Genus Eretmochelys Eretmocheyls imbricata: 4-pairs lateral scutes, 2 pairs prefrontal scales, overlapping scutes, pointed head, overbite; to 85kg, shell 95cm
Family Cheloniidae Eretmocheyls imbricata – Hawksbill sea turtle 4 pairs of overlapping lateral scutes Shell highly prized; $100/lb Until 1992 – 20 net tons/Japan Nests on beaches of Hawaii
Family Cheloniidae Eretmocheyls imbricata – Hawksbill sea turtle
Major Nesting Areas E. imbricata
Genus Lepidochelys Description: 5-6+ lateral scutes, round carapace 2 extant species: Lepidocheyls olivacea Lepidocheyls kempi Olive Kemp’s
Genus Lepidochelys Lepidocheyls olivacea: 6+-pairs lateral scutes, carapace nearly circular, 4 bridge scutes with pores, juvenile-charcoal, adult-olive green; to 45kg, shell 70cm Restricted to tropical waters
Family Cheloniidae Lepidocheyls olivacea – Olive ridley sea turtle 6+ pairs of non-overlapping lateral scutes Widely Distributed Doing fairly well Rarely found around Hawai′i
Family Cheloniidae Lepidocheyls olivacea – Olive ridley sea turtle
Major Nesting Areas L. olivacea
5-6 Genus Lepidochelys Lepidocheyls kempi: 5-6 pairs lateral scutes, carapace very round, 4 bridge scutes with pores, juvenile-charcoal, adult-grey-green; to 45kg, shell 70cm Restricted to Gulf of Mexico & S. Atlantic
Family Cheloniidae Lepidocheyls kempi – Kemp’s ridley sea turtle 5 pairs of non-overlapping lateral scutes Most critically Endangered 1947-42,000 ♀; 1980’s -1,000♀ Shrimp trawl bycatch
Family Cheloniidae Lepidocheyls kempi – Kemp’s ridley sea turtle
Major Nesting Areas L. kempi
Genus Caretta Description: 5-6 lateral scutes, carapace longer than wide 1 extant species: Caretta caretta Loggerhead Kemp’s
Genus Caretta Caretta caretta: 5-6 pairs lateral scutes, carapace longer than wide, 3 bridge scutes with no pores, broad head, red to red-brown; to 200kg, shell 120cm
Family Cheloniidae Caretta caretta – Loggerhead sea turtle 5 pairs of non-overlapping lateral scutes Nests in S. Japan – only in N. Pacific; prevalent in Gulf of Mexico and Atlantic
Family Cheloniidae Caretta caretta – Loggerhead sea turtle
Major Nesting Areas C. caretta
Genus Natator Description: 4 pairs of lateral, non-overlapping scutes; 1 extant species: Natator depressus
Genus Natator Natator depressus: 4-pairs lateral scutes, 1 pair prefrontal scales, non-overlapping scutes, round head, serrated jaw; to 90kg, shell 100cm Dorso-ventrally flattened