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Conservation and Ecology of Marine Reptiles MARE 490 Dr. Turner Summer 2012. Reptilian Origins. Mammalia. Aves. Reptilia. Class Reptilia. Order Chelonia – marine turtles Order Squamata – marine snakes and iguanas Order Crocodilia – saltwater crocodile. Class Reptilia. - PowerPoint PPT Presentation
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Conservation and Ecology of Marine Reptiles
MARE 490Dr. Turner
Summer 2012
Mammalia
Reptilian OriginsAves Reptilia
Class Reptilia
Order Chelonia – marine turtles
Order Squamata – marine snakes and iguanas
Order Crocodilia – saltwater crocodile
Class Reptilia6,000 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 TurtlesMarine turtles tied to terrestrial environment for oviposition - process of laying eggs
Other Aquatic Reptiles: iguanas, crocodilians, ichthyosaurs - tail undulation for locomotion
Marine TurtlesMarine turtles: lost capacity of tail undulation
Developed shortened, rigid body form & corselet (breastplate)
Limbs required profound modification from terrestrial existence
Limb ModificationForelimbs modified into paddles: - elongate phalanges enmeshed in a continuous matrix of tough connective tissue
Foreclaws reduced to three on each limb
Order Chelonii2 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 CheloniiTurtles & tortoises – monophyletic group or clade
“Pseudoturtle” Placochelys
Order CheloniiCretaceous – 4 families: Toxichelyidae Protostegidae Cheloniidae Dermochelyidae
Order Chelonii
- Extinct
- Extant
Family ToxichelyidaeSmall/medium sized, broad-shelled marine turtles - diverged from Cheloniidae
Family ProtostegidaeA group of large to gigantic turtles - Rhinochelys sp.Parallels with dermochelyidae
Family Protostegidae
Order Chelonii
- Extinct
- Extant
Family CheloniidaeShell covered in horny scutesVariable in numberTypically 5 pairs on carapace; 6 of plastron
Family DermochelyidaeReduction in bones of the carapace & plastronNo scutes
Cheloniid DiversityAt one point – 31 genera5 extant:
Chelonia sp.Eretmochelys sp.Lepidochelys sp.Caretta sp.Natator sp.
Genus CheloniaDescription: 4 pairs of lateral, non-overlapping scutes
2 extant species:Chelonia mydasChelonia agassizii
Genus CheloniaChelonia mydas: 4-pairs lateral scutes, 1 pair prefrontal scales, non-overlapping scutes, round head, serrated jaw; to 230kg, shell 125cm
Family CheloniidaeChelonia mydas – green sea turtle
Herbivore Fibrilopapilloma – 49-92%Nest French Frigate Shoals≈1,000 females
Family CheloniidaeChelonia mydas – green sea turtle
Major Nesting Areas
C. mydas
Genus CheloniaChelonia agassizii: 4-pairs lateral scutes, 1 pair prefrontal scales, non-overlapping scutes, round head, serrated jaw; to 230kg, shell 125cm
Black pigmentationRestricted to E. Pacific
Family CheloniidaeChelonia agassizii – black sea turtle
Pacific coast of S. America
4 pairs of non-overlapping lateral scutes
Family CheloniidaeChelonia agassizii – black sea turtle
Major Nesting Areas
C. agassizii
Genus EretmochelysDescription: 4 pairs of lateral, overlapping scutes
1 extant species:Eretmocheyls imbricata
Genus EretmochelysEretmocheyls imbricata: 4-pairs lateral scutes, 2 pairs prefrontal scales, overlapping scutes, pointed head, overbite; to 85kg, shell 95cm
Family CheloniidaeEretmocheyls imbricata – Hawksbill sea turtle
Shell highly prized; $100/lbUntil 1992 – 20 net tons/JapanNests on beaches of Hawaii
4 pairs of overlapping lateral scutes
Family CheloniidaeEretmocheyls imbricata – Hawksbill sea turtle
Major Nesting Areas
E. imbricata
Genus LepidochelysDescription: 5-6+ lateral scutes, round carapace
2 extant species:Lepidocheyls olivaceaLepidocheyls kempi
Olive Kemp’s
Genus LepidochelysLepidocheyls 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 CheloniidaeLepidocheyls olivacea – Olive ridley sea turtle
Widely DistributedDoing fairly wellRarely found around Hawai′i
6+ pairs of non-overlapping lateral scutes
Family CheloniidaeLepidocheyls olivacea – Olive ridley sea turtle
Major Nesting Areas
L. olivacea
Genus LepidochelysLepidocheyls kempi: 5-6 pairs lateral scutes, carapace very round, 4 bridge scutes with pores, juvenile-charcoal, adult-grey-green; to 45kg, shell 70cm
5-6
Restricted to Gulf of Mexico & S. Atlantic
Family CheloniidaeLepidocheyls kempi – Kemp’s ridley sea turtle
Most critically Endangered1947-42,000 ♀; 1980’s -1,000♀Shrimp trawl bycatch
5 pairs of non-overlapping lateral scutes
Family CheloniidaeLepidocheyls kempi – Kemp’s ridley sea turtle
Major Nesting Areas
L. kempi
Genus CarettaDescription: 5-6 lateral scutes, carapace longer than wide
1 extant species:Caretta caretta
Loggerhead Kemp’s
Genus CarettaCaretta 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 CheloniidaeCaretta caretta – Loggerhead sea turtle
Nests in S. Japan – only in N. Pacific; prevalent in Gulf of Mexico and Atlantic
5 pairs of non-overlapping lateral scutes
Family CheloniidaeCaretta caretta – Loggerhead sea turtle
Major Nesting Areas
C. caretta
Genus NatatorDescription: 4 pairs of lateral, non-overlapping scutes;
1 extant species:Natator depressus
Genus NatatorNatator depressus: 4-pairs lateral scutes, 1 pair prefrontal scales, non-overlapping scutes, round head, serrated jaw; to 90kg, shell 100cm
Dorso-ventrally flattened
Family CheloniidaeNatator depressus – Flatback sea turtle
Australia – limited range
4 pairs of non-overlapping lateral scutesThin, smooth, & waxy
Family CheloniidaeNatator depressus – Flatback sea turtle
Major Nesting Areas
N. depressus
Dermochelyid DiversitySingle extant species shows very little geographic variability - probably no subspecies exist
However discussion of named populations
Genus DermochelysDermochelys coriacea: Flexible, tapered, & leathery carapace, 5 distinct ridges, no scutes, jaw deeply notched; to 500kg, shell 180cm
Family DermochelyidaeDermocheyls coriacea – Leatherback sea turtle
20,000-30,000 WorldwideCaught in longlines; jellyfishSighted offshore Kona
Family DermochelyidaeDermocheyls coriacea – Leatherback sea turtle
Major Nesting Areas
D. coriacea
Current Taxonomic Questions1. What subfamilies should be recognized?2. Correct placement of flatback?3. Relationship within Lepidochelys4. Status of black turtle in eastern Pacific
Subfamilies?Probably notComplex history of OrderMore work to be done within families
Flatback TurtleWhat is the correct placement of the flatback?
Originally Chelonia depressa
Shows characteristics of both Chelonia & Lepidochelys
Systematic ControversiesNatator depressus – Taxonomic Assignment?
Originally Chelonia depressa
Actually more closely aligned with Caretta & Lepidochelys – both carnivorous
Relationship Between RidleysSlight external difference between juveniles
- only color patterns
Kemp’s Ridley Olive Ridley
Relationship Between RidleysGenetics - differences to species level
Systematic ControversiesRidleys? Believe it or not!
Readily distinguished by color but not morphometrically
Atlantic and Pacific species probably isolated due to formation of Isthmus of Panama – caused large changes in recent speciation (e.g. walrus, bottlenose dolphins, etc.
Systematic ControversiesDermocheyls coriacea – Ancient lineage?
Distinguished from other turtles by: skeletal features partial endothermy modified external morphology
Molecular evidence indicates that leatherbacks represent an early offshoot of the lineage that gave rise to extant marine turtles
Eretnochelys imbricata – Origin of unusual diet?
Appears to have arisen from a carnivorous ancestor
Genus closely aligned with Caretta & Lepidochelys – both carnivorous
“So, you think you’re sponge-worthy?” - Elaine Benice
Systematic Controversies
Systematic ControversiesMarine Turtle Hybrids – Turtle Bastards?
Loggerhead female – Green maleLoggerhead female – Hawksbill maleKemp’s Ridley female – Loggerhead maleGreen female – Hawksbill male
May be oldest vertebrate lineages known to hybridize in nature
Why Do We Care?“Well, that's why I asked. That's how you learn, by asking.. you dumbass.” - Carl Carlson
Population/species level distinction is critical for efficient management practices
International, National, State regulations
Cultural uses
Economic implications
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