marine reptiles Flashcards
what species are classed as marine reptiles
turtles
snakes
iguana
crocodiles
what are some characteristics of marine reptiles
approx 80 species
- air breathing
- ectothermic
- body covered with scales
- oviparous= lay eggs on land
outline the geological history of sea turtles
- tortoises are one of the oldest reptile group
- found in the fossil record 200 million years ago
- common in cretaceous 130 mya
outline turtle anatomy
one of the most derived vertebrates
encased in bone, limbs inside the ribs and horny bones instead of teeth
what is used to identify turtle species ID
Scutes + shape of shell and head = species ID
compare turtles to tortoises/terrapin morphology
Turtle= flat shell, 4 flippers, cant retract head or flippers
Tortoise= shape varied, 4 limbs, can retract head and flippers
how many species of sea turtle are there
7 all with a specialist diet of sponges, crabs, molluscs and other inverterbrates
- green turtle- herbivore
- leather back - obligate planktivore
outline the general structure of turtle shells
- apart of the skeleton and does not match up
1) dorsal carapace = dermal bone
2) ventral plastron = dermal ossifications
3) carapace bone covered
outline the general shell structure of soft shelled families
no peripheral ossifications and epidermal scutes
distal ends of ribs in flexible connective tissues
carapace and plastron covered in skin
outline the shell structure of leatherback turtles
carapace of soft cartilage
plastral bones reduced to a thin rim around plastron edges
oestoderm overlays thick blubber layer overlapping ribs etc
outline endothermy in leatherback turtles
maintain a body temp at 25 degrees even in subpolar waters
thick insulating layer of adipose tissues
counter current heat exchangers maintain the heat generated by swimming muscles inside the limbs preventing hyperthermia
define gignathermy
large, bulky ectothermic animals are more easily able to maintain a constant, relatively high body temperature than smaller animals
what are the 7 species of sea turtle
1) leatherback
2) Australian flat back
3) green turtle
4) hawksbill
5) kemps ridley
6) olive ridley
outline the characteristics of sea turtles
all have same basic morphology
all breathe air
all lay eggs in spring/summer
none exhibit parental care
ecotherms
outline the life history patterns of sea turtles as described by Bolten 2003
1) complete development in the neritic zone = flat back
2) development in oceanic and neritic zone = logger head, green, hawksbill and kemps ridley
3) complete development in oceanic zone = olive ridley and leatherback
how are sea turtles distributed in the ocean
leatherbacks can tolerate cool waters and hard shelled species prefer warmer
what are some selection pressures on both K and r traits
r selective = egg laying, high clutch frequency with extended nesting season
k selective = long distance migration
outline the anatomy of sea snakes
eye with fixed lens
thin forked tongue
distinct scales with ventral scutes extended across body
males have longer tails than females
what are some adaptations of sea snakes
- fully marine execpt the laticauda
- laterally flattened body with paddle like tail
- wide range of habitats
- indo-pacidic
- all omnivorous
- carnivorous
outline some population traits in sea snakes
- all but one have k selected traits
- pop is highly clustered as dispersal is limited
- cutaneous respiration
- bites can be fatal to humans
outline some characteristics of the saltwater croc
red list = least concern
australia, indian ocean and some western pacific islands
-highly predatory
can grow over 7m
outline some characteristics of the american croc
vulnerable
tolerates sea water and can be found in lagoons and other costal regions
males larger than 6,
feed mostly on fish
outline some characteristics of the marine iguana
vulnerable
12 yr life span
one species specific to the Galapagos
most time in water
females forage in intertidal region and males in subtidal
what are some adaptations to marine iguanas
lots of time basking to warm up from dives
low food availability so respond by shrinking
cartilage and connective tissues forms 10% of length so they reabsorb bone matter
females shrink more than males
