L01 - Chelonians Flashcards
1
Q
Basics points to determine a tortoise?
A
- dry land terrestrial species
- largely herbivorous
- high dome shell and elephantine feet
- forelimbs clad in large overlapping scales
2
Q
Basic points to determine a turtle?
A
- marine species
- largely carnivorous
- tendency for flatter shells and have webbed feet
3
Q
Basic points to determine a terrapin?
A
- freshwater/brackish (slightly salty)
- largely carnivorous
- webbed feet with claws, are multifunctional
4
Q
Key characteristics of chelonians?
A
- ectothermic (require external heat source)
- heliothermic (bask in sun to heat up)
- size: 10cm to 2.4m
- lifespan: 10 to 200 years
- no outer ear
- oviparous (lay eggs, bury, no maternal care)
- will bromate to avoid extreme cold
5
Q
Locomotion in chelonians?
A
- limbs project sideways and have an awkward gait
- muscles tire easily and progress is laborious
- can move a great speed and cover quite a distance
6
Q
What is terrestrial chelonians general anatomy?
A
- high domed
- stump legged
- small headed vegetarians
- usually found in hot and arid climates
7
Q
What is marine chelonians general anatomy?
A
- flatter and softer shell for better streamlining
8
Q
What is freshwater chelonians general anatomy?
A
- webbed feet
- smooth shell
9
Q
What are the types of necks seen in chelonians?
A
- crytodira (hidden neck) so flex vertebrae vertically
- pleurodira (side necked) so flex vertebrae laterally
10
Q
What is included in cryptodira families?
A
- most living tortoises and turtles
- sea turtles
- leatherback turtles
- tortoises
- soft shell turtles
- snapping turtles
11
Q
What neck movement is seen in cryptodira families?
A
- they lower their necks and pull their head straight back into the shell
12
Q
What is included in pleurodira families?
A
- mata mata
- snake necked turtles
- side neck turtles
(all are freshwater aquatic species)
13
Q
What neck movement is seen in pleurodira families?
A
- neck folds sideways along the body under the shells margin
- the venerable exposure of the neck area is likely to have prevented the evolution of terrestrial side-necks
14
Q
What is the carapace?
A
- an endoskeleton
- their upper shell structure
15
Q
What is the structure of their ribs and vertebrae?
A
- modified rib cage and vertebrae
- thoracic and lumbar
- compromised of fused living dermal bone covered by keratinised epidermis
16
Q
What is the structure of the carapace?
A
- the upper shell
- plates is he nine bony layer
- fusion of dermal bone, ribs, thoracic, lumbar vert
- scutes (sections) is the outer layer which is made of keratinised scales
17
Q
How many scutes does each area have?
A
- 5 central (vertebral) scutes
- 4 lateral (pleural/costal) scutes
- numerous marginal scutes
- 1 nuchal cute
18
Q
What is the structure of the plastron?
A
- the lower part of the shell
- compromised of living dermal bone covered by keratinised epidermis
- joined by pillars of shell
- some species have hinges which help shut the shell
19
Q
What is the structure of their vertebral column and ribs?
A
- limited vertebrae
- 8 cervical vertebrae and 10 trunk vertebrae
- trunk vertebrae have rib attachment which fuses to the dermal bone plates
- have no sternum
20
Q
What is the structure of the pectoral and pelvic girdles?
A
- unique in chelonians
- act like vertical pillars which add strength
- attached to both the plastron and carapace by pectoral and pelvic muscles
21
Q
What is the structure of their limbs?
A
- humerus and femur are short
- fused carpus and tarsus for strength
- 5 claws on each foot
- tortoises have only 4 claws on the hindlimb
- have scales
22
Q
What is the structure of their skull?
A
- head is small to allow retraction
- have sturdy skill and rigid upper and lower jaws
- possess a horny beak which is edged with keratin
23
Q
What is the structure of their nares and hard palate?
A
- paired nostrils
- partial hard palate
24
Q
What is the structure of their trachea?
A
- protected by their glottis
- complete cartilaginous rings
- bifurcates high into the neck, into 2 bronchi which lead into the lungs
25
What is the structure of their lungs?
- spongy
- occupy a large volume in the body cavity
- strong trunk muscles expand and contract the lungs
26
Do they have a diaphragm?
No
27
What special ability do chelonians have?
- the ability to switch to anaerobic respiration
28
What is the process of inspiration in chelonians?
- achieved by increasing the lung volume
- this causes a decrease in lung air pressure
- as a result air is sucked in
29
What is the process of expiration in chelonians?
- limbs are retracted in the shell
- causes an increase in soft tissue and pressure within the coelomic cavity
- this forces air out of the lungs
30
What is the process of respiration in aquatic species?
- aided by the pressure of the water which can draw in and out of the lungs
- some absorb oxygen via their cloaca
- some breathe through their skin
31
What is the structure of chelonians oral cavity?
- horny beak
- they have no teeth
- tongue is fleshy and tightly attached
- salivary glands are just mucus, no digestive enzymes
32
What is the structure of the stomach and large intestine?
- stomach is pointless shaped and simple
- have a wide and large intestine for microbial digestion
- caecum is present
33
What is the passage of food?
- passage of food is slow
- allows maximum absorption
34
What is the structure of the heart?
- lies in the midline
- 3 chambered organ
- 2 atria and 1 common ventricle
- ventricle is partial lay divided by a septum to prevent mixing of oxygenated and deoxygenated blood
- blood vessels have a paired aorta
35
What is included in the urogenital system?
- paired kidneys
- two ureters
- bladder
36
What is the structure of the paired kidneys?
- located caudally
- tightly adhered to the ventral surface of inside the carapace
37
What is the structure of the two ureters?
- they empty into the urogenital sinus (urodeum)
- also connects with the bladder
38
What is the structure of the bladder?
- large billowed structure with thin walls
- capable fo some reabsorption of water
- acts as buoyancy aid and can reabsorb some sodium in aquatic species
39
What is the structure of the males reproductive system?
- only have 1 penis which lies in the ventral aspect of the cloaca at rest
- when engorged it is protected through the vent and curves cranially
40
What is the structure of females reproductive system?
- fertile eggs can be carried for 4 weeks to 4 years
- sperm can also be stored for long periods too
41
Chelonian species reproductive system characteristics?
- sexual maturity linked to size
- sexual dimorphism noticed by tail length and width and their shell shape
42
Sexual dimorphism in 4 chelonians species?
Tropical species = normally males larger than
Temperate European = normally females larger
Terrapins = males have longer forelimbs claws
Chelonians = males have more concave plastron
43
What are chelonian senses?
- good colour vision and have scaled eyelids
- marine species have good vision in and out of water
- no external ear, have eardrum but have poor hearing
- good sense of smell
44
What are African Hingebacks defence mechanism?
- have modified bony layers of their shell so they are hinged
- this allows the rear of the shell to close inwards so protecting the back legs of the tortoise
45
What are Box Turtles defence mechanisms?
- have a hinge on their plastron, when the turtle withdraws into the shell the 2 halves close upwards the carapace, closing the turtle inside
46
What are African Pancake Tortoise defence mechanism?
- has a light, soft and flat shell
- when disturbed will run and hide in a rock crevice and inflate itself so making it impossible to remove
47
What are Snapping/Soft Shell Turtles defence mechanism?
- due to vulnerability from poor shell protection
- they provide a very fast and nasty bite
