Reptiles 2 Flashcards
Chelonia order
chelonia/testudines
Shell is characteristic to chelonia
Chelonia sub orders
Only good to know for ease of handling!
a. Pleurodira – snake/ side neck
i. Can bend their neck at 3 points horizontally
ii. Can retract head but it neve goes furrly in shell
iii. Makes more flexible so more able to bite
b. Crytodira
i. Flex neck at 2 points vertically
ii. Can retract head right back fully into shell
Temp control
- heliothermic = gain heat by basking in sun
- shell can hamper cooling
- Subtropical and temperate species will hibernate in response to decreasing temperature
Chelonia shell nerves? and shedding
- Keratin overlines bony plates
Layer of epidermis over bone nerve and blood supply. Any damage the tortoise will feel it AND bleed - in the terrestrial tortoise scutes are not shed – just more keratin laid down from base
- In some turtles scutes are shed or peel away to make room for new scutes
NAming aprts of the chelonia shell
- Dorsal domed part = carapace
- Ventral flattened part = plastron (males more concave to females)
- Scutes overlie dermal bone plates
Talk ribs and vertebrae, pleuras
- ribs fused with bony plate
- 5 vertebrae, names after the body part that is adjacent to it
- 4 pleuras where expect lungs
- 12 marginals at the side
How is the shell useful for a vet?
- Shell gives lot of information on health
- Will see changes in scute shape and date if diet, UV light etc is inadequate
- Useful to see if any abnormalities
Shell oldest and newest
oldest part on top
Chelonia skeleton, modifications
- Limbs project laterally
- spine and ribs fused
- Pectoral and Pelvic girdle are vertical within rib cage!
• Scapular forms sort of buttress for shell, giving strength
• Modified pectoral girdle that is fused like birds with acromian process that sticks out front
• Pelvis vertical within rib cage and gives shell shape
• Spine and ribcage fused and overlain by bony plates
Chelonia cardiorespiratory
- Nasal breathers
- Trachea short and bifurcates quite early on
- NO diaphragm - there is a sheet of tissue that separates abdominal cavity from lungs but it has no functional use
- Lungs lie dorsally under carapace
Structure of the trachea means what
- STRUCTURE: short and bifurcates quite early on
- Shortness allow to breath in unhampered manor even when neck withdrawn – trachea remains straight even when got a kink in the neck
- Reptiles easy to intubate but tortoise are actually really tricky as glottis is closed until takes breath! – short tube needed so don’t go down a bronchi!
Significance of no diaphragm in chelonia
No cough reflex therefore so much more susceptible to respiratory disease
Movement of limbs and head help to alter internal pressure within the body and assist respiration
No real separation, just a membrane so more prone to respiratory disease and no coughing reflex
Lungs and chelonia
- Lungs lie dorsally under carapace
- Aid buoyancy in aquatic species
- Able to breath hold for long periods of time, gaseous anaesthesia won’t work as can breath hold!
Chelonia heart
- chambers
- Other system>
- location
- All (apart from crocs) ahve 3: Left atrium, right atrium, ventricle (separated by muscular rings
- Renal portal system
- Chelonia, heart lies posterior to pectoral girdle
How to auscultate chelonia heart
Shell can make auscultation difficult, 2 options
OPTION 1: Use damp towel round shell and stethoscope on that which reduces the air interface and makes it easier to hear
OPTION 2: Doplar ultrasound to visualise blood flow, place in between neck and forelimb = least hampered view
Make sure Posterior when ultra sound!
How to blood sample chelonia
Jugular vein if can get head out
Dorsal coccygeal vein in tail
Chelonia GI
25% species completely herbivorous
Others omnivorous – prefer slow prey!
No teeth, use sharp keratinous beak instead
Thick fleshy tongue – helps prehend food
Stomach simple, lies near large bilobed liver (lies either side of stomach)
Short small intestine
Colon large in herbivores, and cecum distinct if lots of plant material
Digestion can be slow -2-4 weeks transit time – when hibernating can’t eat 2-4 weeks before otherwise food would rot inside
Chelonia urinary system:
- location of kidneys and appearance
- Excrete
- Kidney located under carapace and lobulated. NO loop of henle and NO renal pelvis
- Excrete wither urea or uric acid
About chelonia urine
Urine hypo or iso tonic to blood.
Urine often very dilute – often have to reabsorb (refluxed into bladder or colon)
Urine can be excreted directly into urodeum, or refluxed into either bladder or colon for further water conservation
Quite prone to forming bladder and cloaqual stones
Chelonia male repro
- Single phallus which protrudes from the proctodeum
Not involved in urination, just mating! - Testes in caudal coelomic cavity, just cranial to kidneys
- Testes Increase in size during breeding season and decrease for rest of time
- As ectothermic, find with having abdominal testes
How to sex
MALES:
- Concave plastron to assist with mounting
- Presence of phallus (although clitoral hyperplasia can look like a phallus – don’t get it wrong)
- Longer distance from caudal edge of plastron to cloaca
- Longer, broader tails than females
What sort of egg layers are chelonia?
Oviparous lay eggs and young nourished by yolk sac
Chelonia and sperm and egg bound
Can store sperm for a very long time – up to 6 years
Flat plastron, shorter distance between caudal carapace and cloaca
Can get egg bounds (ovarian follicular stasis) seen to be husbandry related- e.g. lack of Ca and light
Lizard taxonomy
Kingdom: Animalia Phylum: Chordata Class: Reptilia Suborder: Lacertilian Order: Squamata
LArgest and biggest smallest
- 3 cm chameleon
2. 3.3 m Komodo dragon huge
List the four recognised infraorders
- Iguania = Includes iguanas, anoles, water and bearded dragons, chameleons
- Gekkota = Includes geckos
- Scincomorpha = Includes tegus and skinks (likely to see)
- Varinoidea = Includes Gila monster, komodo dragon, monitor lizards