2. Diverse group of animals
◦Lizards
◦Snakes
◦Tortoises
◦Crocodiles
◦Extinct dinosaurs etc.
3.
4. From a latin word
"reptilis" meaning
"creeping“
Repere or reptum
means creep/ crawl
5. Herpatology- study of reptiles
Smallest reptile- dwarf gecko
Sphaerodactylus aurieus(16mm)
Largest reptile living-
Crocodylus porosus(20.6 feet, over
1900kgs)
Golden age of reptiles-
Mesozoic era
11. Body -head, neck , trunk
and a tail
Body –dry, water proof
epidermal scales-
epidermal in origin,
osteoderms beneath
horny scales- crocodiles
Skin– few glands(musk
glands, femoral glands,
etc) or no glands
Dermis -
chromatophores
12. Skull bears single
condyle
One or two temporal
fossae are usually found
Pineal foramen is present
in the skull
Teeth are simple, conical
and thecodont
Ribs single headed
Gastralia(abdominal ribs)
rob like membrane
bones-ventral body
14. Pulmonary
respiration i.e.
respiration through
lungs takes place
Intercoastal muscles
assist in respiration
Cloacal respiration –
turtles
Cutaneous gas
exchange in many
turtles, sea snakes
15. Heart consists of a
sinus venosus, 2
auricles and 1
incompletely divided
ventricle
Has both left and
right systemic arches
Hepatic and Renal
portal systems
RBC-Oval and
Nucleated
16. Metanephric kidneys with no
nephrostomes
Uricotelic
Cloaca with three chambers-
Coprodaeum(opening of large intestine),
Urodaeum(openings of the Excretory and
genital ducts)& Proctodaeum opens out
by cloacal aperture
17. Two meninges- the duramater and the
pia-arachnoid membrane
12 pairs of cranial nerves seen
Tympanic membrane in external auditory
meatus, middle ear with single ossicle-
Columella auris
Third eyelid nictitating membrane present
in most
In Snakes-Jacobson’s organs (vomeronasal
organs)
18. Sexes are separate
Males possess
copulatory organs
Fertilization is
internal
Large eggs with
considerable yolk
Eggs covered by
porous calcareous
shell(cleidoic &
megalecithal)
Cleavage -
meroblastic
19.
20. Embryo develops
within embryonic
membranes –
amnion and
allantois
Most reptiles are
oviparous
Some snakes are
viviparous