Presentation by-Deepak Rawal

Assistant ProfessorMohanlal Sukhadia University

Udaipur India

REPTILIA CLASSIFICATION

General characters• Reptiles means creeping • Limbs are clawed when present• Study of reptiles is called herpetology• Cold- blooded(poikilothermic)• Exoskeleton of horny scales,scutes or bony plates• Skin dry,cornified and non glandular• Skull is monocondylic• T-shaped interclavicle present• Heart with 2 auricle and incompletely divide ventricle(3.5 chambers) except crocodiles

whose have 4 chambers• R.B.C. oval and nucleated• 3-chambered Cloaca present• Uricotelic excretion • Metanephric kidney• Cranial nerves 12 pairs (except snakes which have 10 pairs)• Sexual dimorphism present• Fertilisation internal• Eggs are cleidoic(large yolky eggs with calcareous shell)• No larval stage• Amniotes(all 4extra-embryonic membranes present)

Class-Reptilia

subclass- Anapsida

Order-Chelonia

Subclass-Diapsida

Order-Rhynchocephalia

Order-Squamata

Order-Crocodilia

Classification of only living reptiles

Amniotic cleidoic egg

Types of teeth in reptiles

ORDER-CHELONIA• Chelone means turtles• Anapsid skull• Body enclosed in a dorsal carapace and ventral plastron made of dermal bony plates• Teeth absent jaws with horny beaks• Single nasal opening• Limbs of aquatic forms modified into paddles• Short tail• Single intromittent organ in male• Sternum is absent• Cloacal respiration found• Longest lifespan• marine turtles;freshwater terrapins and terrestrial tortoises• Example- Chelone

ORDER-RHYNCHOCEPHALIA• Single species sphenodon punctatum(tuatara) of new

zealand• Skull diapsid• Skin with scales and mid dorsal row of spine• Vestigial pineal eye present in parietal foramen• No copulatory organ in male• Teeth acrodont• Eggs hatches in 13 months• Living fossils

ORDER-CROCODILIA• aquatic reptiles• Sternum present• Skin thick with bony plates and scutes• Limbs are clawed and webbed• Males have one intromittent organ• Teeth thecodont• Heart completely 4 chambered• Examples-gharial, alligator and crocodile• Example- Crocodylus

ORDER-SQUAMATA• Lizards and snakes• Suborder lacertilia/sauria- lizards• Suborder ophidia/serpentina- snakes• Bifid tongue in most• Jacobson organ (gustatory and and olfatory organ) present in

the roof of mouth• horny epidermal scales• Teeth acrodont or pleurodont• Male with double copulatory organ(hemipenes)• Example- Calotes (garden lizard)

JACOBSON ORGAN

Difference between lizards and snakes

LIZARDS

1. Limbs present usually2. Sternum present3. Eyelids are movable4. Tympanum is present5. Both lungs well developed6. Nictitating membrane present

SNAKES

Limbs absent usuallySrernum absentEyelids are immovableTympanum is absentLeft lung usually reducedNictitating membrane absent

Dinosaurs• Dino-terrible; saurus-lizard• They were diapsid• Extict reptiles• Thecodont teeth• Clavicle and interclavicle absent• Double headed ribs• Extinct due to meteor attack on earth • Dinosaurs were aquatic,aerial and terrestial• They was present on earth on jurassic epoch of mesozoic era

IDENTIFICATION OF POISONOUS AND NON-POISONOUS SNAKES

E.g.- HydrophisE.g- Pythons

E.g- Pitless vipers E.g- Pit vipers

E.g- CobrasE.g- Kraits

E.g- Rat snakes

Scales in head region of snakes

POISONOUS AND NON-POISONOUS SNAKES OF INDIA

POISONOUSHAEMOTOXIC• Pit vipers; examples- Lechesis,Ancistrodon• Pitless vipers;Daboia russeli (russell

viper) Echis carinatus (saw scale viper)

NEUROTOXIC • Indian cobra-Naja naja(spectacle cobra)• King cobra – Ophiophagus hanna• Comman krait- Bungarus caeruleus• Sea snake- Hydrophis obscurus• Coral snake- Callophis

NON-POISONOUS• Python- Python regis• boas• Blind snake-Typhlops• Rat snake(dhaman)- Ptyas

mucosa

POISONOUS SNAKES OF INDIA

Indian Cobra The common krait.

Russell's viper.

The saw-scaled viper.

SNAKE VENOM• There are about more than 300 species of snakes in INDIA out of

which only 20 % are poisonous and 80 % are non-poisonous.• Fangs are modified maxillary teeth’s• Poison glands are modified parotid salivary glands• Snake venom is modified saliva used by snakes to immobilize and

digest prey or to serve as a defence mechanism against a predator• Venom is mixture of enzymes and proteins• It is tasteless, odourless and acidic in nature• It is fatal only when mixed in blood• Haemotoxin affect circulatory system by damaging blood vessels

and haemorrhage• Neurotoxin affect nervous system and cause death due to paralysis

of respiratory muscles and asphyxia

Medicinal uses of venom•In Drug researches•Have antibacterial applications•To cure Excessive bleeding: some of the enzymes in venom has been found to clot blood which stop excessive bleeding.•To cure Stroke: Pit Viper venom has potential for breaking blood clots and treating stroke victims.•To cure Neurological diseases :Enzymes from cobra venom may be cures for Parkinson's disease and Alzheimer's disease.•To cure Cancer (various types) : An enzyme derived from copperhead venom could be used to treatment for breast cancer.•To prevent Aging: some are even used in a commercial wrinkle cream•To cure arthritis •To cure paralysis

Antivenom/Antivenin

• Antivenom is a antibody (ig G) for snake venom• It is a protein• It is prepared by hyperimmunising horses against venoms of

snake• It neutralises the free, unbound venom & also dissociates the

bound toxin• If venom is obtained from a single species, then it is

called monovalent antivenom. If the antivenom obtained from two or more species of snakes, then it is called polyvalent.

• In India Antivenin is produced at the Haffkin’s Institute at Bombay and Central Research Institute at Himachal Pradesh.