External FeaturesOf theFrog

(External Anatomy)

The body of the frog may be divided into:

Axial Region: Head Trunk

Appendicular Region: Two pairs of Appendages Forelimbs

Hindlimbs

External Feature of the Frog

Head Eyes – located posterior to the nostril. Upper Eyelid – borders the dorsal side; immovable. Lower Eyelid – borders the ventral side; immovable, thinner than upper eyelid. Third eyelid (nictitating membrane) – allows the frog to see underwater. Serves

to moisten the eyes when it is on land. Brown spot – circular spot at the anterior level of the eyes.

Ears – Tympanic Membrane – covering the eardrum; They are basically engaged in transmitting the sound waves to the inner ear, so that it gets protected from water and other objects.

Snout – the anterior blunt tip of the head.

External Nares – paired opening located at the snout connected to internal nares (breathing).

Anus or Vent – the most posterior opening found at the median and posterior end of the trunk.

TrunkForelimbs – used to raise or support

the body when the frog is at rest. Three divisions: brachium (upper arm), antebrachium (forearm), manus (hand).

Hindlimbs – well adapted for jumping and swimming. Three division: thigh (upper leg), shank/crus (lower leg), pes (long foot).

Foot – divided into tarsus (long ankle), metatarsus (instep), and five fully-webbed toes or digit.

Male frog vs. Female frogMale is smaller than female. Male has a black band or dark pigment

area at the ventral surface of the lower jaw.

During breeding season, male’s forelimbs differ from that of the female.

The forearm of the male is relatively thicker due to a great muscular development in clasping.

The inner digit or thumb of the hand of the male is larger and swollen at the base due to the glandular secretion of the skin.

Mouth or BuccalCavity

a. Esophagus opening.b. Vomerine teeth.1. Grove of the maxilla.2. Maxillary teeth.3. Internal nare.4. Eye ball.5. Eustachian tube

opening.6. Jaw ridge.7. Underside of the

tongue.8. Glottis.9. Cut muscle and bone.

Buccal Cavity

Orbits or eyesockets – pair of rounded prominences.

Internal or Posterior Nares – frog can breath through these with it's mouth closed, can be opened or closed with sphincter muscles.

Vomerine Teeth – located between the internal nares, serve to prevent the escape of prey.

Maxillary Teeth – fine saw like teeth. For holding the prey.

Sulcus Mariginalis – marginal groove internal to maxillary teeth. Receives the lower jaw.

Pulvinar Rostrale – low elevation at the side of the median subrostral fossa.

Median Subrostral Fossa – depression in the sulcus marginalis. Located at the tip of upper jaw.

Lateral Subrostral Fossae – depression on each side of the pulvinar rostrale.

Eustachian Tube – equalize pressure in the tympanic membrane.

Vocal Sac – only in males, can be inflated with air to make the mating call.

Hyroid Cartilage – where the tounge and other muscles are attached and which continously moves during respiration.

Bilobed Tongue – covered with sticky secretion can be readily extended and withdrawn again.

Tuberculum Prelinguale – located at the tip of the lower jaw. Fits into the median subrostral fossa.

Prelingua Fossa – depressions on either side of tuberculum prelinguale.

Glottis – narrow slit of larygeal prominence; leads into the lungs.

Esophagus (gullet) – passageway for good, from the mouth to the stomach.