Chelonian Reproduction - Anatomy & Physiology
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- Long, yellow and oval in shape.
- Attached to the cranioventral pole of the kidneys.
- Ductus deferens runs alongside ureters to the cloaca.
- Ventral proctodeum is modified and thickened into a single phallus.
- Two pairs of fibrous tissue separated by a central trough.
- Cannot be inverted (unlike lizards and snakes).
- Highly vascular.
- When inserted into the female cloaca it becomes engorged.
- Semen is conveyed through the central sulcus.
- A retractor muscle returns the phallus back into the cloaca.
- Paired ovaries lie symmetrically, cranial to the kidneys.
- Irregular, sac-like.
- Different sized ova that become prominent with mature follicles.
Sperm Storage in the Female Tract
- Females in some species can retain sperm in their uterus.
- Can successfully fertilize two or more clutches, often several years after copulation.
All chelonians are oviparous.
- Lay eggs with soft, flexible, leathery shells.
- Can absorb and loose moisture.
- Develop more rapidly.
- Incubation ~2 months.
Tropical Species and Land Tortoises
- Lay eggs with a hard, brittle shell.
- Prevents eater loss.
- Develop less rapidly.
- Incubation ~8-9 months.
- Egg hatching depends on climate conditions such as spring warmth and seasonal rains.
- Courtship and mating is very vocal.
- Crying, grunting and barking
- Male mounts from the rear.
- Internal fertilization