The upcoming discussion will update you about the difference between prototheria and theria.
Difference # Prototheria:
1. Eggs or Young ones :
Oviparous
2. Mammary:
Mammary glands are without nipples or teats.
3. Glands:
Indistinct or absent.
4. Pinna:
Present and is formed by the nasal and premaxilla bones.
5. Beak Cloaca or anus:
Cloaca
6. Teeth:
Absent, only temporary molar milk teeth present in Ornithorhynchus which disappear in adult state. Tachyglossus lacks teeth in any stage of development.
7. Position of testes:
Abdominal.
8. Ureters:
The ureters open into a urinogenital sinus, not open into the urinary bladder.
9. Pectoral girdle:
(a) With a large coracoid
(b) Scapula without spine
10. Interclavicle:
T-shaped interclavicle
11. Fully homeothermic or not:
Not fully homeothermic
Example:
Platypus (Ornithorhynchus sp.)
Echidna (Tachyglossus sp.)
Pro-echidna (Zaglossus sp.)
Difference # Theria:
1. Eggs or Young ones:
Viviparous
2. Mammary glands:
Mammary glands with nipples or teats.
3. Pinna:
Generally present (absent in aquatic mammals).
4. Beak:
Mammary glands with nipples or teats.
5. Cloaca or anus:
All therians possess anus expected pikas (pika), a lagomorph type.
6. Teeth:
Present except scaly ant-eater (Man is sp.) and Baleen whales etc.
7. Position of testes:
Generally within the scrotal sacs.
8. Ureters:
The ureters open directly into the urinary bladder.
(a) Coracoid small
(b) Scapula with a spine
9. Pectoral girdle:
(a) Coracoid small
(b) Scapula with a spine
10. Interclavicle:
Absent
11. Fully homeothermic or not:
Fully homeothermic
Example:
Kangaroo (Macropus giganteus)
Indian elephant (Elephas maximus)
Man (Homo sapiens sapiens)