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The upcoming discussion will update you about the difference between lacertilia and ophidia.
Difference # Lacertilia:
1. Shape:
Elongated body, usually with two pairs of limbs.
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2. Neck:
Distinct
3. Limbs:
Excepting the limbless lizards, the limbs are pentedactylus, each digit ending in a claw
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4. Eyelids:
Usually an upper and a lower eyelid are present. In the members of the family, Gekkonidae, the eyelids are fused over the eyes.
5. Nictitating membrane:
Movable
6. Scales:
Small and overlapping. Sortie forms develop osteoderms. May be modified into spines and ‘frills’ in many lizards.
7. Tympanum:
Distinct.
8. Occipital condyle:
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Single.
9. Inter-orbital septum:
Present.
10. Fossae:
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Well-developed.
11. Jugal:
Present.
12. Zygomatic arch:
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More or less complete.
13. Epipterygoid:
Usually present.
14. Quadrate:
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Slightly movable.
15. Inter-parietal foramen:
Present.
16. Basisphenoid:
Not prolonged anteriorly into a rostrum.
17. Lower jaw:
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Rami are united firmly by bony symphysis. Each ramus is composed of six pieces of bones.
18. Vertebral column:
Differentiated into different regions, like cervical, thoracic, lumbar, sacral, etc. Vertebrae are procoelous except in Gekkonidae where the vertebrae are amphicoelous.
19. Ribs:
Restricted to some vertebrae.
20. Teeth:
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Homodont, conical teeth— borne on the premaxillae, dentary and palatine.
21. Lungs:
Both are equally developed.
22. Arterial arches:
Symmetrically disposed with ductus caroticus.
23. Urinary bladder:
Present.
24. Brain:
Cerebral hemispheres are short,
25. Cranial nerves:
12 pairs.
Difference # Ophidia:
1. Shape:
Cylindrical body without limbs
2. Neck:
Usually indistinct
2. Limbs:
Secondarily lost. Vestiges of hind limbs are present in Python.
3. Eyelids:
Absent and fused with the eyes. The eyes are protected by transparent scale covering the eyes as spectacles.
4. Nictitating membrane:
Immovable.
5. Scales:
Scales tack osteoderm. Exhibit regional differentiation—forming head shields,, ventral shields, etc. The ventral scales are extremely large and transversely arranged.
7. Tympanum:
Indistinct or absent.
8. Occipital condyle:
Distinctly triple.
9. Inter-orbital septum:
Absent
10. Fossae:
Absent secondarily.
11. Jugal:
Absent.
12. Zygomatic arch:
Complete.
13. Epipterygoid:
Absent.
14. Quadrate:
Highly movable.
15. Inter-parietal foramen:
Absent.
16. Basisphenoid:
Prolonged anteriorly into a rostrum.
17. Lower jaw:
Rami are united loosely by ligament. Coronoid may be absent in some snakes.
18. Vertebral column:
Differentiated only into precaudal and caudal regions. Vertebrae are strongly procoelous with extra articulating points— zygantra and zygosphene.
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19. Ribs:
Present in almost all the vertebrae except the atlas. Each rib is bifid distally and remains attached with the ventral scales by ligaments.
20. Teeth:
Conical recurved teeth—borne by maxillae, palatine, pterygoid, dentary and very rarely by premaxillae. In poisonous snakes, the maxillary teeth become modified into fangs with open or closed venom canal.
21. Lungs:
Left one is usually smaller or may be absent.
22. Arterial arches:
Asymmetrically placed without ductus caroticus.
23. Urinary bladder:
Absent.
24. Brain:
Extremely elongated and project in between the eyes.
25. Cranial nerves:
10 pairs.
