From Wikibooks, the open-content textbooks collection
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| Parent key: Chordata |
| Subphyla |
| Vertebrata |
| Key: Amphibia |
| Vertebrata |
| Amphibia |
|
- Number of vertebrae
- Nine or fewer - 2
- More than nine - 3
Bold text
[edit] 2: Salientia
- Tailwagging muscles
- Present - 6
- Not present - 7
- Tail
- Present in all life stages - 5
- Not present in all life stages - 4
[edit] 4: Gymnophiona
[edit] 5: Caudata
- Narrow grooves between each nostril and the upper lip
- Endochondral ossifications in the hyoid plate (distinct from parahyoid bones)
- Narrow epipubic cartilage plate
- Metatarsal spade
- Present - 13
- Not present - 11
- Elongate atlantal neural arch
- Fertilization
- Internal - 15
- External - #16
[edit] 15: Salamandroidea
- Premaxillae
- Fused - 18
- Separated - 19
Dicamptodontidae, Salamandridae, Ambystomatidae, Proteidae, Rhyacotritonidae, Amphiumidae
- Metamorphosis
- Present (fully or partially) - 17
- Not present - Sirenidae
[edit] 17: Cryptobranchoidea
- Operculum
- Present - 20
- Not present - 21
- Bilaterally paired septomaxillary bones