* Character 10: Anterior ventral glands: Anterior ventral glands are absent (state 0).
* Character 11: Posterior ventral glands: Posterior ventral glands are absent (state 0).
The presence of anterior ventral glands (character 10, state 1) may represent a non-ambiguous synapomorphy for all salamanders to the exclusion of the Sirenidae, while the presence of posterior ventral glands (character 11, state 1) was recovered as the ancestral state for the Salamandroidea with a subsequent loss (character 11, state 0) on the branch leading to the Amphiumidae.