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. The presence of Kingsbury's (character 12, state 1) and dorsal pelvic (character 13, state 1) glands may represent a non-ambiguous synapomorphy for the Salamandroidea, whereas the presence of lateral pelvic glands (character 14, state 1) evolved on the branch leading to the Salamandroidea, with subsequent independent losses in the Amphiumidae and Salamandridae.
Non-anastomizing collecting ducts (character 2, state 0) were recovered as the ancestral state for salamanders, and collecting ducts that do anastomose (character 2, state 1) may have evolved independently on the branches leading to the Ambystomatidae + Dicamptodontidae + Salamandridae and Amphiumidae + Plethodontidae clades.
The Cryptobranchidae + Hynobiidae, Ambystomatidae Dicamptodontidae + Salamandridae, and Proteidae lineages possess a Bidder's duct, while this characteristic is lacking on the branches leading to the Sirenidae and Amphiumidae + Plethodontidae + Rhyacotritonidae.
The lack of posterior ventral glands (character 11, state 0) was recovered as the ancestral state of salamanders and these glands (character 11, state 1) may have evolved independently on the branches leading to the Proteidae and Ambystomatidae + Dicamptodontidae + Salamandndae + Rhyacotritonidae + Amphiumidae + Plethodontidae.