A Bidder's duct is lost on the branch leading to the Amphiumidae + Plethodontidae + Rhyacotritonidae.
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.
2010), Amphiumidae (Baker, 1945), Plethodontidae (Strickland, 1966), and Salamandndae (Francis, 1934; Baker, 1965).
tigrinum (Green), tiger salamander I Family Salamandridae (newts) Notophthalmus viridescens (Rafinesque), eastern new I Family Plethodontidae
(lungless salamanders) Aneides aeneus (Cope & Packard), green salamander SE Desmognathus fuscus (Green), northern SE dusky salamander Eurycea cirrigera (Green), two-lined salamander C, S E.