The middle free limb segment, between the autopod and stylopod segments. Includes as parts the zeugopodial skeleton. Examples: There are two types of zeugopod: forelimb zeugopod (aka forearm), hindlimb zeugopod (aka crus).
Comment:
There exists some controversy about which podial segments are present in some fishes, e.g. if the autopod is not newly evolved in tetrapods, there is a question as to which segments are actually present in basal vertebrate taxa.[PHENOSCAPE:curators]