祖そ先せん形けい質しつ

noun

plesiomorphy; ancestral character

Technical term in evolutionary biology for a primitive trait inherited from a common ancestor, as opposed to a derived trait (apomorphy).

• 系けい統とう解かい析せきでは、祖そ先せん形けい質しつと派は生せい形けい質しつを区く別べつすることが重じゅう要ようだ。

  In phylogenetic analysis, it is important to distinguish between ancestral and derived characters.