According to this, the "evolutionists" believe the appendix to have evolved twice, independently.
Incidentally, the appendix seems to pose other challenges for evolutionary arguments. As it is found in both marsupial and placental mammals, evolutionists are forced to believe that the same appendix evolved twice, independently, in a striking case of organ-level convergent evolution.
Is this an actual claim of "evolutionists", or do they have some other explanation for the dual appendices?