Genus Zapotecia Eisen, 1900

Remarks. Zapotecia is characterized by having three gizzards, and therefore presumed to share ancestry with the trigastrid group of genera. However, it is worth noting that Zapotecia differs from the trigastrids (in a strict application of the clade definition) by having holonephridia. This suggests that Zapotecia might share a closer ancestry with Protozapotecia and Diplocardia, and not to the trigastrids. Regardless if Zapotecia shares a closer common ancestor with the trigastrids or Protozapotecia and Diplocardia, all of these genera are considered to be more closely related to each other than to other achantodrilid species (Fragoso & Rojas 2016; James & Davidson 2012). The specific evolutionary history of these genera remains unknown.