Diagnosis_Genus: Apodinium Chatton 1907. Ectoparasite of appendicularians, attached by a peduncle. Sporogenesis occurs during the trophont stage by palisporogenesis.
Diagnosis_Species: Apodinium zygorhizum Cachon and Cachon 1973. Type host: Fritillaria pellucida, the parasite is localised at the proximity of the mouth. The peduncle penetrates inside the tegument, and is directed toward the pharynx.