Macrostomorpha

Macrostomorpha is a clade of free living flatworms in the group Rhabditophora.

Description

Species of Macrostomorpha are characterized by having the necks of the viscid gland and releasing gland emerging in a common collar of anchor cell microvilli. They also gave aciliary speratozoa and a pharynx of the simplex coronatus type. Macrostomorpha constitute a basal group in Rhabditophora, showing such plesiomorphic condition as entolecithal eggs and spiral cleavage. Another trait found among members of the clade is the presence of hard stylet in the male copulatory organ.

Phylogeny and systematics

Originally the clade Macrostomorpha was divided into two groups: Haplopharyngida and Macrostomida. However, molecular studies revealed that these groups are not monophyletic. The current phylogenetic classification is presented in the following tree: