Phylogeny and systematics of Aphroditiformia

Area of Science:

• Marine Biology
• Evolutionary Biology
• Annelid Taxonomy

Background:

• Aphroditiformia is a successful annelid group crucial for studying evolutionary patterns.
• Previous phylogenetic studies had limitations, excluding certain species and failing to resolve relationships within Sigalionidae.

Purpose of the Study:

• To resolve phylogenetic relationships within Aphroditiformia, including anchialine and interstitial species.
• To improve the understanding of evolutionary history and taxonomic classifications within the group, particularly Sigalionidae.

Main Methods:

• Analysis of four molecular markers and 87 morphological characters from 127 species.
• Application of parsimony and model-based phylogenetic methods with sensitivity analyses.
• Inclusion of newly sequenced anchialine and interstitial species, and additional Sigalionidae taxa.

Main Results:

• Congruent recovery of six monophyletic clades corresponding to Aphroditiformia families.
• Identification of an anchialine polynoid lineage within deep-sea species.
• Resolution of Sigalionidae into four distinct clades, leading to the proposal of new subfamilies.

Conclusions:

• The study provides a robust phylogeny for Aphroditiformia, resolving previous limitations.
• New subfamilies (Pelogeniinae, Pholoinae, Pisioninae, Sthenelanellinae) are proposed within Sigalionidae.
• The findings enhance the understanding of annelid diversification and evolutionary adaptations.