Phylogenetic Relationships within the Excavating Hadromerida (Porifera), with a Systematic Revision

Area of Science:

• Marine Biology
• Taxonomy
• Phylogenetics

Background:

• The classification of clionid and spirastrellid sponges from the Mediterranean Sea requires phylogenetic clarification.
• Existing taxonomic frameworks may not accurately reflect evolutionary relationships within these sponge groups.

Purpose of the Study:

• To ascertain the phylogenetic relationships among clionid and spirastrellid species in the Mediterranean Sea.
• To re-evaluate the taxonomic status of species currently assigned to the genus Cliona.

Main Methods:

• Phylogenetic criteria were applied using a matrix of 34 taxa and 20 characters.
• Cladistic analysis was performed using PAUP, resulting in 12 equally parsimonious trees.

Main Results:

• The genus Cliona was found to be polyphyletic, indicating an artificial grouping of species.
• Six monophyletic groups were identified, supporting the establishment of new genera: Scantilletta, Pione, Volzia, and Bernatia.
• The diagnoses for Scantilletta and Pione were amended, and Volzia and Bernatia were proposed as new genera.

Conclusions:

• The study supports the separation of several species from the genus Cliona into distinct genera based on phylogenetic evidence.
• Skeletal characters are useful but insufficient for fully resolving the phylogeny; additional data (biochemical, genetic) are recommended.
• This reclassification provides a more accurate taxonomic framework for Mediterranean clionid and spirastrellid sponges.