Chemotaxonomy of marine sponges: Families Microcionidae, Raspailiidae and Axinellidae, and their relationships with other families in the orders Poecilosclerida and Axinellida (Porifera : Demospongiae)

Abstract

Biochemical studies on 72 species of marine sponges from tropical Australia showed that 42 of 132 biochemical characters were useful in describing relationships between the families Microcionidae, Raspailiidae and Axinellidae, and other members of the orders Poecilosclerida and Axinellida. Chemotaxonomic characters were obtained from profiles of free amino acids (34 species), carotenoid pigments (41 species), general proteins (62 species) and antibiotic activity against three human pathogens (42 species of sponges). Biochemical data essentially supported the existing division within class Demospongiae, i.e. Ceractinomorpha and Tetractinomorpha, with the notable exception that the 'tetractinomorph' families Raspailiidae and two genera of Axinellidae were found to be more closely related to the Ceractinomorpha. Within-group comparisons demonstrated that Microcionidae (14 species) and Raspailiidae (15 species) were relatively homogeneous in their biochemical profiles, indicating that they should remain separated at the family level, supporting similar conclusions based on morphological data. Similar trends were also shown for the families Desmacellidae (2 species) and Desmoxyidae (3 species), contrary to recent taxonomic revisions by other authors who hypothesised that these families might be heterogenous. Conversely, Axinellidae (27 species) contained at least three disparate groups of genera: one (i.e. Phakellia, Reniochalina) showing strong affinities with ceractinomorphs, a second (i.e. Acanthella, Pseudaxinyssa) and possibly a third (i.e. Axinella, Teichaxinella) showing closer similarities to Desmoxyidae, Hemiasterellidae and outgroups from Hadromerida and 'Lithistida'. These results provided a measure of support for the removal of Raspailiidae to Poecilosclerida, and the division of Axinellidae into several families, as proposed independently in recent revisions based on morphological evidence.