Phylogeny and revision of Leucaltis and Leucettusa (Porifera: Calcarea), with new classification proposals and description of a new type of aquiferous system.

Leucaltidae (Calcinea: Clathrinida) was proposed for a group of calcareous sponges with a well-developed cortical region, while the choanosomal and atrial skeletons are reduced. Currently, it comprises the genera Ascandra , Leucaltis , Leucettusa and Leuclathrina , but molecular phylogenies provide evolutionary scenarios different from those based on morphology, recovering a non-monophyletic Leucaltidae. Leucaltis and Leucettusa have long been difficult taxa to distinguish due to their reduced choanosomal and atrial skeletons. Therefore, our objective in this paper is to redescribe all species of Leucaltis and Leucettusa and provide a taxonomic revision to assess their generic status through morphological and molecular tools. Leucaltidae were confirmed polyphyletic and Leucettusa is, therefore, synonymized under Leucaltis. Moreover, several species currently identified as Leucettusa represent a distinct evolutionary lineage. For these species, we propose the new genus Rowella gen. nov. This new genus is allocated to Leucettidae. Based on their phylogenetic position and morphology, Ascandra and Leuclathrina are transferred to Dendyidae. [ABSTRACT FROM AUTHOR]