Redescription and establishment of a holotype and three paratypes for the species sp. nov.

Background: In a recent paper, we described a new sponge species named Uriz, Garate & Agell, 2017. However, we failed to designate a holotype and a type locality, as required by the International Commission on Zoological Nomenclature (ICZN). Although the validity of the previous conclusions remains unchanged, the species name cannot be considered available according to ICZN regulations until a holotype is designated.

Molecular phylogenies confirm the presence of two cryptic species in the Mediterranean and reveal the polyphyly of the genera and (Demospongiae: Poecilosclerida).

Background: Sponges are particularly prone to hiding cryptic species as their paradigmatic plasticity often favors species phenotypic convergence as a result of adaptation to similar habitat conditions. is a sponge genus (Family Hymedesmiidae, Order Poecilosclerida) with four formally described species, from which only has been recorded in the Atlanto-Mediterranean basin, on shallow to 80 m deep bottoms. Contrasting biological features between shallow and deep individuals of suggested larger genetic differences than those expected between sponge populations.

Endosymbiotic calcifying bacteria across sponge species and oceans.

From an evolutionary point of view, sponges are ideal targets to study marine symbioses as they are the most ancient living metazoans and harbour highly diverse microbial communities. A recently discovered association between the sponge Hemimycale columella and an intracellular bacterium that generates large amounts of calcite spherules has prompted speculation on the possible role of intracellular bacteria in the evolution of the skeleton in early animals. To gain insight into this purportedly ancestral symbiosis, we investigated the presence of symbiotic bacteria in Mediterranean and Caribbean sponges.

Correction: Phylogenetic Reassessment of Antarctic Tetillidae (Demospongiae, Tetractinellida) Reveals New Genera and Genetic Similarity among Morphologically Distinct Species.

[This corrects the article DOI: 10.1371/journal.pone.

Phylogenetic Reassessment of Antarctic Tetillidae (Demospongiae, Tetractinellida) Reveals New Genera and Genetic Similarity among Morphologically Distinct Species.

Species of Tetillidae are distributed worldwide. However, some genera are unresolved and only a few genera and species of this family have been described from the Antarctic. The incorporation of 25 new COI and 18S sequences of Antarctic Tetillidae to those used recently for assessing the genera phylogeny, has allowed us to improve the resolution of some poorly resolved nodes and to confirm the monophyly of previously identified clades.

Endosymbiotic calcifying bacteria: a new cue to the origin of calcification in metazoa?

Sponges show the highest diversity of associated bacteria among marine invertebrates. Immunological evidence traces the origin of the sponge bacterial symbioses to the Precambrian era. Hence, sponges appear to be ideally suited for studying the evolutionary origins of prokaryote-metazoan associations.

Siliceous spicules and skeleton frameworks in sponges: origin, diversity, ultrastructural patterns, and biological functions.

Silica deposition is a fundamental process in sponges. Most sponges in the Classes Demospongiae and Hexactinellida secrete siliceous elements, which can subsequently fuse, interlock with each other, or form three-dimensional structures connected by spongin. The resulting skeletal frameworks allow sponges to grow upwards and facilitate water exchange with minimal metabolic cost.

Long-term culture of sponge explants: conditions enhancing survival and growth, and assessment of bioactivity.

Sponges are an important source of secondary metabolites with pharmaceutical interest. This is the main reason for the increasing interest of sponge culture recent years. The optimal culture system depends on the species to be cultured: while some species easily produce sponge aggregates after dissociation (primmorphs), others show a great capacity to regenerate after fragmentation (explants).