A population level study of the lithistid (‘rock’) sponge, Isabella mirabilis, revealed a new species, Isabella tanoa sp. nov., living on five seamounts on the Norfolk Ridge, SW Pacific, and representing the third species to be discovered since the genus was first described in 2005. Comparisons between the three species showed significant differences in morphological characters that corresponded to differences in their respective CO1 barcoding sequences. Conversely, three of the four genotypes of Isabella mirabilis remain unresolved using morphological markers.

Botryllids are colonial styelid ascidians for which morphological characters distinguishing genera and species are often difficult to identify and frequently ambiguous. Botrylloides perspicuus, Botrylloides giganteus, and Botrylloides pizoni have similar colony and zooid appearances and over recent years have been found in dispersed localities around the world. In order to determine how many valid Botrylloides species there are, and how they are geographically distributed, we performed both molecular and morphological analyses on fresh and archival museum specimens of these Botrylloides coming from six distant localities: southern Italy, southern California, Brazil, Galapagos Islands, New Zealand, and Australia. Moreover, we re-analysed the morphology of a number of formalin-preserved museum specimens. We concluded that both B. perspicuus and B. giganteus are indeed valid species and report morphological and molecular characters that distinguish these species; B. pizoni is concluded to be a junior synonym of B. giganteus. The geographic distribution, collection dates, and growth substrates of B. giganteus indicate that this species is rapidly spreading worldwide and has traits that may enhance invasiveness (i.e., presence in intertidal regions; high tolerance to air exposure, temperature and salinity variation). Therefore, B. giganteus should be a focus of both researchers and managers concerned with marine biosecurity. Interestingly, the morphological re-analyses of archival museum samples guided by molecular results, led to the taxonomic reassignment of several botryllid specimens as well as to the identification of a new species, Botrylloides conchyliatus sp. nov., which is here described. http://www.zoobank.org/urn:lsid:zoobank.org:pub:0D896E42-F460-45E2-B74C-576A011D9214

Four new brominated tyrosine metabolites, aplyzanzines C–F (1–4), were isolated from the French Polynesian sponge Pseudoceratina n. sp., along with the two known 2-aminoimidazolic derivatives, purealidin A (5) and 6 , previously isolated, respectively, from the sponges Psammaplysilla purpurea and Verongula sp. Their structures were assigned based on the interpretation of their NMR and HRMS data. The compounds exhibited quorum sensing inhibition (QSi) and antifouling activities against several strains of bacteria and microalgae. To our knowledge, the QSi activity of this type of bromotyrosine metabolite is described here for the first time.