A large diversity of 2-aminoimidazolone alkaloids is produced by various marine invertebrates, especially by the marine Calcareous sponges Leucetta and Clathrina. The phylogeny of these sponges and the wide scope of 2-aminoimidazolone alkaloids they produce are reviewed in this article. The origin (invertebrate cells, associated microorganisms, or filtered plankton), physiological functions, and natural molecular targets of these alkaloids are largely unknown. Following the identification of leucettamine B as an inhibitor of selected protein kinases, we synthesized a family of analogues, collectively named leucettines, as potent inhibitors of DYRKs (dual-specificity, tyrosine phosphorylation regulated kinases) and CLKs (cdc2-like kinases) and potential pharmacological leads for the treatment of several diseases, including Alzheimer’s disease and Down syndrome. We assembled a small library of marine sponge- and ascidian-derived 2-aminoimidazolone alkaloids, along with several synthetic analogues, and tested them on a panel of mammalian and protozoan kinases. Polyandrocarpamines A and B were found to be potent and selective inhibitors of DYRKs and CLKs. They inhibited cyclin D1 phosphorylation on a DYRK1A phosphosite in cultured cells. 2-Aminoimidazolones thus represent a promising chemical scaffold for the design of potential therapeutic drug candidates acting as specific inhibitors of disease-relevant kinases, and possibly other disease-relevant targets.

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Trichomycterus pauciradiatus, new species, is described from the rio Paraná basin, southeastern Brazil. It differs from all other species of Trichomycterus by having four pelvic-fin rays. The new species is possibly closely related to T. reinhardti (Eigenmann, 1918), since both share a unique color pattern consisting of a yellow body with a broad dark brown stripe along the lateral midline.  The stripe is bordered dorsally by a longitudinal bright yellow zone lacking dark chromatophores.

Two new species of Trichomycterus from isolated small river basins of southeastern Brazil are described: T. pantherinus, new species, from the Rio Santa Maria da Vitória basin, and T. caudofasciatus, new species, from the Rio Itabapoana basin. Both new species are diagnosed by a combination of morphological features, also occurring in T. alternatus and T. longibarbatus, including number of pectoral-fin rays, odontodes and branchiostegal rays, long filamentous first pectoral-fin ray and wide opercular patch of odontodes. Trichomycterus pantherinus differs from other congeners by possessing a light orangish yellow flank with dark brown to black rounded spots. Trichomycterus caudofasciatus is distinguished from other species of the genus by having four gray bars on the caudal fin.

This paper reports four new Leucettidae (Porifera, Calcarea) from Western Australia, with two representatives of Leucetta and two of Pericharax: L. foliata sp. nov., L. purpurea sp. nov., Pericharax crypta sp. nov., and P. vallii sp. nov. This is the first time tripods have been described within Pericharax. In addition, one species (L. foliata sp. nov.) has an external morphology not previously reported for Leucetta, and for the first time tetractines of the inhalant and exhalant canals have been distinguished. Leucettidae now comprises 28 species, eight of them occur in Western Australia, which means this Australian State has the highest species richness for this family in Australia. The WA coastline has been largely unexplored for Calcarea so it is likely that further collecting will yield additional species. Leucetta microraphis is the most widespread species of Leucettidae in Australia, occurring in all States except the Northern Territory and Tasmania. We highlight the importance of a revision of the Leucettidae using molecular and morphological characters to determine which morphological characters have a phylogenetic signal.