Ascidians are a fascinating group of filter-feeding marine chordates characterized by rapid evolution of both sequences and structure of their nuclear and mitochondrial genomes. Moreover, they include several model organisms used to investigate complex biological processes in chordates. To study the evolutionary dynamics of ascidians at short phylogenetic distances, we sequenced 13 new mitogeno...

Almost all ascidian larvae bear three mucus secreting and sensory organs, the adhesive papillae, at the anterior end of the trunk, which play an important role during the settlement phase. The morphology and the cellular composition of these organs varies greatly in the different species. The larvae of the Clavelina genus bear simple bulbous papillae, which are considered to have only a secreto...

Pyura stolonifera is a large solitary ascidian found in Africa, Australasia and South America. The taxonomic status of different populations of this species is disputed, especially since there is evidence for several distinct morphological and genetic units that point towards the existence of multiple cryptic species. While some researchers still recognize P. stolonifera as a single species, ot...

The ascidian fauna of the Pacific coast of Panama is poorly known and only recently four species in the family Ascidiidae were reported on. Ascidia is the only known genus of Ascidiidae in Pacific Panama waters. In the present research, we describe a new species, Ascidia sideralis sp. nov., and we document the new occurrence of A. cf. gemmata and A. cf. liberata (both previously known to the We...

Little is known about the number and rate of introductions into terrestrial and marine tropical regions, and if introduction patterns and processes differ from temperate latitudes. Botryllid ascidians (marine invertebrate chordates) are an interesting group to study such introduction differences because several congeners have established populations across latitudes. While temperate botryllid i...

Knowledge of the marine bryozoan fauna Uruguay is mostly based on scattered records found in local faunistic surveys and taxonomic results two oceanographic cruises to Southwest Atlantic, but a comprehensive study has not yet been published for this area. This paper aims compile an updated checklist, bringing together all information about Uruguayan fauna. Of 73 recorded taxa, 30 (41%) are know...

columns like the stigmata of ascidian and doliolid tunicates, while the presumed atria extended far forwards right and left of the stigmata and therefore right and left of the pharynx, as in ascidian tunicates. Furthermore, the atria opened antero-dorsally as in ascidian tunicates, and these anterior openings were paired as in post-larval ascidian tunicates. As a tunicate, Jaekelocarpus probabl...

During regular surveys and collection of ascidians along the Red Sea coast of Israel, several specimens of an undescribed species of Rhopalaea were collected. Samples were collected by SCUBA from the natural coral reef and man-made structures at depths between 10 to 40m. This is the first species of the genus Rhopalaea described from the Red Sea, which is characterized by a transparent, uncolor...

Human-mediated dispersal interplays with natural processes and complicates understanding of the biogeographical history of species. This is exemplified by two invasive tunicates, Ciona robusta (formerly Ciona intestinalis type A) and C. intestinalis (formerly Ciona intestinalis type B), globally distributed and sympatric in Europe. By gathering new mitochondrial sequences that were merged with ...

A new ascidian species belonging to the Botryllinae was discovered in the Gulf of Taranto (South Italy). This new species was collected in different seasons over a period of several years, which allowed information about its biology to be obtained. The new species presents large zooids arranged in ladder systems. The zooids have several rows of stigmata, the second one complete, ovary posterior...