Integrative taxonomy justifies a new genus, Nodastrella gen. nov., for North Atlantic "Rossella" species (Porifera: Hexactinellida: Rossellidae)

Abstract

Molecular systematic studies have indicated that the hexactinellid sponge species Rossella nodastrella Topsent (Lyssacinosida, Rossellidae), previously only known from the NE Atlantic, is only distantly related to its congeners, which are restricted to the Southern Ocean, representing the only case thus far reported of a diphyletic genus in the class Hexactinellida. Here we describe new material of "Rossella" nodastrella from cold-water coral reefs in the NW Atlantic (Florida). Morphological comparison with the holotype from the Azores and specimens recently reported from off Ireland reveal at least two distinct species, which we corroborate with molecular data. Because the diphyletic nature of "Rossella" is further supported with inclusion of the new specimens in the molecular phylogeny, we erect a new genus, Nodastrella gen. nov., for these two species. The Irish specimens are synonymized with our new species Nodastrella asconemaoida sp. nov. Subtle morphological and molecular differences between the E and W Atlantic specimens are for the time being ascribed to intraspecific geographic variation, but indicate that Nodastrella might contain more (sub)species, pending investigation of additional specimens, especially from intermediate locations.

Cyphobasidium gen. nov., a new lichen-inhabiting lineage in the Cystobasidiomycetes (Pucciniomycotina, Basidiomycota, Fungi)

“…Integrative taxonomy -which combines several lines of evidence to delimit taxa is a particularly useful approach in groups with a challenging taxonomy due to scarcity of characters, homoplastic characters, or both (Damm et al 2010;DeSalle et al 2005;Pires and Marinoni 2010). This applies not only to species delimitation, but is also useful at the generic rank (Dohrmann et al 2012, Vicente et al 2013). In the case of Cyphobasidium, combining molecular and ecological evidences has allowed establishing a new genus within Pucciniomycotina, and to re-interpret morphological characters (e.g., presence of a thick-walled probasidium) previously considered as potential synapomorphies.…”

Sponge Grounds as Key Marine Habitats: A Synthetic Review of Types, Structure, Functional Roles, and Conservation Concerns

“…Similarly, the cup-shaped up to 40 cm high Nodastrella asconemaoida forms aggregations with densities up to six individuals m À2 at 560-630 m depth on cold-water coral reefs on Rockall Bank west of Ireland. It is a rare species, with only a few specimens known from off Florida and possibly from the Mid-Atlantic Ridge (Dohrmann et al 2012).…”

New Palaeogene sponges from the Red Bluff Tuff, Chatham Island, New Zealand

“…The Late Cretaceous Rossella bromleyi Bru¨ckner and Janussen, 2005 from Bornholm (Denmark) shows no clear conules, but it shows a veil of pentactins protruding beyond the dermal surface, which was not observed in the new species R. cylindrica. Today, Rossella is restricted to the Southern Ocean; the species Rossella nodastrella Topsent, known from the North Atlantic, has been reassigned to the new genus Nodastrella (Dohrmann et al 2012).…”