Rossellid glass sponges (Porifera, Hexactinellida) from New Zealand waters, with description of one new genus and six new species

Abstract

New Zealand’s surrounding deep waters have become known as a diversity hotspot for glass sponges (Porifera: Hexactinellida) in recent years, and description and collection efforts are continuing. Here we report on eight rossellids (Hexasterophora: Lyssacinosida: Rossellidae) collected during the 2017 RV Sonne cruise SO254 by ROV Kiel 6000 as part of Project PoribacNewZ of the University of Oldenburg, Germany. The material includes six species new to science, two of which are assigned to a so far undescribed genus; we further re-describe two previously known species. The known extant rossellid diversity from the New Zealand region is thus almost doubled, from nine species in five genera to 17 species in eight genera. The specimens described here are only a small fraction of hexactinellids collected on cruise SO254. Unfortunately, the first author passed away while working on this collection, only being able to complete the nine descriptions reported here. The paper concludes with an obituary to him, the world-leading expert on glass sponge taxonomy who will be greatly missed.

Expanded sampling of New Zealand glass sponges (Porifera: Hexactinellida) provides new insights into biodiversity, chemodiversity, and phylogeny of the class

“…As exploration of the deep sea with modern equipment is steadily increasing in recent years, there has been a marked rise in new hexactinellid species, a trend that is likely to continue in the near future. The deep waters of the New Zealand (NZ) region (SW Pacific) provide a particularly striking example: While historical expeditions reported only few species from that region, it is now recognized as one of the biggest hotspots of glass sponge diversity, with 50 new species and 5 new genera described during the last ten years ( Reiswig & Kelly, 2011 ; Reiswig & Kelly, 2017a ; Reiswig & Kelly, 2017b ; Reiswig & Kelly, 2018 ; Reiswig et al, 2021 ).…”

“…Identification of these specimens through integration of molecular and morphological methods revealed the presence of 18 species, one subspecies, and two genera new to science, along with 18 previously described species that had not been included in molecular systematics studies thus far. Morphological descriptions of six of these species and one of the new genera were published recently, after the untimely passing of our co-author and eminent glass sponge specialist Henry M. Reiswig ( Reiswig et al, 2021 ). Here, we report on the molecular phylogenetic results of the study, which increases the taxon sampling of Hexactinellida by 37 species and 12 genera (compared to Dohrmann, 2019 ) and present a preliminary morphological account of the new species, full taxonomic treatment of which will be published elsewhere.…”

A new species of Caulophacus (Hexactinellida: Lyssacinosida: Rossellidae) from the western Pacific Ocean, with new insights into the mitochondrial genome characteristics of hexactinellid sponges

“…However, their spicules are very different. Caulophacus (Caulophacus) ramosus has thin-rayed stellate discohexasters and lacks onychohexasters (Reiswig et al, 2021).…”

Rossellidae (Porifera: Hexactinellida) from the Bering Sea and off Bering Island

“…Tabacknick (2002b) abolished the latter subfamily due to the presence of spicules resembling discoctasters in the holotype of the type species for the genus Caulophacus -C. (Caulophacus) latus. This genus together with Caulophacella was later moved from the Rossellinae to the Lanuginellinae (Dohrmann et al, 2017;Reiswig et al, 2021). Reiswig and Stone (2013) resurrected the subfamily Acanthascinae, arguing that discoctasters were only found in the three genera within that group, without comment on the possible presence of these distinctive spicules in the genus Caulophacus.…”

“…Dermal pentactins have tangential rays 0.081-0.196 mm long (n=25, avg: 0.150 mm, std: 0.029 mm), the proximal rays 0.104-0.233 mm long (n=25, avg: 0.169 mm, std: 0.032 mm), and rudiments of the distal ray if present 0.007-0.019 mm long (n=19, avg: 0.011 mm, std: nick, 2002b). Now the new phylogenetic data led to the transferring of the genus Caulophacus (it is unclear complete (with numerous subgenera) or only a part of it) and suggestion of a new diagnosis for Lanuginellinae (Reiswig et al, 2021). This operation is a final point in the disappearance of the last reliable differences between the two remaining subfamilies and this fact requires the final formal action of the entire abolishment of discussed subfamilies.…”