Abstract
Lithistid sponges are globally distributed in temperate and sub-tropical areas, constituting an important component of deep-sea benthic communities where they form structurally complex and vulnerable marine ecosystems (VMEs). In this study, we assess the diversity and investigate the spatial and bathymetric distribution of the lithistid sponges of the Azores archipelago (North Atlantic) based on historical records and examination of samples accidentally collected during deep-sea longline fishing operations in the region. Eleven lithistid species are recognized to occur in the Azores, includingLeiodermatium tuba, recently described from material collected in several Northeast Atlantic seamounts that is hereby reported for the first time to the archipelago. We provide molecular barcodes (mtDNA COI and rRNA 28S) for seven of these species, includingDiscodermia ramifera,Macandrewia azorica, andExsuperantia archipelagus, for which the Azores constitutes the type locality. We further discuss the phylogenetic and biogeographic affinities of the Azorean lithistids in the context of the Porifera classification, and the wider Northeast Atlantic upper bathyal fauna. Our study also warrants the addition of some lithistid species to the list of VME indicators for the Northeast Atlantic in support of the sustainable management and conservation of these species and habitats, as well as the ecological functions they deliver.
Highlights
Lithistids are a polyphyletic group of demosponges, distributed across three orders and 13 families, which share the presence of a hypersilicified skeleton formed by an intricately articulated spicule type called desmas (Pisera and Lévi, 2002)
The two datasets, elevate to 11 the total number of lithistid species reported from the Azores archipelago
Specimens within the genus Leiodermatium Schmidt, 1870 could not be assigned with full confidence to the two species previously reported for the Azores archipelago, i.e., Leiodermatium lynceus Schmidt (1870) and Leiodermatium pfeifferae (Carter, 1873), either because we did not find consistency in the characters traditionally used to distinguish the two species, i.e., location of the inhalant and exhalant openings, the thickness of the plate and the hispidity of its margin; or, in some instances, because we only had access to small fragments which prevented such analyses
Summary
Lithistids are a polyphyletic group of demosponges, distributed across three orders and 13 families, which share the presence of a hypersilicified skeleton formed by an intricately articulated spicule type called desmas (Pisera and Lévi, 2002). Uniqueness or rarity, functional significance, fragility, low recovery potential, and structural complexity, defined for vulnerable marine ecosystems (VMEs) by the Food and Agriculture Organization within the scope of the International Guidelines for the Management of Deep-Sea Fisheries in the High Seas (FAO, 2009, ICES, 2020). Uncovering their distribution patterns is critical to inform the development of appropriate conservation measures to ensure long-term sustainability and minimize the impacts of the various anthropogenic activities operating over the deep seafloor
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
