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, including Leiodermatium 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, including Discodermia ramifera, Macandrewia azorica, and Exsuperantia
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.
Link: https://doi.org/10.3389/fmars.2021.600087