Abstract
Sponges are amongst the most difficult benthic taxa to properly identify, which has led to a prevalence of cryptic species in several sponge genera, especially in those with simple skeletons. This is particularly true for sponges living in remote or hardly accessible environments, such as the deep-sea, as the inaccessibility of their habitat and the lack of accurate descriptions usually leads to misclassifications. However, species can also remain hidden even when they belong to genera that have particularly characteristic features. In these cases, researchers inevitably pay attention to these peculiar features, sometimes disregarding small differences in the other "typical" spicules. The genus Melonanchora Carter, 1874, is among those well suited for a revision, as their representatives possess a unique type of spicule (spherancorae). After a thorough review of the material available for this genus from several institutions, four new species of Melonanchora, M. tumultuosa sp. nov., M. insulsa sp. nov., M. intermedia sp. nov. and M. maeli sp. nov. are formally described from different localities across the Atlanto-Mediterranean region. Additionally, all Melonanchora from the Okhotsk Sea and nearby areas are reassigned to other genera; Melonanchora kobjakovae is transferred to Myxilla (Burtonanchora) while two new genera, Hanstoreia gen. nov. and Arhythmata gen. nov. are created to accommodate Melonanchora globogilva and Melonanchora tetradedritifera, respectively. Hanstoreia gen. nov. is closest to Melonanchora, whereas Arhythmata gen. nov., is closer to Stelodoryx, which is most likely polyphyletic and in need of revision.
Keywords:
Aleutian Islands; Atlanto-Mediterranean; Biogeography; Deep-Sea; Melonanchora; New species; Okhotsk Sea; Poecilosclerida; Porifera; Spicule evolution.
© 2021 Santín et al.
Grants and funding
This research has been performed in the scope of the SponGES project, which received funding from the European Union’s Horizon 2020 Research and Innovation Programme under grant agreement no. 679849. This study was funded by the European Commission LIFE C “Nature and Biodiversity” call, and included in the INDEMARES (07/NAT/E/000732) and INTEMARES (LIFE15 IPE ES 012) projects. The Biodiversity Foundation, of the Ministry of Environment, was the institution responsible for coordination these projects. The present investigation was undertaken as part of the NAFO Potential Vulnerable Marine Ecosystems-Impacts of Deep-Sea Fisheries project (NEREIDA) (Grant Agreement S12.770786), which is supported by Spain’s General Secretary of the Sea (SGM), Spain’s Ministry for the Rural and Marine Environment, the Spanish Institute of Oceanography, the Geological Survey of Canada, the Canadian Hydrographic Service, Fisheries and Oceans Canada, the UK’s Centre for the Environment Fisheries and Aquaculture Science (Cefas), the Russian Polar Research Institute of Marine Fisheries and Oceanography, and the Russian P.P. Shirshov Institute of Oceanology (RAS). Sample MZB 2019–1740 was collected under the ABRIC project (Ref. RTI2018-096434-B-I00) funded by the Spanish Ministry of Science and Innovation. Finally, AS was the recipient of the 2019 Young Scientist Best Paper Award of the Dept. of Marine Biology and Oceanography at the Institute of Marine Sciences, which provided funding for the SEM imaging, alongside with the grant Consolidate SGR378 Benthic Ecology from the Generalitat de Catalunya awarded to MJU with the institutional support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S). There was no additional external funding received for this study. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.