Megafauna of the German exploration licence area for seafloor massive sulphides along the Central and South East Indian Ridge (Indian Ocean) Author Gerdes, Klaas https://orcid.org/0000-0003-0164-8311 INES - Integrated Environmental Solutions, Wilhelmshaven, Germany kgerdes@ines-solutions.eu Author Kihara, Terue Cristina INES - Integrated Environmental Solutions, Wilhelmshaven, Germany Author Martinez Arbizu, Pedro Senckenberg am Meer, German Centre for Marine Biodiversity Research, Wilhelmshaven, Germany Author Kuhn, Thomas Federal Institute for Geosciences and Natural Resources, Hannover, Germany Author Schwarz-Schampera, Ulrich International Seabed Authority, Kingston, Jamaica Author Mah, Christopher L Smithsonian Institution National Museum of Natural History, Washington, DC, United States of America Author Norenburg, Jon L Smithsonian Institution National Museum of Natural History, Washington, DC, United States of America Author Linley, Thomas D Newcastle University, School of Natural and Environmental Sciences, Newcastle, United Kingdom Author Shalaeva, Kate Natural History Museum London, London, United Kingdom Author Macpherson, Enrique Centro de Estudios Avanzados de Blanes (CEAB), Blanes, Girona, Spain Author Gordon, Dennis NIWA, Newmarket, Auckland, New Zealand Author Stoehr, Sabine https://orcid.org/0000-0002-2586-7239 Swedish Museum of Natural History, Stockholm, Sweden Author Messing, Charles G Department of Marine and Environmental Sciences, Nova Southeastern University, Dania Beach, United States of America Author Bober, Simon University of Hamburg, Hamburg, Germany Author Guggolz, Theresa University of Hamburg, Hamburg, Germany Author Christodoulou, Magdalini Senckenberg am Meer, German Centre for Marine Biodiversity Research, Wilhelmshaven, Germany Author Gebruk, Andrey P. P. Shirshov Institute of Oceanology, Moscow, Russia Author Kremenetskaia, Antonina P. P. Shirshov Institute of Oceanology, Moscow, Russia Author Kroh, Andreas https://orcid.org/0000-0002-8566-8848 Naturhistorisches Museum, Vienna, Austria Author Sanamyan, Karen Far-Eastern Branch of the Russian Academy of Sciences, Petropavlovsk-Kamchatsky, Russia Author Bolstad, Kathrin Auckland University of Technology, Auckland, New Zealand Author Hoffman, Leon Senckenberg am Meer, German Centre for Marine Biodiversity Research, Wilhelmshaven, Germany Author Gooday, Andrew J National Oceanography Centre, University of Southampton Waterfront Campus, Southampton, United Kingdom Author Molodtsova, Tina https://orcid.org/0000-0001-7171-6952 P. P. Shirshov Institute of Oceanology, Moscow, Russia text Biodiversity Data Journal 2021 2021-09-28 9 69955 69955 http://dx.doi.org/10.3897/BDJ.9.e69955 journal article http://dx.doi.org/10.3897/BDJ.9.e69955 1314-2828-9-e69955 3627CBB8E2915973B82E80F917CD11AD Hapalosoma sp. indet. Materials Type status: Other material . Occurrence: recordedBy: BGR/ GEOMAR ; individualCount: 1 ; lifeStage: Adult ; behavior: on sediment; occurrenceStatus: present; preparations: DNA voucher and animal stored in 96% ethanol; associatedMedia: 2013-12-14 _10-56-53_Sonne_INDEX2013-2_055ROV08_Logo.jpg; associatedOccurrences: none; associatedSequences: COI; Taxon: taxonID: I13_379; scientificNameID: Sperosoma biseriatum; taxonConceptID: Hapalosoma sp. indet.; kingdom: Animalia; phylum: Echinodermata; class: Echinoidea; order: Echinothurioida; family: Echinothuriidae; genus: Hapalosoma; taxonRank: Genus; scientificNameAuthorship: Mortensen, 1903; Location: waterBody: Indian Ocean; stateProvince: Central Indian Ridge ; locality: Edmond/ Vent site 7 ; verbatimLocality: Cluster 4; maximumDepthInMeters: 3286; locationRemarks: FS Sonne Cruise INDEX2013 Leg 2; decimalLatitude: -23.8780 ; decimalLongitude: 69.6014 ; geodeticDatum: WGS84; coordinateUncertaintyInMeters: 32; Identification: identifiedBy: Andreas Kroh ; identificationRemarks: Identified by morphology and DNA of collected specimen; identificationQualifier: sp. indet.; Event: eventDate: 2013-12-14 ; eventTime: 10:56:53 am; year: 2013; fieldNumber: INDEX2013-55ROV; Record Level: language: en; institutionCode: DZMB; collectionCode: I13_55RO_BB_1; datasetName: INDEX; basisOfRecord: Human Observation Notes Remarks: The echinoid seen in Fig. 166 clearly is a member of the subfamily Echinothuriinae , based on the presence of primary spines with their characteristic terminal hoofs. Identification to genus and species level is difficult in echinothurioids, specifically when based on images, since many forms are largely differentiated by details of their plate arrangement and pedicellarial morphology. In the present case, however, some information on the pedicellariae can be gained from the images. The specimen possesses very large tridentate pedicellariae with rounded blades which broaden towards the tip from a narrow base, a feature only known from species of the genus Hapalosoma (see Mortensen 1935 , Anderson 2013 ). Four species of this genus are known ( Anderson 2013 ), but none of them occurring in the Indian Ocean (having been reported from the New Zealand region, Malay Archipelago and Sagami Sea). That fact, combined with the divergent colouration of the observed specimen, suggests that it might belong to a new, yet undescribed species of Hapalosoma . Less detail can be recognszed in an individual seen in images R1915_00209 and R1915_00213, but the high similarity to the specimen in Fig. 166 suggests that this might be a second representative of this putative new species.