Acknowledgements
Financial support for the expeditions was given from the German Science Foundation to SB (BR3843/4-1,5-1 and MerMet17-06) with support of the shiptime on RV Sonne by the BMBF (Bundesministerium für Bildung und Forschung, Germany). This work was also supported by the DFG initiative 1991 ‘Taxon-omics’ [grant number RE2808/3-1 and RE2808/3-2]. We are happy about the excellent support of the sampling during the expeditions by the crews of the research vessels RV Meteor, RV Poseidon, RV Maria Sybilla Merian and RV Sonne. The processing of the samples would not have been possible without the technical support of Karen Jeskulke, Nicole Gatzemeier and Antje Fischer during the sorting and data management at the DZMB. Kathrin Phillipps-Bussau provided the final museum numbers from the CeNak. Thanks to Michael Sheridan for checking our English grammar. Thanks to Jørgen Olesen and the Museum in Copenhagen for allowing access to the Wolff material of H. b. bicuspis and H. b. tepidus . Terue Kihara, Karlotta Kürzel and Alex Kienecke are thanked for making it possible to complete the CLSM pictures in Wilhelmshaven to illustrate the male developmental stages. This is publication 77 of the Senckenberg am Meer Molecular Laboratory, XX of Confocal Laboratory and 13 of Proteomics Laboratory.