GWR, HC, and CAS conceptualized the project. GWR designed the methodology. GWR, LAL, and EEC secured funding and ship time. EEC and LAL served as chief scientists for the cruises. EEC and JC secured collection permits. JC obtained authorization for the genetic components of this project and led the ongoing collaboration with the University of Costa Rica. EEC, JC, SKG, LAL, and GWR supervised field operations. Shipboard specimen identification was led by GWR with contributions from OSA, OB, EEC, JC, SKG, ASH, LAL, AKM, MFM, CAS, JS, ET, AW, and NGW. Live specimen photography, documentation, and preservation were led by GWR along with ASH, AKM, MFM, CAS, JS, ET, and NGW. Specimens were vouchered and catalogued by HC and CAS. For most specimens, JIC, HC, ASH, and MFM performed DNA extraction and sequencing, and GWR led the analysis of the sequences to arrive at identifications. Taxon-specific DNA extraction, sequencing, analysis, and identification were conducted by KMK (Aplacophora) and TDO (Ophiuroidea). Morphological identifications, biogeographic and taxonomic expertise, and/or additional phylogenetic analyses were contributed by: STA (Galatheoidea), OSA (Peracarida), OB (Anthozoa), JC (Anthozoa), DJE (Polyplacophora), MEH (Decapoda), NMK (Echinoidea), KMK (Aplacophora), CLM (Asteroidea), AKM (Holothuroidea), RM (Echinoidea), TDO (Ophiuroidea), FP (Phyllodocidae), GWR (Annelida), PVS (Bivalvia), JS (Terebelliformia), ET (Sabellidae), AW (Gastropoda), MKW (Decapoda), and NGW (Gastropoda). Haplotype networks were prepared by CAS and GWR. CAS wrote the initial draft, prepared figures, and coordinated contributions from all authors with input from GWR. All authors reviewed and approved the final version.