New Genera, Species and Occurrences of Deep-Sea Asteroidea (Valvatacea, Forcipulatacea, Echinodermata) collected from the North Pacific Ocean by the CAPSTONE Expedition.

Between 2015 and 2018, the NOAA ship Okeanos Explorer embarked on the CAPSTONE expedition, that collected video and specimen data from the Hawaiian Islands region and other American territories in the Central and South Pacific Ocean. Ultimately 20 species, 12 of which are newly described, from 14 genera in 3 families are described herein with one further undescribed species of Pythonaster currently in preparation. Okeanos Explorer collected a total of 17 sea star specimens, of which 9 represent new species and 4 new genera. Additionally, one species imaged by Okeanos Explorer during the campaign was discovered in a museum collection is described herein. Supplementary collections from the tropical Pacific by the R/V Nautilus resulted in a further 11th newly described species which had been originally observed by Okeanos Explorer. A total of 21 specimens were involved as part of this effort. Heligmaster n. gen. is the first new genus of the rarely encountered deep-sea Myxasteridae since Fisher (1906). The Goniasteridae, particularly the corallivorous subfamily Hippasterinae were most heavily represented in the collected material. Video imagery was extensive and provided new occurrence data for rarely seen species as well as several new records that likely represent undescribed species. Many of the new species collected were observed preying on of deep-sea octocorals and sponges.