Aphyonids are poorly-known, live-bearing brotulas (Ophidiiformes, Bythitidae) that until recently were considered to be in a distinct family, Aphyonidae. A single, ca. 9.3 cm total length aphyonid observed during a remotely-operated vehicle survey in the Mariana Archipelago at 2504.2 m on Explorer Ridge (20.68152°N, 145.08750°E) is the first seen alive in its natural habitat.

Over a century of study in American Samoa has built a foundation of coral reef ecology within the region. However, this work has been restricted to shallow coral reefs (SCRs; <30 m) until recently, where a few studies have started describing American Samoa’s mesophotic coral ecosystems (MCEs). MCEs are defined as coral reef communities with zooxanthellate corals and associated biotic assemblages between 30 and 150 m depth. Mapping efforts within the territory have documented habitat characteristics for SCRs, as well as MCEs.

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Over a 3-year period, the National Oceanic and Atmospheric Administration (NOAA) organized and implemented a Pacific-wide field campaign entitled CAPSTONE: Campaign to Address Pacific monument Science, Technology, and Ocean NEeds. Under the auspices of CAPSTONE, NOAA mapped 597,230 km² of the Pacific seafloor (with ∼61% of mapped area located within US waters), including 323 seamounts, conducted 187 ROV dives totaling 891.5 h of ROV benthic imaging time, and documented >347,000 individual organisms.

In August of 2016, NOAA Ship Okeanos Explorer conducted the first-ever deepwater exploration of the Wake Atoll Unit of the Pacific Remote Islands Marine National Monument. In total, the ship conducted 14 ROV dives ranging from 350 to 3,136 meters depth. All explored seamounts are flat-topped guyots with mainly pillow lavas coated in ferromanganese crust exposed on their lower flanks. 

absolute age, alkaline earth metals, Ar/Ar, basalts, Cenozoic, Emperor Seamounts, Eocene, geochemistry, hafnium, Hawaiian Ridge, Hf-177/Hf-176, igneous, rocks, isotope, ratios, K/Ar, large igneous provinces, lava, lead, magmas, major elements, mantle, metals, Nd-144/Nd-143, neodymium, Pacific Ocean, Paleogene, Pb-206/Pb-204, Pb-207/Pb-204, Pb-208/Pb-204, petrology, radioactive isotopes, rare earths, Sr-87/Sr-86, stable isotopes, strontium, submarine volcanoes, Tertiary, trace elements, volcanic rocks, volcanism, volcanoes

Here, we present (1) the first observation of an extensive exposure of an undeformed Cretaceous seamount currently being subducted at the Mariana Trench inner slope;(2) vertical deformation of the forearc region related to subduction of Pacific Plate seamounts and thickened crust; (3) recovered Ocean Drilling Program and International Ocean Discovery Program cores of serpentinite mudflows that confirm exhumation of various Pacific Plate lithologies, including subducted reef limestone; (4) petrologic, geochemical and paleontological data from the cores that show that Pacific Plate seamount e

Shallow coral reef and seamount-based ecosystems associated with Pacific islands and atolls host a high and abundant biodiversity, yet many of the ecosystems are threatened by a range of climatic, oceanographic, and anthropogenic stresses. In these types of environments, the morphology and composition of the seabed have been shown to be useful proxies/surrogates for the distribution and abundance of benthic organisms, as well as the other organisms and communities that depend on them.

ancestral state reconstruction; character evolution; classification; Hexactinellida; integrative systematics; phylogeny; Porifera; total evidence

The Mountains in the Deep Expedition (EX1705), conducted from April 27, 2017, to May 19, 2017, onboard NOAA Ship Okeanos Explorer, collected valuable new information to support management and science needs throughout the Central Pacific Basin.