UH discovers new species in deep Pacific Ocean seabed

  • A specimen of Abyssalia, a new genus of sponges. (Slim Chraiti, University of Geneva//Special to West Hawaii Today)

  • Moanammina semicircularis on the seafloor. (Jennifer Durden and Craig Smith, DeepCCZ Project/Special to West Hawaii Today)

Two new genera and four new species of giant, single-celled xenophyophores (protozoans belonging to a group called the Foraminifera) were discovered in the deep Pacific Ocean during a joint project between scientists at the University of Hawaii at Manoa, the National Oceanography Centre, U.K. National Oceanic Centre (NOC) and the University of Geneva.

The findings were recently published in European Journal of Protistology available on Science Direct.

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“Moana” inspired the name Moanammina for one of the new genera, while the second has been named Abyssalia in recognition of its abyssal habitat.

The species descriptions required two years of detailed studies of morphology and genetic data, using specimens collected with UH’s Remotely Operated Vehicle Luukai on an expedition to the western Clarion Clipperton Zone (CCZ) aboard the RV Kilo Moana in 2018. The seabed in this area is more than 3 miles deep. The CCZ occupies a vast swathe of the Pacific Ocean with extensive seafloor polymetallic nodule deposits, and is targeted for deep-sea mining.

“We were excited to find these beautiful new xenophyophores,” said Andrew Gooday, professor at NOC and lead author. “It seemed appropriate to name one after ‘Moana,’ a Hawaiian word meaning ocean. Xenophyophores are one of the most common types of large organisms found on the CCZ abyssal plains, so the name of the second genus was chosen to reflect this.”

Like some other types of foraminifera, xenophyophores construct shells, called tests, composed of particles that they obtain from the surrounding environment. These are often elaborate structures that can reach sizes of four inches or more.

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Moanammina semicircularis sp. nov., the new species of the new genus, has a stalked, fan-shaped test, around 3 inches tall and three and 1.5 inches wide. Two other new species, Abyssalia foliformis sp. nov. and Abyssalia sphaerica sp. nov., have tests that resemble a flat leaf and an almost perfect sphere. They are remarkable for being constructed entirely of glass sponge spicules. The fourth new species is Psammina tenuis sp. nov., which has a delicate, thin, plate-like test.

Moanammina semicircularis is genetically identical to another specimen found in 2017 in the eastern CCZ. Thus, this study provided the first genetic confirmation of wide geographic ranges (at least 2,300 miles) for an abyssal xenophyophore species.

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