New species of the xenophyophore genus Aschemonella (Rhizaria: Foraminifera) from areas of the abyssal eastern Pacific licensed for polymetallic nodule exploration

  • publication
  • 03-03-2018

Andrew J Gooday, Maria Holzmann, Clemence Caulle, Aurélie Goineau, Daniel O B Jones, Olga Kamenskaya, Erik Simon-Lledó, Alexandra A -T Weber, Jan Pawlowski. Zoological Journal of the Linnean Society, Volume 182, Issue 3, March 2018, Pages 479–499,

We describe Aschemonella monile Gooday and Holzmann sp. nov. from the Clarion–Clipperton Zone (CCZ, abyssal eastern equatorial Pacific), a region characterized by commercially significant concentrations of polymetallic nodules. The new species is the most abundant xenophyophore (giant agglutinated foraminifera) in our main sampling area (12–14°N; 116°30′–117°26′W). Additional specimens originate from the central CCZ, and from a third area, ~900 km NW of the main area, where A. monile numerically dominates the megabenthos in photographic surveys of the seafloor (average densities 1.54 individuals/m2; peak densities > 3 individuals/m2). Aschemonella monile is much larger (≥ 7 cm in length) than previously described species of the genus, with a test comprising an irregular sequence of self-contained, partly overlapping ‘segments’, creating a multichambered structure. A similar, much rarer species from the main study area, described here as Aschemonella aspera Gooday and Holzmann sp. nov., has an unsegmented test with a very rough, coarsely agglutinated wall. Genetic data suggest that A. monile is distinct from A. aspera and most closely related to a group comprising Rhizammina algaeformis and Aschemonella ramuliformis. Both new species have delicate tests that are often attached to nodule surfaces, making them particularly vulnerable to seafloor disturbances.

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