Xenophyophore-associated mitogenomes: genomic investigations of two specimens from the Clarion-Clipperton Zone

Xenophyophores are large, benthic protists in the supergroup Rhizaria that are confined to deep-sea habitats (Tendal, 1972, 1996). They have a test made of agglutinated material encapsulating a single branched, multinucleate cell enclosed within an organic tube (together forming the ‘granellare’ system) and large masses (the ‘stercomare’) of waste particles (stercomata) contained within an organic envelope (Tendal, 1972). The first species was described almost 150 years ago (Brady, 1883), but the taxonomic position of xenophyophores remained unresolved until the development of molecular methods, which revealed them to be giant agglutinated monothalamous foraminifera (monothalamids) (Pawlowski et al., 2003). In morphology-based foraminiferal classifications they are currently assigned to the monothalamid suborder Xenophyophoroidea Tendal, 1972 (Kaminski, 2014).