First Record of a Rhizaria Litharachnium eupilium (Haeckel 1887) Takahashi 1991 (Class: Polycystinea, Order: Nassellaria) and Description of Litharachnium tentorium (Haeckel 1862) From the Indian Ocean

Abstract

Rhizarians form an important component in ocean biogeochemistry, used as paleoproxies and significantly contribute to marine biodiversity. These organisms, which are fragile in nature, are poorly studied and understood. A rhizarian species, Litharachnium eupilium (Haeckel 1887) Takahashi 1991 (syn. Sethophormis eupilium Haeckel 1887), was recorded for the first time in the Indian Ocean in plankton samples of central Arabian Sea from 25 to 110 m depth. Another species Litharachnium tentorium (Haeckel 1862) was observed in samples collected from four different stations in multiple depth ranges (upto 1500 m). Additionally, L. tentorium was observed from the plankton samples collected from the Andaman Sea. Studies being scarce on Rhizarians in the Indian Ocean region, this work focuses to expand the knowledge on these protists in this region, which will be useful for future studies to understand their contribution to the biogeochemistry. Study expanding the known geographic range can help understand the factors controlling their distribution and abundance in the world oceans and their fate in a changing environment.