An international research team led by the Complutense University of Madrid has discovered a new species of kinorhynch, named Echionderes australis, in the South Orkney Trench in the Antarctic Ocean, at a depth of 6,000 meters. This finding expands knowledge about the biodiversity of kinorhynchs in hadal environments—those deeper than 6,000 meters—and adds to a small group of known kinorhynch species at these depths. Until now, only two species of kinorhynchs were known in hadal zones.
Kinorhynchs are small marine invertebrates measuring between 100 micrometers and 1 millimeter and are part of the meiofauna, a community of animals that is relevant for the proper functioning of marine ecosystems, according to the UCM. Also known as mud dragons, these creatures play a role in the marine environment, contributing to the ecological balance of the ocean floor.
The study describing the new species was published in the journal Zoologischer Anzeiger. It highlights the technical difficulties of exploring such environments. The research states that it describes a new species "in a very little explored environment, due to the technical difficulty it entails."
The sampling was carried out in December 2019 during the oceanographic campaign KH-19-6_leg4 aboard the Japanese research vessel R/V Hakuho-Maru. The sediment was separated into layers one centimeter thick up to a depth of five centimeters. The kinorhynchs were extracted from the substrate using a flotation method.
The kinorhynchs were then separated by hand under a binocular microscope at the University of Southern Denmark. For identification and analysis, optical microscopy (LM) and scanning electron microscopy (SEM) were used, along with interactive keys and specialized bibliography to identify and describe the new species. This process was detailed by the UCM.
In addition to the Complutense University of Madrid, the study involved the University of Southern Denmark, the Federal University of Rio Grande (Brazil), the Japan Agency for Marine-Earth Science and Technology, and the French Institute for Research in Exploitation of the Sea.
"Intensive oceanographic campaigns take many different samples for different purposes, but the ones used in this study were taken with a multicorer (MUC), an instrument specific for sample collection that minimally alters the surface layers of the sediment," said Alberto González Casarrubios, a researcher at the UCM, according to El Mundo.
This article was written in collaboration with generative AI company Alchemiq