A new species of Neostygarctus (Arthrotardigrada) from the Condor Seamount in the Azores, Northeast Atlantic

Abstract

The tardigrade fauna of Condor Seamount, west of the Azores, is relatively rich, and species from at least seven genera are represented. A new species of the rare marine genus Neostygarctus (Arthrotardigrada) was found at 206 m depth at the summit of the seamount. This is the first record of the genus from the Atlantic Ocean, and also the deepest record of the genus. The new species Neostygarctus oceanopolis sp. nov. is easily distinguished from the Mediterranean type species N. acanthophorus by the number of middorsal spines. N. acanthophorus has five dorsal spines, whereas the adult of N. oceanopolis sp. nov. has seven. The cave tardigrade from Japan, Neostygarctus lovedeluxe also has dorsal spines on all five segments, but only the cephalic and the caudal segments have a middorsal spine, while the three other trunk segments have two spines on each of the dorsal segmental body plates. For the first time, ventral plates are recorded for a species of Neostygarctus. A membranous coating of the all spines of the cephalic segment, the lateral processes of the first three trunk segments, and the spines of the fourth leg pair are unique for Neostygarctus.

A molecular approach to arthrotardigrade phylogeny (Heterotardigrada, Tardigrada)

“…The findings of Styraconyxidae (new rank) clade and Tanarctidae (new rank) clade further support the parallel evolution of digits as suggested by Kristensen et al . (). On the other hand, considering that ‘claws directly inserted on legs’ is the ancestral state (e.g.…”

A new tardigrade species of the genus Neostygarctus Grimaldi de Zio et al., 1982 (Tardigrada, Arthrotardigrada) from the Great Meteor Seamount, Northeast Atlantic

“…Hansen et al (2001) and Hansen (2005) discovered 35 tardigrade species on the Faroe Bank in the NE Atlantic Ocean. Other findings of seamount tardigrades were made also in the same region Hansen et al 2003) or in other regions of the NE Atlantic (Kristensen et al 2015).…”

“…Terminology for the description is generally adopted from Kristensen et al (2015) and Fontoura et al (2017).…”

The Deep-Sea Genus Coronarctus (Tardigrada, Arthrotardigrada) in Brazil, South-Western Atlantic Ocean, with the Description of Three New Species

“…Animals were examined, measured (all measurements in micrometers-µm) and microphotographed under 1000x oil immersion, with a Leica DM 2500 Phase Contrast Microscopes (Leica Microsystems, Wetzlar, Germany) and a Zeiss Axioimager 2 Differential Interference Contrast Microscope (ZEISS Microscopy, Jena, Germany), both equipped with digital cameras and imaging software (Leica Application Suite V4. 9 and Zen Imaging Software for Leica and Zeiss microscopes respectively). All photomicrographs were made under DIC, and structures were measured only if they were undamaged and if their orientation was suitable.…”

“…Since the first report of abyssal tardigrades by Thiel [8], from 2600 to 4690 m deep in the Indian Ocean, only 21 tardigrade species were recorded from the deep-sea (> 200 m depth, including bathyal and abyssal zones) [4,[9][10][11]. From these, only three species were recorded from abyssal depths in the Eastern coast (Angola and Namibia) of the South Atlantic Ocean, Angursa abyssalis Renaud-Mornant, 1981, A. lanceolata Renaud-Mornant, 1981, andCoronarctus tenellus Renaud-Mornant, 1974 [11,12].…”