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

Abstract

A new species of Neostygarctus Grimaldi de Zio et al., 1982 is described from the Great Meteor Seamount summit plateau in the Northeast Atlantic. Neostygarctus grossmeteori sp. nov. is characterized by the number and position of dorsomedian spines (five spines on the cephalic plate and each body plate and on the caudal plate, the spines decreasing in length backwards); the presence of eyes and of one or two pairs of ventral cervical spines; a transversal row of two to five short but strong spikes on the ventral side of the lateral body processes; only the internal claws of each leg provided with a normal accessory spine. The new species is related to N. acanthophorus Grimaldi de Zio et al., 1982 but differs by details of the dorsal body spines and the sculptures, the presence of ventral neck spines and ventral spikes on lateral body projections. Neostygarctus grossmeteori sp. nov. differs from two other known species of Neostygarctus, N. oceanopolis Kristensen et al., 2015 (Condor Seamont, NE Atlantic) and N. lovedeluxe Fujimoto & Miyazaki, 2013 (submarine cave NW Pacific), even more obviously by the number and position of dorsal body spines.

Deep-Sea Tardigrades from the North-Western Pacific, with Descriptions of Two New Species

“…In particular, the description of Ang. bicuspis lacks information on the structures of the secondary and tertiary clavae [10,24]. Thus, an assumption can be made that, in several cases, data on the very wide distribution of species and occurrence in both intertidal and abyssal zones may be associated with incorrect species identification.…”

“…Tardigrade taxonomy followed Guil et al, 2019 [18], and Degma et al, 2009Degma et al, -2022, and morphological terminology followed Møbjerg et al, 2018 [19]. The identification and differentiation of the new species were conducted using the key by Gomes-Júnior et al, 2019 [12], for the genus Coronarctus; the key by Fujimoto and Hansen, 2019 [10], for the genus Angursa; and the original descriptions of all valid species of genera Angursa, Coronarctus, and Moebjergarctus. Abbreviations for the names of genera are given according to Perry et al, 2019 [20].…”

“…Deep-sea species (reported deeper than 200 m) make up only ca. 20 percent of the known diversity of marine tardigrades [5,[10][11][12][13]. Data on tardigrade fauna are almost absent in some regions of the world ocean.…”

Cambrian lobopodians shed light on the origin of the tardigrade body plan

“…While cA of several arthrotardigrades occurs at the dorsolateral part of the head near the eyes (if eyes are present) (e.g., Archechiniscus bahamensis and Neostygarctus grossmeteori ) or at the middle of the head (e.g., Wingstrandarctus unsculptus , Actinarctus neretinus , and Parastygarctus renaudae ) ( Fig. 1 B ), echiniscoidean cA tends to occur at the posterior part of the head segment ( 34 , 35 ) ( Fig. 1 G ).…”

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

“…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].…”