Deep‐sea tardigrades in the northern Gulf of Mexico with a description of a new species of Coronarctidae (Tardigrada: Arthrotardigrada), Coronarctus mexicus

Abstract

During May and June 2000, for the first time, benthic samples were collected from 43 stations in the northern Gulf of Mexico deep sea that included seven transects along the northern continental slope and abyssal plain ranging in depth from 625 to 3159m. A total of 54 tardigrades (36 identified) were extracted from samples, ranging in depth from 625 to 3150m. Collected tardigrades belong to five genera and represented eight species, Angursa bicuspis abyssalis (two specimens from 1401 and 2020m depth), four species of Coronarctus (29 specimens from 625 to 3159m depth), Euclavarctus convergens (one specimen from 2743m depth), E. thieli (one specimen from 2635m depth), Proclavarctus sp. (one specimen from 2600m depth), Styraconyx sp. (two specimens from 1565 and 2600m depth). The most abundant genus was Coronarctus (80.5% of identified species) and was present in most areas sampled with the exception of the central and Mississippi trough regions and comprised four species, Coronarctus laubieri (15 specimens), C. stylisetus (one specimen), C. disparilis (three specimens) and a new species C. mexicus (10 specimens). Tardigrades were mostly found in the western regions (NW, W, WC) and in deep waters, 2290m average depth. Analyses of tardigrade and depth collected gave a slight positive correlation (R2=0.029), while analyses of tardigrade and degrees longitude resulted in a slight negative correlation (R2=0.022). © 2011 Blackwell Verlag GmbH

First records of marine tardigrades of the genus Coronarctus (Tardigrada, Heterotardigrada, Arthrotardigrada) from Mexico

“…(1 specimen The collected specimens conform to the descriptions given by Romano et al (2011) in all observed characters of either the first-stage larvae (two-clawed) or the second-stage larvae (four-clawed) (Fig. 2) in terms of both qualitative characters and morphometric values for measurable structures.…”

“…In the description of Coronarctus mexicus, Romano et al (2011) included only a limited illustration of the secondary clavae in ventral view. As the shape of these structures is species-specific and therefore crucial in discriminating between Coronarctus species, new detailed illustrations of the secondary clavae of the four-clawed larva in both ventral (Fig.…”

“…3C) was recognized on the new specimens. Romano et al (2011) described only a single accessory spine on each claw. The second accessory spine was likely overlooked by the describing authors, as the visibility of this minute structure depends strongly on the orientation of the claw.…”

“…Baguley et al 2006;Landers et al 2012;Reuscher et al 2017;Cisterna-Céliz et al 2019), these did not include identifications at lower taxonomic levels. Thus far, only 15 tardigrade taxa have been recorded from the Gulf of Mexico (Romano 2009 and references therein;Romano et al 2011;Santos et al 2019). Six taxa are known from coastal studies in Alabama and Florida, USA (Chitwood 1951(Chitwood , 1954King 1962;Riggin 1962;McKirdy 1975;Romano 2009;Santos et al 2019).…”

“…Six taxa are known from coastal studies in Alabama and Florida, USA (Chitwood 1951(Chitwood , 1954King 1962;Riggin 1962;McKirdy 1975;Romano 2009;Santos et al 2019). A single offshore investigation focusing on the Gulf's northern continental slope and abyssal plain recovered the remaining nine taxa (Romano et al 2007a(Romano et al , 2007bRomano et al 2011). All of these records originate from localities within the USA territorial sea boundary or Economic Exclusive Zone (EEZ).…”