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

Abstract

Deep-water sampling in the Perdido Fold Belt, Gulf of Mexico, Mexican Economic Exclusive Zone yielded five specimens of tardigrades belonging to the genus Coronarctus Renaud-Mornant, 1974. The specimens represent the first records of the genus for Mexico. Two two-clawed larvae and two four-clawed larvae of Coronarctus mexicus Romano, Gallo, D'Addabbo, Accogli, Baguley & Montagna, 2011 and a single four-clawed larval specimen of an undescribed Coronarctus species were identified. Taxonomic analysis of the specimens contributed to the knowledge of deep-sea and Mexican marine tardigrades, two data-poor areas of study.

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

“…In general, the distribution pattern of tardigrades in the NWPO is mosaic. This type of distribution is often reported for marine tardigrades [28,33,34].…”

A Strategy to Provide a Present and Future Scenario of Mexican Biodiversity of Tardigrada

“…Although numerous records were generated in the period 2011-2019 in non-specialized literature, both of genera [34][35][36][37]42,44,87] and species [41,88], these were not included in the latter listing, nor in the calculations of national diversity presented in later works [43,47]. From 2019 onwards the diversity of tardigrades increased notably in Mexico, due to the description of new species [46][47][48][49] and the recognition of new records at the specific and generic level [38,43,47,49]. For example, in 2020 alone, 61 species were recognized [47] and in 2021 84 species [43].…”

“…This is a global phenomenon, as marine tardigrades are less well known than limnoterrestrial ones [50], which comprise approximately 15% of the tardigrade fauna [21]. In Mexico, marine tardigrades have been collected at depths ranging from 0.2 m in the littoral zone to 2847 m depth in the bathypelagic zone [38], while in the rest of the world they have been found up to 4170 m [115]; therefore, in Mexico, there remain coast and deep ocean areas missing for exploration, such as the abyssal zones present in the Gulf of Mexico, Caribbean and Atlantic Ocean [116].…”

“…Until 2011, the knowledge of tardigrades in Mexico was based on very restricted and occasional sampling, in some cases not even intended to address this taxon, with collections that did not include habitat descriptions and/or distribution patterns at local or regional scales [26][27][28][29][30][31][32]. However, studies over the last 10 years include species listings [33][34][35][36], new records [37][38][39][40][41][42][43][44], and descriptions of new species [45][46][47][48][49]. The results of these researchers suggest that, by the year 2021, in Mexico, more than 70 tardigrade species were recognized, and most of them are limnoterrestrial moss dwellers [43] and to a lesser extent marine species.…”

“…The colors indicate the taxa recorded, while the different icons symbolize the taxonomic categories: square order, triangle family, and circle genus. Taxa richness is distributed similarly to records: 33 taxa from TVBP, 25 in SMOrP, 17 in YP, 16 in SMOcP, 11 in TP, 11 in VP, 5 in PLP, 4 in ChDP, 4 in BCP, 3 in BBP, 2 in SMSP and 1 in ChHP; while in the marine ecoregions we find 9 taxa in NGM and 2 in CS.The list of recorded Mexican tardigrades and the integration of their national and global distribution is shown in Table 1[25,[34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49]87,88,[94][95][96][97][98][99][100][101]. This information allows us to recognize that 58 taxa are present in Mexico, and display a broad distribution in at…”