Marine Tardigrada from the Mexican Caribbean with the description of Styraconyx robertoi sp. nov. (Arthrotardigrada: Styraconyxidae)

Abstract

Marine tardigrades were sampled at three sites on Mexico’s Caribbean coast. Eleven taxa were collected, one of which is described as a new species. Styraconyx robertoi sp. nov. is characterized by: asymmetric primary clavae; dorsal cuticle with a grid-like sculpture; claws with reduced accessory hooks; females with peduncles on only two digits (the external) of legs I–IV; males with peduncles only on the external digits of legs I–III and peduncles on all four digits of leg IV. Styraconyx robertoi sp. nov. is most similar to S. craticuliformis Chang & Rho, 1998 and S. kristenseni Renaud-Mornant, 1981 by having asymmetric primary clavae but differs from S. craticuliformis mainly by the number of peduncles and from S. kristenseni mainly by the presence of a grid-like dorsal sculpture. Additionally, a comparison of material collected from the same region, but reported previously only as genus level records, was carried out in order to produce a refined list of the known Mexican marine tardigrade species.

Two new Bryodelphax Thulin, 1928 species (Heterotardigrada: Echiniscidae) from the Republic of Ireland with comments on the ‘weglarskae group’ and other heterotardigrade taxa, including the controversial genus Bryochoerus Marcus,1936

“…Drawings for figures were made using a drawing tube. Specimens were prepared for and examined with SEM as per the protocol described by Pérez-Pech et al (2020). All figures were assembled with Corel Draw Graphics Suite X6.…”

A new marine tardigrade genus and species (Arthrotardigrada, Styraconyxidae) with unique pockets on the legs

“…However, the new taxon's compact conical secondary clavae differ from Styraconyx's flat sac to dome-shaped ones (Kristensen and Higgins 1984). Further, although it is not included in the generic diagnosis (Kristensen and Higgins 1984), it is apparent from all the original descriptions of Styraconyx species that they have a cylindrical body shape differing from the new taxon's dorso-ventrally flattened body and also the anus is not known to be developed as the large bi-lobed anus of the new taxon (Thulin 1942;Robotti 1971;Kristensen 1977;Renaud-Mornant 1981b;Pollock 1983;Kristensen and Higgins 1984;D'Addabbo Gallo et al 1984, 1989Chang and Rho 1998;Bartels et al 2015;Pérez-Pech et al 2020).…”

“…Marine tardigrades, specifically arthrotardigrades, exhibit remarkable morphological diversity (see comprehensive drawings of arthrotardigrade genera in Fontoura et al (2017) and drawings of additional genera in Fujimoto and Yamasaki (2017) and Fujimoto and Ohtsuka (2019)). Styraconyxidae Kristensen and Renaud-Mornant, 1983 is one of the arthrotardigrade families and it is comprised of 38 species and subspecies of ten genera: Angursa Pollock, 1979 (eight species), Bathyechiniscus Steiner, 1926 (monotypic), Lepoarctus Kristensen and Renaud-Mornant, 1983 (monotypic), Paratanarctus D'Addabbo Gallo et al, 1992 (monotypic), Pleocola Cantacuzène, 1951 (monotypic), Raiarctus Renaud-Mornant, 1981a (five species), Rhomboarctus Renaud-Mornant, 1984 (three species), Styraconyx Thulin, 1942 (15 species and subspecies), Tetrakentron Cuénot, 1892 (monotypic) and Tholoarctus Kristensen and Renaud-Mornant, 1983 (three species and subspecies) (Guidetti and Bertolani 2005;Degma and Guidetti 2007;Degma et al 2019;Pérez-Pech et al 2020). In addition to these ten genera, reported an undescribed genus related to Styraconyx and Tetrakentron from a submarine cave in Japan (for detail of this cave see Yamamoto et al 2009).…”

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

“…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.…”