Zelinkaderes yong sp. nov. from Korea - the first recording of Zelinkaderes (Kinorhyncha: Cyclorhagida) in Asia

Abstract

Background: A new kinorhynch species, Zelinkaderes yong sp. nov., is described from Korea.Results: Zelinkaderes yong sp. nov. is described from coastal, sandy habitats in Korea by means of light and scanning electron microscopic techniques. The new species is characterized by the presence of cuspidate spines in lateroventral positions on segments 2 and 9, ventrolateral positions on segment 5, and lateral accessory positions on segment 8; flexible tiny acicular spines in lateroventral positions on segment 2, more regular-sized lateroventral acicular spines on segment 8, and middorsal spines on segments 4, 6, 8, 9, and 11. Females furthermore have acicular spines in middorsal and midlateral positions on segment 10, whereas males have crenulated spines on this segment. The absence of acicular spines in the lateral series of segment 9 makes it easy to distinguish the new species from all previously described congeners. The new species differs most from Zelinkaderes submersus, whereas it is morphologically closest to Zelinkaderes klepali. In regard to the spine patterns, the new species only differs from Z. klepali by its lack of lateroventral acicular spines on segment 9. Conclusions: The finding of a new species of Zelinkaderes in East Asia extends the distributional range of the genus, which suggests that the genus basically could be present anywhere in the world and could be considered as cosmopolitan.

Myoanatomy of three aberrant kinorhynch species: similar but different?

“…1). For detailed external descriptions of Z. yong see Altenburger et al (2015); for F. kalenesos see Dal Zotto et al (2013) and Rucci et al (2020); for C. styx, see Higgins (1968), Neuhaus and Kegel (2015) and Herranz et al (2019). Detailed data of all myoanatomical studies on kinorhynchs to date, including the results presented herein, are compiled in Table 1.…”

“…Ten specimens of F. kalenesos fixed in 4% PFA were dehydrated through a water-ethanol series, and transferred to acetone through an ethanol-acetone series, critical point dried, mounted on aluminium stubs, sputter coated with a mix of platinum-palladium and examined under a JEOL JSM-6335F Field Emission SEM. SEM specimens of Z. yong and C. styx from Altenburger et al (2015) and Herranz et al (2019) stored in MVS' collection were re-examined. Additional SEM photos of Z. yong were kindly provided by Andreas Altenburger.…”

“…The aim of the present study is to investigate if the external morphology that characterises aberrant kinorhynchs is correlated with modifications in the arrangement of the internal organ systems. Here, we focus on the muscular system, using CLSM and F-actin staining to reconstruct three-dimensionally the myoanatomy of three species and genera: C. styx, F. kalenesos Dal Zotto et al, 2013 and Zelinkaderes yong Altenburger et al, 2015. Through examination and comparison of distantly related representatives of both Allomalorhagida and Cyclorhagida, we establish hypotheses on putative convergences and homologies in the musculature and anatomy of worm-like Kinorhyncha and their adaptations to the interstitial environment.…”

The enigmatic kinorhynch Cateria styx Gerlach, 1956 – A sticky son of a beach

“…Outside Echinoderidae, the number of spinoscalids is constant around 60e67 in both the Allomalorhagida and the two remaining orders of Cyclorhagida; a spinoscalid number of 65 seems to be frequent. The only other genus with a considerably lower number of spinoscalids is Zelinkaderes, with 45 spinoscalids in Zelinkaderes brightae Sørensen et al, 2007, Zelinkaderes klepali Bauer-Nebelsick, 1995and Zelinkaderes yong Altenburger et al, 2015, and only 30 in Z. floridensis Higgins, 1990(Altenburger et al 2015Bauer-Nebelsick 1995;Higgins 1990;Sørensen et al 2007). In the descriptions of Z. brightae and Z. yong, the authors show that the lower number of spinoscalids are due to a lack of spinoscalids in the anterior part of the introvert, and demonstrate that either anlagen or remains of reduced spinoscalids are present in Rings 02 and 03 in shape of fringe-like structures (Altenburger et al 2015;Sørensen et al 2007).…”

“…H. Details of the cuticular folds of the posterior part of the dorsal organ. conspicuous longitudinal lines (e.g., Altenburger et al 2015;Bauer-Nebelsick 1995;Higgins 1990;Sørensen et al 2007). One might speculate if the cuticular ornamentation in C. styx is a habitat adaptation, rather than a trait of phylogenetic significance, but it also differs considerably from other beach-and sand dwelling kinorhynch species.…”