Chaetonotus (Hystricochaetonotus) arcanus
Reference
Rataj Križanová F. & Vďačný P. (2022) A huge undescribed diversity of the subgenus Hystricochaetonotus (Gastrotricha, Chaetonotidae, Chaetonotus) in Central Europe. European Journal of Taxonomy 840: 1-93. https://doi.org/10.5852/ejt.2022.840.1941
Chaetonotus (Hystricochaetonotus) arcanus, schematic drawings. (A) Dorsal overview showing the scale and spine pattern. (B–C) Dorsal and lateral views of a head scale. (D) Dorsal view of a neck scale. (E–F) Lateral and dorsal views of a trunk scale. (G) Detail showing the mouth region. (H) Internal morphology. Scale bars: 30 µm.
© 2022 Rataj Križanová F. & Vďačný P. This picture is licensed under a CC BY-NC-ND 4.0 license.
Secondary structure of the 18S rRNA molecule of Chaetonotus (Hystricochaetonotus) arcanus. The reference 18S secondary structure map of Saccharomyces cerevisiae (inset) is from apollo.chemistry.gatech.edu/RibosomeGallery.
© 2022 Rataj Križanová F. & Vďačný P. This picture is licensed under a CC BY-NC-ND 4.0 license.
Secondary structure of the first two domains of the 28S rRNA molecule of Chaetonotus (Hystricochaetonotus) arcanus. Diagnostic molecular autapomorphies are marked by red arrows. The reference 28S secondary structure map of Saccharomyces cerevisiae is from apollo.chemistry.gatech.edu/RibosomeGallery.
© 2022 Rataj Križanová F. & Vďačný P. This picture is licensed under a CC BY-NC-ND 4.0 license.
Morphological diagnosis
Body stocky and around 100 µm long. Head wider than neck, separated from trunk by a distinct neck constriction. Clearly demarcated cephalion, epipleurae and hypopleurae inconcpisuously marked. Trunk widest at ca U37, gradually tapers towards furca base (U82). Mouth almost apical, no cuticular teeth. Hypostomium bears a single small boomerang-like cuticular structure. Pharynx with delicate dilatations. Intestine straight, with a marked anterior section. Scales spined, three-lobed, not overlapping, distributed in about 12 columns, 14 scales per column. Spines with a short lateral denticle. Scales and spines increase gradually in size in a posterior direction. Dorsal surface covered by scales from posterior end of cephalion (ca U3) to furca branches (ca U73). Furca branches slightly longer than adhesive tubes, lateral margins more or less straight, furcal indentation deeply U-shaped, adhesive tubes well-developed.
Molecular diagnosis
ITS2: 163 G, 172 T.
28S rRNA gene: 562 A, 693 C.
Cytochrome c oxidase subunit I (codon ordinal numbers are followed by the corresponding span of nucleotide positions in parentheses): 58 (172‒174) ATA, 97 (289‒291) ACG, 122 (364‒366) GTA, 167 (499‒501) CGG, 174 (520‒522) GCG, 181 (541‒543) CTG, 184 (550‒552) TTA, 185 (553‒555) TCA, 193 (577‒579) ATC.
Type material
A DNA sample of the holotype specimen STV 67 has been deposited in the Natural History Museum, Vajánskeho nábrežie 2, 810 06 Bratislava, Slovakia (ID Collection Code 01427571).
Type locality
Shallow section of the River Váh near the village of Stankovany, Veľká Fatra Mts, Slovakia 49°08′26.3″ N, 19°10′14.6″ E.