Chaetonotus (Hystricochaetonotus) mirabilis
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) mirabilis, schematic drawings. (A‒B) Dorsal and lateral overviews showing the scale and spine pattern. (C) Detail showing the cuticular teeth protruding from the mouth ring. (D) Elongated dorsal spines with a membrane. (E) Terminal dorsal spines. (F) Internal morphology of a strongly squeezed specimen (body shape hence not representative). (G) Ventral overview. Scale bars: 20 μm (F–G) and 30 μm (A).
© 2022 Rataj Križanová F. & Vďačný P. This picture is licensed under a CC BY-NC-ND 4.0 license.
Chaetonotus (Hystricochaetonotus) mirabilis, schematic drawings of scales. (A) Head lateral scales. (B) Head dorsal scales. (C) Neck dorsal scales. (D) Trunk lateral scale. (E) Trunk dorsolateral scale. (F) Trunk dorsal scale. (G) Terminal dorsal scale. (H) Furcal ventral three-lobed scales. (I) Furcal ventral oblong scales.
© 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) mirabilis. The single diagnostic molecular autapomorphy (red arrow) is situated in the terminal loop of helix 21es6c in the V4 region of the C domain. 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 5.8‒28S rRNA molecule of Chaetonotus (Hystricochaetonotus) mirabilis. Diagnostic molecular autapomorphies are marked by red arrows. The reference 28S 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.
Morphological diagnosis
Body slender and about 83‒107 μm long. Head wider than neck, separated from trunk by a distinct neck constriction. Cephalion clearly demarcated, epipleurae and hypopleurae only inconspicuously marked in head outline. Trunk widest at ca U62, gradually tapers towards furca base (U85). Mouth ventral, with two cuticular teeth. Pharynx with anterior and posterior dilatations. Intestine straight, with a marked anterior section. Scales spined, three-lobed, not overlapping, distributed in 10–12 columns, 17 scales per column. Dorsal surface covered from anterior end of hypopleurae (ca U6) to neck constriction with fairly small scales bearing short spines. Neck caries broader scales with longer spines. Anterior trunk region bears similarly shaped, slightly bigger scales with posterior lobes closer together. Dorsolateral and lateral scales with elongated base and posterior lobes more divergent, spine with an inconspicuous denticle. Mid-trunk to terminal trunk region covered by (i) five horizontal rows of big, anteriorly tapered scales carrying very elongated, massive spines with a denticle and membrane and (ii) two horizontal rows of smaller, anteriorly rounded scales carrying significantly shorter spines with a denticle. Furca base short, lateral margins vaulted, furcal indentation U-shaped, adhesive tubes well-developed, diverging posteriorly. Furca base and branches covered with three-lobed, spined scales and oblong, keeled scales.
Molecular diagnosis
18S rRNA gene: 672 T, 1072 ‒.
ITS2: 26 G, 28 A, 40 G, 41 T, 53 G, 60 C, 62 T, 84 A, 96 A, 107 ‒, 117 T, 131 A, 132 A, 133 A, 136 ‒, 137 ‒, 139 C, 156 G, 157 T, 159 T, 168 A, 173 ‒.
28S rRNA gene: 530 G, 608 C, 687 A, 690 G, 717 A, 719 C, 756 C.
Cytochrome c oxidase subunit I (codon ordinal numbers are followed by the corresponding span of nucleotide positions in parentheses): 23 (67‒69) ATT, 28 (82‒84) CTT, 44 (130‒132) GTC, 45 (133‒135) GTA, 63 (187‒189) GGA, 72 (214‒216) CTT, 82 (244‒246) CCA, 97 (289‒291) AGT, 98 (292‒294) TTA, 100 (298‒300) CTT, 103 (307‒309) GCG, 129 (385‒387) AGG, 142 (424‒426) GCA, 146 (436‒438) TTG, 155 (463‒465) ACC, 156 (466‒468) CTA, 162 (484‒486) GGT, 165 (493‒495) TTT, 167 (499‒501) CGT, 170 (508‒510) TTA, 179 (535‒537) GTT, 184 (550‒552) CTG, 190 (568‒570) GCC, 212 (634‒636) GGA, 221 (661‒663) CTA.
Type material
A DNA sample of the holotype specimen BZs 02 has been deposited in the Natural History Museum,
Vajanského nábrežie 2, 810 06 Bratislava, Slovakia (ID Collection Code 01427888).
Type locality
Greenhouse pond, Botanical Garden of Comenius University, Karlova Ves, Bratislava, Podunajská rovina plain, Slovakia, 48°08′46.8″ N, 17°04′22.6″ E.