Macrobiotus ariekammensis ARIEKAMMENSIS WEGLARSKA 1965
Creators: name: Stec, Daniel
name: Vončina, Katarzyna
name: Kristensen, Reinhardt Møbjerg
name: Michalczyk, Łukasz
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Tardigrada
Eutardigrada
Parachela
Macrobiotidae
Macrobiotus
Macrobiotus ariekammensis

description: MACROBIOTUS ARIEKAMMENSIS ARIEKAMMENSIS WĘGLARSKA, 1965
(TABLES 2, 3; FIGS 1–4)
Material examined: Seven animals and four eggs. Specimens mounted on microscope slides in Hoyer’s medium (four animals + four eggs), processed for DNA sequencing (three animals).
Population locality: 78°40’33’’N, 16°38’49’’E; 208 m a.s.l.: Norway, Svalbard, Fortet; moss on soil.
Specimen depositories: Four animals (slides: NO.393.393.2-4) and four eggs (slide: NO.393.01) are deposited at the Institute of Zoology and Biomedical Research, Jagiellonian University, Gronostajowa 9, 30-387, Kraków, Poland.
Description of the Norwegian population from Spitsbergen
Animals (measurements and statistics in Table 2): Body transparent in smaller individuals (juveniles) and whitish in adults, after fixation in Hoyer’s medium transparent (Fig. 1A). Eyes present in all specimens, visible after mounting in Hoyer’s medium. Cuticular pores (0.7–1.2 µm in diameter) present, clearly visible under PCM (Fig. 1B–E) and scattered randomly on the entire body cuticle, including the external and internal surface of all legs. Patches of fine granulation present on internal and external surfaces of all legs I–III, as well as on legs IV and visible clearly in PCM (Fig. 1C–E). A pulvinus present on the internal surfaces of legs I–III (Fig. 1D). Granulation on legs IV is visible as a single large granulation patch on dorsal and lateral leg surfaces (Fig. 1E).
Claws slender, with flat and wide common tract, beginning with a visible stalk that connects the claws to the wide lunulae and ending with elongated branches (especially the primary branch; Fig. 2A, B). Primary branches with distinct accessory points, visible in PCM (Fig. 2A, B). Lunulae I–III smooth (Fig. 2A), whereas lunulae IV with clear dentation (Fig. 2B, D). A single continuous cuticular bar and double muscle attachments visible on each leg I–III (Fig. 2C).
Mouth anteroventral with ten peribuccal lamellae. Bucco-pharyngeal apparatus of the Macrobiotus - type (Fig. 3A). Under PCM, oral cavity armature extremely reduced to only one large tooth present in the dorsal portion of the third band of teeth, whereas other bands of teeth invisible or absent (Fig. 3A, B). Pharyngeal bulb spherical, with triangular apophyses, cuticular spikes, two rod-shaped macroplacoids (macroplacoid sequence: 2 <1) and a triangular small microplacoid (Fig. 3A, D–E). The first macroplacoid with a weak central constriction, whereas the second macroplacoid is weakly subterminally constricted (Fig. 3D, E).
Eggs (measurements and statistics in Table 3): Eggs laid freely, whitish, spherical or slightly oval (Fig. 4A, B). The spaces between processes are small, the surface between processes is of the persimilis - type, i.e. with the continuous smooth chorion, with no pores visible (Fig. 4A, B). Egg processes single-walled (without reticulation caused by the labyrinthine layer) with dome-shaped basal part and thinner and elongated distal portions (Fig. 4C–H). Internal septa are sometimes visible between the basal and the distal portion of the process in PCM (Fig. 4H). The basal portions of the processes are pierced by pores that are arranged alternately with dark thickenings and around the process base (Fig. 4A, B). The apical parts of the processes are flat but devoid of terminal discs, and are covered with short, thin and flexible filaments (Fig. 4C–H).
Reproduction: The population is dioecious (the examination of specimens freshly mounted in Hoyer’s medium revealed testis filled with spermatozoa), but no secondary sexual dimorphism has been observed. DNA sequences: All obtained DNA sequences were represented by a single haplotype per each marker:
18S rRNA: MZ463668, MZ463669, MZ463670. 28S rRNA: MZ463674, MZ463675, MZ463676. ITS2: MZ463656, MZ463657, MZ463658.
COI: MZ460999, MZ461000, MZ461001.
description: Published as part of Stec, Daniel, Vončina, Katarzyna, Kristensen, Reinhardt Møbjerg & Michalczyk, Łukasz, 2022, The Macrobiotus ariekammensis species complex provides evidence for parallel evolution of claw elongation in macrobiotid tardigrades, pp. 1067-1099 in Zoological Journal of the Linnean Society 195 on pages 1070-1072, DOI: 10.1093/zoolinnean/zlab101, http://zenodo.org/record/6994499