NanoCT slices of the tardigrade Hypsibius exemplaris. Anterior is left (in a-c), dorsal is up (in all images except for c). The slices have a voxel size of 270 nm (in a, c and e), and 200 nm (in b and d), respectively. a Sagittal view through the midline of the body showing the digestive tract. The transition between the midgut and hindgut is marked by the attachment sites of the Malpighian tubules. b Sagittal view through the head region showing the pharynx and the lumen of the buccal tube. c Horizontal view through the ventral body (at the level of the ganglia) showing the second and third leg pairs. The trunk ganglion in each segment lies anterior to the legs of the same segment. Notice the thick ventral longitudinal muscles. d Transverse view through the head region showing the pharynx, a large storage cell, and paired dorsoventral muscles. e Transverse view through the third trunk segment showing the large midgut and paired dorsoventral muscles. Notice how the storage cell labeled in e shows a relatively homogeneous gray value while that in d appears hollow. Abbreviations: br, brain; bt, buccal tube; cg, claw gland; cl, cloaca; es, esophagus; hg, hindgut; le1-le3, legs one to three; mg, midgut; mt, Malpighian tubules; mu, muscle; ph, pharynx; sc, storage cells; sg, salivary glands; tg1-tg2, trunk ganglia one and two. Scale bars: 20 μm (in a), 10 μm (in b and c), 5 μm (in d and e) (Gross, Vladimir & Müller, Mark & Hehn, Lorenz & Ferstl, Simone & Allner, Sebastian & Dierolf, Martin & Achterhold, Klaus & Mayer, Georg & Pfeiffer, Franz. (2019). X-ray imaging of a water bear offers a new look at tardigrade internal anatomy. 5. 10.1186/s40851-019-0130-6.)
