Everything in it fits inside a cube fourteen micrometres on a side
A whole central nervous system. This animal has been carried into orbit, exposed to vacuum and to unfiltered sunlight, and brought back alive.
Lateral aspect, body rendered at seven per cent opacity. Designations assigned here; components b–e had no published volumes before this catalogue. Geometry from X-ray nano-tomography, Gross et al. 2019, CC BY 4.0.
Four objects that were never catalogued
The nerve cord is a single connected strand of 1,607 µm³ that brightens four times, once per pair of legs. The study that produced this scan states that it did not measure them.
Cut wherever the cross-section passes 10 µm² — the connecting fibres never exceed 6, the swellings never fall below 47 — and four discrete objects resolve.
| Designation | Component | Volume | Relative |
|---|---|---|---|
| nHd·1 a | Brain | 1,389 µm³ | — |
| nHd·1 b | Ganglion I | 385 µm³ | 1.00 |
| nHd·1 c | Ganglion II | 430 µm³ | 1.12 |
| nHd·1 d | Ganglion III | 379 µm³ | 0.98 |
| nHd·1 e | Ganglion IV | 194 µm³ | 0.50 |
b through e sum to 1,386. The brain is 1,389. Three parts in fourteen hundred. We record the coincidence and offer nothing to explain it.
A gene that rises like a variable star
Sixty-two embryos, each read once at a known hour across the ninety-six between laying and hatching. The genes that lay out the nervous system brighten together between the forty-first and fifty-third hours, then fade.
Within that window one rises 288-fold from below detection — this animal's counterpart of unc-86, by which a nematode assigns identities to its neurons. It sits with unc-86 at 93 per cent bootstrap support.
No gene of this family has ever been reported in any tardigrade.
Conditions of observation
One adult, fixed and critical-point dried — a single exposure of a single object. Expression read from whole embryos, so nothing here can be assigned to a cell. The volumes depend on a threshold; swept from 8 to 25 µm² they move by under a tenth and their order does not move at all.
And an orthologue is not a function. What unc-86 does in a nematode is a reason to point the instrument, not a measurement.