Central nervous system
general arrangement
One adult, 152 µm overall length, from X-ray nano-tomography at 0.27 µm per voxel. Items 2 through 5 on this drawing were dimensioned here for the first time; the source study states that it did not dimension them.
| Item | Description | Volume | Rel. item 2 | Origin |
|---|---|---|---|---|
| 1 | Brain, saddle over gut | 1,389 µm³ | — | source study |
| 2 | Ganglion I | 385 µm³ | 1.00 | this drawing |
| 3 | Ganglion II | 430 µm³ | 1.12 | this drawing |
| 4 | Ganglion III | 379 µm³ | 0.98 | this drawing |
| 5 | Ganglion IV | 194 µm³ | 0.50 | this drawing |
| 6 | Connectives, paired | 214 µm³ | — | this drawing |
| — | Items 2–5 summed | 1,386 µm³ | — | cf. item 1: Δ 3 µm³ |
| — | Assembly total | 2,728 µm³ | — | cube 14 µm/side |
Note A — method of dimensioning
The cord is one connected strand of 1,607 µm³. It is cut wherever the cross-section passes 10 µm²; the connectives never exceed 6 and the swellings never fall below 47.
Swept from 8 to 25 µm²: volumes move by under 10% and the front-to-back order does not move at all.
Note B — build sequence
From 62 embryos. Patterning members fire 41–53 h after laying, a twelve-hour window in a ninety-six-hour build. Synaptic members climb from 45 h to hatching.
The pattern is set out fast; the wiring is run slowly.
Note C — control gene
One gene rises 288× inside the patterning window, from near zero. Sister to unc-86 at 93% bootstrap.
No part of this family has previously been recorded in any tardigrade.
Note D — limits of this drawing
One specimen, fixed and dried. Expression read from whole embryos, so no part may be assigned to a cell. An orthologue is not a function.