| Species | Clade | Brain type | Gene expression in the brain | |||||||
|---|---|---|---|---|---|---|---|---|---|---|
| pax6 | ref | nk2.1 | ref | nk2.2 | ref | rx | ref | |||
| Lineus ruber | Nemertea | Complex | Broadly expressed with the exception of ventro-median domain | this study | Ventral brain, dorso-lateral domains | this study | Scattered expression in ventral, dorso-lateral and dorso-posterior domains | this study | Dorsal brain, ventro-lateral domains | This study |
| Platynereis dumerilii | Annelida | Complex | Paired lateral domains | [47, 54] | Ventro-median domain | [47, 54] | No expression in the brain | [46] | anterior brain | [47] |
| Dimorphilus gyrociliatus | Annelida | Compact | Paired lateral domains | [48] | Ventro-median and medio-lateral domains | [48] | No expression in the brain | [48] | N/A | |
| Capitella teleta | Annelida | Compact | Paired lateral domains | [53] |
nk2.1a: paired medio-lateral domains nk2.1b: paired medio-lateral domains | [52] | N/A | N/A | ||
| Terebratalia transversa | Brachiopoda | Larval apical organ | Paired dorso-lateral domains | [78, 79] | Ventral domain | [51, 80] | No expression in the apical organ | [45] | N/A | |
| Novocrania anomala | Brachiopoda | Larval apical organ | Dorso-lateral domain | [79] | Ventral domain | [80] | No expression in the apical organ | [45] | N/A | |
| Phoronopsis harmeri | Phoronida | Larval apical organ | No expression in the apical organ | [81] | No expression in the apical organ | [82] | N/A | N/A | ||
| Schmidtea mediterranea | Platyhelminthes | Compact |
pax6A: broadly expressed throughout the brain pax6B: lateral brain | [49] | Ventral brain, dorso-median domains | [50] | No expression in the brain | [83] | N/A | |
| Epiphanes senta | Rotifera | Compact | Paired lateral domains | [45] |
nk2.1a: dorso-median domain nk2.1b: median domain nk2.1c: ventro-median domain | [45] | Paired lateral domains | [45] | N/A | |