The dorsoanterior brain of adult amphioxus shares similarities in expression profile and neuronal composition with the vertebrate telencephalon

Table 1 Staging criteria for the specimens utilised in this study

Nomenclature	HPF @ 20C	Morphological criteria
8s	24h	8 somite embryos
1 GS	48h	Larvae with a well-formed first primary gill slit
2.5 GS	60h	Larvae with a well-formed first primary gill slit and the primordia of the second primary gill slit
5GS	3 months	Larvae with 5 primary gill slits
9-10 GS	6 months	Pre-metamorphic larvae with 10 primary gill slits**

HPF hours post-fertilisation
**B. lanceolatum larvae initiate metamorphosis when they have between 11 and 12 primary gill slits

ISSN: 1741-7007