What is the leading hypothesis explaining the conserved larval pigment patterns across diverse Danio species?

The conserved pattern evolved early to act as a protective UV shield for vital developing structures

Although adult *D. rerio* display five distinct blue stripes, the larval pigment patterns across various *Danio* species are nearly identical, suggesting strong evolutionary conservation. The compelling hypothesis for this shared ancestral pattern is that it functions as a crucial protective mechanism against intense solar radiation. Specifically, this pattern is hypothesized to shield developing vital components, such as the central nervous system and the gonads, from damaging ultraviolet (UV) light while the larvae develop in the shallow, sunlit waters characteristic of their natural habitat. The refinement to the distinct adult striping is considered a more recent evolutionary modification regulated by hormones and involving differential recruitment of pigment stem cell lineages.