Watch zebrafish cells chase each other into patterns!

An amazing article from Ed Yong describes a new mechanism for pattern formation:

Coloured Cells Chase Each Other To Make A Fish’s Stripes

Zebrafish patterns aren’t just controlled by a chemical reaction-diffusion mechanism — the pigment cells actually chase each other! The different color cells sort themselves into stripes, spots, or other patterns depending on their relative speeds.

dvdp:

Today’s Smile by qubibi

<meta property=“og:description” content=
This is a website I created after being affected by the 3.11 Earthquake in Japan,
and the nuclear power plant incidents that followed.”

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UPDATE 2012-02-05
Shortly after I’ve posted this The Daily Dot wrote more about
qubibi (Kazumasa Teshigawara), the process and emotions behind this work.

Gonodactylus platysoma, UV-excited fluorescence

From http://arthropoda.southernfriedscience.com/?p=2592 : 
I talked previously about fluorescence in stomatopods here. However, I don’t know if the patterns on G. platysoma are used to amplify any particular signals. These animals live in shallow water and would have less use for fluorescent signal amplification.”

Madreporites on sea stars

The madreporite is a lightcolored calcerous opening used to filter water into the water vascular system of echinoderms. It acts like a pressure-equalizing valve. […] Close up, it is visibly structured, resembling a “madrepore” (stone coral, Scleractinia) colony.” — Wikipedia

Image 1: Madreporites, from Pierce and Maugel’s 1987 Illustrated Invertebrate Anatomy (via “How Starfish Move”)

Image 2: Madreporite of Henricia pumila:The madreporite is creamy colored as in the type specimen.  Notice the papulae extended among the pseudopaxillae.” (Source)