Victor Kirik, Myeong Min Lee, Katja Wester, Ullrich Herrmann, Zhengui Zheng, David Oppenheimer, John Schiefelbein and Martin Hulskamp Development132, 1477-1485.

The e-press version of the article that was published on the 23rd February contains the incorrect acceptance date. The correct date is 19 January 2005

Both the published print and online versions of this article are correct.

We apologise to the authors and readers for this mistake.