FIGURE 1. Cast of the elongate tail feathers of C.dui (IVPP Collection V 11553) whitened with ammonium chloride, showing that it was probably male.
From the following article:
A diapsid skull in a new species of the primitive bird Confuciusornis
Lianhai Hou, Larry D. Martin, Zhonghe Zhou, Alan Feduccia and Fucheng Zhang
Nature 399, 679-682(17 June 1999)
doi:10.1038/21411
