SAN DIEGO ARTS : Dance

The audience at Friday’s Mark Morris Dance Group concert at the East County Performing Arts Center got even more than they bargained for. Morris made an unscheduled solo appearance in a “world premiere”--a brief but thoroughly delightful bit of improvisational dance, performed with a metal pizza pan as an all-purpose prop. Why did the guru decide to include this impromptu dance on an already generous program? “Because I wanted to do another piece,” he said matter-of-factly after the performance. These impromptu solos have become a recent Morris trademark.