Experimental searches for pentaquark hadrons comprised of light flavors have a long and vivid history.No undisputed candidates have been found in 50 years.The first wave of observations of pentaquark candidates containing a strange antiquark occurred in the early seventies,see e.g.a review in the 1976 edition of Particle Data Group listings for Z0(1780),Z0(1865) and Z1(1900) [1].