Crossover and coexistence of quasiparticle excitations in the fractional quantum hall regime at [formula presented]

New low-lying excitations are observed by inelastic light scattering at filling factors [Formula presented] of the fractional quantum Hall regime with [Formula presented]. Coexisting with these modes throughout the range [Formula presented] are [Formula presented] excitations seen at [Formula presented]. Both [Formula presented] and [Formula presented] excitations have distinct behaviors with temperature and filling factor. The abrupt first appearance of the new modes in the low-energy excitation spectrum at [Formula presented] suggests a marked change in the quantum ground state on crossing the [Formula presented] boundary at [Formula presented].