Source : Webster's Revised Unabridged Dictionary (1913)

Clamatores \Clam`a*to"res\, n. pl. [L. clamator, pl. clamatores,
   a bawler.] (Zo["o]l.)
   A division of passerine birds in which the vocal muscles are
   but little developed, so that they lack the power of singing.

Source : WordNet®

Clamatores
     n : used in some classification systems; a suborder or
         superfamily nearly coextensive with suborder Tyranni;
         Passeriformes having relatively simple vocal organs and
         little power of song: clamatorial birds [syn: {suborder
         Clamatores}]