Mandible
Description:
The first "jaw". The paired, heavily sclerotized appendages of the mouthparts with which the ants manipulate their environment. The shape of the mandibles not only varies between ant species but also frequently between the castes of a single species. They are usually triangular to subtriangular shape in full-face view, however they may also be elongate or falcate for instance. Mandibles have an internal and an external margin. The external margin is sometimes called the lateral margin. On the internal margin, it is often possible to differentiate a basal margin (the later is the mandibular margin the closest to the anterior clypeal margin) and a masticatory (or apical) margin. These two margins may be joined through a curve, or meet in an angle (the basal angle) or a tooth (the basal tooth). The masticatory margin is usually armed with teeth or denticles, or both. (If teeth alone are present, the mandible is termed dentate. If denticles alone are present, the mandible is denticulate. If no armament are present, the mandible is edentate). The distalmost tooth of the masticatory margin is called the apical tooth, the remaining teeth are called the subapical teeth or preapical teeth although these terms may sometimes be restricted to the tooth immediately behind the apical tooth only.
