Setae
Homology (Bi)Weekly: Dentiform Labral Setae

Red Hot Chilli Peppers? No, dentiform setae in the labrum of an Onychomyrmex doddi worker (Scanning Electron Micrograph, Roberto Keller/AMNH)
Just as the anterior margin of an ant’s cranium can sometimes be armed with rows of dentiform clypeal setae (that is, especially modified hairs), the lid that closes the insect’s mouth called labrum can bear identical structures. The image above shows two of these specialized teeth-like pieces (in red) flanking an empty broad socket where a third piece used to be inserted.
Homology Weekly: Dentiform Clypeal Setae

Anterior part of the head of an Australian Onychomyrmex doddi worker (Scanning Electron Micrograph, Roberto Keller/AMNH)
Among the many interesting features found in members of the subfamily Amblyoponinae is the presence of unique teeth-like structures at the anterior margin of the ant’s cranium. They are arranged in one or two parallel rows, right above the opening of the oral cavity, in a plate called clypeus. › Continue reading