Interstitial Gular Scales of Furcifer verrucosus

The gular area, or the so-called chin area is basically an area situated under lower surface of the body between the mental symphysis and the arc of the hyoid bone. In chameleons, it usually consists of three types of scales: 

• THE GULAR CREST: 

  The most prominent ones very often ordered in one sagittal row (or two parallel parasagittal rows) is called the gular crest (crista gularis). It is composed of scales, which are semi-spherical or conical, sometimes flattened, very prominently visible from the side. They play an important role in the intraspecific and interspecific sex and species recognition, so that the females have a clue which males belong to their own species, and identify that they are males at all.

  
  

• THE STANDARD SCALES: 

  The second type of scales are the standard scales which are either of standard flat shape or modified in form to be semi spherical or semi ovoid. They are very often ordered into lines or bands running diagonally between the lower jaw and the gular crest. 

  
  

• THE INTERSTITIAL SCALES: 

  The third type of scales are very fine and tiny granular scales, the so-called interstitial scales which cover the fields between the above mentioned rows or bands of standard scales. In many species, they are heavily extendable and colored and surprisingly vivid colours like yellow, white, black, crimson, orange, violet etc. sometimes ordered in diverse additional patterns. The scales on the so-called interstitial skin, or in the interstitial grooves, become visible only when the gular pouch is inflated by the pulmonary gular sack and play a role in intraspecific communication and in the predatory aposematic behavior. 

A very interesting dimorphism of these interstitial scales is present in the Warty Chameleon, Furcifer verrucosus, as as demonstrated by the pictures.