Comparative lung-morphology in the genus Chamaeleo Laurenti, 1768 (Sauria: Chamaeleonidae) with a discussion of taxonomic and zoogeographic implications

In this paper the lung-morphology of a large number of chameleons is described. Various characters can be distinguished, e.g. the septa-arrangement and the caecal outgrowths or “diverticula” on the ventral and caudal margin of the lungs. These characters are variable, but their shape often is characteristic of the species or the group of species. Next to C. pumilus (Gmelin, 1789), the only species known to lack diverticula so far, various other species without diverticula were found. Various lung-types, i.e. lungs with a similar combination of characters can be distinguished. Similarities in lung-structure tend to coincide with established affinities between species, but may also affirm assumed ones or even indicate new affinities. The geographical distribution of the lung-types is in accordance with the prevalent theory about the origin of chameleons. Some alternative hypotheses are formulated concerning the evolution and dispersion of chameleons.