Diagnostic Features of Furcifer major

In 2012, A. M. Florio, C. M. Ingram, H. A. Rakotondravony, E. E. Louis, and C. J. Raxworthy published an article titled "Detecting Cryptic Speciation in the Widespread and Morphologically Conservative Carpet Chameleon (Furcifer lateralis) of Madagascar" in the Journal of Evolutionary Biology, Volume 25, Issue 7, pages 1399-1414. They confirmed that Furcifer lateralis and Furcifer major are not conspecific and, in fact, represent separate evolutionary lineages. Additionally, they described a newly identified chameleon species from northwestern Madagascar that is part of the complex of Furcifer lateralis.

There is no doubt that the species are well defined, and the separation is justified based on geography and DNA analysis. The authors made an attempt to define some morphological features, which are not easy to find in a morphologically conservative and atavistic species like all three mentioned. The scale counts they provide seem to give a rough orientation for separating the forms, but they overlap. The presence of the axillary pits selected as a key diagnostic feature seems quite unfortunate because it is soft tissue-based and unstable. The presented photographs show that Furcifer major has at least as deep axillary pits as Furcifer lateralis. This feature is therefore not diagnostic.

However, there seem to be two very stable and easily visible features that can be used for determination in the field as well as in captivity. 

• The underside of the tail and the lower extremities and pelvic region in both sexes of Furcifer major is marked by a darker area of usually grayish coloration, marginated by distinct white lines. It stretches long enough to reach even the second half of the tail and runs very far on the thighs, forming a shape resembling a letter Y. In Furcifer lateralis, this feature is present as well, but it usually does not extend to the lower limbs, remaining as a stripe from the pelvic region toward the tip of the tail.

• Furcifer major shows in both sexes a bright orange markings in the area sometimes referred to as the temporal pouch or temporal gland. In Furcifer lateralis, it remains inconspicuous.
  

In the context of deep scientific analysis, including DNA studies, we often end up with the segregation of previously collectively handled species into separate taxa based on features that cannot be observed with the eye and need to be analyzed via specimens or tissue samples in the laboratory. Therefore, these features are very hard to use in practical fieldwork, especially by laypeople without highly advanced technology available. It is always useful to find such observable features that can be practically used without the necessity of killing the animals or takink samles and doing postponed expensive and technically demanding laboratory work.