New Surprising Findings Concerning Chamaeleo roperi (BOULENGER, 1890)

Chamaeleon roperi BOULENGER 1890: 85
Chamaeleon dilepis roperi — ANGEL 1925
Chamaeleon dilepis roperi — LOVERIDGE 1936: 76
Chamaeleo (Chamaeleo) dilepis roperi — KLAVER & BÖHME 1997: 34
Chamaeleo (Chamaeleo) roperi — NECAS 1999: 127
Chamaeleo dilepis roperi — GLAW 2015
Chamaeleo dilepis roperi — MAIN et al. 2018

Chamaeleo roperi was described by Boulenger in 1890 and long considered a subspecies of Chamaeleo dilepis. 

I have examined the type series in BMNH and come to the conclusion they are not conspecific with C. dilepis and treated them as a separate species. Confusion arose from the fact that no one really looked at the Kenyan Chameleons of the C. dilepis appearance, and even Tilbury in his atlas referred to the distinctions among specimens and populations as variability and made a taxonomically very problematic decision, treating them as "forms," which is not a taxonomic category. Thus, he technically synonymized all by declaring former species and subspecies synonyms of C. dilepis. 

The distinctive features include smaller size, lack of spurs in males, finer body scales, and special arrangement of the occipital flaps, which do not meet at the top of the casque and are separated from each other by a diastema. 

A significant source of confusion is that there are populations of chameleons similar to the Flap-necked Chameleon, having these characteristics, namely the highland forms, which inhabit the mountains in Kenya like Mount Kenya, Warges, and even the suburbs of Nairobi, extending scatteringly to high altitudes in Tanzania, around Arusha on the foothills of Mount Meru. 

The type locality of Chamaeleo roperi, however, lays in the coastal region, so these two populations are very unlikely to be conspecific due to the completely different climates and the large gap between their ranges. 

The situation and data I have collected over the last 20 years indicate that the taxonomy should be changed, and actually, the highland populations represent a new, previously undescribed taxon. 

There is a very interesting situation on the coastal region where two species that are very similar to each other occur, and they likely do not share the same niches. 

• The typical Flap-Necked Chameleon Chamaeleo dilepis

  inhabits the hot savanna climate. 

• The smaller species, Chamaeleo roperi, is confined to small populations just along the seacoast, approximately from Lamu up to Zanzibar, probably taking advantage of the tiny coastal stripe of milder climate influenced by the presence of the ocean.. 

I just need to find the time to write it down and make the formal taxonomic changes in a publication.

The highland form, Chamaeleo sp.