Taxonomy Article

Status of Chamaeleo (Trioceros) jacksonii willegensis  

by Rob Pilley, M.Sc.

My work with "willegensis" started after I received some animals from Europe and heard the claims of the apparent "new" subspecies. My own comparison of the squamation, dorsal crest formation, and parietal crest formation showed that they were identical to the type specimen of C. jacksonii jacksonii as well as to specimens of C.jacksonii. jacksonii from the southwest side of Mount Kenya and the vicinity of Nairobi to the south. My final confirmation came from Gary Ferguson, one of the co-authors of the paper describing C. jacksonii xantolophus (Eason, Ferguson and Hebrard, 1988). Their paper not only described xantholophus but took into account all specimens of jacksonii that they found throughout the entire described range of this species, thus comparing all morphometric varieties found from all around Mount Kenya, Nairobi, west to the Aberdare mountains and south to Tanzania. After a morphometric comparison of all the forms found throughout the range, Eason, et al. concluded that there were indeed 3 separate subspecies: C. j. xantolophus from the east and south side of Mt Kenya (possibly north to the Marsabit mountains in Central Kenya), C. j. jacksonii from the south and west sides of Mount Kenya and south to Nairobi and west to the Abderdares. The third subspecies, C. j. merumontanus is found in the Arusha District of northern Tanzania as well as on Mt. Meru.

Incidentally, there is a transition zone on the southern slope of Mt. Kenya between jacksonii jacksonii and j. xantholophus where intermediates are present. I described to Gary Ferguson, this apparent new form that I had been sent and its described name, "willegensis". He explained from my description that it sounded like the j. jacksonii that he had seen around Nairobi and southwest Mt Kenya. He then sent me slides of all the forms that he found throughout the wild range and sure enough, the specimens of jacksonii jacksonii exhibited the blue background, yellow side stripe and black dorsal crest attributed in the pet trade to "willegensis". He said that all the wild male specimens he saw exhibited this colouration, some more brown, some more green, but all have it to some extent. He also explained that he had often found a brilliantly coloured male next to a very dull brownish one, thus suggesting that C. jacksonii jacksonii is highly variable within the study population. Indeed, my own captive-bred animals have come out with all manner of different colourations, even from the same clutch. Some are a bright sky blue with canary yellow while some of their siblings are brownish or even reddish with a duller side stripe. Some have blue eye turrets while others have red stripes. C.jacksonii jacksonii does seem to represent a highly variably coloured subspecies so beware of those selling them as a new subspecies!

Eason, P., Ferguson, G. W., and Hebrard, J. 1988. Variation in Chamaeleo jacksonii (Sauria, Chamaeleontidae): Description of a new subspecies. Copeia (3) 580-590.

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