DGS finds sutures in Trioceros (Jackson’s chameleon) skull

I wanted to add a chameleon to the large reptile tree because I had only three taxa in the Iguania, Draco, Phrynosoma and Iguana. The problem is, the skull of Trioceros jacksonii, (Jackson’s chameleon, Fig. 1) has very indistinct sutures. So I used DGS.

Figure 1. The chameleon Trioceros jacksonii colored using DGS. The sutures are difficult to see in the original skull, much easier in the colorized tracing.

Figure 1. The chameleon Trioceros jacksonii colored using DGS. The sutures are difficult to see in the original skull, much easier in the colorized tracing.

Using the above data, gathered after determining skull sutures with DGS, Trioceros nested with Phyrnosoma (the horned lizard) which shares the following traits: 1) tiny premaxillary teeth; 2) vertical quadrate; 3) squared off (hyper-exaggerated in this case) rostral profile; and 4) several other traits. And, nicely, that’s exactly where others nest it.

I don’t know chameleon skulls so well (this is my first exposure). The dentary appears to extend a bit too far behind the coronoid, but then, maybe that’s what chameleons do. Comparisons to other species seem to bear this out.

Figure 2. Trioceros jacksonii overall. Size is 12 inches (30 cm) from tip to tip.

Figure 2. Trioceros jacksonii overall. Size is 12 inches (30 cm) from tip to tip.

Jackson’s chameleon gives birth to live offspring. Eight to thirty are born after a six-month gestation. Sexual maturity is at 5 months of age. Adutl size is 12 in. (30cm). The diet is insects caught by a hyper-extensible tongue. The tail is prehensile. Fingers 1-3 oppose fingers 4 and 5. Toes 1 and 2 oppose toes 3-5, as in other chameleons.

References
Boulenger GA 1896 Description of a new chameleon from Uganda. Annual Natural History 6(17):376.

wiki/Trioceros

 

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