Chamaeleo Laurenti 1768

Tilbury, Colin R. & Tolley, Krystal A., 2009, A re-appraisal of the systematics of the African genus Chamaeleo (Reptilia: Chamaeleonidae), Zootaxa 2079, pp. 57-68 : 63-65

Genus Chamaeleo Laurenti 1768

Type species: Chamaeleo chamaeleon (Linnaeus 1758)

Generic synonyms:

Phumanola Gray 1864 . Type species Chamaeleo namaquensis Smith 1831 Calyptosaura Gray 1864 . Type species Chamaeleo calyptratus Dumeril & Bibron 1851 Erizia Gray 1864 . Type species Chamaeleo senegalensis Daudin 1802 .

Species content: africanus , anchietae , arabicus , calcaricarens , calyptratus , chamaeleon , dilepis , gracilis , laevigatus , monachus , namaquensis , necasi , senegalensis , zeylanicus .

This genus has a wide ranging pan African distribution extending into Europe, the Middle East, Arabia and the Indian sub-continent ( Fig. 2 ). One species is confined to the island of Socotra. The distribution areas of the mainland species tend to be large and continuous except for Ch. anchietae which appears to have population pockets restricted to highland plateaux. Although some species may penetrate into lowland forest, or high altitude grasslands, the species of the genus generally occupy moist and dry woodland savannahs, thorn scrub, semi desert and in one species, true desert.

Apart from occipital lobes in some species and prominent parietal crests in others, they have little other head ornamentation. None of them possess horns or any form of rostro-nasal or pre-orbital projections. A gular-ventral crest of single cones is found in all species being more or less developed in the various forms from very prominent in Ch. calyptratus to almost indiscernible in Ch. namaquensis . None of the species of this genus demonstrate a temporal crest. The casque is edged in a lateral parietal crest originating as a posterior continuation of the supra-orbital ridge which delineates the posterior ramus of the squamosal bone. The temporal zone is undivided. The background scalation of the flanks is generally composed of relatively homogeneous to finely heterogeneous closely packed granular tubercles. The tail of all species within this group is smooth. The plantar surfaces are smooth and claws simple. This is the only genus where the presence of tarsal spurs is seen in several of the species ( Ch. arabicus , Ch. monachus , Ch. chamaeleon , Ch. necasi , Ch zeylanicus , Ch. dilepis , Ch. gracilis , Ch. calyptratus , Ch. africanus ). These tend to be best developed in males and usually absent or much reduced in females. Tarsal spurs may be a synapomorphy for the genus Chamaeleo .

The basic internal lung morphology consists of two large septae arising from the region of the hilum of the lung which end freely within the lung, dividing it into three chambers viz a small dorsal, a large middle and a small ventral chamber. All species possess a gular pouch and in the lung - a membrano-fibrous diaphragm that partially separates off a small dorso-cranial compartment. Many species also have several small partial septae that arise from the dorsal wall of the lung near the cranial end. The lungs are invariably adorned with varying numbers of diverticulae that trail from the inferior and posterior margins of the lung. The diverticulae vary in length and number and may be branched ( Klaver 1973, 1977, 1981).

Hemipenes are calyculate, with a multi rotulae arrangement of between three to five pairs of denticulated rotulae except for Ch. arabicus and Ch. namaquensis which have retained the plesiomorphic four rotulae (two pairs) configuration ( Klaver & Böhme 1986).

The genus is oviparous with a cyclic reproductive strategy – usually a single brood but up to three clutches of eggs per year in some species in ideal conditions. These species tend to have relative longevity. Females are usually sexually mature within one year and over the next few years will produce at least one clutch of eggs annually. The parietal peritoneum is unpigmented.

The documented karyotype of the several species so far examined ( Matthey 1931, 1957, Matthey & van Brink 1956) is 2n=24=12M+ 12m and appears to be restricted to this genus as a synapomorphic character ( Klaver & Böhme 1986)

Figures

FIGURE 2. Map showing the recorded distributions of the combined species within the genus Chamaeleo demonstrating its pan-African, European, Arabian and Asian spread.