# Trioceros

Trioceros is a genus of lizards in the family Chamaeleonidae, the chameleons, native to lowlands and highlands in the African mainland, ranging from Ethiopia south to Mozambique and west as far as Ghana. Trioceros was considered a subgenus of the genus Chamaeleo until 2009, when it was elevated to full genus level.
Trioceros vary greatly in appearance and size. Many species in the genus have various ornaments, such as one to four horns on the head, crests on the nape or throat, or spines or sail-like structures on the top of the back or tail. They are primarily found in adult males, but generally reduced or even absent in females, and there are also many species in the genus where both sexes lack conspicuous ornaments. Although horn-like structures are found in certain other chameleon genera, Trioceros is the only where it can be cylindrical, annulated and bony.
Trioceros contains species that lay eggs (similar to most other chameleon genera) and species that give birth to live young (similar to only Bradypodion). It is likely that giving birth to live young is an adaption to temperature, as it in Trioceros generally is found in species from highlands. The relatively cold highland climate slows the development of eggs laid in the ground; when instead retained inside the body until birth, a female can actively sun bask to increase the temperature.

## Species

The following species are recognized as being valid.
| Name | Common Name | Subspecies | Distribution |
| Trioceros affinis (Rüppell, 1845) | beardless Ethiopian montane chameleon, Rüppell's desert chameleon | | Ethiopia. |
| Trioceros balebicornutus (Tilbury, 1998) | Bale two-horned chameleon | | Ethiopia. |
| Trioceros bitaeniatus (Fischer, 1884) | side-striped chameleon, two-lined chameleon | | Ethiopia, southern Sudan, Somalia, Kenya, Tanzania, Uganda, and the northeastern Democratic Republic of the Congo. |
| Trioceros camerunensis (L. Müller, 1909) | Cameroon dwarf chameleon | | Cameroon. |
| Trioceros chapini (de Witte, 1964) | Chapin's chameleon, grey chameleon | | Gabon and Democratic Republic of the Congo. |
| Trioceros conirostratus (Tilbury, 1998) | South Sudanese unicorn chameleon | | South Sudan and Uganda. |
| Trioceros cristatus (Stutchbury, 1837) | crested chameleon, fringed chameleon | | Bioko, Equatorial Guinea, Cameroon, Central African Republic, Democratic Republic of the Congo, Republic of the Congo, Gabon, Nigeria, Ghana, and Togo. |
| Trioceros deremensis (Matschie, 1892) | Usambara giant three-horned chameleon, wavy chameleon | | East Usambara, Uluguru, Nguu and Nguru Mountains, and Udzungwa Mountains. |
| Trioceros ellioti (Günther, 1895) | Elliot's chameleon, montane side-striped chameleon, Elliot's groove-throated chameleon | | Burundi, Kenya, South Sudan, Rwanda, Tanzania, Uganda, and Democratic Republic of the Congo. |
| Trioceros feae (Boulenger, 1906) | Bioko hornless chameleon, Bioko montane chameleon, Fea's chameleon | | Bioko. |
| Trioceros fuelleborni (Tornier, 1900) | (named after Friedrich Fülleborn), flapjack chameleon, Ngosi Volcano chameleon, Poroto three-horned chameleon, mountain three-horned chameleon | | Tanzania |
| Trioceros goetzei (Tornier, 1899) | Goetze's chameleon, Ilolo chameleon, Goetze's whistling chameleon | Trioceros goetzei goetzei (Tornier, 1899) – Goetze's whistling chameleon Trioceros goetzei nyikae (Loveridge, 1953) – Nyika whistling chameleon | Tanzania and Malawi. |
| Trioceros hanangensis Krause & Böhme [de], 2010 | Mount Hanang montane dwarf chameleon, Mount Hanang chameleon | | Tanzania |
| Trioceros harennae (Largen, 1995) | Harenna hornless chameleon | Trioceros harennae harennae (Largen, 1995) – Harenna hornless chameleon Trioceros harennae fitchi (Nečas, 2004) – Fitch's Harenna hornless chameleon | Ethiopia |
| Trioceros hoehnelii (Steindachner, 1891) | helmeted chameleon, high-casqued chameleon, von Höhnel's chameleon | | Kenya and Uganda |
| Trioceros incornutus (Loveridge, 1932) | Ukinga hornless chameleon | | Tanzania |
| Trioceros ituriensis (K.P. Schmidt, 1919) | Ituri forest chameleon | | Democratic Republic of the Congo and Kenya. |
| Trioceros jacksonii (Boulenger, 1896) | Jackson's chameleon | Trioceros jacksonii jacksonii (Boulenger, 1896) – Jackson's three-horned chameleon Trioceros jacksonii merumontanus (Rand, 1958) – dwarf Jackson's chameleon Trioceros jacksonii xantholophus (Eason, Ferguson & Hebrard, 1988) – Mount Kenya three-horned chameleon, yellow-crested Jackson's chameleon | south-central Kenya and northern Tanzania. |
| Trioceros johnstoni (Boulenger, 1901) | Johnston's chameleon, Johnston's three-horned chameleon, Ruwenzori three-horned chameleon | | Democratic Republic of the Congo, Burundi, Rwanda, and Uganda |
| Trioceros kinangopensis Stipala et al., 2012 | Aberdare Mountains dwarf chameleon | | Kenya. |
| Trioceros kinetensis (K.P. Schmidt, 1943) | Mount Kineti montane dwarf chameleon, Mount Kineti chameleon | | South Sudan. |
| Trioceros laterispinis (Loveridge, 1932) | spiny-flanked chameleon | | Tanzania. |
| Trioceros marsabitensis (Tilbury, 1991) | Marsabit one-horned chameleon, Mt. Marsabit chameleon, Tilbury's chameleon | | Kenya. |
| Trioceros melleri (Gray, 1865) | giant one-horned chameleon, Meller's chameleon, Meller's giant one-horned chameleon | | Malawi, northern Mozambique, and Tanzania |
| Trioceros montium (Buchholz, 1874) | Cameroon sailfin chameleon | | Cameroon. |
| Trioceros narraioca (Nečas, Modrý & Šlapeta, 2003) | Mount Kulal chameleon or Mount Kulal stump-nosed chameleon | | Kenya |
| Trioceros ntunte (Nečas, Modry & Slapeta, 2005) | Mount Nyiru chameleon, Nyiru montane dwarf chameleon | | Kenya |
| Trioceros nyirit Stipala et al., 2011 | Mount Mtelo stump-nosed chameleon, Pokot chameleon | | Kenya |
| Trioceros oweni (Gray, 1831) | Owen's chameleon | | Nigeria in the north, to Angola in the south, and Burundi in the east |
| Trioceros perreti (Klaver & Böhme, 1992) | Perret's chameleon, Perret's montane chameleon | | Cameroon. |
| Trioceros pfefferi (Tornier, 1900) | Pfeffer's two-horned chameleon, Pfeffer's chameleon, Bakossi two-horned chameleon | | Cameroon. |
| Trioceros quadricornis (Tornier, 1899) | four-horned chameleon | Trioceros quadricornis quadricornis (Tornier, 1899) – southern four-horned chameleon Trioceros quadricornis eisentrauti (Mertens, 1968) – Rumpi Hills chameleon Trioceros quadricornis gracilior (Böhme & Klaver, 1981) – northern four-horned chameleon | western Cameroon and southeastern Nigeria. |
| Trioceros rudis (Boulenger, 1906) | coarse chameleon, rough chameleon, Ruwenzori side-striped chameleon, Rwenzori bearded montane dwarf chameleon | | western Uganda, Rwanda, Burundi, and eastern DR Congo |
| Trioceros schoutedeni (Laurent, 1952) | Schouteden's montane dwarf chameleon | | Rwanda and Democratic Republic of the Congo. |
| Trioceros schubotzi (Sternfeld, 1912) | Mount Kenya montane dwarf chameleon, Mount Kenya side-striped chameleon, Schubotz's chameleon | | Kenya |
| Trioceros serratus (Mertens, 1922) | | | Cameroon |
| Trioceros sternfeldi (Rand, 1963) | (named after Richard Sternfeld), Crater Highlands side-striped chameleon, Tanzanian montane dwarf chameleon | | Tanzania |
| Trioceros tempeli (Tornier, 1899) | Tanzania mountain chameleon, Tempel's chameleon, Udzungwa double-bearded chameleon | | Tanzania |
| Trioceros werneri (Tornier, 1899) | Werner's chameleon, Wemer's chameleon, Wemer's three-horned chameleon | | Tanzania |
| Trioceros wiedersheimi (Nieden, 1910) | Mount Lefo chameleon, Wiedersheim's chameleon | | Cameroon and Nigeria |
| Trioceros wolfgangboehmei Koppetsch, Nečas & Wipfler, 2021 | | | Ethiopia. |
Nota bene: In the above list, a binomial authority or trinomial authority in parentheses indicates that the species or subspecies was originally described in a genus other than Trioceros.

## Footnotes

* ↑ Trioceros oweni at the Reptarium.cz Reptile Database. Accessed 17 May 2022.
* 1 2 Tilbury, C.R., & Tolley, K.A. (2009). "A re-appraisal of the systematics of the African genus Chamaeleo (Reptilia: Chamaeleonidae)". Zootaxa 2079: 57–68.
* ↑ Hughes, D.F.; Blackburn, D.G. (2020). "Evolutionary origins of viviparity in Chamaeleonidae". Journal of Zoological Systematics and Evolutionary Research. 58 (1): 284–302. doi:10.1111/jzs.12328.
* ↑ Trioceros at the Reptarium.cz Reptile Database
* ↑ Beolens et al., p. 51.
* ↑ Beolens et al., p. 82.
* ↑ Beolens et al., p.95.
* ↑ Beolens et al., p. 103.
* ↑ Beolens et al., p. 90.
* ↑ Beolens et al., p. 124.
* ↑ Beolens et al., p. 132.
* ↑ Beolens et al., p. 135.
* ↑ Beolens et al., p. 175.
* ↑ Beolens et al., p. 198.
* ↑ Beolens et al., p. 203.
* ↑ Beolens et al., p. 205,
* ↑ Beolens et al., p. 237.
* ↑ Beolens et al., p. 238.
* ↑ Beolens et al., 253.
* ↑ Beolens et al., p. 263.
* ↑ Beolens et al., p. 282.
* ↑ Beolens et al., p. 285.