Mountain horned agama  (Ceratophora stoddarti)

Classified as Endangered (EN) using the IUCN (2001) Red List criteria (1), but not yet officially listed on the IUCN Red List.

The mountain horned agama is one of five Ceratophora species endemic to Sri Lanka, commonly known as ‘horn-nosed lizards’ or ‘horned lizards’ for the elongated projections the males have at the tip of their snout (2). Even the Latin name Ceratophora means ‘horn-bearer’, referring to this unusual ornamentation (3). The shape of the ‘horn’ differs with the species; the mountain horned agama possesses a long, sharp, upward-pointing white ‘horn’ composed of a single conical scale, for which it is often called the ‘rhino-horned lizard’ (2). Males have a white chin and throat, while the rest of the body is a mixture of black, brown, rusty-orange to yellow and olive-green, with conspicuous black rings around the tail. Females, by contrast, are mostly dark brown, and possess a shortened brown ‘horn’ (4) (5).

Confined to the mountain tops of Horton Plains, Hakgala, Namunukula, Galaha, Pidurutalagala and Peak Wilderness towards the south of Sri Lanka’s central massif (1) (2).

Found in the tropical moist montane cloud forests of Sri Lanka’s ‘wet zone’ (more than 2,000 mm of rainfall per year), between 1,200 and 2,200 m above sea level (1) (2).

Few studies of the mountain horned agama have taken place and little is therefore known of its biology, although more general information on agamids as a family does exist. Agamids are diurnal and visually-orientated, with their crests and other ornamentation thought to serve as important signals in establishing and maintaining territories or in courtship (6). Most agamids feed on insects and other small animals, although a few also feed on plant matter as adults (7). Like the vast majority of agamids, the mountain horned agama is oviparous, or egg-laying (6).

The principle threats to the mountain horned agama are habitat fragmentation and loss, rainwater acidification, pesticides and the effects of climate change. Only five percent of the country’s original wet zone tropical moist forest now survives, heavily fragmented, as a result of clearance for cinchona, coffee, tea and rubber plantations, for grazing livestock, by logging companies, illegal logging and removal of timber by peripheral villagers. With a rapidly growing human population and increasing demand for agricultural land, the destruction of Sri Lanka’s montane forests continues at an alarming rate. Surrounding vegetable cultivations and tea plantations often lack clearly demarcated boundaries, leading to significant encroachment into the forest. Isolation of lizard populations prevents both important genetic flow between subpopulations and means of escape from forest fires. Further more, there is intensive use of pesticides on vegetable cultivations and tea plantations in Sri Lanka, which could be having a serious polluting affect. Although the impact these chemicals are having on non-target species is not yet known, studies elsewhere indicate that they could potentially be devastating, with possibilities for bioaccumulation. There is also evidence in the tropical moist montane forests of Horton Plains of large-scale forest die-back, thought to be the result of acid rain, and these forests are considered particularly at risk from climate change, especially global warming (1).

With 11 out of Sri Lanka’s 17 agamid species being threatened with extinction, in what is the most heavily populated of the world’s 25 Biodiversity Hotspots, this group of lizards and their diminishing forest habitat are clearly in need of serious conservation attention. It is vital that threatened species restricted to small forest fragments, such as the mountain horned agama, be continuously monitored to assess population trends and, if necessary, the establishment of captive-breeding programmes could play an important role in ensuring their future survival (1).

For more information on the mountain horned agama and other threatened agamids of Sri Lanka see:

• Bahir, M. & Surasinghe, T. (2005) A conservation assessment of the Sri Lankan agamidae (Reptilia: Sauria). The Raffles Bulletin of Zoology, 12: 407 - 412. Available at:
  http://rmbr.nus.edu.sg/rbz/biblio/s12/s12rbz407-412.pdf