Order: Squamata - Lizards and Snakes
Phylum: Chordata - Vertebrates
Red List status: Not listed
Snout-vent length: 48 mm 47 mm
Total length: 108 mm 113 mm
Throughout eastern Madagascar. but absent from the south. The species has also been reported from the far northwest. It is possible that some records of this species are, however, of the related C. fallax.
A small species characterised by a very low casque, the absence of occipital lobes, and the presence of a soft rostral appendage in both sexes, which is 2-3 mm long and flattened laterally. Body scalation is homogenous, or with scales on the legs only slightly enlarged. The tail is slightly longer than the snout-vent length. Lateral crests are indistinct or absent, and there are no gular or ventral crests. A short dorsal crest of 8-11 small tubercles may be present in males. Males possess a distinct temporal crest running behind the eye from below the eye orbit to the base of the casque.
Colouration is generally dull, ranging from grey to brown or dull green, with dark vertical crossbars along the flanks. A white lateral band is present in some specimens. There may be yellow or blue elements, and the legs are greenish. The rostral appendage is typically the same colour as the body, but may be blue.
Similar species: The presence of a rostral appendage in both sexes, in combination with the low casque, small size and lack of occipital lobes, distinguishes the nose-horned chameleon from most species. It most closely resembles Calumma fallax, which has a higher casque and scales that are more heterogenous (variable in size). C. nasutum exhibits 5-8 temporal scales (a triangle of enlarged scales behind the ring of scales surrounding the eye); C. fallax has fewer. C. gallus exhibits different patterning, and the rostral appendage is red in females (that of males does not resemble C. nasutum). Rostral appendages in Furcifer species are bony and more rigid than that in the nose-horned chameleon.
This is a common rainforest species, typically encountered in low vegetation up to 3 m off the ground. The nose-horned chameleon is able to persist in secondary as well as primar forest and can often be found at forest edges.
Courtship behaviour: Males appear to recognise females largely by the presence of the rostral appendage; once they commence display behaviour, females may develop five whitish to turquoise spots on the head as a signal of receptivity.
Breeding biology: Gestation in this species takes around 40 days, with eggs taking a further 90-100 days to hatch.
Several species may be included within the widespread C. nasutum.
Glaw, F. and Vences, M. (2007) A Field Guide to the Amphibians and Reptiles of Madagascar. Third Edition. Cologne, Vences & Glaw Verlag: 496pp
Calumma nasutum male, Andasibe, Madagascar