Occipital Elegance: Insights into Calumma malthe

Calumma malthe is a distinctive chameleon species endemic to Madagascar's eastern rainforests, with confirmed populations in Andasibe, Anjanaharibe-Sud, and Marojejy National Parks. It is strictly forest-dependent, favoring dense evergreen vegetation with high humidity, often near small rivers. Individuals are typically found at night, concealed within epiphyte-laden branches and mossy undergrowth, making diurnal detection challenging.

Morphologically, C. malthe is characterized by prominent occipital lobes and a nasal appendage in males. Adult males reach up to 31 cm in total length, females slightly smaller at 28 cm. The dorsal crest features alternating spine sizes, with every third or fourth spine notably enlarged. Both sexes exhibit one or two enlarged throat scales. Coloration is predominantly green-grey, with grass-green flanks and lobes. During the mating season (January–April), females display striking blue highlights around the occipital lobes and eyelids.

Behaviorally, C. malthe employs lateral body movements and occipital lobe expansion as threat displays, often accompanied by hissing. These displays are particularly evident under stress or during territorial disputes.

Microclimatic data from Andasibe reveal average daytime temperatures of 19–24°C, with nighttime lows of 10–15°C during the dry season. Relative humidity remains high year-round, with frequent rainfall even in drier months. UVB exposure peaks in March–April, aligning with peak chameleon activity. Soil temperature measurements at 20 cm depth and atmospheric pressure data further underscore the species' sensitivity to microhabitat conditions.

C. malthe is subject to CITES quotas: no exports from 2011–2013, 500 specimens annually from 2014–2022, reduced to 250 in 2023, and restored to 500 in 2024–2025. Its ecological specificity and limited distribution make it a key indicator species for Madagascar's montane rainforest health.