Echoes from the Littoral: Unveiling Madagascar’s Hidden Herpetofauna

24/08/2025

A two-year field study conducted in the fragmented littoral forests of Sainte Luce, southeastern Madagascar, documented 76 species of amphibians and reptiles:

  • 22 amphibians

  • 54 reptiles

  • 13 candidate species likely new to science, identified via integrative taxonomy (morphology + DNA barcoding)

Chameleon Species Identified

Only four chameleon species were recorded, all restricted to intact forest fragments:

  1. Palleon sp. aff. nasus – A genetically distinct dwarf chameleon, potentially undescribed. Found only in undisturbed leaf litter microhabitats2.

  2. Calumma tjiasmantoi – A rare, forest-dependent species endemic to southeastern Madagascar.

  3. Furcifer major – A larger-bodied chameleon, typically found in lowland forests.

  4. Furcifer verrucosus – Widespread across Madagascar, but in Sainte Luce, only present in intact forest zones.

No chameleons were found in forest fragments affected by mining activity. This absence is ecologically significant: it suggests that chameleons in this region are highly sensitive to habitat degradation and fragmentation.

Sampling Methods

  • Visual encounter surveys along transects

  • Pitfall traps (4 lines × 100 m)

  • Artificial refugia (tree bark shelters, corrugated sheets) at 12 locations

  • Tissue sampling (tail tips, toes) for genetic analysis

  • Species identifications confirmed via molecular sequencing

Forest Fragmentation and Mining Impact

Out of 17 forest fragments:

  • Only 1 was fully intact

  • 1 was intact but heavily fragmented

  • The remaining 15 showed clear signs of degradation, primarily due to rare earth mining

Chameleons were found exclusively in the Angalavinaky, Ambandrika, and Andranangy/Amboronteny/Agnalarofragments. These areas are now proposed for inclusion in "Mining Avoidance Zones" to prevent further biodiversity loss.

Key Scientific Insights

  • High endemism and cryptic diversity: Genetic tools revealed species not distinguishable by morphology alone.

  • Microhabitat fidelity: Chameleons and other reptiles showed strict dependence on intact forest structure.

  • Conservation urgency: The study provides empirical evidence to support habitat protection policies, especially in biodiversity hotspots under industrial pressure.

Reference

Hyde Roberts, Sam, Marco Sannolo, Hoby Tsimijaly Longosoa, Ryan Clark, Leo Jhaveri, Gonçalo M. Rosa, Walter Cocca, Franco Andreone, and Angelica Crottini. 2025. "A Littoral Treasure Trove: A Comprehensive Assessment of the Herpetofauna of Sainte Luce, Southeastern Madagascar." Systematics and Biodiversity 23(1): 2513472. https://doi.org/10.1080/14772000.2025.2513472


all pictures from the original publication

Author: Petr Nečas
My projects:   ARCHAIUS   │   CHAMELEONS.INFO