First Record of Brookesia minima from Ankify, NW Madagascar

By Petr Nečas

Abstract

We report the first verified record of Brookesia minima Boettger, 1893 from Ankify, Ambanja District, Diana Region, NW Madagascar. A female specimen was observed on 22 January 2026 in degraded forest leaf litter under a mango tree at 13°35′05″ S, 48°20′41″ E, 10 m a.s.l. Morphometric data (HBTL 32 mm, HBL 20 mm, HL 5 mm, TL 12 mm) are consistent with published values for the species. This record extends the known distribution beyond Nosy Be (Lokobe National Park) and Nosy Komba, confirming presence on the semi‑islet of Ankify. We discuss taxonomic history, recent additions to the Brookesia minima group, geological separation of Ankify, and conservation implications given the lack of formal protection.

Keywords: Brookesia minima, Ankify, Madagascar, chameleon, distribution, conservation, microendemism

Introduction

Brookesia minima Boettger, 1893 is one of the smallest chameleons globally. Its taxonomic distinctness was clarified by Glaw et al. (1998), who compared hemipenial and external morphology of B. minima, B. peyrierasi, and B. tuberculata. The species belongs to the Brookesia minima group, also referred to as the Evoluticauda subgenus, which has expanded with several minute taxa described in recent years: Brookesia micra Glaw, Köhler, Townsend, & Vences, 2012; Brookesia tedi Scherz, Köhler, Rakotoarison, Glaw & Vences, 2019 and Brookesia nofy Rakotoarison, Hasiniaina Glaw & Vences, 2024.

The IUCN Red List assessment (Glaw & Jenkins 2014) lists B. minima as Endangered (EN), with confirmed distribution on Nosy Be (Lokobe National Park), Nosy Komba, and Manongarivo Reserve.

Geographic and Geological Context of Ankify

Ankify is a volcanic semi‑islet in the Ambanja District, Diana Region, northwestern Madagascar, geologically related to Nosy Be and Nosy Komba. It is separated from the mainland near Doany village by a mangrove belt regularly flooded by seawater, forming an effective biogeographical barrier not only for Brookesia minima but also for sympatric chameleons such as Brookesia stumpffi, Brookesia ebenaui, Calumma boettgeri, Furcifer oustaleti and F. pardalis.

Geologically, Ankify shares the volcanic substrate of Nosy Be and Nosy Komba, which were formed during volcanic activity between about 5 million and 20 million years ago, associated with intraplate magmatism in northwestern Madagascar (Cucciniello et al., 2016; Emerick & Duncan, 1982). Nosy Be's basalts and trachytes, together with the volcanic cone of Nosy Komba, testify to this eruptive origin.

During the Last Glacial Maximum, around 20,000 years ago, global sea levels were approximately 120 meters lower than present (Lambeck et al., 2014). At that time, Ankify, Nosy Be, and Nosy Komba were likely connected to the mainland by continuous land corridors. Rapid sea‑level rise between about 12,000 and 6,000 years ago (Camoin et al., 2004; Hanebuth et al., 2000) flooded low‑lying valleys and mangrove zones, severing terrestrial connections and isolating these volcanic landforms as islands or semi‑islets. This marine transgression created effective dispersal barriers, restricting gene flow among reptile populations and reinforcing microendemism.

Thus, Ankify's semi‑islet character, with mangrove separation, makes it distinct in terms of faunal dispersal compared to Nosy Be and Nosy Komba, which are fully insular. The geological history of uplift followed by Holocene isolation explains the unique assemblages of chameleons and other reptiles in this region.

Observation

In the last three decades, the author visited repeatedly all concerned regions and conducted non-invasive observations of the local herpetofauna, with the focus on chameleons.

On 22 January 2026, at 12:00 local time, a female Brookesia minima was observed in degraded forest leaf litter under a mango tree in the south-east of the Ankify semi‑islet, Ambanja District, Diana Region, NW Madagascar at coordinates 13°35′05″ S, 48°20′41″ E, altitude 10 m a.s.l.

The specimen was photographed and left undisturbed. Morphometric data (based on photo reference scaling):

• Total length (HBTL): 32 mm

• Head + body length (HBL): 20 mm

• Head length (HL): 5 mm

• Tail length (TL): 12 mm

These values are consistent with literature data (Glaw et al. 2012; Scherz et al. 2019), which report females at ~34 mm total length, SVL ~20 mm, tail ~12–14 mm.

This constitutes the first verified record of Brookesia minima from Ankify, extending its known range.

Conservation Context and Threats

The conservation landscape of the Ambanja region islands is uneven, reflecting differences in legal protection, accessibility, and human pressure. Lokobe National Park on Nosy Be, established in 2011 as an IUCN Category II protected area, covers approximately 862 hectares and is managed under Madagascar National Parks. It represents the only formally designated conservation area in the region, safeguarding remnant lowland rainforest and providing legal protection for populations of Brookesia minima and other endemic reptiles (Glaw et al., 1998; Glaw & Jenkins 2014).

By contrast, Nosy Komba, a central volcanic massif with steep slopes and difficult access, has long been recognized for its conservation value but lacks formal national park status. Its relative inaccessibility has offered some de facto protection, and populations of B. minima and B. stumpffi persist there (Glaw et al., 2012).

Ankify, however, remains entirely unprotected. This semi‑islet is under increasing pressure from tourism development, village expansion, deforestation, and the extraction of volcanic rock for gravel. These activities fragment habitats and directly threaten the survival of B. minima populations, which here lack the partial refuge afforded by Nosy Be's national park or Nosy Komba's rugged terrain.

Thus, while Brookesia minima populations on Nosy Be and Nosy Komba benefit from partial protection, the Ankify population is exposed to significant anthropogenic threats, underscoring the urgent need for conservation measures beyond the boundaries of Lokobe National Park.

Chameleon Fauna of the Ambanja Region Islands

The Ambanja region of northwestern Madagascar comprises a cluster of volcanic islands and semi‑islets — Ankify, Nosy Be, Nosy Komba, Nosy Sakatia, Nosy Tanikely, and Nosy Faly. These landforms, separated from the mainland by mangrove belts and shallow straits, form a distinct biogeographical complex where isolation, volcanic origin, and Holocene marine transgression have shaped the distribution of chameleons.

The chameleon fauna of these islands is dominated by a mixture of widespread arboreal species (Furcifer pardalis, Calumma boettgeri) and microendemic leaf chameleons (Brookesia minima, B. stumpffi, B. ebenaui). Their occurrence reflects both geological connectivity during lower sea levels and subsequent isolation following Holocene flooding (Glaw et al., 1998; Glaw et al., 2012).

Verified Distribution of Chameleons in Ambanja Islands

Across all surveyed islands, the Panther Chameleon (Furcifer pardalis) is universally present, including Nosy Faly, where it is the only verified chameleon species. This reflects its ecological adaptability and tolerance of coastal scrub, secondary forest, and anthropogenic habitats (Glaw & Jenkins 2014).

Nosy Be is the type locality of Brookesia minima (Boettger, 1893) and B. stumpffi (Boettger, 1894), and continues to serve as a stronghold for these dwarf chameleons. Nosy Komba is particularly noteworthy: in addition to verified records of B. minima, B. stumpffi, B. ebenaui, F. pardalis, and Calumma boettgeri, it has yielded observations of an undescribed form of a leaf‑nosed chameleon, recorded by Necas (2019; pers. obs. 2026). This form has been provisionally referred to Calumma cf. radamanus (Protzel, in litt.), underscoring Nosy Komba's role as a site of potential cryptic diversity.

Nosy Sakatia supports B. stumpffi and F. pardalis (Glaw et al., 1998), while Nosy Tanikely, a marine reserve dominated by coastal scrub, hosts only F. pardalis. Ankify, a semi‑islet connected to the mainland by mangroves, is exceptional in that it harbors F. oustaleti alongside B. minima, B. stumpffi, F. pardalis, and Calumma boettgeri.

The absence of Furcifer oustaleti from all islands except Ankify is remarkable. Given its wide distribution across mainland Madagascar and tolerance of disturbed habitats (Glaw & Jenkins 2014), its failure to colonize Nosy Be, Nosy Komba, Nosy Sakatia, Nosy Tanikely, and Nosy Faly highlights the biogeographic barriers imposed by mangrove belts and shallow straits.

Conclusion

This record confirms Brookesia minima in Ankify, highlighting the need for urgent conservation measures in unprotected semi‑islets of NW Madagascar. The species' microendemism and habitat specificity make it highly vulnerable to anthropogenic pressures.

References

Boettger, O. (1893). Neue Reptilien und Amphibien aus Madagascar. Berichte der Senckenbergischen Naturforschenden Gesellschaft, 1893: 163–164.

Boettger, O. (1894). Diagnosen neuer Reptilien und Amphibien aus Madagascar. Berichte der Senckenbergischen Naturforschenden Gesellschaft, 1894: 163–165.

Camoin, G.F., Montaggioni, L.F., & Braithwaite, C.J.R. (2004). Late glacial to postglacial sea levels in the western Indian Ocean. Marine Geology, 206(1–4): 119–146.

Cucciniello, C., Melluso, L., Morra, V., et al. (2016). Petrogenesis of Cenozoic volcanic rocks from Nosy Be Archipelago, Madagascar. Lithos, 252–253: 1–15.

Emerick, C.M., & Duncan, R.A. (1982). Age progressive volcanism in the Comores Archipelago and northern Madagascar. Earth and Planetary Science Letters, 60(3): 415–428.

Glaw, F., Vences, M., Ziegler, T., Böhme, W., & Köhler, J. (1998). Specific distinctness and biogeography of the dwarf chameleons Brookesia minima, B. peyrierasi and B. tuberculata. Spixiana, 21(1): 11–27.

Glaw, F., Köhler, J., Townsend, T., & Vences, M. (2012). Rivaling the world's smallest reptiles: Discovery of miniaturized and microendemic new species of leaf chameleons (Brookesia) from northern Madagascar. PLoS ONE, 7(2): e31314. https://doi.org/10.1371/journal.pone.0031314

Glaw, F., & Jenkins, R.K.B. (2014). Brookesia minima. The IUCN Red List of Threatened Species 2014: e.T67009871A47583723. https://doi.org/10.2305/IUCN.UK.2014-3.RLTS.T67009871A47583723.en

Hanebuth, T.J.J., Stattegger, K., & Grootes, P.M. (2000). Rapid flooding of the Sunda Shelf: A late glacial sea level record. Science, 288(5468): 1033–1035.

Lambeck, K., Rouby, H., Purcell, A., Sun, Y., & Sambridge, M. (2014). Sea level and global ice volumes from the Last Glacial Maximum to the Holocene. Proceedings of the National Academy of Sciences (PNAS), 111(43): 15296–15303.

Madagascar National Parks. (2011). Lokobe National Park legal designation. Antananarivo: Madagascar National Parks.

Rakotoarison, A.F.H., Hasiniaina, A.F., Glaw, F., & Vences, M. (2024). A new miniaturized species of leaf chameleon, genus Brookesia, from a littoral forest fragment in eastern Madagascar. Zootaxa, 5506(4): 533–547. https://doi.org/10.11646/zootaxa.5506.4.3 (doi.org in Bing)

Scherz, M.D., Köhler, J., Rakotoarison, A., Glaw, F., & Vences, M. (2019). A new dwarf chameleon of the genus Brookesia from the Marojejy massif in northern Madagascar. Zootaxa, 4559(3): 389–404. https://doi.org/10.11646/zootaxa.4559.3.7 (doi.org in Bing)

Uetz, P., Freed, P., & Hošek, J. (eds.). (2026). The Reptile Database. Accessed January 2026 at: https://www.reptile-database.org