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| Calumma roaloko
Prötzel, Lambert, Andrianasolo, Hutter, Cobb, Scherz & Glaw, 2018
DOI: 10.3897/zse.94.27305
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Abstract
On a recent expedition to eastern Madagascar, we discovered a distinct new species of the genus Calumma that we describe here using an integrative approach combining morphology, coloration, osteology and molecular genetics. Calumma roaloko sp. n. has a dermal rostral appendage and occipital lobes, and belongs to the C. boettgeri complex, within the Madagascar-endemic phenetic C. nasutum species group. It is readily distinguished from other species of the C. boettgeri complex by a characteristic two-toned body coloration and small body size with a snout-vent length of 45.6 mm in an adult male. The osteology of the skull, with a prominent maxilla and broad parietal, is similar to the closest related species, C. uetzi. Analysis of uncorrected genetic distances within the C. nasutum group using the mitochondrial gene ND2 shows a minimum pairwise distance of 11.98% to C. uetzi from the Sorata massif and Marojejy National Park >500 km north of the type locality of C. roaloko sp. n.. Given an apparently small range (potentially <300 km2), located entirely outside of any nationally-protected areas, we recommend this new species be classified as Endangered under criterion B1ab(iii) of the IUCN Red List. The discovery of clearly distinct species like C. roaloko sp. n. in an area of Madagascar that is comparatively thoroughly surveyed highlights the critical role of continued field surveys for understanding the true extent of Madagascar’s spectacular biodiversity.
Key Words: Calumma roaloko sp. n., Integrative taxonomy, Micro-computed tomography, Osteology, Calumma nasutum group
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| Figure 5. In-life photos of four specimens of Calumma roaloko sp. n.; (a) subadult male (ZSM 244/2018, KU 343177); (b) the holotype, adult male (KU 343178); (c) subadult male (UADBA-R, KU 343167); (d) adult female (KU 343168). |
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| Figure 6. Posed photos of a subadult male specimen of Calumma roaloko sp. n. (ZSM 244/2018, KU 343177); (a) Indigo coloration on the rostral appendage and head scalation is apparent; (b) portrait of the same specimen. |
Calumma roaloko sp. n.
Suggested common English name: The two-toned soft-nosed chameleon
Suggested common Malagasy name: Tanalahy roa loko
Diagnosis: Calumma roaloko sp. n. is a member of the phenetic C. nasutum species group (Prötzel et al. 2016), on the basis of the presence of a soft, dermal unpaired rostral appendage, absence of gular and ventral crests, and heterogeneous scalation on the lower arm, consisting mostly of tubercles of 0.4–0.7 mm diameter. With 44.5–45.6 mm SVL and 85.5–93.7 mm total length in adult specimens it is currently the smallest known species in the genus Calumma. The body of the chameleon is uniquely two-colored with beige/white on the ventral and bright green on the dorsal half. Furthermore, it is characterized by a prominent and distally rounded rostral appendage, occipital lobes that are slightly notched, a distinctly elevated rostral crest, absence of a dorsal crest (or presence of at most two cones) in both sexes, absence of axillary pits, and a unique skull morphology.
Etymology: The specific epithet “roaloko” is a combination of the Malagasy words “roa” meaning “two” and “loko” meaning “color”, in reference to the characteristic two-toned body colorations of males (green and white) and females (brown and tan) of this species. The epithet is to be treated as an invariable noun in apposition.
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| Figure 7. In-situ photograph of an uncollected (in sleeping position) female of Calumma roaloko sp. n., from the same locality as KU 343168. |
Natural history: The specific natural history of Calumma roaloko sp. n. is little-known, but assumed to be similar to other small-bodied Calumma. As with other C. nasutum group species, individuals of C. roaloko sp. n. were encountered sleeping at night on leaves (Fig. 7) or small branches, and most often spotted ~2–5 m above the ground. Calumma roaloko sp. n. may be restricted to higher-elevation habitats, as it has only been found at ca. 1100 m a.s.l., although this is difficult to determine with certainty as most forests below ~1000 m a.s.l. in the area have been cleared. Interestingly, it is known from only two sites, both on the periphery of the forest fragment, and characterized by qualitatively more degraded habitat and/or secondary forest growth as compared to two sites located with more intact primary forest, where it was not encountered (Fig. 4). In summary, either C. roaloko sp. n. may have a higher detection probability in disturbed habitats, and/or may be out-competed in primary forest by close relatives (e.g., C. nasutum complex species that we found in all four sites). Several specimens were observed to have small red acarid ectoparasites (visible on the hindlimb in Fig. 6a).
Distribution: Given current evidence, the distribution of Calumma roaloko sp. n. is potentially restricted to a small fragment (~300 km2) of mid-elevation rainforest that lies outside of nearby Analamazaotra Special Reserve and Andasibe-Mantadia National Park in central-eastern Madagascar (Fig. 4), but within the Réserve de Ressources Naturelles du Corridor Ankeniheny-Zahamena newly protected area. However, we believe that C. roaloko sp. n. may still be discovered in nearby areas, including Andasibe-Mantadia National Park, although it has never been found over dozens of surveys in nearby protected areas over the last century, including our own surveys (Hutter, Lambert, Scherz, Prötzel, Glaw, etc. unpubl. data). It is also possible that C. roaloko sp. n. could be found in other smaller and more fragmented forests located to the west of the type locality of C. roaloko sp. n., south of the city of Moramanga, but recent work in one remnant forest fragment in that area discovered C. juliae there, and no specimens of C. roaloko sp. n. were found (Prötzel et al. 2018).
David Prötzel, Shea M. Lambert, Ginah Tsiorisoa Andrianasolo, Carl R. Hutter, Kerry A. Cobb, Mark D. Scherz and Frank Glaw. 2018. The Smallest ‘True Chameleon’ from Madagascar: A New, Distinctly Colored Species of the Calumma boettgeri complex (Squamata, Chamaeleonidae). Zoosystematics and Evolution. 94(2): 409-423. DOI: 10.3897/zse.94.27305
