Friday, October 13, 2017

[Herpetology • 2017] Splitting and Lumping: An Integrative Taxonomic Assessment of Malagasy Chameleons in the Calumma guibei complex results in the New Species C. gehringi sp. nov.

Calumma gehringi
Prötzel, Vences, Scherz, Vieites & Glaw, 2017

  Vertebrate Zoology. 67(2)

Calumma guibei (Hillenius, 1959) is a high-altitude chameleon species from the Tsaratanana massif in north Madagascar. Since its description was based on a juvenile holotype, its taxonomic identity is uncertain and little is known about its morphology. A recent molecular study discovered several deep mitochondrial clades in the Tsaratanana region assigned to C. guibei and C. linotum (Müller, 1924). In this paper we study the taxonomy of these clades and clarify the identity of C. guibei. Using an integrative taxonomic approach including pholidosis, morphological measurements, osteology, and molecular genetics we redescribe C. guibei and describe the new species C. gehringi sp. nov. which comprises two deep mitochondrial lineages. In terms of external morphology the new species differs from C. guibei by an elevated rostral crest, the shape of the notch between the occipital lobes (slightly connected vs. completely separated), presence of a dorsal and caudal crest in males (vs. absence), and a longer rostral appendage in the females. Additionally, we analysed skull and hemipenis morphology using micro-X-ray computed tomography (micro-CT) scans and discovered further differences in skull osteology, including a large frontoparietal fenestra, and separated prefrontal fontanelle and naris in C. guibei. Furthermore, we provide a comparison of micro-CT scans with traditional radiographs of the skull. The hemipenes have ornaments of two pairs of long pointed cornucula gemina (new term), two pairs of dentulous rotulae, and a pair of three-lobed rotulae, and are similar in both species, but significantly different from other species in the C. nasutum group. Geographically, C. guibei has been recorded reliably from the higher elevations of the Tsaratanana Massif above 1580 m a.s.l., whereas C. gehringi sp. nov. is found at mid-altitude (730-1540 m a.s.l.) in Tsaratanana and the surrounding area.  

Key words: Calumma guibeiCalumma gehringi sp. nov., Chamaeleonidae, micro-computed tomography, hemipenis morphology, skull structure, Madagascar, diceCT.

Calumma gehringi sp. nov.male holotype ZSM 2851/2010, clade EII

Fig. 2. Calumma gehringi sp. nov. colouration in life:
 (C, D) male holotype ZSM 2851/2010, clade EII; (E) male ZSM 2843/2010; (F) male ZSM 43/2016, clade EI.

Calumma gehringi sp. nov.  

Diagnosis. Calumma gehringi sp. nov. is a member of the phenetic C. nasutum group (Prötzel et al., 2016), because of the presence of a soft, dermal, unpaired rostral appendage, absence of gular or ventral crest and heterogeneous scalation at the lower arm, consisting mostly of tubercles of large diameter (0.4–0.9 mm). Within the genus it is a small-sized, grey to greenish chameleon (SVL 44.7 – 55.5 mm, TL 92.6–123.6 mm) that is characterized by a large rostral appendage of green or blue colour in males and yellow in females when unstressed, occipital lobes that are clearly notched but usually still slightly connected, distinctly elevated rostral crest, absence of axillary pits, presence of a dorsal crest in males, and a unique skull morphology. .....

Available names. Apart from C. guibei there is no other valid species or synonym in the Calumma nasutum group with deeply notched occipital lobes.

Etymology. We dedicate the new species to Philip Sebastian Gehring. His comprehensive molecular phylogenetic study on the Calumma nasutum group was the basis for the description of the new species, and will be instrumental to the resolution of the rest of this complex. The species epithet ‘gehringi’ is a patronym in the Latin genitive form.

 David Prötzel, Miguel Vences, Mark David Scherz, David Vieites and Frank Glaw. 2017. Splitting and Lumping: An Integrative Taxonomic Assessment of Malagasy Chameleons in the Calumma guibei complex results in the New Species C. gehringi sp. nov.  Vertebrate Zoology. 67(2); 231-249. 

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