Species Description: Rakotoarison A, Glaw F, Vieites DR, Raminosoa NR, Vences M 2012 Taxonomy and natural history of arboreal microhylid frogs (Platypelis) from the Tsaratanana Massif in northern Madagascar with description of a new species. Zootaxa 3563: 1-25.
Platypelis olgae is distinguished from Cophyla phyllodactyla, C. berara, P. alticola, P. cowanii, P. grandis, P. mavomavo, P. milloti, P. pollicaris, and P. tuberifera by its smaller body size. An adult Platypelis olgae reaches a snout vent length of 20 - 22 mm while the other species mentioned above have a snout-vent lenghts of 23 - 105 mm. Furthermore, Platypelis olgae lacks or has rudimentary vomerine teeth while all the previously mentioned species, including P. tsaratananaensis and P. tetra, have vomerine teeth. Platypelis olgae has a green-yellow ventral side that sets it apart from all the species except P. mavomavo and juvenile P. grandis (Rakotoarison et al. 2012).
Platypelis barbouri, P. ravus, and C. occultans are three species that are small and have no vomerine teeth. However, there are ways to distinguish them from P. olgae. Platypelis olgae has a green-yellow ventral side while P. barbouri has a red ventral side. Platypelis ravus lacks the three symmetrical dorsal dark patches and C. occultans has a green-yellow venter while P. olgae’s is grey. Platypelis olgae can be distinguished by molecular relationships and genetics divergence (Rakotoarison et al. 2012).
In life, the ventral side of the body and limbs of a Platypelis olgae has a green to yellowish hue with most coloration concentrated at the throat. Dorsally, there are three symmetrical dark patches that appear to have no distinct pattern. In addition, there is no obvious distinction between the dorsal and lateral color (Rakotoarison et al. 2012).
After about two years in preservation, the dorsal side of the organism is uniformly brown with a lighter brown coloration anterior to the eyes. The forelimbs and hindlimbs are also dorsally brown with white dots that are more pronounced on the hands and feet. The dark crossbands on the limbs are not distinguishable. On the ventral side, the throat is white and brown, the chest is brown and yellowish, the belly is dark brown and whitish, and the limbs are brown and yellowish (Rakotoarison et al. 2012).
Two known male specimens, the holotype and paratype, both have small tubercles on the dorsal sides. The female, however, is smoother. Compared to the holotype, both paratypes had a yellow ventral color and less dark patterns. In addition, the mitochondrial DNA fragment studied showed no differentiation in both the holotype and the female paratype (the male paratype was not sequenced). In all three specimens, the third finger is as long as the fourth finger. However, the third toe is as long, or is longer than the fifth toe. None of the specimens had distinct vomerine teeth; however, a presence of rudimentary vomerine teeth may be possible (Rakotoarison et al. 2012).
Distribution and Habitat
Country distribution from AmphibiaWeb's database: Madagascar
Life History, Abundance, Activity, and Special Behaviors
However, given the known information on cophyline frog reproduction (non-feeding tadpoles in water-filled phytotelmes or other cavities, or in terrestrial foam or jelly nests) and the use of bamboo plants for tadpole rearing in its sister species, to P. tsaratananaensis, it is possible P. olgae also uses some sort of water-filled cavity for reproduction too (Rakotoarison et al. 2012).
Trends and Threats
Possible reasons for amphibian decline
General habitat alteration and loss
The phylogenetic tree based on the DNA sequences of the 16S rRNA gene clearly shows a distinct presence of four genetic lineages in Tsaratanana Massif. Those four genetic lineages are P. olgae, P. alticola, P. tsaratananaensis, and P. sp. 8. Platypelis olgae is sister to P. tsaratananaensis (Rakotoarison et al. 2012).
Platypelis olgae is dedicated to Professor Olga Ramilijaona, the former head of the zoology department at UADBA, in recognition of his hard work in developing zoological science in Madagascar (Rakotoarison et al. 2012).
Possible junior synonyms of P. olgae are Paracophyla tuberculata, Platypelis barbourii, Platyhyla verrucosa, Platyhyla voeltzkowi, Cophyla tuberculata and all junior synonyms of Platypelis grandis (Rakotoarison et al. 2012).
Rakotoarison, A., Glaw, F., Vieites, D., Raminosoa, N., Vences, M. (2012). ''Taxonomy and natural history of arboreal microhylid frogs (Platypelis) from the Tsaratanana Massif in northern Madagascar, with description of a new species.'' Zootaxa, 3563, 1-25.
Written by Jina Moon (jina.moon AT berkeley.edu), UC Berkeley
First submitted 2015-05-29
Species Account Citation: AmphibiaWeb 2015 Platypelis olgae <http://amphibiaweb.org/species/7942> University of California, Berkeley, CA, USA. Accessed Mar 25, 2017.
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Citation: AmphibiaWeb. 2017. <http://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 25 Mar 2017.
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