Description
Platypelis karenae has a snout-vent length of 16.1 – 17.4 mm in males and 16.7 – 18.3 mm in females. The head is broad, and the body is stocky. The snout appears rounded when viewed from the back and the sides. The nostrils are directed towards the sides, do not protrude, and are closer to the snout than to the eye. It has a faint canthus rostralis and tympanum, though the supratympanic fold is noticeable and straight. The tongue is elliptical, wide, and slightly uneven. The vocal sac is somewhat expandable. The skin on the back is smooth and lacks dorsolateral folds. The skin on the underside is grainy, though less so on the throat. The arms are slim. The subarticular tubercles are faint, the outer metacarpal tubercle is big but not pronounced, and the inner metacarpal tubercle is fairly big and protrudes at the base of the first finger. The fingers are not webbed, but are flattened and relatively wide. The relative finger lengths are: I < II = IV < III. The legs are also slim, with a small inner metatarsal tubercle and no outer metatarsal tubercles. Like the fingers, the toes are not webbed, but are flattened and relatively wide. The relative toe lengths are: I < II < III ≤ V < IV (Rosa et al. 2014).

This species has the following combination of characters that distinguish it from other Platypelis species: it has a small adult size, a unique call, enlarged circular toe and finger pads, no webbing on hands or feet, a tarso-metatarsal articulation that reaches the tympanum, a smooth dorsal surface, light yellow-green coloration on the back, and a broad black-brown dorsolateral stripe that runs from the eye to the armpit. It is most similar in appearance to P. tuberifera, though P. tuberifera is larger, spotted on the back, and has little to no lighter spots. Platypelis karenae differs from P. alticola, P. grandis, P. mavomavo, P. milloti, P. pollicaris, and P. tsaratananaensis by its much smaller size. Platypelis karenae is most similar to P. tetra when compared to species of similar size, but P. tetra differs by having a darker body color with brown spots, legs with uneven tan spots, four large white spots on its back, 3^rd toe that is shorter than the 5^th, and an entirely smooth back. Platypelis karenae differs from P. barbouri, P. milloti, P. mavomavo, P. olgae, and P. ravus by its completely white underside. It differs from P. barbouri, P. grandis, and P. mavomavo by its completely smooth back (Rosa et al. 2014).

In life, it is light yellow with some lighter spots on the back, with a broad brown-black stripe running from the back of the eye to just before the forearm insertion, where it fades into individual dark spots. The iris is light brown with black spotting. The stomach is white, and the vocal sac is transparent and blue. In preservative, it is gray (Rosa et al. 2014).

Males have a vocal sac. Juveniles are greener have more light spots on their body than adults. Additionally, juveniles have a red-brown snout tip and iris. The black stripe on the side varies in length among specimens (Rosa et al. 2014).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Madagascar

View distribution map in BerkeleyMapper.

It is only found in a small rainforest fragment in Betampona Reserve (Réserve Naturelle Intégrale N. 1 de Betampona) on the central east coast of Madagascar. Within this range, it only occurs at an elevation range of 250 – 550 m asl (Rosa et al. 2014).

Life History, Abundance, Activity, and Special Behaviors
This species lives on the leaf axils of Pandanus and Crinum plants, though males move to the edge of the leaf to vocalize. Males will move up and down the leaves at nighttime, and vocalize the most during rainfalls. The expanding of the vocal sac follows after vocalizations. Males will retreat back into the leaf axil if scared (Rosa et al. 2014).

Females lay 2 – 3 eggs at a time, which are 19 – 24 mm in diameter. The eggs are white and encapsulated in transparent jelly (Rosa et al. 2014).

Trends and Threats
The species suffers threats from a small occurrence range. The Pandanus and Crinum plants on which it resides are threatened by the introduction of invasive guava plants. It is additionally threatened by agriculture and charcoal production (Rosa et al. 2014).

Relation to Humans
Betampona Reserve, where it occurs, is a nature reserve managed by people (Rosa et al. 2014).

Possible reasons for amphibian decline

General habitat alteration and loss
Habitat modification from deforestation, or logging related activities
Intensified agriculture or grazing
Mining
Subtle changes to necessary specialized habitat
Introduced competitors
Loss of genetic diversity from small population phenomena

Comments
The species authority is: Rosa, G. M., Crottini, A., Noël, J., Rabibisoa, N., Raxworthy, C. J., Andreone F. (2014). "A new phytotelmic species of Platypelis (Microhylidae: Cophylinae) from the Betampona Reserve, eastern Madagascar." Salamandra, 50(4), 201-214.

Platypelis karenae is sister to P. tuberifera but has a smaller size, vocalization pattern, and a different color pattern. The mitochondrial, nuclear, and morphological data also show genetic divergence between both species (Rosa et al 2014).

The species epithet, karenae, is named after and dedicated to Karen L. M. Freeman, former Madagascar Fauna and Flora Group field coordinator and current research coordinator, in recognition of her research and work for the conservation of the Betampona rainforest (Rosa et al. 2014).

References

Rosa, G. M., Crottini, A., Noël, J., Rabibisoa, N., Raxworthy, C. J., Andreone F. (2014). ''A new phytotelmic species of Platypelis (Microhylidae: Cophylinae) from the Betampona Reserve, eastern Madagascar.'' Salamandra, 50(4), 201-214.

Species Account Citation: AmphibiaWeb 2015 Platypelis karenae <https://amphibiaweb.org/species/8280> University of California, Berkeley, CA, USA. Accessed Nov 21, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 21 Nov 2024.

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