AMPHIBIAWEB
Scaphiophryne gottlebei
Gottlebe's Narrow-mouthed Frog; Sahon'orana (in Malagasy)
family: Microhylidae
subfamily: Scaphiophryninae

© 2008 Miguel Vences and Frank Glaw (1 of 16)

  hear Fonozoo call

View distribution map using BerkeleyMapper.


Conservation Status (definitions)
IUCN (Red List) Status Endangered (EN)
See IUCN account.
CITES Appendix II
Other International Status None
National Status None
Regional Status None

   

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Description
Scaphiophryne gottlebei is a small to medium conspicuously coloured frog, characterised by a typical white, reddish, greenish and black dorsal pattern, rounded morphology, and greyish belly. Borders between all colors very distinct. Typically, the females are bigger (30-40 mm), and also have a brighter and more contrasted colouration, than males. Males are smaller (20-30 mm), and are generally paler than females. Skin on the back smooth. Tympanum indistinct. The snout is very short, the mouth is small, the eyes are prominent, and the legs are relatively short. The hindlimbs are quite robust, and the underside of the foot displays a typical horny metatarsal tubercle, which is used by this frog to burrow. The hands also have typical claws, which permit the frog to cling to the vertical stony walls of the canyons within which it lives. Hands are characterised by the presence of large digital expansions. Tips of toes not enlarged. Fingers without webbing, toes with a well developed web.

Scaphiophryne gottlebei is unique in colouration. The other Scaphiophryne species, except for S. marmorata and S. boribory, do not have enlarged fingertips. Scaphiophryne gottlebei is syntopic with S. brevis and S. calcarata.

The tadpole has a robust, ovoid body with a flattened ventrum. The snout is trapezoidal with nares in a shallow, light-colored furrow and located closer to the eyes than to the tip of the snout. Nares do not open until stage 41. Dorsolateral eyes. Rounded oral disc surrounded by dense marginal and submarginal conical-shaped papillae, sometimes pigmented except for tips. Labial teeth lacking; well-developed jaw sheath, with lower jaw sheath partially pigmented underneath. Tail fins relatively high, with ventral fin higher than dorsal. Spiracle ventrolateral, opening to posterior, and vent tube ventrally directed with medial opening (Mercurio and Andreone 2006).

The background color of tadpoles transforms from gray-brown at night to black in the daytime. All surfaces are scattered with melanophores which increase in density on the dorsal and lateral posterior surfaces. There is a translucent diamond-shaped area between the eyes. The tail fins are also transparent with dark edges. Tadpoles begin to take on the adult coloration pattern near metamorphosis. Metamorphs are 10-15mm long and less conspicuous than adults but with similar white, red, and black designs (Mercurio and Andreone 2006).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Madagascar

View distribution map using BerkeleyMapper.
Type locality: Isalo Massif (Vallée des Singes; actually known as Vallée des Makis), in south-central Madagascar. Also found in surrounding areas, including Ilalaka and the PN de Isalo. Within the rocky, montane part of the Isalo Massif, this species is found in narrow, sandy-bed canyons with vertical rock walls. The habitat is dark, cool (19-22 degrees C), and humid (close to 100%). Vegetation is absent or limited to occasional trees.

Surprisingly until recently the species – although intensively collected for the pet trade - had a poorly known distribution. The recent survey work carried out by one of us (FA), in collaboration with V. Mercurio, Jasmin E. Randrianirina, and Gennaro Aprea, allowed to confirm the presence of the species in the Isalo Massif and nearby areas. There, we found it outside the protected area, in the Ilakaka surroundings, from which most of the animals are captured for the pet-trade. Furthermore, we also found it at several sites within the PN de l’Isalo. There, S. gottlebei was already known for the Canyon des Makis (from which the type series came). Surprisingly enough, it seems that within this canyon the species is very rare, or even not regularly present. The habitat appears not suitable for the species' reproduction, and we believe that its presence (if the collecting information provided within the description work were correct) was very casual, and possibly due to the occasional finding of erratic specimens.

After our surveys carried out in 2004 (January-February and November-December), we are quite convinced that S. gottlebei is present almost anywhere in the rocky Isalo Massif. The preferred habitat is represented by typical narrow canyons. These canyons host a cool and wet atmosphere, which is quite stable in temperature, contrasted to the “external” savannas, which are subject to strong seasonal and day/night thermal excursions. During the rainy season (October to February) these canyons become temporary fast running streams. After the rainfall the water remains in small pools within the rocks. There S. gottlebei breeds and completes its larval development. We also found the species outside these canyons, where it is likely that it finds refuge under rocks and in deep crevices.

Life History, Abundance, Activity, and Special Behaviors
On the occasion of the 2004 survey (which was sponsored by the Nando Peretti Foundation), I had the chance to witness some peculiar behaviours and life history traits of this species. So far, it seems that it leads two kinds of life. First, it has a typical fossorial life style, which is shared by most of the species belonging to the genus Scaphiophryne. Using its robust hindlegs and horny metatarsal tubercle, S. gottlebei digs in the sand or other soft substrate available in its natural habitat. Second, it also has a scansorial life style, witnessed in this by the presence of largely expanded fingertips. We observed on several occasions overnight active specimens which jumped on the vertical canyon’s walls, and indeed were able to climb at several meters from the ground. This also allowed the frogs to find refuges in small holes present on the walls, and caused by the loss of chalks from the karstic matrix.

Calling males were found swimming at the water surfaces of pools from recent rain, or clinging to rocky surfaces. The call itself consists of 20 seconds of short, discordant notes at constant intensity, similar to that of other Scaphiophryne species (Andreone, Mattioli and Mercurio 2005). The call ranges in frequency from 500-1400 Hz and has a note repetition rate of 32–36 notes/s (Andreone, Mattioli, and Mercurio 2005).

Tadpoles live in the temporary rocky pools, and most likely have a very fast development. Indeed, the strong water course which forms after rainfalls literally wipes away any tadpole present there and excludes the possibility to have completed the metamorphosis. At Ilakaka and Isalo we found metamorphosing tadpoles (with only a portion of the tail, and already having contrasting back colouration) in late January. Taking into consideration the large number found also in a sub-optimal season, we believe that the species is very abundant during the rainy season. We also found many tadpoles in the pools during November-December. Metamorphosis appears to take about 2-3 months (Mercurio and Andreone 2006).

The feeding behavior of the tadpoles is unique. During the day, they stay close to the pool bottom and often burrow into the sandy, muddy substrate, such that the head is almost buried in the substrate and the tail is projecting out at a 30-45° angle. This position allows the tadpoles to feed on substrate particles. In all collected tadpoles, the intestine was completely filled with detritus. At night, the tadpoles leave the bottom to swim around in the water column, apparently filter-feeding on suspended particles, and occasionally reaching the surface for air.

Due to the unique feeding habits and physical characteristics of these tadpoles, a new ecomorphological category has been proposed, "psammonektonic." Psammonektonic tadpoles are active both by day and by night, have keratinized mouthparts and papillae, dorsolateral eyes, a ventrolateral spiracle, and have dual feeding modes: filter-feeding within the water column and direct substrate ingestion via active burrowing (Mercurio and Andreone 2006).

Trends and Threats
Scaphiophryne gottlebei was until recently actively collected for the pet-trade. Thousands of individuals are captured each year, especially during the breeding season. For this it is potentially threatened. According to recent evaluations it has been included in the IUCN category CR, “critically endangered”. Although the number collected is high, the species appears potentially widely distributed in the Isalo Massif, and its life history stresses the good capacity of recovery. The species is potentially able to breed in captivity: the high number of deposited eggs and the rapidity of larval development are positive factors for the realisation of captive stocks, which would therefore limit the capture from the wild environment. Thus although this species is included in CITES II, we have reasons to believe that S. gottlebei is not threatened by the capture activity. The pet-trade should be controlled, however, and for this an export quota number is urgently needed.

On the other hand, it is probable that some small (sub)populations are threatened by mining activity, which occurs in the Ilaka area. As is the case for many other critically endangered species, more data are badly needed to complete a comprehensive conservation scenario. The inclusion in CITES II provides some protection.

Relation to Humans
Only pertinent to the interest for pet-trade and market demand. The species is tetraploid.

Possible reasons for amphibian decline

General habitat alteration and loss
Habitat modification from deforestation, or logging related activities
Prolonged drought
Floods
Mining
Drainage of habitat
Loss of genetic diversity from small population phenomena
Intentional mortality (over-harvesting, pet trade or collecting)

Comments

NOTE: The study by F. Andreone, V. Mercurio, G. Aprea, and J. E. Randrianirina in January-February 2004 benefited from financial support by the Nando Peretti Foundation, the Declining Amphibian Population Task Force, and the National Amphibian Conservation Center. R. Rossi and the Istituto Oikos also greatly helped with financial support. Thanks also to Euan J. Edwards and Dodine Edwards (Antananarivo) for the help in gathering information about the pet-trade in this species.

References
 

Andreone, F. and Luiselli, L.M. (2003). ''Conservation priorities and potential threats influencing the hyper-diverse amphibians of Madagascar.'' Italian Journal of Zoology, 70, 53-63.  

Andreone, F., Mattioli, F., and Mercurio, V. (2005). ''The call of Scaphiophryne gottlebei, a microhylid frog from the Isalo Massif, southcentral Madagascar.'' Current Herpetology, 24(1), 33-35.  

Busse, K., and Böhme, W. (1992). ''Two remarkable frog discoveries of the genera Mantella (Ranidae: Mantellinae) and Scaphiophryne (Microhylidae: Scaphiophryninae) from the west coast of Madagascar.'' Revue Française d'Aquariologie, 19, 57-64.  

Glaw, F. and Vences, M. (1994). Amphibians and Reptiles of Madagascar. M. Vences and F. Glaw Verlags GbR., Köln.  

Guibé, J. (1956). ''La position systématique des genres Pseudohemisus et Scaphiophryne (Batraciens).'' Bulletin du Muséum National d’histoire Naturelle, Série 2, 28(2), 180-182.  

Mercurio, V. and Andreone, F. (2006). ''The tadpoles of Scaphiophryne gottlebei (Microhylidae: Scaphiophryninae) and Mantella expectata (Mantellidae: Mantellinae) from Isalo Massif, southcentral Madagascar.'' Alytes, 23(3-4), 81-95.  

Vences, M., Aprea, G., Capriglione, T., Andreone, F., and Odierna, G. (2002). ''Ancient tetraploidy and slow molecular evolution in Scaphiophryne: ecological correlates of speciation mode in Malagasy relict amphibians.'' Chromosome Research, 10, 127-136.



Written by Franco Andreone*, Vincenzo Mercurio*, Frank Glaw and Miguel Vences, updated by Xi Zhai, UC Berkeley (* f.andreone AT libero.it, m.vences AT tu-bs.de), * Museo Regionale di Scienze Naturali (Torino), and Istituto Oikos (Milano)
First submitted 2001-10-19
Edited by Kellie Whittaker (2010-07-19)



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Citation: AmphibiaWeb: Information on amphibian biology and conservation. [web application]. 2014. Berkeley, California: AmphibiaWeb. Available: http://amphibiaweb.org/. (Accessed: Oct 30, 2014).

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