Frogs of Borneo.

Description
This frog is medium to large-sized, with males reaching 42-52 mm in SVL and females measuring 75-80 mm in SVL. It is the only Bornean frog with recessed tympana. The snout is rounded. Hind limbs are long. Both finger and toe tips are expanded, with the digital pads slightly pointed in shape. Toes are fully webbed, with webbing extending to the base of the pads. Dorsally the skin is smooth; the sides of the body have small, rounded tubercles, and the sides of the head are roughened (Inger and Stuebing 2005).

The dorsal surface of the body and head is chocolate brown. In contrast, the sides of the body and head, as well as the upper surfaces of the limbs, are tan with darker brown bars or spots. Ventral surfaces are white or yellowish orange. The iris is bicolored, with the upper half light gold and the lower half brown. (Inger and Stuebing 2005).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Indonesia, Malaysia

Malaysian region distribution from AmphibiaWeb's database: Sabah

View distribution map in BerkeleyMapper.

Huia cavitympanum is found only on Borneo. It prefers primary forest in the hills, from 250-750 m above sea level (Inger and Stuebing 2005). It breeds in stretches of stream with foaming rapids and big boulders (Inger and Voris 1993).

Life History, Abundance, Activity, and Special Behaviors
This frog has been shown to communicate using ultrasound (frequencies above 20 kHz), which is extremely unusual in non-mammalian vertebrates. It is one of only two anuran species to emit ultrasound and to have recessed tympanic membranes, with the other species being Odorrana tormota (Arch et al. 2008; Feng et al. 2006). Similar to mammals, the tympanic membranes of male Odorrana tormota are located at the end of ear canals (Feng et al. 2006).

Huia cavitympanum calls are highly variable in both frequency modulation and spectral range, both within individual males and between individuals. Calls are produced either singly or in a series of two to six notes. Almost all of the ultrasonic signals are produced toward the end rather than at the beginning of the call series. Within males, the dominant frequency distribution is bimodal, with calls being either clustered in a low-frequency (mean of 11.6 kHz) or high-frequency (mean of 20.3 kHz) group. Of the high-frequency calls, 14% of the calls were found to be purely ultrasonic, with an additional 38% being above 18 kHz and thus inaudible to human ears (Arch et al. 2008). Although the highest known detectable frequency by the amphibian basilar papilla is 8.2 kHz (Loftus-Hills and Johnstone 1970), the vast majority (>97%) of Huia cavitympanum calls are made at a dominant frequency above this previously described limit (Arch et al. 2008).

This species appears to be the only anuran capable of emitting purely ultrasonic calls that are "structurally independent" rather than being harmonic elements of audible sounds (Arch et al. 2008). So far the only other vertebrate capable of emitting structurally independent ultrasonic sounds is the blue-throated hummingbird, (Lapornis clemenciae; Pytte et al. 2004). This is in contrast to the other frog species using ultrasound communication (Odorrana tormota), for which the dominant call frequency is actually within the audible range of 5-9 kHz (Arch et al. 2008).

It is not known what organ within the ear is responsible for ultrasonic sensitivity (Feng et al. 2006). Frogs have two known auditory organs, the amphibian papilla, which responds to low/intermediate frequencies, and the basilar papilla, which responds to high frequencies (Feng et al. 1975; Lewis and Narins 1999). The upper limit for frog hearing was previously thought to be 8.2 kHz, based on the sensitivity recorded for basilar papilla nerve fibers (Loftus-Hills and Johnstone 1970). Thus either the upper frequency sensitivity has been dramatically increased for the basilar papilla in this species, or another as yet undescribed mechanism is responsible for the detection of ultrasonic calls (Arch et al. 2008).

Although this species can be found throughout its primary forest habitat, breeding occurs along stretches of fast-moving water in medium to large streams. Tadpoles cling to rocks in the fastest-moving currents, using the abdominal sucker (Inger and Stuebing 2005).

Larva
This species has large tadpoles, some of the largest of Bornean anurans, reaching up to 70 mm. An abdominal sucker is present, allowing the larvae to adhere to rocks in fast-moving currents. The caudal muscle has light spots on a dark background. Caudal fins also have a dark background, with a light band along the base and light spots on the margin (Inger and Stuebing 2005).

References

Arch, V. S., Grafe. T. U., and Narins, P. M. (2008). ''Ultrasonic signalling by a Bornean frog.'' Biology Letters, 4, 19-22.

Cai, H.-X., Che, J., Pang, J.-F., Zhou, E.-M. and Zhang, Y.-P. (2007). ''Paraphyly of Chinese Amolops (Anura, Ranidae) and phylogenetic position of the rare Chinese frog, Amolops tormotus.'' Zootaxa, 1531, 49-55.

Feng, A. S., Narins, P. M., Xu, C.-H., Lin, W.-Y., Yu, Z.-L., Qiu, Q., Xu, Z.-M. and Shen, J.-X. (2006). ''Ultrasonic communication in frogs.'' Nature, 440, 333-336.

Feng, A. S., Narins, P. M., and Capranica, R. R. (1975). ''Three populations of primary auditory fibers in the bullfrog (Rana catesbeiana): their peripheral origins and frequency sensitivities.'' Journal of Comparative Physiology, 100, 221-229.

Inger, R. F. and Stuebing, R. B. (2005). A Field Guide to the Frogs of Borneo, 2nd edition. Natural History Publications (Borneo), Kota Kinabalu.

Inger, R. F., and Voris, H. K. (1993). ''A comparison of amphibian communities through time and from place to place in Bornean forests.'' Journal of Tropical Ecology, 9, 409-433.

Lewis, E. R., and Narins, P. M. (1999). ''The acoustic periphery of amphibians: anatomy and physiology.'' Comparative Hearing: Fish and Amphibians. R. R. Fay and A. N. Popper, eds., Springer, New York, 218-268.

Loftus-Hills, J. J. and Johnstone, B. M. (1970). ''Auditory function, communication, and the brain-evoked response in anuran amphibians.'' Journal of the Acoustic Society of America, 47, 1131-1138.

Pytte, C. L., Ficken, M. S., and Moiseff, A. (2004). ''Ultrasonic singing by the blue-throated hummingbird: a comparison between production and perception.'' Journal of Comparative Physiology A, 190, 665-673.

Stuart, B. L. (2007). ''The phylogenetic problem of Huia.'' Molecular and Phylogenetic Evolution, 46, 49-60.

Species Account Citation: AmphibiaWeb 2024 Huia cavitympanum: Hole-in-the-head Frog <https://amphibiaweb.org/species/4717> University of California, Berkeley, CA, USA. Accessed Nov 23, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 23 Nov 2024.

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