AmphibiaChina 中国两栖类.

Description
Males average 32.5 mm in SVL while females average 56 mm in SVL (Feng et al. 2002). The head width is about the same as the head length (Fei 1999). The tympana of males are sunken, while female tympana are not (Fei 1999). Vomerine teeth are present (Fei 1999). Tiny small bumps are present on the dorsum, with the sides and venter bearing numerous, densely concentrated small warts, and scattered small warts are present on the throat (Fei 1999). Dorsolateral folds are present (Fei 1999). Fingers are about half as long as the toes (Fei 1999). The ground color is tan, with occasional black dots on the dorsum. A dark brown stripe runs from each side of the snout to the eyes, broadening behind the eye, running across the top of the ear canal, and continuing as an interrupted dark streak following the dorsolateral fold. Both forelimbs and hind limbs are barred. The venter is light yellow (Fei 1999). The top third of the iris is gold, with the bottom third dark brown, so that the stripe running from the snout appears to continue through the eye. A white stripe runs from the snout along the upper lip, continuing to the shoulder.

Males have ear canals with recessed tympanic membranes at the end of the canals, like mammals but unlike all other anurans except for Huia cavitympanum (Feng et al. 2002). In Odorrana tormota, the tympanic membranes have been shown to be exceptionally thin, which facilitates transmission of high-frequency sounds to the inner ear (Feng et al. 2006). The middle ear bones (ossicles) are reduced in both size and mass, due to the shortened distance between the tympanum and inner ear; this also facilitates high-frequency sound transmission (Feng et al. 2006).

Males also have two pairs of vocal sacs (Feng et al. 2002). In addition, the larynx appears to be specialized for production of ultrasound frequencies and the generation of calls with nonlinear features such as subharmonics and chaos (Suthers et al. 2006). These specializations include variations in thickness along the lengths of the vocal cords, and reverse size dimorphism, with males having smaller larynxes (about half as large as that of the female), unlike other anuran species (Suthers et al. 2006).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: China

View distribution map in BerkeleyMapper.

This species has a restricted distribution within China, in Zhejiang Province (Jiande and Anji counties) and Anhui Province (Huangshan). It occurs between 150-700 m in elevation (Feng et al. 2002). It resides in vegetation along permanent streams and waterfalls running through mountains and hills, in subtropical/tropical moist lowland forest and shrubland (Feng et al. 2002).

Life History, Abundance, Activity, and Special Behaviors

This frog is one of only two anuran species (the other being Huia cavitympanum) that has been shown to communicate using ultrasound (frequencies above 20 kHz), which is extremely unusual in non-mammalian vertebrates (Feng et al. 2002; Feng et al. 2006; Arch et al. 2008). Male Odorrana tormota make melodic calls resembling those of birds, with distinct frequency modulations that are primarily in the audible range (5-9 kHz) but often reach into the ultrasonic range (Feng et al. 2002; Feng et al. 2006; Arch et al. 2008).

Males are territorial and call from low vegetation adjacent to noisy streams, with calling males spacing themselves at about 1.5 m apart (Feng et al. 2002). The calls consist of either two notes of short tone "pips" or a single note with short or long duration, all of which have very variable components (Narins et al. 2004). However, unlike other anurans, which have a limited repertoire of calls typical of each species, Odorrana tormota has a vocal repertoire that cannot be accurately estimated in size; analysis of 12 hours of tape from 21 calling males revealed no two calls alike (Feng et al. 2002). (In contrast, the frog Boophis madagascariensis from Madagascar makes 28 distinct calls, by far the most previously described for any anuran species (Narins et al. 2000).)

The unusually rich and complex vocal repertoire of Odorrana tormota shares aspects of passerine bird, primate, or whale sounds, such as ultrasonic components, musical warbling (multiple upward and downward frequency modulation sweeps), and sudden onset/cessation of selective harmonic components within a single call note (Feng et al. 2002). Males have two pairs of vocal sacs, which contributes to the harmonic complexity of the call (Feng et al. 2002), as well as a specialized larynx (Suthers et al. 2006). Laryngeal specializations include unusually intricate vocal cord morphology, with varying thickness along their length; very thin portions of the medial vocal ligaments appear to contribute to ultrasound production (Suthers et al. 2006). Both the ultrasound frequencies and the nonlinear dynamics (subharmonics and chaos) associated with the calls of this species may thus arise from complex nonlinear oscillatory patterns of the vocal cords (Suthers et al. 2006). In addition, there is reverse sexual size dimorphism of the larynx; unlike all other frogs examined to date, which have larger larynxes in the male than the female, in O. tormotus the male larynx is smaller than that of the female (Suthers et al. 2006). Interestingly, most of the acoustic features present in normal male Odorrana tormota vocalizations can be generated by forcing airflow through the larynx of a euthanized frog (Suthers et al. 2006).

Electrophysiological recordings from the auditory midbrain confirm that this species can hear as well as generate ultrasound (Feng and Narins 2007). Hearing in this species spans the range from less than 1 kHz to about 35 kHz (Narins et al. 2004; Feng et al. 2006), which is a considerably higher range than had previously been thought to exist for anurans (up to 5-8 kHz, Fay 1988; Loftus-Hills and Johnstone 1970). 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).

In addition to being heard, the ultrasound components of the call do function in male-male interaction, since playback of both ultrasonic and audible components of recorded calls evoked vocal responses from males (Feng and Narins 2007).

While ultrasound is used and perceived in male-male territorial interactions in this species, it is not clear whether ultrasound is also involved in male-female communication. Males have recessed tympanic membranes, whereas females do not (Chen 1991).

This species shelters in moist rock crevices during the day, and is found in thick brush alongside streams at night (Fei 1999).

The reproductive season begins in June. Eggs are milky yellow in color, and measure about 2 mm in diameter (Fei 1999).

Possible reasons for amphibian decline

Habitat modification from deforestation, or logging related activities
Intensified agriculture or grazing

Comments

This species (Odorrana tormota) was formerly known as Amolops tormotus.

The two frog species with ultrasound communication (Odorrana tormota and Huia cavitympanum) are both found in Southeast Asia but are neither sympatric nor closely related (Cai et al. 2007; Stuart 2007). Rather, they are found in similar habitats, with males calling adjacent to noisy, rushing streams (Arch et al. 2008).

A related species from the same province, Odorrana livida, also has the ability to detect ultrasound, as shown by recordings from the auditory midbrain. Odorrana livida has very thin, transparent tympanic membranes, but in this species the membranes are not recessed. It has not yet been shown whether Odorrana livida is also emitting ultrasonic frequencies in its calls (Feng et al. 2006).

This species was featured in News of the Week April 8, 2024:

In populations with highly skewed male sex ratios, females may be overwhelmed with male suitors. In these situations, female choice may be nullified. However, Chen et al. (2024) recently documented a strategy that maximizes Odorrana tormota female choice. These frogs live in noisy, waterfall environments with a 10:1 male to female sex ratio. Both males and females call to attract partners, but field observations and laboratory mate trials both indicate that females show their willingness to mate by blinking at a particular male. To further test the importance of female blinking, males were given preference tests with two simultaneous videos, one of a blinking female and one without blinking. Those tests showed a clear male preference for blinking females. All together, these results indicate that blinking is an effective form of private communication for this species with intense male competition, and this may be the first time blinking has been shown as a social signal in a non-primate species. (Ann Chang)

This species was featured in News of the Week September 9, 2024:

Understanding regions of high species diversity, rarity, and endemism is fundamental to conservation strategies to effectively direct limited resources to protect biodiversity. Thus, the efforts of Xu et al 2024 combining 20 years of field work in China, a large, amphibian-rich country, with new molecular analysis of over 500 species, including 100 cryptic species, is extraordinary, which resulted in spatially delineating 10 biodiversity hotspots including six new ones. The six previously unknown hotspots include the Nanling Mountains and other Southern China mountain ranges, and most of the 186 amphibian species which occur there are subjected to high human impacts (over 88%) while only a few species (9.7%) occur in protected areas. Altogether the 10 biodiverse hotspots are made of almost 60% of China’s known species, 49% of cryptic species, and 55.6% of species known only to occur in China. Their extensive years of surveys and multiple lines of inquiry including calculating and mapping phylogenetic diversity and endemism highlight the importance of these regions to evolutionary and biodiversity richness and the need for conservation attention. (Michelle Koo)

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.

Chen, B.-H. (1991). The Amphibian and Reptile Fauna of Anhui. Anhui Publishing House of Science and Technology, Heifei, Anhui.

Fay, R. R. (1988). Hearing in Vertebrates: a Psychophysics Databook. Hill-Fay Associates, Winnetka, Illinois.

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.

Feng, A. S., Narins, P. M., and Xu, C.-H. (2002). ''Vocal acrobatics in a Chinese frog, Amolops tormotus.'' Naturwissenschaften, 89, 352-356.

Feng, A. S., and Narins, P. M. (2008). ''Ultrasonic communication in concave-eared torrent frogs (Amolops tormotus).'' Journal of Comparative Physiology A: Neuroethology, Sensory, Neural, and Behavioral Physiology, 194, 159-167.

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.

Narins, P. M., Feng, A. S., Lin, W., Schnitzler, H.-U., Denzinger, A. Suthers, R. A., and Xu, C. (2004). ''Old World frog and bird vocalizations contain prominent ultrasonic harmonics.'' The Journal of the Acoustical Society of America, 115, 910-913.

Narins, P. M., Lewis, E. R., and McClelland, B. E. (2000). ''Hyperextended call note repertoire of the endemic Madagascar treefrog Boophis madagascariensis (Rhacophoridae).'' Journal of Zoology, 250, 283-298.

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

Suthers, R. A., Narins, P. M., Lin, W.-Y., Schnitzler, H.-U., Denzinger, A., Xu, C.-H., and Feng, A. S. (2006). ''Voices of the dead: complex nonlinear vocal signals from the larynx of an ultrasonic frog.'' Journal of Experimental Biology, 209, 4984-4993.

Wu, G. F. (1977). ''A new species of frogs from Huang-Shan, Anhui, Amolops tormotus Wu.'' Acta Zoologica Sinica, 23, 113-115.

Species Account Citation: AmphibiaWeb 2024 Odorrana tormota: Concave-eared Torrent Frog <https://amphibiaweb.org/species/4661> University of California, Berkeley, CA, USA. Accessed Nov 20, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 20 Nov 2024.

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