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Asiatic Herpetological Research, Vol. 11

pp.71–75

The Tadpole of A Little-known Frog, Rana tormotus Wu, 1977
PIPENG LI*, YUYAN LU, ANG LI AND LINA YU
Herpetodiversity Research Group, Shenyang Normal University, P. R. China 110034.
*Corresponding author E-mail: lipipeng@yahoo.com
Abstract.- The tadpoles of a Chinese endemic and rare frog, Rana tormotus were collected from the type locality andreared with other coexisting tadpoles of Paa spinosa, Rana schmackeri and Amolops wuyiensis in comparison. The
tadpole of Rana tormotus is small (about 27 mm in total length) and brown to slightly olive in color. Its body is ovoid
in dorsal view, widest at about midpoint, depressed and elliptical in lateral view. Body length is nearly one-third of
total length. Lateral line pores are visible on the body and tail. No glands (such as ventral and dorsal glands in tadpolesof genus Amolops) are visible. The snout is round, slightly flatted in dorsal profile, and rounded in lateral and ventral
profiles. Eyes directed dorsolaterally with diameter 31% of body height, closer to tip of snout than eye. Spiracle isshort and sinistral posteriorly. Tail approximately 2.1 times body length. Tail fins convex and approximately fusiform.
Tail tip is V-shaped or narrowly rounded. Vent tube is dextral and attached to ventral fin.
Oral disc is large and anteroventral in position. Labial tooth row formula 5(2-5)/4(1). Upper jaw sheath is finely
serrate and narrow, lower jaw sheath is finely serrate and shallowly V-shaped. No abdominal sucker was observed
behind the oral disc. It is similar to those of Rana andersonii and R. schmackeri in shape and oral disc characters.
From the characters of the tadpole of Rana tormotus, it does not belong to the Amolops type. It should be placedin the genus Rana (sensu lato) as Rana tormotus firstly or placed in a new genus (as Wurana by Li et al. [2006]) byfurther analysis.
Keywords.- Amolops tormotus, Rana tormotus, Wurana tormota, tadpole, sunken ear frog, concave-eared torrent frog.

Introduction
Rana tormotus Wu, 1977 is an arboreal frog in the family Ranidae found in the mountain streams of the Anhui
and Zhejing Provinces of Eastern China (SichuanInstitute of Biology (Wu, G. F.), 1977; Zhao and Adler,1993). This frog has an interesting characteristic: themales warble melodies like a bird in order to attract
females (Feng et al., 2002), calling nightly from the low
vegetation along the banks of rivers and streams. Their
vocal repertoire is extraordinarily rich; individual calls
exhibit multiple upward and downward frequency
sweeps, rapid frequency “steps,” and sudden onset andoffset of selective harmonic components within a note
(Feng et al., 2002; Peter et al., 2004). This is the first
species of frog known to use diverse rising and falling
modulations – most frog calls only go either up or down.
These calls are also the first terrestrial frog noises
known to extend into the ultrasonic range (Feng et al.,
2002; Peter et al, 2004). Both of these phenomena are
related to the frog’s unique ear.
This frog, which is called the “sunken ear frog” or“concave-eared torrent frog” in Chinese, has a conspicuous character that makes it different from most otherfrogs: the males have visible ear canals leading toeardrums within the skull, similar to Amolops cavitympanum Boulenger (Sichuan Institute of Biology [Wu G.

© 2008 by Asiatic Herpetological ResearchF.], 1977; Feng et al., 2002; Fei et al., 1991, 2005). Fei
et al. (1991, 2005) and Dubois (1992) placed this species
in Amolops because its tadpole might “belong to [the]Amolops type” (Fei et al., 1990 (1991); Zhao and Zhao,
1994). Because the tadpoles have never been recorded,
however, it has been argued that this species should
instead be assigned to "Rana" (Zhao and Zhao, 1994;
Zhao et al., 2000; Global Amphibian Assessment, 2005).
Here, for the first time, we describe the tadpole ofthis little-known species of frog and provide information
on its natural history. The importance of these findings
lies in the necessity for larval characters in anuran classification (Chou and Lin 1997), and may allow for clarification of the uncertain position of Rana tormotus in
relation to Rana and Amolops.

Materials and Methods
Field work was conducted in a small stream of
Longjiang Forest, Zhejiang Province (China), and thetype locality of Taohuaxi stream in the Huangshan Mts,
Anhui province. Field studies were done from June toAugust 2005.
The tadpoles of Rana tormotus Wu, 1977, Paa spinosa (Daivd, 1875), Rana schmackeri Boettger, 1892 andA. wuyiensis (Liu and Hu, 1975) were observed andsampled in Taohuaxi, a permanent stream. Some tad-

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poles of R. tormotus and R. schmackeri were reared until
stages 36–38 (Gosner, 1960) for description, or throughmetamorphosis to confirm their identification and todescribe and compare adult coloration. Tadpoles wereraised in captivity in a plastic box (260 x 175 x 160 mm)
with 1.5 L of water. Egg yolk and vegetable leaves were
provided regularly. The tadpoles were preserved in 5%
formalin. This material, together with adult voucher
specimens, is deposited in the collections of Shenyang
Normal University.
Tadpoles were staged according to Gosner (1960).
Tadpoles in stage 38, included both reared and freshly
captured specimens, were used in the descriptions andmeasured. No changes were observed in the oral morphology or general shape of reared tadpoles.
Measurements, terminology, and labial tooth row formula follow Altig and McDiarmid (1999); labial tooth row
formula also follows Dubois (1995).
All measurements were taken with a digital caliper(0.01 mm) and a stereomicroscope, except for total
length, which was measured directly with a hand caliper.
Drawings were made with the aid of a camera lucida
attached to a stereomicroscope. The photographs weretaken with a Nikon D100 camera.
Measurements are abbreviated as follows: BL(body length), TL (total length), TaL (tail length), BW(maximum body width), BH (maximum body height),
TH (height of tail), DFH (dorsal fin height), VFH (ven-Figure 1. Standard morphometric measurements for tadpoles used in this study.

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tral fin height), SO (snout-ocular axis distance), SN(snout-nasal axis distance), E (eye diameter), IN(internarial distance), IO (interorbital distance), SS(snout-spiracle distance), ODW (oral disc width).
Standard measurements are shown in Figure 1.
Decription of external morphology at stage 38.- Themean measurements and standard deviations of eighttadpoles in stage 38 are shown in Table 1. Mean total
length at stage 38: 27±1.07 mm (n = 8; Table 1). Body
ovoid in dorsal view, widest at midpoint, depressed andelliptical in lateral view; lateral part of marginal papillaeof oral disc slightly visible; Body length nearly one-third(32%) of total length, body 1.5 times longer than wide,
2.1 times longer than high, 1.4 times wider than high.
Lateral line pores (neuromasts of caudal, dorsal,
supranaso-orbital, infranaso-orbital, lateral, mental,
postgular, postspiracle and pregular lines) visible on
body and tail. No glands visible. Snout rounded, slightly
flatted in dorsal profile, rounded in lateral and ventral
profiles; eyes moderate, not part of dorsal profile, directed dorsolaterally, diameter 31% of body height, separated by distance about 2.8 times eye diameter; interorbital
distance 88% of body width; nostrils directed dorsolaterally, closer to tip of snout than eye, internarial distance
60% of interorbital distance.
Spiracle sinistral, short, posterior, opening slightly
above midline at about 5/7 of body length, directed posterodorsally at about 15°, lateral wall longer than medialwall, inner wall confluent with body, wall forming
around aperture.
Tail approximately 2.1 times body length and 3.0
times body width, maximum height 28% of tail length,
maximum tail height at end of first third of tail length.
Tail musculature highest at base, slightly higher thandorsal and ventral fins, gradually tapering to pointed tip,
weakly developed. Tail fins convex and approximately
fusiform. Dorsal fin originates from tail muscle (the posterior edge of the first section) near tail-body junction,tallest just past to midpoint; ventral fin of nearly equal
height throughout its length; dorsal fin height 1.3 times
ventral fin height at highest point. Tail tip V-shaped or
narrowly rounded; vent tube dextral, short, attached toventral fin.
Oral disc large, anteroventral in position, widthabout 0.73 times distance between eyes and approximately 45% of body width, emarginate laterally, withsingle row of truncate marginal papillae in lateral posterior margin of upper lip and wide rostral gap, two rowsof completely marginal papillae on lower lip but bases ofpapillae originate in same line; rostral gap equal inlength of A-1. No lateral submarginal papillae. Labial
tooth row formula 5(2-5)/4(1) and 1:4+4/1+1:3 (following Dubois [1995]); A-1 and A-2 longest, slightly longer

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Table 1. Mean measurements and standard deviation(mm) of eight tadpoles in stage 38 of Gosner (1960).
Mean±SD

Range

TL

27.13±1.07

25.91–27.86BL

8.69±0.13

8.52–8.92

BW

5.83±0.24

5.47–6.30

BH

4.12±0.20

3.81–4.46

TaL

18.45±1.06

17.10–20.43

TH

5.14±0.36

4.82–5.71

DFH

1.58±0.14

1.40–1.72

VFH

1.21±0.14

1.00–1.41E

1.28±0.09

2.07–2.20

SO

3.07±0.14

2.68–3.19SN

1.26±0.13

1.07–1.35

IO

3.62±0.09

3.48–3.75IN

2.16±0.07

2.07–2.30

SS

6.6±0.23

6.24–6.96

ODW

2.63±0.09

2.51–2.74

than all other rows and similar in length, A-2 gap narrow, length of row becoming progressively shorter from
A-3 to A-5 (A-5 22% length of A-2); P-2 and P-3 equalin length and longer than P-1 and P-4 (80% P-2); A-2
gap narrower than P-1. Labial teeth small, blunt anddevoid of cusps; longest at middle of row, teeth becoming progressively smaller from P1 to P4, but equal in P2
and P3, teeth of A1 smaller than A2 and those of A2
equal. Jaw weakly developed. Upper jaw sheath finely
serrate, narrow, width slightly less than width of lower
jaw; lower jaw sheath finely serrate, shallowly Vshaped.
From stage 26 onward, labial tooth row formula stabilizes with very small variation in some specimens.
Larval denticles disappear after disappearance of venttube. Tadpole matching Orton’s Type-IV category(Orton, 1953): oral disc elaborate and spiracle sinistral.
In preserved specimens, dorsal surface of body darkbrown; gut and heart visible ventrally, not visible laterally; anterior half of ventral part of body pale brownwith dark brown spots on sides, and abdominal region
whitish without dark brown spots. Coloration of muscular part of tail similar to that of body in reticulated pattern. Tail fins with small brown spots.
In life, tadpole body coloration dark-brown withhead pale brown. Pupil of eye round, black, andenclosed by narrow sliver ring.
Natural history notes.- Relative to the size of the adult(male 35 mm, female 48 mm), the tadpole is small. If thetadpole had not been reared to adulthood, it would have73

been difficult to believe that the tadpole and frog were of
the same species.
The tadpoles gathered in groups in the small stream,
and were found to swim freely among small stones
where there was no swift water current or side pools thatwere poorly connected with the main permanent stream
at night. During the daytime, the tadpoles hid understones and were rarely seen. The tadpoles were nocturnal and used their sites for grazing, avoiding areas withsilty sediment and fast water flow. The large oral discand numerous blunt rows of teeth suggested a greater
capacity for grazing than for suspension feeding.
The color of the tadpoles camouflaged them against
the small stones and sand on the bottom of the stream
where they spent the day. Although collected from amountain stream, the tadpoles were able to live in theirjars for a long time, sometimes in good condition after
three day’s travel. After 40 days of captivity, the larvae
completed metamorphosis and became froglets similar
to the adult in body shape and coloration. The biggest of
the tadpoles was less than 30 mm in total length.
Froglets were 11.4 mm (10–11.6 mm, n = 5, SD = 0.73)
from snout to vent just after metamorphosis.
The frogs and larvae that were found coexistingwith Rana tormotus in the stream were Paa spinosa

Figure 2. Rana tormotus tadpole at stage 38 (Gosner,1960), (A) Dorsal view, (B) Lateral view, (C) Ventral View,(D) Oral disc.

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Asiatic Herpetological Research, Vol. 11(Daivd, 1875), Rana schmackeri and A. wuyiensis (Liuand Hu, 1975). While the tadpole of R. schmackeri wassimilar to R. tormotus in shape, coloration and generaloral disc characters, the other two appeared conspicuously different.
Although Rana schmackeri also had a small tadpole
belonging to Orton’s Type-IV category (Orton, 1953), it
was larger than the tadpole of Rana tormotus. The total
length of R. schmackeri tadpole was more than 30 mm
from stage 35, while the maximum total length of the R.
tormotus tadpole was less than 30 mm at any later stage.
At stage 36, the body and tail length was 11.1 mm and20.25 mm for R. schmackeri, and 8.36 mm and18.83mm for R. tormotus. At stage 44, the back of R.
schmackeri became greenish, and after metamorphosis,
yellow patches appeared on the back.
The tadpole of Amolops wuyiensis was also of thesmall type, but the ventral suctorial disc easily identified
it. This species was found at the edge of side water-bodies of the stream with little current. The tadpole used thesuctorial ventral disc to adhere to the rocky substrata to
overcome the stream’s water current.
The tadpole of Paa spinosa is of the big type, and isfound alone or in groups of a few individuals at the bottom of pools beside or below cascades and gently flowing parts of the Taohuaxi stream. The oral disc of thisspecies is emarginate, with two rows of marginal papillae, lateral submarginal papillae and a strong beak. The
most conspicuous character of the tadpole is a gray or
black band at the base of tail. The labial tooth row formula is 5(2-5)/3(1).
Discussion of taxonomic status.- Examination of thetadpole of Rana tormotus reveals that it is not of the“Amolops type”, because there is no abdominal sucker
and no ventral or dorsal glands (Yang, 1991). The tadpole of this species is more similar to that of Ranaandersonii (Liu, 1940) and O. schmackeri in shape andoral disc morphology, but the tadpole and froglet justafter metamorphosis is smaller, differently shaped, andwithout green or yellow back patches.
The body and tail length of the Rana andersonii tadpole averaged 12.27 mm (12–12.5 mm, n = 3) and 26.27mm, and the froglet 12.7 mm (Liu, 1940). Four days
after metamorphosis, uneven green patches appeared on
the back (Liu, 1940).
While the larvae are similar in appearance, theadults of odorous frogs and Rana tormotus are remarkably different in morphology, with the sunken ear andabsence of odor gland cells in the skin of R. tormotus
being most the notable characters.
Based on the above evidence, this species should
either be left to Rana as Rana tormotus, or placed in the
new genus as Wurana tormota, although further study isneeded.

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Acknowledgments
We are grateful to Prof. Gu H. Q., Dr. Lu S. Q., Mr. Tang
X. S. and Ms. Zhao H. for their field working help. This
research was supported by China National Nature
Science Foundation and Special Invited Professor Grandof Shenyang Normal University to Dr. Pipeng Li.

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Submitted: 03 March 2006
Accepted: 25 November 2007