Species Description: Dehling JM 2015 A new species of Rhacophorus (Anura: Rhacophoridae) from Gunung Kinabalu, Borneo. Salamandra 51: 1-11
Rhacophorus malkmusi can be distinguished from all other South East Asian species of the genus Rhacophorus by a few key features. It has a relatively short snout-vent length (see description above) with a head that is wider than long and wider than the body. It has low, short vomerine ridges that run between choanae. Along the forearm is a row of small white tubercles without a dermal flap. There is webbing on both sides of the third finger and toe. More specifically, R. malkmusi is most like R. granui from which it was split. The two species can be differentiated because R. malkusi does not have a large, pointy tubercle on the upper eyelid, has small teeth on its vomerine ridges, has a larger interorbital distance, has a shorter head, has a more stub-like snout, has an oblique loreal region, has a small thenar tubercle, and has weaker digit webbing (however, R. granui has highly variable finger webbing and may have a finger with less webbing than R. malkusi's standard formula). Rhacophorus malkmusi is also similar to R. bimaculatus, R. belalongensis, and R. gadingensis. However R. malkmusi can be differentiated because the latter three have longer heads and blue spots on their flanks. Rhacophorus malkmusi can be further differentiated from R. bimaculatus and R. gadingensis because the latter two do not have vomer ridges or teeth. Additionally, Rhacophorus malkmusi can be further differentiated from R. belalongensis and R. gadingensis because the later two have more extensive webbing on the toes and they have shorter interorbial distances. Lastly, the advertisement call of all four species is similar in that they all comprise of 1 – 3 short clicks, but R. malkmusi can be differentiated from R. belalongensis, the only other one analysed, by the latter having a higher frequency of 5800 Hz and longer duration of 70 milliseconds (see Life History for more specifics on R. malkmusi's call; Dehling 2015).
In life, R. malkmusi has an ochre dorsal coloring during the day and light brown at night. The dorsum is patterned with many, evenly spaced, small dark dots and several large, irregularly shaped dark brown spots. Between the eyes and extending to the margins of the upper eyelids is a narrow, dark brown, interorbital band. On each sides of the head is an irregular, large, white infraorbital spot surrounded by a thin dark brown line. There are two smaller white spots below the tympanum. There are crossbars on the dorsal sides of arms and legs that turn from greyish during the day to dark brown at night. The tubercles on the limbs are white. The groin area, anterior and posterior sides of the thighs, ventral sides of the lower leg, anterior side of the foot, and the tops of toes I and III are bright yellow. The other toes are white as is the throat and venter. The ventral surface of the limbs is unpigmented. The ventral surfaces of the hands and feet are brown. The webbing of the digits is greyish. The iris is ruby and lightens to yellow at the margins with a black rim along the outer edge. In preservation, dorsal coloration fades to light grey and all the dark dorsal markings become faintly visible except the interorbital band, which remains distinct. The yellow regions fade but are still visible. The iris becomes bluish grey and the dermal calcars appear shriveled but still apparent (Dehling 2015).
Females have more brown coloration in preservative while males are more grey (Dehling 2015).
Distribution and Habitat
Life History, Abundance, Activity, and Special Behaviors
Eighteen advertisement calls from four males were recorded at 21oC. The calls were produced at irregular intervals lasting between 28 seconds to several minutes and consisted of 1 – 3 very short click notes with a duration of 10 – 36 milliseconds and an energy maximum of 4650 – 5400 Hz. When more than one note was in a call the interval between notes lasted 55 and 168 milliseconds and the notes differed by 50 – 400 Hz. The prominent harmonics were recoreded at 15,000 Hz (Dehling 2015).
Trends and Threats
Possible reasons for amphibian decline
General habitat alteration and loss
Rhacophorus malkmusi was placed into this genus based off of its similar morphological characteristics to other species of the genus Rhacophorus. It was split from R. granui (Dehling 2015).
The species epithet, malkmusi, is in honor of Rudolf Malkmus’ contributions to the knowledge of the amphibians of Gunung Kinabalu (Dehling 2015).
Dehling, J. M. (2015). ''A new species of Rhacophorus (Anura: Rhacophoridae) from Gunung Kinabalu, Borneo.'' Salamandra , 51(1), 1-11.
Sheridan, J. A., Howard, S.D., Yambun, P., Rice, J.L., Cadwallader-Staub, R., Karoulus, A., Bickford, D (2012). ''Novel Behaviors of Southeast Asian Rhacophorid Frogs (Anura, Rhacophoridae) with an Updated Anuran Species List for Danum Valley, Sabah, Malaysian Borneo.'' Tropical Natural History, 12(1), 1-8.
Written by Miko Thule (mthule AT ucsc.edu), University of California Santa Cruz
First submitted 2016-08-08
Edited by Ann T. Chang (2016-08-21)
Species Account Citation: AmphibiaWeb 2016 Rhacophorus malkmusi <http://amphibiaweb.org/species/8386> University of California, Berkeley, CA, USA. Accessed Mar 24, 2018.
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Citation: AmphibiaWeb. 2018. <http://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 24 Mar 2018.
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