Description
Sigalegalephrynus mandailinguensis is a moderately-sized, slender member of the Bufonidae family described from four male specimens (Smart et al. 2017, Sarker et al. 2019). This species exhibits a snout-vent length ranging from 30.6 – 38.0 mm. The head width is slightly larger than the head length and both are about 30% of the snout-vent length. When viewed from above they have distinct snouts that end abruptly at a point with a median keel. In the profile, the snout slopes backward towards the mouth. Their nares are closer to the snout tip than the eyes. The internarial distance is approximately equal to the eye length. The canthus rostralis and the loreal are distinctly concave with the latter being slightly tuberculated. Their dorsolateral eyes are large and protuberant with horizontal pupils. The flat interocular space is longer than the eye length. The tympanum is small but visible and has a moderately developed supratympanic fold. The species lacks parotid glands and cranial crests (Smart et al. 2017).

The forelimb is slender with the forearm length being slightly longer than the hand length. The elongated inner metacarpal tubercle is located on finger I and equal in size to the outer metacarpal tubercle. The fingers have rudimentary webbing and relative finger lengths of I < II < IV < III. The fingertips are truncated but expand into large pads that are approximately equal in size. Each finger has one weakly developed, round subarticular tubercle. Males have glandular nuptial excrescences that are located dorsomedially on Finger I and have keratinized spicules at the base of the finger (Smart et al. 2017).

The hindlimb is also slender with the femur being slightly shorter than the tibia. The foot is only slightly shorter than the tibia. The heels and outer metatarsals lack tubercles, but a prominent elongated tubercle can be found on the inner metatarsals. The relative toe lengths are I < II < III < V < IV and the toes tips are truncated but not expanded. They are approximately the same size as the fingertips. The toes are moderately webbed but with varying amounts of webbing between the toes between individuals. The first phalanx of each toe exhibits a prominent subarticular tubercle (Smart et al. 2017).

The dorsal surface is rough to finely shagreen with some large scattered tubercles and smaller round tubercles. The skin of the forearm also has tubercles. They lack dorsolateral, paravertebral, and occipital folds. The abdomen has small, smooth, round tubercles uniformly distributed (Smart et al. 2017, Sarker et al. 2019).

As of 2019, there are five species of Sigalegalephrynus described that are endemic to Sumatra (Sarker et al. 2019). All adult Sigalegalephrynus can be distinguished from other Sundaland toads (except for Pelophryne) by their smaller size (< 40 mm snout-vent length). Of the Sundaland toads, Sigalegalephrynus most closely resembles the genus Ansonia but can be further distinguished by their lack of mandibular spines. Sigalegalephrynus can be distinguished from Pelophryne by examining Finger I and the nuptial outgrowths. Finger I of Sigalegalephrynus extends past the webbing by two phalanges and the nuptial outgrowth has prominent keratinized spicules (Smart et al. 2017).

Within the Sigalegalephrynus genus, S. mandailinguensis can be distinguished from the other species by their size (adult males > 30 mm), rougher tuberculate dorsal skin, and distinct color patterning (Smart et al. 2017, Sarker et al. 2019). More specifically, from Sigalegalephrynus burnitelongensis, S. mandailinguensis is distinguished by having dorsal crossbars on the limbs, a mucronate shaped snout, lanky limbs, tuberculated skin, an hourglass marking on the dorsum. From Sigalegalephrynus gayoluesensis, S. mandailinguensis is differentiated by having a mucronate shaped snout, tuberculated skin, an hourglass marking on the dorsum, a shorter call with fewer notes but more notes per second, and a lower dominate frequency. From Sigalegalephrynus harveyi, S. mandailinguensis can be distinguished by having a larger snout-vent length, moderately expanded fingertips, black tipped tubercles, black nuptial pads, distinct white loreal spot, lacking an outer metacarpal tubercle (Sarker et al. 2019). From S. minangkabauensis, S. mandailinguensis is differentiated by having a distinct tympanum, tuberculated skin, larger black and white tubercles posterior to the tympanum, prominent finger pads, subarticular tubercles under Fingers III and IV and Toes IV and V, less webbing of the fingers, and incomplete webbing between Toes I and II (Smart et al. 2017, Sarker et al. 2019).

In life, S. mandailinguensis is cryptically colored with distinct patterning. The dorsal coloration is white and brown. On either side of the head, a whitish band runs along the upper jaw just below the eye from the edge of the snout to the base of the head. This white band exhibits brown spots in the lore area and under the eye. The dorsum has a beige hourglass-like marking from snout to sacral vertebrae. Inside this hourglass pattern, there is a dark band above the eyes that join medially and then extends to the sacrum in an interrupted track. Another dark band borders the hourglass pattern beginning at the snout, through the eye, along the flanks to the top of the humeral-ulnar joint and into the groin area. Two small dark brown stripes can be seen on either side of the pubic junctions. Dorsolateral to the sacral and iliac joints are dark brown spots. The dorsal side of the limbs exhibit alternating dark and light brown bands. The abdomen and ventral surfaces of the head show yellowish-white with black splotches. The chest and ventral surface of the limbs exhibit a pinkish orange coloration with scattered yellowish dots. The finger and toe tips are also pinkish orange but lack the yellowish dots. The nuptial pads are dark brownish. The irises are bright gold with black reticulations. In preservative, the dorsal hourglass marking fades and the venter becomes whitish gray with brown splotches (Smart et al. 2017).

The webbing of the fingers and toes vary slightly between individuals with webbing formulas for the hands of all the individuals in the species description being I [1¾ – 2], [2 – 2], [2 – 2], [1¾ – 2] II [1¾ – 2½], [1¾ – 2½], [1¾ – 2½], [1¾ – 2½] III [2⅓ – 2], [2⅕ – 2⅕], [2¾ – 2], [2½ – 2¼] IV and a webbing formula for the feet of I [0 – 1⅓], [0 – 1], [1 – 1½], [0 – 1¼] II [0 – 1¾], [1 – 2], [1 – 2], [1 – 2] III [2 – 2⅕], [1⅓ – 3], [1½ – 2⅓], [1 – 2¾] IV [2⅕ – 1⅔], [2⅔ – 2], [2⅔ – 1⅔], [2⅔ – 1¾] V) (Smart et al. 2017).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Indonesia

View distribution map in BerkeleyMapper.

Sigalegalephrynus mandailinguensis is a microendemic found on the slopes of Gunung Sorikmarapi in Batang Gadis National Park, in the Sumatera Utara Province. This species has only been found at elevations between 1297 - 1383 m. Gunung Sorikmarapi is a stratovolcano with densely vegetated rainforest habitat (Smart et al. 2017).

Life History, Abundance, Activity, and Special Behaviors
Sigalegalephrynus mandailinguensis is nocturnal and can be found in various habitats. One individual was found inactive below ground on a cave wall, 2 m from the opening, while others were found perched on liana (large vine-like vegetation) between 0.5 – 3.0 m above ground (Smart et al. 2017).

Nocturnal vocalization behavior has been described from two male individuals perched on liana at 2 and 3 m above ground. These advertisement calls start with low-amplitude ticks that get progressively louder until a uniform pulse rate is reached. The main calling period is described as a series of tonal pulses that coalesce into regularly placed high-pitched (3.4 ± 0.04 Hz) ticks that last a total of ~15 s. Each pulse lasts 29 ± 4 ms with ~12 ± 9 ms breaks between them organized into discrete series that repeat ~6 times/s (Smart et al. 2017).

Trends and Threats
As of 2020, S. mandailinguensis has an IUCN Red List status of “Data Deficient” (IUCN 2018). However, recent analysis of area of occupancy and extent of occurrence suggest that all Sigalegalephrynus species meet the criteria necessary to be listed as “Endangered.” Threats to these amphibians are compounded by the increasing spread of zoonotic diseases, over-harvesting, habitat alteration, and climate change. The most pressing threat to Sigalegalephrynus is the high rate of deforestation at the borders of their habitat for agriculture and natural resource extraction. All Sigalegalephrynus species have extremely range limited and are highland forest specialists with habitat suitability mostly based on elevation (64.5%) and land cover (7.1%) (Sarker et al. 2019).

Possible reasons for amphibian decline

General habitat alteration and loss
Habitat modification from deforestation, or logging related activities
Intensified agriculture or grazing
Mining

Comments
The species authority is: Smart, U., Sarker, G.C., Arifin, U., Harvey, M.B., Sidik, I., Hamidy, A., Kurniawan, N., Smith, E.N. (2017). “A new genus and two new species of arboreal toads from the highlands of Sumatra with a phylogeny of Sundaland toad genera.” Herpetologica, 73(1), 63 - 75.

Maximum Likelihood and Bayesian Inference of 12S and 16S mtDNA and NCX1 and CXCR4 nuclear DNA supported the monophyly of Sigalegalephrynus (Smart et al. 2017). Within Sigalegalephrynus, Maximum Likelihood and Bayesian Inference analyses of 16S mitochondrial rRNA showed significant divergence between northern and southern populations with S. mandailinguensis, S. minangkabauensis and S. harveyi making up the southern clade. The northern clade consists of S. burnitelongensis and S. gayoluesensis. Sigalegalephrynus mandailinguensis is sister to the clade composed of S. minangkabauensis and S. harveyi (Sarker et al. 2019).

The genus name Sigalegalephrynus is derived from “Sigale Gale,” which are life-sized wooden puppets used by the indigenous Batak people of the Toba region in Sumatera Utara. The Sigale Gale are used in special funeral ceremonies to appease the spirits of individuals who pass away without surviving children. Like Sigale Gale, Sigalegalephrynus have gangling arms and hands and a woody appearance (Smart et al. 2017).

The species epithet, “mandailinguensis” is derived from the Mandailing Batak people who inhabit the same region where the species can be found (Smart et al. 2017).

Habitat suitability modeling has found 17 mountains in the Barisan Mountain range with conditions that could support Sigalegalephrynus habitat requirements, making it is possible that 12 populations of Sigalegalephrynus have not yet been discovered (Sarker et al. 2019).

References

IUCN SSC Amphibian Specialist Group. (2018). ''Sigalegalephrynus mandailinguensis''. The IUCN Red List of Threatened Species 2018: e.T114107654A114107665. https://dx.doi.org/10.2305/IUCN.UK.2018-2.RLTS.T114107654A114107665.en. Downloaded on 02 May 2020.

Sarker, G.C., Wostl, E., Thammachoti, P., Sidik, I., Hamidy, A., Kurniawan, N., Smith, E.N. (2019). ''New species, diversity, systematics, and conservation assessment of the Puppet Toads of Sumatra (Anura: Bufonidae: Sigalegalephrynus).'' Zootaxa, 4679(2), 365-391. [link]

Smart, U., Sarker, G.C., Arifin, U., Harvey, M.B., Sidik, I., Hamidy, A., Kurniawan, N., Smith, E.N. (2017). ''A new genus and two new species of arboreal toads from the highlands of Sumatra with a phylogeny of Sundaland toad genera.'' Herpetologica, 73(1), 63-75. [link]

Species Account Citation: AmphibiaWeb 2020 Sigalegalephrynus mandailinguensis: Mandailing Puppet Toads <https://amphibiaweb.org/species/8597> University of California, Berkeley, CA, USA. Accessed May 5, 2021.

Citation: AmphibiaWeb. 2021. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 5 May 2021.

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