Description

Pulchrana guttmani is a moderately large frog in the Pulchrana signata complex. Initially the species was only known from one persevered female specimen. The species was not seen between 1993 and 2020 when four more specimens were collected. P. guttmani has a snout-vent-length of 72.0 - 82.0 mm (Brown 2015, Pitogo and Saavedra 2021). Its head is a shade more slender than the broadest region of the body and it has a short, rounded snout. The canthus is very slightly angled and curved at the ends. Pulchrana guttmani has a loreal region that caves in and a prominent supralabial region that almost appears as if it is filled with air. Its nares, which appear toward the rostral end of the snout, flare to the sides and are spread apart from one another by about the same distance as the eyes are spread (internarial distance - 6.7 mm, interorbital distance - 7.0 mm). It has a level interorbital region and rostrum, although its eyes protrude from the orbits. When viewed from a ventral position, the eyes do not appear to extend laterally past the jaw. Pulchrana guttmani has pupils with a greater horizontal than vertical radius. Its tympanum and tympanic annulus are clearly visible and have a smaller circumference than the eye. The supratympanic ridge is only slightly visible. Its choanae are big but cannot be viewed from the ventral aspect as they are blocked by the maxilla (Brown 2015).

The skin on the dorsum, sacrum, and back of the skull is smooth, as is that on the limbs, belly, and dorsal sides of the hands and feet. The posterior portion of the eyelids, facial regions surrounding the orbits, and the region superior to the mouth all appear finely grained. The skin posterior and superior to the tympana appears grained, although not as finely as the aforementioned regions. The ventral femoral surface and cloacal skin is even less finely grained (Brown 2015).

The humeral and forearm are both slim. Pulchrana guttmani has unwebbed fingers with large, distal disks and relative lengths of III > IV > I ≃ II. The terminal disks on the fingers have a wrinkle that divides the dorsal and ventral surfaces. The articular surfaces of the third and fourth digits have a superficial cutaneous flap. It has very big subarticular tubercles on all four fingers and at the articulation of the hand with the forearm. Pulchrana guttmani also has very big metacarpal tubercles and even bigger supernumerary tubercles that are found on all four fingers (Brown 2015).

Pulchrana guttmani has slim hind limbs with femoral and tibial lengths that are nearly identical. It has long, thickly webbed toes with terminal disks that are not as large as those of the fingers. The relative toe lengths are IV > III ≃ V > II > I. The subarticular tubercles of the foot are very large, as are the subarticular tubercles of the toes. Its inner metatarsal tubercle is bigger than all the subarticular tubercles while its outer metatarsal tubercle is little (Brown 2015).

Pulchrana guttmani is most similar to Pulchrana grandocula and Pulchrana melanomenta, which are part of the Pulchrana signata complex. All organisms within the complex have slim bodies with smooth skin, a second forefinger that is shorter than the first, large terminal disks on the digits with wrinkles that separate the dorsal and ventral halves, two metatarsal tubercles that touch on their medial surfaces or are very close to one another, and a moderate snout-vent-length from 30 - 70 mm in adults. Pulchrana guttmani is differentiated from other species in the Pulchrana signata complex by the morphology of its phalanges, coloration, and biochemical characters (Brown 2015).

Pulchrana grandocula is the most similar species to Pulchrana guttmani. The two are distinguished by P. guttmani's larger terminal disks, supernumerary tubercles, and medial metacarpal tubercles. The two are also differentiated by their different colorations. Whereas P. grandocula has brown, white, and black spotting on its sides and khaki colored ventral surfaces, P. guttmani, in preservative, has dark black sides, a brown venter and throat, and space gray ventral surfaces on its hands and feet. Pulchrana guttmani also has a shorter snout than P. grandocula (Brown 2015). Finally, P. guttmani has a larger body size than P. grandocula (Pitago and Saavedra 2021).

Pulchrana guttmani can be differentiated from Pulchrana melanomenta by its series of dorsolateral wrinkles and its dorsolateral coloration (brown dorsally and black on the sides). Moreover, P. melanomenta has a black throat and dark transverse striations on its limbs, while P. guttmani has a brown throat and no striations (Brown 2015).

In life, individuals have a dorsal coloration of bright yellow to gold-brown. There are small dark spots, a few roughly round blotches, and two straight dorsolateral stripes starting at the tip of snout and continuing, uninterrupted over to the sacrum. The stripes are golden yellow bordered by black. The tympanum is dark brown and is surrounded by dark skin, making it indistinct. The dark brown flanks have irregular golden brown blotches that extend to the bluish belly and throat. There are inconspicuous dark transverse bars on the limbs. The ventral surfaces of the hands and feet, including the digits, can be light or dark (Pitago and Saavedra 2021).

In preservative, the dorsal regions of the head and body in are chocolate-brown with faded dark circular dots and several non-uniform charcoal splotches. It has two charcoal longitudinal lines that stretch from the supratympanic area to the sacrum; these lines do not cross over the eyelids or extend to the canthus. The sides of the head and snout are black. The area above the lips is charcoal but lightens in color closer to the chocolate-brown tympana. The region where the forelimbs articulate with the body is black, as are most of the lateral areas on the body. The venter is the same chocolate-brown color as the dorsum but also presents khaki colored splotches. Pulchrana guttmani has chocolate-brown dorsal surfaces on both pairs of limbs with some lighter brown spots and no crossbands that traverse the limbs. The dorsal surfaces of the hands, feet, and toe webbing are a lighter shade of brown than the dorsum. The dorsal half of the terminal disks on the fingers and toes are charcoal and the superficial cutaneous flap that covers the articulation of fingers III and IV is khaki. The ventral hind limbs, upper arm, and throat are all chocolate-brown. The ventral surfaces of the forearm, fingers, toes, hands, and feet are charcoal. The ventral portions of the terminal disks are also charcoal. The superior cloacal region is charcoal and the inferior portion is chocolate-brown with some spots of a lighter shade of brown. The posterior femur has several khaki spots (Brown 2015).

The specimens found in 2020 differed slightly in coloration from the original preserved specimen in that the transverse tibial bars were absent in the preserved individual and black flanks were present. It's unclear if this is due to preservative or if these are variable traits (Pitago and Saavedra 2021).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Philippines

View distribution map in BerkeleyMapper.

The first specimen of P. guttmani was found at Mount Busa in the southern part of Mindanao Island, Philippines at an elevation of 1200 m (Brown 2015). Four more individuals were found north of the type locality at a high-elevation montane forest stream, at 1432 m, on the north slope of Mount Busa at Bulul Tbotu, Lake Sebu, South Cotabato. As of 2021, a more detailed range of the species is unknown, however, it is believed to be restricted to high elevations (Pitogo and Saavedra 2021).

Life History, Abundance, Activity, and Special Behaviors

The holotype of P. guttmani was found in soil beneath a 4 - 5 meter stone. It was collected in an early evening of April, during the dry season, although rain still occurred every few days during the period that the author made the discovery. The author suspected the species to be a habitat specialist (Brown 2015).

The 2021 individuals were found in the late evening of early September, perching on riparian vegetation 2 m above a high-elevation stream. The small, cool, fast-flowing stream was hard-to-access, about 3 - 4.5 meters wide, and had thick vegetation along the banks (Pitogo and Saavedra 2021).

Habitat vegetation consisted mostly of shrubs of the genera Elatostema, Asplenium, Angiopteris, Impatiens, Schismatoglottis, and Plenasium. The tree canopy covered 80 - 90% at a hight between 10 - 15 m (Pitogo and Saavedra 2021).

Trends and Threats

Extensive efforts to collect specimens of P. guttmani between 1993 and 2020 were unsuccessful. When the species was found again, researchers initially thought they were individuals of P. grandocula. The authors concluded that P. guttmani is a high-elevation specialist with little to no tolerance to disturbance. This explains the species' absence from the type locality as that location was heavily logged and converted to abaća farms in the early 1990's, around the time the type specimen was collected. Remnant populations could still be present in areas of Mount Busa that have been logistically challenging to survey (Pitogo and Saavedra 2021).

Although the new locality of P. guttmani is within in a proposed strict protection zone for the Allah Valley Watershed Forest Reserve, the site still experiences anthropogenic threats, including slash-and-burn agriculture (Pitogo and Saavedra 2021).

The authors who found the 2020 specimens recommend an updated IUCN Red List status to “Near Threatened” for the species due to its restricted distribution and rarity in disturbed areas. The authors also recommend extensive surveys throughout Mindanao at higher elevations (Pitogo and Saavedra 2021).

Possible reasons for amphibian decline

General habitat alteration and loss
Habitat modification from deforestation, or logging related activities
Subtle changes to necessary specialized habitat
Habitat fragmentation

Comments

The species authority is: Brown, R.F. (2015). "A new species of Stream Frog of the genus Hylarana from the mountains of southern Mindanao Island, Philippines." Herpetologica 71(3): 223-233.

Pulchrana guttmani is the basal species to clade that includes Pulchrana melanomenta, Pulchrana grandocula, and Pulchrana similis (Brown 2015).

Pulchrana guttmani is a member of the Pulchrana stignata complex. It was originally described as Hylarana guttmani but was transferred to Pulchrana due to the partition of Hylarana by Oliver et al. (Brown 2015; Oliver et al. 2015).

The holotype was collected 22 years before its description was published and assumed to be a specimen of P. grandocula (Brown 2015).

Over the years, the holotype has been labelled as Rana grandocula and Hylarana grandocula (Brown 2015).

The description of this species marks the first instance that two species of the Pulchrana stignata complex have been found in sympatry. Brown (2015) suggested two possible methods that this may have evolved. The first is that P. guttmani evolved in isolation on a paleoisland precursor that collided with other paleoislands to form Mindanao Island. The second is that the species evolved in an isolated high-elevation range, which is the presumed manner in which species of Philippine Platymantis and Limnonectes evolved.

Pulchrana guttmani is named after Sheldon I. Guttman, a researcher who made many discoveries in the field of amphibian biochemical systematics (Brown 2015).

References

Brown, R.F. (2015). ''A New Species of Stream Frog of the Genus Hylarana from the Mountains of Southern Mindanao Island, Philippines.'' Herpetologica, 71(3), 223-233.

Oliver, L.A., Prendini, E., Kraus, F., and Raxworthy, C.J. (2015). ''Systematics and biogeography of the Hylarana frog (Anura: Ranidae) radiation across tropical Australasia, Southeast Asia, and Africa.'' Molecular Phylogenetics and Evolution, 90, 176-192.

Pitogo, K.M.E., Saavedra, A.J.L. (2021). "Rediscovery of Guttman’s Stream Frog, Pulchrana guttmani (Brown, 2015) in the mountains of southern Mindanao, Philippines." Herpetology Notes, 14: 163-167

Species Account Citation: AmphibiaWeb 2021 Pulchrana guttmani <https://amphibiaweb.org/species/8364> University of California, Berkeley, CA, USA. Accessed Nov 21, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 21 Nov 2024.

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