Description
Litoria aplini is a relatively small pelodryadid frog from Papua New Guinea that was described from four male specimens. The snout vent length range is 30 - 35 mm and the head is slightly longer than wide. The snout is moderately broad, truncated with an angular tip in the dorsal view and steeply sloping in the lateral view. The nostrils are closer to the tip of the snout than the eyes. The canthus rostralis is rounded and distinctly curved. The loreal region is slightly concave and steep. The internarial distance is larger than the distance between the nostrils and the large eyes, which are prominent in both the dorsal and ventral view. The tympanum is prominently raised above the surrounding skin and slightly less than half the size of the eye diameter. The supratympanic fold is thick. The skin on the dorsal and lateral surfaces is finely granular while the ventral skin is coarsely granular with tubercles around the vent and on the thighs. There is a series of low tubercles along the outer margin of the forearm from the disc of the 4th finger to the elbow. The palm has many prominent turbercles. The moderately short fingers have lateral fringes, extensive webbing, and a relative finger length of 3 > 4 > 2 > 1. The subarticular tubercles of fingers 3 and 4 are bilobed. The discs on fingers are prominent with a mean diameter of 1.58 mm and circum-marginal grooves. A nuptial pad can be found on the first finger that is narrow on the proximal end and widens on the distal end. The hind limbs are moderately long with a distinguishing characteristic of the species being the presence of crenelated folds along the tarsi's outer margin. There is a patch of low tubercles on the heel along with a series of tubercles along the outer margin of the tarsus from the fifth toe to the heel. The inner metatarsal tubercle is bean shaped and elongated. There is no outer metatarsal tubercle. The extensively webbed toes have a relative toe length of 4 > 5 = 3 > 2 > 1 and partially or completely bilobed subarticular tubercles on toes 2 - 5. Like the fingers there are large discs on the toes with circum-marginal grooves that have a mean diameter of 1.43 mm (Richards and Donnellan 2020).

DIAGNOSIS:

Litoria aplini is most morphologically similar to L. iris, L. majikthise, L. ollauro, L. richardsi, L. singadanae, and L. verae. Litoria aplini can easily be distinguished from the first four species by the presence of crenelated skin on the foot, the green to brown dorsal coloration, golden yellow coloration in the posterior ventral area, and the blue brown mottling in the inner hidden ventral surfaces of the thighs. Additionally, L. aplini can be distinguished from L. richardsi and L. singadanae by its larger size. And lastly, L. aplini can be distinguished from L. verea by the golden yellow ventral coloration as opposed to the orange coloration of L. verea (Richards and Donnellan 2020).

COLORATION:

In life, the dorsal coloring is green to brown with fluctuating amounts of each color depending on the time of day. However, the head is mostly light green with flecks of darker green. The tympanum is also light green. The dorsal surface of the limbs has large patches of green mottling and small flecks of dark brown. The anterior ventral surface is white and turns to grey along the lateral edges. There are also small, dark flecks of brown along the ventral edge of the lower jaw. The posterior surfaces of the belly, the axillia, and the ventral surfaces of thighs are golden yellow in color with the hidden surfaces of the thighs being mostly blue with dark brown mottling. The tubercles on the ventral surfaces of thighs, the heel, and the area around the vent are ivory in color. The crenulated skin fold on the foot is white. The nuptial pads are brown. The iris is pale grey with dark-brown reticulations and an inner rim that is pale gold. In preservative, the green markings become blue, the beige-brown background color becomes grey, the blue on the hind limbs becomes darker, and the golden-yellow patches fade to cream (Richards and Donnellan 2020).

VARIATION:

The four male specimens used to describe the species varied in the extent of green in their dorsal markings and the patterning of the brown blotches surrounding the golden-yellow patch near the vent (Richards and Donnellan 2020).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Papua New Guinea

View distribution map in BerkeleyMapper.

Litoria aplini is only known from one location in Papua New Guinea in the northern slopes of the central cordillera. The environment there is mostly hill forest with a limestone substrate and little standing water at elevations of 940 m a.s.l. (Richards and Donnellan 2020).

Life History, Abundance, Activity, and Special Behaviors
The specimens were found in trees next to a dry gully with some scattered water pools, however, no eggs, larvae or females were found (Richards and Donnellan 2020).

Their coloration changes with the time of day, being darker at night (Richards and Donnellan 2020).

Males can be heard calling from 5 m high perches that overhang small, isolated pools of water (Richards and Donnellan 2020).

At air temperatures of 23.7°C, the call consists of a finely pulsed buzzed note lasting 0.026 – 0.062 s, followed by 1 - 7 shorter multi-pulsed clicks, which lasts 0.005–0.020s at a rate of 1.26 calls/s and having a dominant frequency of 2150 - 3336 Hz (Richards and Donnellan 2020). For more call information, please see Richards and Donnellan (2020).

Comments

PHYLOGENETIC RELATIONSHIPS:

Maximum Likelihood and Bayesian Inference analyses of ND4 mtDNA indicate that L. aplini is sister to the clade composed of L. iris and L. majikthise (Richards and Donnellan 2020).

ETYMOLOGY:

The species epithet, “aplini”, is in honor of the late Dr. Ken Aplin, who greatly contributed to New Guinean herpetology and was a friend and collaborator of the authors of the species description (Richards and Donnellan 2020).

References

Richards, S.J., Donnellan, S.C. (2020). "Litoria aplini sp. nov., a new species of treefrog (Pelodryadidae) from Papua New Guinea." Records of the Australian Museum 72(5), 325–337. [link]

Species Account Citation: AmphibiaWeb 2022 Litoria aplini: Aplin’s Treefrog <https://amphibiaweb.org/species/9294> University of California, Berkeley, CA, USA. Accessed Apr 19, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 19 Apr 2024.

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