Description
Leptobrachella neangi was described based on two adult female species with snout-vent lengths of 35.4 and 36.3 mm. The holotype has a longer, rather than wide head shape with a bluntly rounded snout and obtuse point in the dorsal view. The snout protrudes over the lower jaw, and the nares project closer to the snout than the eye. Like the snout, the canthus rostralis has a blunt roundedness, while the lores slope slightly concave. The eye diameter is about 79% of the snout’s entire length. The pineal ocellus is absent. The supraympanic ridge is raised above the posterior corner of the eye at the axillary gland and extends to the ventral margin of the supratympanic fold to the level of the axilla. The large inner palmar tubercle and smaller palmar tubercle are very distinct from one another. The species has no finger webbing or fringes. The fingers are rounded and have relative lengths of I < II < V < III < IV. The tibia is about 53% of the snout-vent length. The tibiotarsal articulation extends past the anterior edge of the eye when the hind limb is adpressed along the body. The oval-shaped inner metatarsal tubercle is pronounced, while the outer metatarsal is absent. The toe tips all have the same width with a relative length order of I < II < V < III < IV. The subarticular tubercles are absent but there are dermal ridges on the II, III, and IV toes. The webbing is not apparent, and lateral fringes are absent. There are small, random-patterned bumps and ridges on the dorsal surface of the skin. The ridges are more evident on the dorsal surfaces of the limbs in life, but in preservative, the limbs are smooth with microscopic tubercles. The ventral surfaces of the skin are smooth. The pectoral and femoral glands are ovular in shape. The humeral gland is raised with the ventrolateral glandular line being absent. The pupil is vertical and elliptical (Stuart and Rowley 2020).

Leptobrachella neangi is placed in the genus Leptobrachella because of its distinctive small body size, rounded fingertips, presence of an elevated thenar tubercle that is not continuous with the thumb, presence of macro glands, vomerine teeth being absent, tubercles on eyelids, and a vertical white bar on snout tip. However, L. neangi differs from other Leptobrachella because of these main characteristics: an absent distinct dorsolateral glandular line and dark inguinal blotch, a transparent purplish-grey color in life, while creamy white color in preservative, black coloration beginning at the tympanum and extending to supratympanic fold, a coppery-orange color on the pupil that fades to gold, and small, unpredictable bumps and ridges on the dorsal surface (Stuart and Rowley 2020).

Leptobrachella neangi differs in coloration from its two closest relatives L. fuliginosa and L. melanoleuca by the absence of a black inguinal patch and a distinct bicolored iris, which is present in both the other species. Additionally, L. neangi has an immaculate, transparent purplish in life, and white in preservative belly while L. fuliginosa has a dusted brown belly and L. melanoleuca has a mottled belly (Stuart and Rowley 2020).

Other closely related Cambodian species that L. neangi differs from are L. melica and L. isos. Leptobrachella neangi differs from L. melica by having a transparent belly (purplish-gray in life, and white in preservative), while the L. melica has a pale pink with dark blotches and white speckling on its belly in life. Additionally, L. neangi does not have a distinct ventrolateral glandular ridge and a black inguinal blotch like L. melica. Leptobrachella neangi differs greatly from L. isos by having a larger snout-vent length in the two female specimens found (35.4 - 36.3 mm versus 28.6 - 31.5 mm respectively), while also lacking the ventrolateral glandular ridge. Lastly, L. neangi has an irregular pattern of bumps and ridges, while L. isos have highly tuberculate ones (Stuart and Rowley 2020).

In life, the dorsum is an irregular light and dark brown color. The tips of the bumps and ridges have an orange color. On the top of its head, there is an indistinct, X-shaped black marking. The head and lateral surfaces of the frog are beige or light grey. Also, on the body, there is an irregular pattern of black spots. On the tips of the tubercles, there is a white or pinkish color present. There is a black botch visible below the canthus with a black oblique bar extending from the canthus to the anterior corner of the eye, until the posteroventral margin to the joint between the two bones (commissure) of the jaw. The supratympanic ridge is orange, with a black streak. The entire tympanum and upper lip are also black in color. The dorsal and posterior areas of the upper arm, elbow, fingers, toes, and lateral tibiotarsus are orange. The dorsal areas of the upper arm, hindlimbs, fingers, and toes are black with transverse barring, making the dorsal side a darker black, with the lateral side becoming a dark brown. The ventral areas of the throat, chest, and belly are a light purple-grey, with the belly being immaculate and transparent. The ventral hind limbs are dark purplish-grey. The throat has dark brown mottling, having a higher concentration near the lateral margin (Stuart and Rowley 2020).

In preservative, L. neangi’s distinct orange and pink colors are lost. The dorsal surfaces became a uniform medium-brown color with some black. The dorsal side of the appendages has transverse barring. The black X-shaped marking on its head becomes less visible while the other black markings on its head and body remain apparent. The throat, chest, and belly are a creamy white color, while the throat is a flecked medium brown. The ventral appendages are also a medium brown with a creamy white speckling. The macroglands remain a creamy white color (Stuart and Rowley 2020).

Because only two female specimens were used to describe the species, a full profile of variation cannot be assessed at this time, however, the paratype has more raised white spots on the dorsum and a greater width of the digits (Stuart and Rowley 2020).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Cambodia

View distribution map in BerkeleyMapper.

Leptobrachella neangi was the first species of its genus to be described in the Cardamom Mountains in South Cambodia, adjacent to southeastern Thailand. The holotype was collected at an elevation of 1,283 m in the Cardamom Mountains of Cambodia by Thy Neang and Meanrith Kris. The paratype was found on a steep plateau approximately 300 m from the stream in Kampong Speu Province, Cambodia (Stuart and Rowley 2020).

Life History, Abundance, Activity, and Special Behaviors

The specimens were collected on a five-night herpetology survey in December 2010 in the Cardamom Mountains of southwestern Cambodia, which is adjacent to Thailand. Both the holotype and paratype were collected on non-rainy nights in the submontane evergreen forest. Leptobrachella are usually found by flowing streams, but these individuals were found farther from the water on the ground near a dirt logging road (Stuart and Rowley 2020).

The paratype had a mature ova, while the holotype was still developing its ova during the dry season (Stuart and Rowley 2020).

Leptobrachella neangi shares its habitat and was found 400 m away from the holotype of the colubrid snake, Lycodon zoosvicortiae. Other species of amphibian and reptile species that are found nearby include Ichthyophis cadamonesis, Philautus cadamonus, and Dibamus dalaiensis (Stuart and Rowley 2020). .

The species' call and larval forms for the Leptobrachella were not known at the time of the original description (Stuart and Rowley 2020).

Comments

Genetic analysis was conducted on the 16S rRNA mitochondrial gene from 246 individuals using Bayesian Inference. The analysis showed that L. melanoleuca and L. fuliginosa are the closest phylogenetic relatives to L. neangi. Bayesian analysis using 1,533 aligned characters (at three nuclear genes) showed that L. neangi is sister to L. melanoleuca while analysis of 2,398 aligned characters (two mitochondrial and three nuclear genes) showed that L. neangi is sister to the clade formed by L. fuliginosa and L. melanoleuca (Stuart and Rowley 2020).

The species epithet is to honor the collector of the species, Mr. Thy Neang, of Cambodia’s Wild Earth Allies. His expertise and contribution to fieldwork with amphibians and reptiles is unparalleled in Cambodia (Stuart and Rowley 2020).

An unspecified Leptobrachella metamorph was collected at an elevation of 780 m at mountain stream in the Phnom Aural Wildlife Sanctuary in Cambodia, almost 130 km from L. neangi’s locality, prior to this species description. However, it is unclear if this specimen is a member of this species or another undescribed Leptobrachella species because of the lack of DNA to test and difficulty of comparing morphology at different developmental stages. Because other Leptobrachella species are often found in sympatry to each other, it would not be surprising if this metamorph was a different species that is sympatric with L. neangi (Stuart and Rowley 2020).

Leptobrachella neangi is the third named species from Cambodia, preceded by L. melica and L. isos (Stuart and Rowley 2020).

References

Stuart, L., B, Rowley J.L.J. (2020). ''A new Leptobrachella (Anura: Megophyridae) from the Cardamom Mountains of Cambodia.'' Zootaxa, 4834(4), 556-572. [link]

Species Account Citation: AmphibiaWeb 2021 Leptobrachella neangi: Cardamom Leaf-litter Frog <https://amphibiaweb.org/species/9251> 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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