Description
Kaloula picta is a stout-bodied painted toad with females averaging a snout-vent length of 35.0 – 56.5 mm and males averaging 32.8 – 51.0 mm (Inger 1954). The head is wider than it is long. Kaloula picta has a short snout with a distinctly rounded canthus rostralis. The eyes are large with vertical pupils. The diameter of the eyes is the same length as the distance between the eye and apex of the snout. A supratympanic fold and transverse occipital fold are present. The skin either obscures or mostly covers the tympanum, which has a diameter one half to three quarters of the eye. Both males and females have mostly smooth skin with occasional scattered tubercles. Females have smooth ventral skin. A glandular ridge runs from the posterior corner of the eye to the groin. However, this ridge may not be present if a specimen has not been preserved properly. The fingers are free of webbing whereas webbing between toes extends to roughly one-third the length of the toe. The relative finger lengths are 3 > 2 = 4 > 1 (Taylor 1966). The digit tips are rounded and are not as wide as the penultimate segment digits (Inger 1954). The hind legs are robust, and are longer than the length of the body. Tubercles can be found on the base of each finger, on metatarsals and metacarpals, and the subarticular regions aid in digging. The relative toe length is 2 > 3 > 1 > 4 > 5. A vocal sac with slit-like opening is located just under the mandibles in males (Taylor 1966).

Within the genus Kaloula, a series of steps can be used to identify a Kaloula picta speciemen. Only three Kaloula species (K. picta, K. conjuncta and K. rigida) have the combination of metacarpal tubercles, no yellow coloration on the thigh and the axilla, a lower leg containing a crossbar that is aligned with the thigh when the leg is fixed, and belly glands in males. Among K. picta, K. conjuncta and K. rigida, K. picta can be differentiated by having an inner metatarsal tubercle that is the same size or longer than the first toe (Inger 1954). A further differentiation can be made between K. picta and K. conjuncta because K. picta does not have any dilation of the digits in males or females. Additionally, K. picta differs from K. rigida in the fact that K. picta exhibits no sexual dimorphism in webbing, whereas K. rigida does (Taylor 1966).

In life, K. picta is olive-brown to dark brownish-red in color. It has a dark mid-dorsal pattern and is dark beneath the lateral glandular fold. The limbs are ground-like in color. The legs have a single dark crossbar on the thigh and lower leg. In preservative, K. picta is brown to violet-gray in color (Inger 1954).

There is variation in the dark band on the thigh that continues over the knee on some individuals. There is also variation in the dark crossbar on the lower leg where it can be found to run completely over the leg, not extend all the way, or be broken into spots across the leg. The tibio-tarsal joint may or may not have a large dark spot. The thighs of K. picta may or may not have stratified light and dark areas. These stratified areas may either be well-defined and continuous from behind the knee to the vent or the dark stratum does not reach the vent at all (Inger 1954).

In terms of sexual dimorphism, there are several differentiating traits. First, females are larger than males. Second, males have green vocal sacs on their chin, and in breeding males the throat shifts to a dark yellow green. In females, the throat is a cream color with no vocal sac. Lastly, males have a gathering of single-celled epidermal glands called a “belly gland” on the ventral surface of the body that is along the abdomen region. This collection of cells can take up one-half to five-sixths of the region (Inger 1954).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Philippines

	View distribution map in BerkeleyMapper.
	View Bd and Bsal data (2 records).

Kaloula picta is endemic to the Philippines and is found between 0 - 150 m ASL on all major Philippine islands (Taylor 1966; Inger 1954). The species is terrestrial and makes use of many habitats, including (but not limited to) moist shrub-land, agricultural land, lowland forest, urban water storage areas, pasture land, irrigation ditches, or almost any other disturbed land with a small amount of standing water (Inger 1954). Due to their preference for relatively open land, it is likely that the conversion of land for human use has increased their prevalence (Blackburn et al. 2015).

Life History, Abundance, Activity, and Special Behaviors
Kaloula picta is common, especially after heavy rains (Inger 1954; Taylor 1966). Adults are nocturnal and semifossorial, burrowing in leaf litter or soil when not seeking mates or hunting (Inger 1954). They dig with kicking motions from their hind feet, accompanied by backwards wriggling that allows the disturbed substrate to sift over them. They can occasionally be found near the bases of broad-leaved plants (Inger 1954).

Males call year round in available standing water and in puddles or pools that form after the frequent rains (Blackburn et al. 2015). Chorus groups can number from a few individuals to several hundred, and individuals in large groups sometimes alternate their calls (Diesmos et al. 2002). Male advertisement calls contain 32 – 37 distinct pulses per call, with a rapid-fire delivery rate of 1.2 calls/sec. A single male’s call sounds to the human ear like a squeaky door swinging on its hinges, a soft ‘whaak, whaak, whaak’; while a group of males of differing sizes alternating their calls resembles the sound ‘ko-kak, ko-kak,ko-kak’ (Diesmos et al. 2002).

Mature eggs can be found in females from mid to late May until March, when the dry season commences. However, the breeding season reaches its peak between July and October, during the heaviest rainfalls. Their breeding behavior is typical of anurans, with males arriving at breeding sites early to form a breeding chorus and females arriving later (Inger 1954).

Kaloula picta uses axillary amplexus with males sticking to females using a gelatinous secretion from their belly glands. Females can lay between 812 – 4029 eggs (Inger 1954).

Like most amphibians, K. picta is an indiscriminate hunter of arthropods, including ants, termites, beetles, crickets, and cockroaches (Inger 1954). One possible predator of K. picta is the snake, Oxyrhabdium leporinum leporinum, which is found in many of the same regions as the K. picta (Brown 2000).

Both male and female individuals of K. picta secrete a thick, sticky mucus from their backs that does not come off handlers’ hands, even with frequent soapy washings, for several days (Inger 1954).

Trends and Threats
Known populations of K. picta are stable and are currently not endangered by any specific threats. It is possible that they will be at risk in the future due to predation from or competition with alien invasive species (Diesmos et al. 2004).

Possible reasons for amphibian decline

Predators (natural or introduced)
Introduced competitors

Comments
The species authority is: Duméril & Bibron, 1841. Erpétologie Genérale ou Histoire Naturelle Complète des Reptiles. Volume 8. Paris: Librarie Enclyclopedique de Roret.

Maximum likelihood and Bayesian inference analysis of 12S and 16S ribosomal RNA genes and valine intervening transfer RNA concluded that there are five total clades in the genus Kaloula: 1) K. picta; 2) a species from the Samar and Leyte islands; 3) K. rigida and K. walteri; 4) K. kalingensis, K. kokacii, and two species from the Panay Island and eastern Luzon Island; and 5) K. conjuncta conjuncta, K. c. meridionalis, K. c. negrosensis, K. c. stickeli, and two taxa, one from the Mindoro Island and the other from the Panay and Sibuyan islands. Kaloula picta was basal to the clade formed by groups 2 and 5 and together they were sister to group 4. The most basal clade was group 3 (Blackburn et al. 2015).

Kaloula picta is colloquially referred to as the painted narrowmouth toad because of its intricate dorsal markings and slender mouth. Kaloula picta is also sometimes called the slender-digit chorus frog because it possesses skinny toes without widened terminal toe pads (Inger 1954).

References

Blackburn, D. C., Siler, C. D., Diesmos, A. C., McGuire, J. A., Cannatella, D. C., Brown, R. M. (2013). ''An Adaptive Radiation of Frogs in a Southeast Asian Island Archipelago.'' Evolution, 67(9), 2631-646.

Brown, R. M., McGuire, J. A., Ferner, J. W., Icarangal, N., Kennedy, R. S. (2000). ''Amphibians and reptiles of Luzon Island, II: Preliminary report on the herpetofauna of Aurora Memorial National Park, Philippines.'' Hamadryad, 25(2), 175-195.

Diesmos, A. C., Brown, R. M., Alcala, A. C., and Guyer, C. (2002). ''New species of narrow-mouthed frog (Amphibia: Anura: Microhylidae; genus Kaloula) from the mountains of southern Luzon and Polillo Islands, Philippines.'' Copeia, 2002(4), 1037-1051.

Diesmos, A., Alcala, A., Brown, R., Afuang, L., Dolino, C., Gee, G., Hampson, K., Diesmos, M.L., Mallari, A., Ong, P., Paguntalan, L., Pedregosa, M., Ubaldo, D., Gutierrez, B. (2004). “Kaloula picta”. The IUCN Red List of Threatened Species 2004: e.T57854A11694467. http://dx.doi.org/10.2305/IUCN.UK.2004.RLTS.T57854A11694467.en. Downloaded on 22 February 2017.

Inger, R.F. (1954). ''Systematics and zoogeography of Philippine Amphibia.'' Fieldiana: Zool., 33, 184-531.

Taylor, E. H. (1966). Amphibians & Turtles of the Philippine Islands. A. Asher and Co., Amsterdam.

Thomas, E. O., Tsang, L, Licht, P. (1993). ''Comparative Histochemistry of the Sexually Dimorphic Skin Glands of Anuran Amphibians.'' Copeia, 1993(1), 133-143.

Species Account Citation: AmphibiaWeb 2017 Kaloula picta: Slender-Digit Chorus Frog <https://amphibiaweb.org/species/2156> University of California, Berkeley, CA, USA. Accessed Dec 3, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 3 Dec 2024.

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