Description
Limnonectes larvaepartus is a robust bodied frog with a snout to vent length from 31.3 to 48.3 millimeters. The head is narrower than the body and its length is 65% of its width. The fairly pointed snout goes over the lower jaw. The nostrils are closer to the snout than to the eye. The length of the eye is about the same as the length of the snout. The pupils are shaped like diamonds, with bumpy upper eyelids, and the area between the eyes is smooth. The tympanum length is a bit longer than the distance between both eyes. Its limbs are fairly thin. The bottoms of its feet are smooth, and the hands are about half as long as the feet. The feet are completely webbed to the tips of the toe discs, but the hands show no signs of webbing. Toe discs and terminal discs on the fingers are somewhat enlarged, and there are no nuptial pads on the forearms. Relative toe lengths go from 4 > 3 > 5 > 2 > 1, and relative finger lengths go from 3 > 1 ≥ 4 ≥ 2. Tubercles are rounded in the subarticular, prominent in the inner metatarsal, and absent in the outer metatarsal region of the foot. Additionally, tubercles are rounded in the subarticular, absent in the supernumerary, and enlarged in the inner and outer metacarpal regions of the hand (Iskandar et al. 2014).

Besides being the only species of frog in the entire world known to give birth to live tadpoles, it differs from other Sulawesi Limnonectes species in many ways: L. microtympanum and L. arathoonii occur in the Southwestern Peninsula of Sulawesi Island away from the range of L. larvaepartus; L. microtympanum is much larger than L. larvaepartus with relatively smaller tympana; L. arathoonii has less webbing, melanic spots above the forelimbs, a ridge coming from running down the back each eye, and no grainy tubercles on the back; L. modestus has a darkish throat with more solid dark coloration running down to the chest region than L. larvaepartus, and more extensive grainy tubercles (Iskandar et al. 2014).

Live specimens tend to have a brown-grey back, with a light yellow vent region. The tympana are typically black. There is a light stripe in the area between the eyes, and this region down to the snout is lighter in color than the rest of the back. The upper half of the iris is gold-orange in at least some of the individuals. The throat of males is darker and may also have a noticeably dark, spotted, crescent shape. The upper tibia usually has a dark spot (Iskandar et al. 2014).

Most of the variation comes from coloration. Though most individuals have a brown-grey back, others may have a red-brown or gold-tan back. The sides of the back are sometimes darker than the rest of the back (Iskandar et al. 2014).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Indonesia

View distribution map in BerkeleyMapper.

This species is known to occur from the Minahassa Peninsula in the north to the western edge of the Central Core on Sulawesi Island. It is unknown if it also occurs within the Central Core, as the mountainous terrain of that region has made it difficult to conduct surveys (Iskandar et al. 2014).

Life History, Abundance, Activity, and Special Behaviors
This species is found in both natural and disturbed forests in Sulawesi, and tends to be in sympatry with other Limnonectes species. Its preferred habitat is on rocks, leaves, or other vegetation at least a few meters away from fast-flowing streams (Iskandar et al. 2014).

Fertilization is internal, though it is unknown exactly how they reproduce. Adult males tend to call in small bodies of water away from streams. Many of these bodies of water have tadpoles in them. The amount of time males spend in proximity to these tadpoles is possible evidence of parental care. In some instances, adults have been found in bodies of water with different sizes of tadpoles, which suggest that both males and females are territorial and may visit the same body of water multiple times to reproduce (Iskandar et al. 2014).

Larva
They are ovoviviparous, and give birth to live tadpoles. Tadpoles inside the oviduct feed on their own yolk reserves, which lasts them until birth, at which point they must find an external food source. It is possible that tadpoles also feed on feces and dead tadpoles within the oviduct (Iskandar et al. 2014, Kusrini et al. 2015).

Tadpoles discovered internally in the enlarged oviducts are slender and tiny, packed in both oviducts. They mostly clear in color with spots around their bodies (Iskandar et al. 2014). In one female, 46 tadpoles (at stage 25) were found in the left oviduct and 50 in the right oviduct; total clutch size was 103 as 7 more were ejected when she was caught. The tadpoles ranged from 13.4−14.0 mm in total length. The labial tooth row formula (LTRF) was 1/2 at stage 25 (Kusrini et al. 2015).

Free-swimming tadpoles found in ponds and small water bodies were at Gosner stages 25−37. They have a sinistral spiracle about midway between the eye and vent, which opens posterodorsally with a definite medial wall. The vent tube is dextral and has a large bore widening distally. The oral disc is oriented ventrally, and the labial tooth row formula is 2(2)/3 with a wide gap in the second upper row; it has large labial teeth which are spaced apart. The body coloration is mottled with melanophores but are absent on the spiracle. The ventrum is clear and transparent making the intestine and some of the jaw muscles visible. The eyes are placed dorsally. Tail and fins are also marked with small dark patches on a pale background; the tail bears faint indistinct bands (much less so than other species of Limnonectes (Kusrini et al. 2015).

Trends and Threats
Unknown, though they occur in both natural and disturbed forests (Iskandar et al. 2014).

Relation to Humans
They can be found in areas of human disturbance (Iskandar et al. 2014).

Comments
Etymology: The name larvaepartus is composed of two parts: “larvae” refers to larva, or a juvenile form of an animal, and “partus” means to give birth. This indicates that this species got its name from its unique reproductive mode of giving birth to live tadpoles (Iskandar et al. 2014).

Limnonectes larvaepartus descended from earlier Limnonectes species that colonized Sulawesi and then radiated throughout the island (Iskandar et al. 2014).

As of March 2015 this is this only species of frog known, other than frogs in the genera Nectophrynoides and Nimbaphrynoides, and the possibly extinct Eleutherodactylus jasperi, to give birth to live young, though all these other species give birth to froglets instead of tadpoles (Iskandar et al. 2014).

This species was featured in PLoSable (February 2015), a science website for teens run by the Public Library of Science (PLOS).

References

Iskandar, D.T., Evans, B.J., McGuire, J.A. (2014). ''A novel reproductive mode in frogs: a new species of Fanged Frog with internal fertilization and birth of tadpoles.'' PLoS ONE, 9(12), e115884.

Kusrini, M.D., Rowley, J.J.L., Khairunnisa, L.R., Shea, G.M., Altig, R. (2015). ''The Reproductive Biology and Larvae of the First Tadpole-Bearing Frog, Limnonectes larvaepartus.'' PLoS ONE, 10(1), e116154.

Species Account Citation: AmphibiaWeb 2022 Limnonectes larvaepartus <https://amphibiaweb.org/species/8292> University of California, Berkeley, CA, USA. Accessed Dec 11, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 11 Dec 2024.

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