Description
The body and arms robust. The head is slightly wider than long with a length of 28% snout-vent length (max snout-vent length of 70.7 mm). The snout is slightly rounded in lateral and dorsal view. The loreal region is slightly rounded in the cross section. The eye diameter is 1.3 times internarial distance. The tympanum is absent. A postocular fold is visible and reaches the middle of the body. The head has small granules, especially the supraocular areas and under the postocular fold. Dentigerous processes (6 - 7) are present on the vomer between the choanae. Relative finger sizes are 1 < 2 < 4 < 3, relative toe lengths are 1 > 2 > 3 > 5 > 4. The dorsal surface and internal border of the first finger has strong thorny excrescences. The internal border of the second finger has a thin band of spines. The chest has the characteristic Alsodes bilateral patches of small spines. The ventral, dorsal and lateral surfaces of thighs have minute granules; a fold of skin is present between the posterior border of the arm and the middle of the body (Cuevas and Formas 2001).

Alsodes hugoi, at larval stage 25 have a total length of 37.9 ± 3.60, body weight of 15.9 ± 1.59, body depth of 6.5 ± 0.89, and fin depth of 6.4 ± 0.62. Their average body length is 16 mm and average 6.5 fin depth. They have ovoid bodies and round snouts. They are are 2.6 times longer than wide. The snout is round. Their small nostrils are located between the tip of their snout and their eyes. Their eyes are antero-dorsolateral, and the distance between their eyes is similar to the distance between their nostrils. These eyes have circular pupils. Their intra-angular oral disc is translucent and its width is 1.4 times the interocular distance of the tadpole. Here a rostral gap is present, but not a mental gap. A line of marginal papillae is found around the periphery of the oral disc with the exception of the rostral region. Sparse intramarginal papillae are found in the disc’s mental region. The labial tooth row formula is (1)(1-1)/(1-1)(2). The spiracle tube is sinistral and laterally located. The proctodeal tube is transparent, wide, and dextrally located. The dorsal fin starts on the posterior third of the body and the ventral fin starts at the end of the proctodeal tube. These transparent fins join to create a tail with a rounded tip. The total fin depth does not exceed the body depth (Cuevas and Formas 2001, Cuevas et al. 2005).

In life, the adult dorsal coloration of back, arms, and legs is light brown with golden tints. Bars are present on the legs and arms with black spots on the dorsum. The thorny excrescences of the first finger are brown in color. Ventral coloration is an off-white (Cuevas and Formas 2001).

The tadpoles’ irises are golden spotted with black reticulations. Many small melanophores are also distributed along the tail fins (Cuevas and Formas 2001, Cuevas et al. 2005).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Chile

View distribution map in BerkeleyMapper.

Known only from the type locality at Rio Lircay, Altos de Vilches, 66 km E of Talca, Talca Province, Region del Maule on the western slopes of the Andes, Chile (Cuevas and Formas 2001).

Life History, Abundance, Activity, and Special Behaviors
Specimens were captured on the banks of the Lircay River during the summer (January). The habitat was woody and Mediterranean subhumid (Cuevas and Formas 2001).

Possible reasons for amphibian decline

General habitat alteration and loss
Habitat modification from deforestation, or logging related activities

Comments

According to Cuevas and Forma (2001), the species is in the Alsodes monticola group.

Karyotypes show 26 biarmed chromosomes (Cuevas and Formas 2001).

References

Cuevas, C. C. and Formas, J. R. (2005). ''A new frog of the genus Alsodes (Leptodactylidae) from the Tolhuaca National Park, Andes Range, southern Chile.'' Amphibia-Reptilia, 26, 39-48.

Cuevas, C. C., and Formas, J.R. (2001). ''A new species of Alsodes (Amphibia, Anura, Leptodactylidae) from Central Chile.'' Amphibia-Reptilia, 22, 187-198.

Gosner, K. L. (1960). ''A simplified table for staging anuran embryos and larvae with notes on identification.'' Herpetologica, 16(3), 183-190.

Species Account Citation: AmphibiaWeb 2021 Alsodes hugoi <https://amphibiaweb.org/species/5836> University of California, Berkeley, CA, USA. Accessed Nov 22, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 22 Nov 2024.

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