Alsodes valdiviensis Formas, Cuevas & Brieva 2002

The snout-vent length of male Alsodes valdiviensis ranges from 39.5 - 59.8 mm while two females specimens are 39.7 and 63.4 mm. The body is robust and the limbs are sturdy. The head is wider than it is long and the snout is truncated. The nostrils are located on the side of the snout towards the front of the head. The canthus rostralis is straight and obvious. The loreal region bends in and the skin is finely granular. There is no tympanum. The eye diameter is larger in size than the distance between the eye and the nostrils. The post-ocular fold is distinct and obvious. The forelimbs are not over-developed. The hands lack webbing, instead exhibiting fingers with globular ends. The relative finger lengths are 1 = 2 < 4 < 3. The oval palmar tubercles are obvious. There are four, small, round subarticular tubercles on each finger. Males have a thorny excrescence on the dorsal side of their first finger and a narrow band of spines on their second finger. The digits on hind feet are slender and fringed, with thin, reduced webbing, and rounded ends. The relative toe lengths are 1 < 2 < 3 = 5 < 4. The inner metatarsal tubercle is obvious, long, and oval. The outer planter tubercle of foot is smaller but similar in appearance to the inner planter tubercle. A thin tarsal fold covers the majority of the tarsus. The skin on the sides and top of the body are grainy, while ventral skin is smooth. The surfaces surrounding the vent and the backs of the thighs are also granular, while the remainder of the skin on the limbs is smooth. Males have two patches of keratinous bristles on their chests (Formas et al. 2002).This frog is considered large for an Alsodes species. A yellow tinged triangle is found on the head. There is no columella in A. valdiviensis versus a presence in A. vanzolinii and A. nodosus. The transverse process of the sixth vertebra is located to the side in A. valdiviensis, to the front in A. gargola, and to the back in A. vanzolinii. This species has 26 chromosomes, distinguishing it from the morphologically similar A. barrioi which has 34 chromosomes. Alsodes nodosus has 22 chromosomes and has black bars on the limbs which are not found in A. valdiviensis. Alsodes valdiviensis can be distinguished from A. tumultuosis, A. kaweshkari, and A. australis using various physical morphologies since all these species have 26 chromosomes and appear otherwise similar. Alsodes tumultuosis shows median amount of webbing rather than highly reduced webbing, as well as a spotting pattern on the top rather than stripes seen in A. valdiviensis. Alsodes kaweshkari has no webbing between toes, only toe fringes. Alsodes australis has a rounded versus truncated snout (Formas et al. 2002).When in alcohol, dorsal surfaces are grey and a triangle of lighter grey may be seen on the head. The space between the eye and nostrils is spotted black. A dark grey triangular stripe extends from the top of the head between the eyes toward the back of the frog. The ventrum is grey and the throat is white, while the posterior side of the legs and the area around the vent is dark brown. Live specimens exhibit a yellow color to the triangle on the head, and the stripe on the head is light brown. The dorsum and limbs are light brown and gold. The ventrum and throat is white. Eyes are black with bronze reticulations (Formas et al. 2002).The species authority is: Formas, J.R., Cuevas, C.C. and Brieva, L.M. 2002. A new species of Alsodes (Anura: Leptodactylidae) from Cerro Mirador, Cordillera Pelada, southern Chile. Proceedings of the Biological Society of Washington: 708-719.This species belongs to the Alsodes monticola group. It was identified based on karyotype, C-band chromosomal pattern, and osteology (Formas et al. 2002).The species epithet, valdiviensis refers to the Valdivia Province where this species was found (Formas et al. 2002).The species has a diploid chromosome number of 2N = 26 (Formas et al. 2002).

The species is presently only found in the coastal mountains of southern Chile, in the area of Cerro Mirador within the Cordillera Pelada, at an altitude of 1100 m. This area consists of residual Nothofagus forest habitat. This area is covered by snow in the winter (Formas et al. 2002, Formas 2004).

Males were found under logs at forest edges in spring and summer. Males who appeared ready to mate were found in November and December. Mating calls have not been described (Formas et al. 2002), but the species is known to reproduces in quick-moving, colder streams where larvae develop (Formas 2004).

There is currently too little information to assess their trends and threats. However, in 2002, several individuals were found at the type locality (Formas 2004).