Alsodes vanzolinii (Donoso-Barros, 1974)
Vanzolini's Spiny-Chest Frog
© 2013 Bert Willaert (1 of 3)
The forelimbs are slender. The relative length of each finger is as follows, from longest to shortest: 3 - 4 - 2 - 1. There is no webbing on the hands, and the fingertips are somewhat enlarged. It has a conspicuous elongate inner palmar tubercle, and a smaller, oval-shaped outer palmar tubercle. Subarticular tubercles are conical, modest, and medium-sized. It also has supernumerary palmar tubercles (Formas 1981).
The hind limbs are also slender. The toes are fairly long, and the relative length of each toe is as follows, from longest to shortes: 4 - (3,5) - 2 - 1. The outer metatarsal tubercle is low in profile and egg-shaped, while the inner metatarsal tubercle is conical and small. The subarticular tubercles are big and tapered, and tiny supernumerary tubercles are present. The tarsal fold, though visible, is reduced, and webbing between fifth and fourth toes is limited. The cloaca is slanted and discreet. The skin is generally smooth, with small tubercles present on the thighs, back, and head. The skin is somewhat bumpy underside of thighs towards the rear (Formas 1981).
The tadpole has a rounded snout, and its nostrils are ovoid and slightly depressed. The pupils are rounded, and the mouth is tapered. There is a rostral gap, but no ventral gap, and there are small fleshy projections that form a single row. The upper jaw extends past the lower jaw. The cloacal tube has a dorsal lip that covers the ventral lip. The tail is 62.2% of its whole length, with a straight tail axis. The back fin originates in a crest that reaches the spiracle, and the ventral fin originates at the end of the cloaca. The tip of the tail is slightly curved. It has a noticeable lateral line (Formas and Brieva 2004).
This species can be distinguished with a combination of characters: the primitive webbing present between fifth and fourth toes, slender limbs, papillae that are present on its uneven tongue, and the yellow triangle on its head (Formas 1981).
In life, the back is brown, with whitish spotting in an uneven pattern. A yellow triangle is noticeable on the head. The underside is whitish up to the throat. The region between the eye and nostril is dark. A dark glandular fold is present behind the eyes. Limbs are striped dark brown (Formas 1981).
Preserved tadpole specimens have transparent dorsal and ventral fins, though unevenly permeated with dark specks. The underside is transparent, with internal organs visible. The jaws are dark for about half the width. Color in life is similar to those that have been formalin-fixed (Formas and Brieva 2004).
Juveniles have a darker belly that is mottled with black and retaining the whitish spotting of adults. Some adults show a white mid-dorsal stripe on the lower half of the dorsum. Snout-vent length proportions vary by approximately 8 mm to 12 mm, based on measurements of 28 adult specimens (Formas 1981).
Distribution and Habitat
Country distribution from AmphibiaWeb's database: Chile
Life History, Abundance, Activity, and Special Behaviors
Trends and Threats
Possible reasons for amphibian decline
General habitat alteration and loss
Alsodes vanzolinii is synonymous with Eupsophus vanzolinii.
Alsodes is sister to Eupsophus, the genus to which A. vanzolinii was originally ascribed; together, they form a strong monophyly within Alsodidae (Blotto et al. 2013). Alsodidae is nested within the superfamily Hyloidea, within the Neobatrachians (Pyron and Wiens 2011).
Alsodes vanzolinii is named for Dr. Paulo Emilio Vanzolini, a herpetologist from Brazil who put together one of the largest herpetological collections of the Americas (Beolens et al. 2013).
This species was most recently sighted in 2008, and determination was based almost exclusively on tadpoles. Three populations were found, but only two adult specimens—both female—were seen (Rabanal and Alarcón 2010).
The original species description, by Donoso-Barros in 1974, was based on 15 adult males and 13 adult females (Formas 1981).
A karyotype comparison refers to 8 male specimens used as samples, but most likely refers to the specimens collected by Donoso-Barros. Since this original discovery, there have been no adult male sightings referred to in the literature (Formas and Vera 1983).
Beolens, B., Watkins, M., Grayson, M. (2013). The Eponym Dictionary of Amphibians. Pelagic Publishing
Blotto, B. L., Nunez, J. J., Basso, N. G., Ubeda, C. A., Wheeler, W. C., Faivovich, J. (2013). Phylogenetic relationships of a Patagonian frog radiation, the Alsodes + Eupsophus clade (Anura: Alsodidae), with comments on the supposed paraphyly of Eupsophus. Cladistics: 113-131.
Formas, J.R. (1981). The Identity of the Frog Eupsophus vanzolinii From Ramadillas, Nahuelbuta Range, Southern Chile. Proceedings of the Biological Society of Washington 93:920-927.
Formas, J.R. and L. Brieva (2004). The tadpoles of Alsodes vanzolinii and A. verrucosus (Anura: Leptodactylidae) with descriptions of their internal oral and chondrocranial morphology. Amphibia-Reptilia 24: 151-164.
Formas, J.R. and M.I. Vera (1983). Karyological Relationships among Frogs of the Genus Alsodes, with Description of the Karyotypes of A. vanzolinii and A. verrucosus. Copeia 1983(4): 1104-1107.
Pyron, R.A., Wiens, J. (2011). ''A large-scale phylogeny of Amphibia including over 2800 species, and a revised classification of extant frogs, salamanders, and caecilians.'' Molecular Phylogenetics and Evolution, 61(2), 543-583.
Rabanal, F. E., Alarcon, D. (2010). Amphibia, Anura, Cycloramphidae, Alsodes vanzolinii (Donoso-Barros, 1974): Rediscovery in Nature, latitudinal and altitudinal extension in Naheulbuta Range, southern Chile. Check List, Journal of species lists and distribution. Online edition ISSN 1809-127X.
Veloso A., Nunez, H., Ortiz, J.C. (2010). Alsodes vanzolinii. The IUCN Red List of Threatened Species. Version 2014.3. www.iucnredlist.org. Accessed 5 March 2015.
Originally submitted by: Vicki Thill (first posted 2015-06-11)
Edited by: Gordon Lau (2015-06-22)
Species Account Citation: AmphibiaWeb 2015 Alsodes vanzolinii: Vanzolini's Spiny-Chest Frog <https://amphibiaweb.org/species/2560> University of California, Berkeley, CA, USA. Accessed Apr 1, 2023.
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Citation: AmphibiaWeb. 2023. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 1 Apr 2023.
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