Pseudopaludicola ameghini is a robust, warty dwarf swamp frog with a snout vent length maximum of 19.0 mm in males and 22.0 mm females (Lynch 1989). The short snout comes to a point but lacks a projecting profile. The canthus rostralis is also absent. The nostrils are located halfway between the snout tip and the eyes. The pupils are horizontal and eyelids shorter than the interorbital space. There is no tympanum (Cope 1887). Their fingers are only slightly webbed (Parker 1927), with the third being longer than the second. When the hind limb is adpressed along the body, the heel reaches halfway between the eye and nostril. There are two small distinct metatarsal tubercles but the foot lacks tarsal tubercles (Cope 1887) that are united at the outer ends (Parker 1927). There is also a fold extending diagonally along the tarsus from the lateral margin of the basal subarticular tubercle of the fifth toe to the distal point of the outer metatarsal tubercle (Lynch 1989, Cope 1887). The soles are smooth. The toes have narrow dermal margins and basal webbing. They lack lumber glands. The warts on the body are irregularly arranged (Cope 1887).
Pseudopaludicola ameghini tadpoles at stages 34 - 38 had a total length range of 24.60 - 31.10 mm, a body length range of 8.83 - 10.60 mm, a body width range of 5.55 - 6.50 mm, and a body height range of 4.60- 5.55 mm. The body is ovoid from the dorsal view, and depressed from the lateral view. The snout is slightly pointed from the dorsal and ventral views, but round from a lateral view. The large eyes are located dorsally and directed dorsolaterally. The nares are large, round, closer to the eyes than the snout, and dorsally positioned and directed. They also have large complete margins and a small ossified marginal rim. The oral disc is positioned anteroventrally and may either have lateral emargination or none. They have a single row of marginal papillae that displays a sizable anterior gap and two narrower posterior gaps resulting in a short row of 4 - 12 ventral papillae. Rarely, submarginal papillae can be present. The tooth row formula is 2(2)/2 or 2(2)/2(1), with the latter occurring more frequently. The first anterior and posterior tooth rows are larger than the second, respectively. A few tadpoles have a third ventral tooth row or an additional fragmented tooth row between the ventral jaw and first posterior tooth row. The labial teeth curve slightly toward the oral opening and tooth heads are spoon-shaped with 5 - 7 termal cusps. The arc-shaped upper jaw sheath is strongly keratinised and the U-shaped lower jaw is about a third the size of the upper. Both have triangular serrations. The spiracle is short, sinistral, cylindrical in shape, directed posterodorsally with a free wall, and positioned in the middle third of the body. The vent tube is long, medial, and fused to the ventral fin. The dorsal fin placement begins at the body-tail junction, is slightly arched, and reaches its maximum height in the middle third. The ventral fin is low, narrow, parallel to the musculature, and straighter than the dorsal fin. The tadpoles do not have flagella or lateral lines (Simioni et al. 2019).
The tarsal fold is very prominent in all the species in the genus (Lynch 1989). However, Parker (1927) provides ways to recognize similar species within the genus Pseudopaludicola by the following characteristics: the tibiotarsal articulation does not reach the end of the individual’s snout in P. ameghini (versus tibiotarsal articulation reaching beyond the end of the snout in P. saltica). Pseudopaludicola ameghini have simple and undilated terminal fingers (versus P. pusilla and P. bolivianus displaying T-shaped terminal fingers and toes with terminal discs). The ventral surfaces are white in color, and the nostril lies midway between the eye and end of the snout in P. ameghini (versus brown spotted breast in P. falcipes).
Additionally, when compared to the two other similar sympatric Pseudopaludicola species, P. mystacalis and P. saltica, P. ameghini has the largest mean snout-vent length, has a more rounded sound profile, exhibits the most warts, lacks a vertical strip, and has a very distinct call (Pansonato et al. 2013). Pseudopaludicola ameghini calls can be similar to P. teretzi but are lower in pulse rate, lower in note rate, and longer in note duration (Simioni et al. 2019).
The dorsal and lateral coloration of adult P. ameghini is either light or dark lead-colored. There is a dark band that extends across both eyes and barely detectable light bars on the upper lips. There is no vertebral stripe. The hind limbs have indirect cross-bands. The posterior region of the femur is dark and the inferior side has a pale longitudinal line. The ventrum is white with black marbling at the lower jaw. It is unclear if this coloration is in life or in preservative (Cope 1887, Pansonato et al. 2013).
In preservative, tadpoles were brown in color with translucent fins displaying brown blotches. Papillae may be pigmented. The labial teeth are dark. The tail musculature is light grey color containing darker grey or brown blotches (Simioni et al. 2019).
Tadpoles of this species show variations in their mouth parts. Approximately half of the tadpoles analyzed had pigmented papillae, some specimens had submarginal papillae. The first posterior tooth row was often broken, but could also be unbroken, there was sometimes a rudimentary tooth row between the lower jaw and the first posterior tooth row, and some specimens had a third posterior tooth row (Simioni et al. 2019).
Distribution and Habitat
Country distribution from AmphibiaWeb's database: Brazil
The species can be found in the highlands of Chapada in the state of Matte Grosso, Brazil (Parker 1927). More specifically, they are found in open habitats with hydromorphic terrains in the Cerrado savannas of Central Brazil (Pansonato et al. 2013, Simioni et al. 2019).
Life History, Abundance, Activity, and Special Behaviors
Pseudopaludicola ameghini have been observed to be active throughout the year especially in upwelling groundwater sites and open habitats with hydromorphic terrains in the Cerrado savannas of Central Brazil (Pansonato et al. 2013, Simioni et al. 2019). Both tadpoles and adults can be foundin slow-moving water habitats (Simioni et al. 2019).
Reproduction occurs in open areas containing shallow water and vegetation (Simioni et al. 2019).
The males begin their calling activities at dusk or, more specifically, around 17:00 hours to approximately 21:00 hours (Simioni et al. 2019). The advertisement call series consists of about 7 - 427 calls with a mean duration of 17.4 ± 20.6 seconds per series. Intervals between calls last 6.9 ± 4.4 seconds. Individual calls lasted between 0.04 - 0.11 seconds at intervals of 0.04 - 0.13 seconds. There were 3 - 6 notes per call, with each note lasting 0.002 - 0.008 seconds and separated by 0.001 - 0.03 seconds. Calls have mean frequencies of about 2067.2 Hz to 5653.3 Hz, and a mean dominant frequency of about 3988.6 ± 246.5 Hz (Pansonato et al. 2013).
Pseudopaludicola ameghini have axillary amplexus (Simioni et al. 2019).
During oviposition, the females tend to submerge their posterior end to a shallow body of water while they engage in axillary amplexus. The pair makes constant stops as they move through the water, leaving a single egg at a time (Simioni et al. 2019).
Eggs were submerged in shallow waters, some on substrate and vegetation. Eggs sit within an outer jelly-like cover to keep them in place (Simioni et al. 2019).
Trends and Threats
Some reproductive sites are potentially altered by anthropogenic activities (Simioni et al. 2019).
Possible reasons for amphibian decline
Local pesticides, fertilizers, and pollutants
Maximum Parsimony and Bayesian Inference were utilized on 12S and 16S rRNA and tRNA Valgene sequences with results that P. ameghini is sister to P. ternetzi. The clade composed of these two species is sister to the clade composed of P. canga, P. facureae and P. mystacalis (Veiga-Menoncello et al. 2014).
Pseudopalidocola ameghini was originally described by Cope (1887) and named after his friend, Dr. Florentine Ameghino, who was a naturalist of Buenos Ayres.
Cope, E. D. (1887). "Synopsis of the Batrachia and Reptilia obtained by H. II. Smith, in the province of Mato Grosso, Brazil." Proceedings of the American Philosophical Society, 24(125), 44-60. [link]
Lynch, J.D. (1989). “A review of the Leptodactylid frogs of the genus Pseudopaludicola in northern South America.” American Society of Ichthyologists and Herpetologists, 1989(3), 577-588. [link]
Pansonato, A., Strüssmann, C., Mudrek, J.H., Martins, I.A. (2013). “Morphometric and bioacoustic data on three species of Pseudopaludicola Miranda-Ribeiro, 1926 (Anura: Leptodactylidae: Leiuperinae) described from Chapada dos Guimarães, Mato Grosso, Brazil, with the revalidation of Pseudopaludicola ameghini (Cope, 1887).” Zootaxa, 3620(1), 147-162. [link]
Parker, H.W. (1927). “LX.—A revision of the frogs of the genera
Pseudopaludicola, Physalæmus, and Pleurodema”, Annals and Magazine of Natural History, 20(118), 450-478 [link]
Simioni, F., Alves, N.C., Picheli, K.O.R., Pansonato, A., Rossa-
Feres, D.C. Strüssmann, C. (2019) “Field and laboratory observations on reproductive aspects of Pseudopaludicola ameghini (Cope, 1887) (Leptodactylidae: Leiuperinae).” Journal of Natural
History, 54(41-42), 2533-2551 [link]
Veiga-Menoncello, A.C.P., Lourenco, L.B., Strussman, C., Rossa-Feres, D.C., Andrade, G.V., GIaretta, A.V., Recco-Pimentel, S.M. (2014). “A phylogenetic analysis of Pseudopaludicola (Anura) providing evidence of progressive chromosome reduction.” Zoologica Scripta 43(3), 261-272. [link]
Originally submitted by: Madeline Frey, John Liu, Michael Brito (2021-10-26)
Edited by: Ann T. Chang (2021-10-26)
Species Account Citation: AmphibiaWeb 2021 Pseudopaludicola ameghini: Dwarf Swamp Frog <https://amphibiaweb.org/species/7975> University of California, Berkeley, CA, USA. Accessed Dec 4, 2023.
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Citation: AmphibiaWeb. 2023. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 4 Dec 2023.
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