AmphibiaWeb - Phyzelaphryne miriamae


(Translations may not be accurate.)

Phyzelaphryne miriamae Heyer, 1977
Miriam's frog
family: Eleutherodactylidae
subfamily: Phyzelaphryninae
genus: Phyzelaphryne

© 2018 Mauro Teixeira Jr (1 of 2)
Conservation Status (definitions)
IUCN Red List Status Account Least Concern (LC)
National Status None
Regional Status None



View distribution map in BerkeleyMapper.

Phyzelaphryne miriamae is a leptodactylid frog with a snout-vent length range for adult females of 19.4 - 20.0 mm and adult males of 13.3 – 16.2 mm (Heyer 1977, Simões et al. 2018). The head is longer than wide (Simões et al. 2018) and narrower than the body (Hoogmoed and Lescure 1984). In the dorsal view, the snout is truncate or subacuminate. In the lateral view the snout is rounded to truncate and protrudes over the lower jaw. The canthus rostralis is indistinct and the loreal region is somewhat concave and nearly vertical. The eyes protrude beyond the circumference of the head when viewed from above. The pupil of the eye is horizontal. The round tympanum is complete, distinct, and 40% of the eye diameter. There is an oblique glandular ridge from below the tympanum to the start of the forelimb. It does not touch the tympanum. Weak supratympanic folds are present (Heyer 1977, Hoogmoed and Lescure 1984, Simões et al. 2018).

The skin texture of the dorsal and lateral areas is shagreened. Skin texture of the ventrum is smooth as is the tarsus, sole, and heel of the foot. There are no folds or defined glands on the body. Males have prominent external vocal sacs under the chin (Heyer 1977, Hoogmoed and Lescure 1984).

Both the inner and outer metarsal tubercles are flat and oval with the inner being slightly smaller than the large outer. There are three additional round palmar tubercles that are all approximately the same size. The thenar tubercle and the subarticular tubercle of the first finger are not fused and do not touch. When pressed together, the relative lengths of the fingers are IV < I < II < III. When measured from the base of the basal subarticular tubercule, the fingers are of equal length giving them a relative length of IV < I ~ II < III. The phalange formula for the fingers is 2 – 2 – 3 – 3 with the second phalange of the fourth finger being rectangular. Characteristic of the species, the terminal phalanges of the fingers are T-shaped. Fingers I, II, and IV each have a single, well-developed subarticular tubercle while finger III has two. All of the pointed fingertips are adorned with discs. However, fingertips one and two are barely disc-shaped and lacking lateral grooves while the third and fourth fingertips are slightly more disc-shaped and shallowly grooved with an interruption at the tip. The fingers do not have webbing or fringes (Heyer 1977, Hoogmoed and Lescure 1984, Simões et al. 2018).

The inner metatarsal tubercle is large, ovoid and flattened. The tubercles does not fuse or touch the subarticular tubercle of the first toe. The outer metatarsal tubercle is smaller and pointed. The phalange formula of the toes is 2 – 2 – 3 – 4 – 3 and the terminal phalanges are T-shaped. Toes I and II have one well-developed subarticular tubercle, toe III and V have two, and toe IV has three. The toe tips have disc that are larger than the fingertips, laterally grooved with a narrow interruption at the pointed tip, and terminal papillae. The toes do not have webbing or fringing (Heyer 1977, Hoogmoed and Lescure 1984, Simões et al. 2018).

Phyzelaphryne miriamae is the first member of the genus Phyzelaphryne and was the only member until 2018 when P. nimio was described (Simões et al. 2018). Phyzelaphryne miriamae can be differentiated from members of many other leptodactylid genera by the presence of terminal digital papillae. From other leptodactylid genera that do have terminal papillae (Phyllonastes and Euparkerella), Phyzelaphryne differs in having discrete vomerine teeth. Phyzelaphryne miriamae can be differed from Eleutherodactylus species that have digital papillae by the former having a sole subarticular tubercle underneath the fourth finger rather than two (Heyer 1977). From Niceforonia nigrovittata, P. miriamae can be differentiated by the latter lacking of sexual dimorphism in snout shape and by having nearly vertical sides of the head, making the eyes appear protruding from the dorsal view (Hoogmoed and Lescure 1984). From members of Adelophryne, P. miriamae can be differentiated by the latter having well-developed palmar and plantar tubercles, and no reduction in phalanges. Generally larger size, equal sized round supernumerary tubercles on the palms, a conspicuous and protuberant supernumerary tubercle at the base of finger IV that is not fused with the tubercle at the base of finger III, a gap between the thenar tubercle and the subarticular tubercle of finger I, and a gap between the inner metatarsal tubercle and toe I differentiate P. miriamae from P. nimio (Simões et al. 2018).

Heyer and Gascon (1995) report that in life the dorsal coloration of P. miriamae is dark green with indistinct darker green markings. However, others report that the dorsal coloration is yellow-brown to brown that fades on the snout and posterior region and can have whitish flecks that are denser on the snout and limbs (Hoogmoed and Lescure 1984, Simões et al. 2018). White to cream flecks that almost forms a nonstop line can be found on the upper or lower lip. The iris is golden copper with a bright red pupil ring and black reticulations (Simões et al. 2018). The lateral surface of the head is a darker brown than the dorsal surface. There is a white subtympanic stripe along the glandular ridge starting below the eye and extending to the insertion of the arm and another darker line from the nostril to the eye. There is a darker, indistinct, interrupted vertebral stripe (Hoogmoed and Lescure 1984). The dorsal surface of the limbs hands, fingers, tarsal region, foot and toes are brown. The forearms have yellow blotches and the hands and feet have grey blotches. The lateral surfaces are lighter brown but become paler towards the ventrum. The ventrum is light brown to grey with small cream spots scattered uniformly on the throat, chest, and abdomen (Heyer and Gascon 1995, Simões et al. 2018). In preserved specimens, the dorsal background color is brown. There are white areas cast on the brown snout. The upper lip retains white specks. The posterior region of the thighs is also brown. The limbs are barred. The ventrum is grey with many definite, tiny, lighter spots on it (Heyer 1977).

Phyzelaphryne miriamae is sexually dimorphic with male fingertips being more stretched out and the toe papillae more noticeable than in the females (Heyer 1977). Males also have vocal slits and a subgular vocal sac (indicated by longitudinal folds in the back of the throat). The throat is also darker in males than in females (Hoogmoed and Lescure 1984).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Brazil


View distribution map in BerkeleyMapper.
Phyzelaphryne miriamae can be found in lowland tropical forests of the State of Amazonas, Brazil. Specifically, they are found in the Madeira, Purus, Jaú, and Solimões river basins. Their most western and southern record is from Cachoeira do Teotônio, Porto Velho, Rondônia. Their most eastern record is from along the Rio Paraconi just outside Floresta Nacional de Pau-Rosa. And their most northern record is from the Rio Negro in Parque Nacional do Jaú (Simões et al. 2018). They are typically found in lowland tropical forest (Heyer 1977) that does not flood but does have creeks and streams. This species has a very uneven distribution (Heyer and Gascon 1995).

Life History, Abundance, Activity, and Special Behaviors
The leaf litter inhabiting P. miriamae is diurnal and rare. During an extensive survey, P. miriamae was only found in four of the eight sites (Heyer and Gascon 1995). Males can be located by their calls, however they stop calling as they are approached. Once located, individuals can be found by removing a few leaves or by raking the leaf litter. They are not found on top of the leaf-litter (Heyer and Gascon 1995, Simões et al. 2018).

Phyzelaphryne miriamae is a terrestrial species that is found underneath leaf-litter (Azevedo-Ramos and Rodrigues 2004) in low-lying forested areas with creeks or streams (Heyer and Gascon 1995). The species may also occupy the superficial soil layer near the base of trees and rocks, despite lacking the body type for digging, and in fact their capture in leaf litter has been hypothesized to be circumstance (due to high groundwater or heavy rainfall) rather than a result of their occupation of that habitat (Hoogmoed and Lescure 1984).

Their reproductive mode is unknown but is thought to be direct development (Azevedo-Ramos and Rodrigues 2004).

Males could be heard calling from leaf litter in low-lying areas associated with streams at dusk and usually follow heavy rainfall (Heyer and Gascon 1995, Simões et al. 2018). Advertisement calls consisted of 2 - 3 pulsed note calls that are emitted at a rate of 12.7 calls every minute. Call durations lasted 0.041 – 0.059 seconds with the first note duration lasting 0.014 - 0.023 seconds and the second 0.010 – 0.022 seconds. Inter-note duration lasted 0.014 – 0.022 seconds. The first note is comprised of four complete pulses and the second note is comprised of either two complete, weak pulses or 2 - 3 faint partial pulses. Both notes have harmonic structure. The dominant frequency of the call is 2810 - 4460 Hz with both notes having approximately the same peak frequency. There may be geographic differences in peak frequency range (Heyer and Gascon 1995, Simões et al. 2018).

Epipedobates femoralis, Adenomera andreae, and Leptodactylus rhodomystax could also be heard calling from the same localities as P. miriamae (Heyer and Gascon 1995).

While the specifics of P. miriamae’s diet are unknown, other leaf-litter microhylids specialize on ants and termites. However, Adelophryne adiastola, a similar species, is known to consume harvestman, so it is possible P. miriamae may have a more general diet than the specialized microhylids (Hoogmoed and Lescure 1984).

Trends and Threats
Despite being listed as a “Least Concern” species with a stable population, P. miriamae is still threatened by deforestation due to agriculture and logging. It is believed that they inhabit several protected areas but more field research is needed to confirm (Azevedo-Ramos and Rodrigues 2004).

Phyzelaphryne miriamae is likely susceptible to Batrachochytrium dendrobatidis infections given the infection of other leptodactylid species (Herrera et al. 2005) and the spread of B. dendrobatidis through the New World (Rosenblum et al. 2013).

Possible reasons for amphibian decline

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

The species authority is: Heyer, W. R. (1977). “Taxonomic notes on frogs from the Madeire and Purus River’s Brazil.” Papeis Avulsos de Zoologia, 31(8), 140-162

Phyzelaphryne miriamae was at one point considered conspecific with Niceforonia nigrovittatus, but this designation has since been discarded (Hoogmoed and Lescure 1984). Phyzelaphryne miriamae shares many characters with other leptodactylid frogs, especially those occupying the same leaf litter habitat, but this is suspected to be convergent evolution rather than the result of close relatedness (Heyer 1977).

Based on Maximum Likelihood analysis on concatenated sequences of 16S and COI mtDNA, P. miriamae is sister to a clade composed of P. nimio and two other unidentified Phyzelaphryne species (Simões et al. 2018). Based on Bayesian Inference and Maximum Parsimony analysis of mtDNA and nuclear DNA, the genus Phyzelaphryne is sister to the genus Adelophryne (Fouquet et al. 2012). Phyzelaphryne and Adelophryne share toe discs with lateral grooves that are interrupted at the tip (Hoogmoed and Lescure 1984).

The genus “Phyzelaphryne” was named from the Greek word “phyzelos”, meaning “shy”, and “phryne”, meaning “toad”. This referred to the individuals of this genus being difficult to locate and capture (Heyer 1977).

The species epithet “miriamae” is in honor of Miriam Heyer, who collected frogs with W. Ronald Heyer and is his wife. W.R. Heyer described Miriam as “an industrious field collector whose quick reflexes result in the captures of many forest floor frogs” (Heyer 1977).

This species was placed in the genus Phyzelaphryne by Heyer (1997). However, J.D. Lynch considered P. miriamae to be conspecific with Niceforonia nigrovittatus (then considered Eleutherodactylus nigrovittatus) and reclassified P. miriamae into the species (Hoogmoed and Lescure 1984). Phyzelaphryne was reinstated in 1984 by Hoogmoed and Lescure after observing that P. miriamae possessed a single subarticular tubercule.


Azevedo-Ramos, C., Rodrigues, M.T. (2004). “Phyzelaphryne miriamae”. The IUCN Red List of Threatened Species 2004: e.T57280A11598104. Downloaded on 22 February 2019.

Fouquet, A., Loebmann, D., Castroviejo-Fisher, S., Padial, J. M., Orrico, V. G. D., Lyra, M. L., Roberto, I. J., Kok, P. J.R., Haddad, C. F.B., Rodrigues, M. T. (2012). ''From Amazonia to the Atlantic forest: Molecular phylogeny of Phyzelaphryninae frogs reveals unexpected diversity and a striking biogeographic pattern emphasizing conservation challenges.'' Molecular Phylogenetics and Evolution, 65(2), 547-561.

Herrera, R.A., Steciow, M.M., Natale, G.S. (2005). ''Chytrid fungus parasitizing the wild amphibian Leptodactylus ocellatus (Anura: Leptodactylidae) in Argentina.'' Diseases of Aquatic Organisms, 64(3), 247-252. [link]

Heyer, W. R. (1977). ''Taxonomic notes on frogs from the Madeira and Purus rivers, Brasil.'' Papeis Avulsos de Zoologia, 31, 141-162.

Heyer, W. R., Gascon, C. (1995). ''Collection Notes and Call Characteristics for Ischnocnema quixensis and Phyzelaphryne miriamae (Amphibia: Anura; Leptodactylidae).” .'' Journal of Herpetology, 29(2), 304-307. [link]

Hoogmoed, M. S., and Lescure, J. (1984). ''A new genus and two new species of minute leptodactylid frogs from northern South America, with comments upon Phyzelaphryne (Amphibia: Anura: Leptodactylidae).'' Zoologische Mededeelingen, 58, 85-115.

Rosenblum, E.B., James, T.Y., Zamudio, K.R., Poorten, T.J., Ilut, D., Rodriguez, D., Eastman, J.M., Richards-Hrdlicka, K., Joneson, S., Jenkinson, T.S., Longcore, J.E., Parra Olea, G., Toledo, L.F., Arellano, M.L., Medina, E.M., Restrepo, S., Flechas, S.V., Berger, L., Briggs, C.J., Stajich, J.E. (2013). ''Complex history of the amphibian-killing chytrid fungus revealed with genome-sequencing data.'' Proceedings of the National Academy of Sciences, 110(23), 9385-9390. [link]

Simões P.I., Costa J.C.L., Rojas-Runjaic F.J.M., Gagliardi-Urrutia G., Sturaro M.J., Peloso P.L.V., Castroviejo-Fisher S. (2018). ''A new species of Phyzelaphryne Heyer, 1977 (Anura: Eleutherodactylidae) from the Japurá River basin, with a discussion of the diversity and distribution of the genus.'' Zootaxa, 4532(2), 203-230. [link]

Originally submitted by: Sara Nece, Josephine Rodgers, and Jenna Boucek (first posted 2019-07-24)
Edited by: Ann T. Chang (2019-07-24)

Species Account Citation: AmphibiaWeb 2019 Phyzelaphryne miriamae: Miriam's frog <> University of California, Berkeley, CA, USA. Accessed Apr 17, 2024.

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Citation: AmphibiaWeb. 2024. <> University of California, Berkeley, CA, USA. Accessed 17 Apr 2024.

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