Description

DESCRIPTION:

Nymphargus manduriacu is a glassfrog described from three males and one female. The males have a snout-vent length range of 24.0 - 25.7 mm and the single adult female is 28.8 mm. The snout is truncated in dorsal view and truncated to slightly rounded in lateral view. The dentigerous process of the vomer is low or absent and the species lacks vomerine teeth. The tympanic annulus is barely visible, and a supratympanic fold is present. The dorsal skin is shagreen and adult males have microspicules; the ventral skin is glandular, with two large subcloacal warts. The hands, arms, feet, and legs lack any tubercles, folds, or fringe. Males lack humeral spines. Fingers I - III lack webbing and there is reduced webbing between Fingers III - IV. Males have Type I and VI nuptial excrescences and a concealed prepollex. Finger I is slightly longer than Finger II, and the width of the disc on Finger III is smaller than the diameter of the eye. The toe webbing is basal between toes I and II, with a formula of II 1 ½ – (2 ½ – 3-) III (1 ⅓ – 1 ½) – (3 – 3-) IV (3 – 3-) – (1½ – 2-) V between the other toes (Guayasamin et al. 2019).

DIAGNOSIS:

The most similar species to N. manduriacu are: N. buenaventura, N. ignotus, N. luminosus, and N. spilotus. These species have a similar colouration and yellow spotted pattern, sometimes with black rings forming false ocelli. They also have similar distributions on the Pacific slopes of the Andes. However, the Manduriacu glassfrog can be differentiated from these similar species by slight differences in color and patterns. Nymphargus buenaventura is light green with diffuse yellow spots; N. ignotus is tan or olive brown with orange or yellow spots surrounded by false ocelli; N. spilotus is olive green with small yellow spots; and N. luminosus is green with numerous yellow spots. Nymphargus luminosus also has slightly extended webbing between fingers III and IV. Additionally, based on snout-vent lengths of adult males, N. manduriacu is larger than N. buenaventura and N. ignotus, but smaller than N. luminosus and N. spilotus. It occupies a higher elevation than N. buenaventura and N. luminosus, but a lower elevation than N. ignotus and N. spilotus. Lastly, N. manduriacu can be differentiated by having a higher dominant frequency in their advertisement call (Guayasamin et al. 2019).

COLORATION:

Nymphargus manduriacu is noted for having a grayish-green dorsum in life, which is covered in yellow spots. These spots are sometimes surrounded by melanophores, forming diffuse black rings that resemble false ocelli. The tympanum is the same color as the dorsal skin. Its upper lip is unpigmented. The venter is anteriorly white and posteriorly translucent. Melanophores are present on both the fingers and toes, abundant on exterior digits and rarer on the interior digits. The inner fingers and toes are yellow. Nymphargus manduriacu has green bones. The iris is light gray with pale yellow around the pupil (Guayasamin et al. 2019).

The one metamorph specimen was a uniform green with some light spotting (Guayasamin et al. 2019).

In preservation, the dorsum is a gray lavender with white spots. The parietal peritoneum is white and partially covered in iridophores. While most visceral peritonea remain unpigmented, the heart is surrounded by a white pericardium (Guayasamin et al. 2019).

VARIATION:

The female is larger than the males and does not have microspicules as the males do (Guayasamin et al. 2019).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Ecuador

View distribution map in BerkeleyMapper.

Nymphargus manduriacu has only been found near streams in the Río Manduriacu Reserve, in the Imbabura Province of Ecuador in a narrow elevation of 1215 - 1242 m on the Pacific slope of the Andes (Guayasamin et al. 2019). The Río Manduriacu Reserve is located at the Chocó and Tropical Andes biogregion. Their habitat is a dense lower montane forest with many small freshwater streams. This area has high rainfall and humidity, as well as temperatures between 18 - 20℃ (IUCN 2020).

Life History, Abundance, Activity, and Special Behaviors

Nymphargus manduriacu is found during the wet season when daily rainfall is heavy. They were found in two locations: first, within a narrow stream with dense vegetation. The second location was in a nearby fast-flowing stream that is about 4 m wide (Guayasamin et al. 2019).

Egg clutches in the second location were also spotted on upper leaf surfaces, and contained about 26 - 32 embryos (Guayasamin et al. 2019).

Nymphargus manduriacu calls consist of a single note of a high-pitched "chirp". Calls last for about 0.093 to 0.118 seconds, with notes having 8 - 12 pulses per note. The dominant frequency is between 4,052 - 4,447 Hz with increasing frequency with time. Inter-calls intervals vary from 3.9 to 8.6 seconds, with increasing frequency with time passing (Guayasamin et al. 2019).

Trends and Threats
Nymphargus manduriacu is listed as“Critically Endangered” on the IUCN Red List. The species’ restricted range contributes to the threats against this species, which include habitat destruction and contamination from cattle ranching, agriculture, and mining. Mining contamination is the main threat to the species as one of the world's largest mining companies gained permission to extract gold and copper within the Rio Manduriacu Reserve (Guayasamin et al. 2019, IUCN 2020).

Possible reasons for amphibian decline

General habitat alteration and loss
Habitat modification from deforestation, or logging related activities
Intensified agriculture or grazing
Urbanization
Mining
Local pesticides, fertilizers, and pollutants
Long-distance pesticides, toxins, and pollutants

Comments

PHYLOGENETIC RELATIONSHIPS:

Based on Maximum Likelihood and Bayesian Inference analyses of 12S and 16S mitochondrial genes, N. manduriacu is sister to N. balionotus (Guayasamin et al. 2019).

Etymology:

The specific epithet “manduriacu” is a reference to the Río Manduriacu Reserve, where the species is found (Guayasamin et al. 2019).

References

Guayasamin, J. M., Cisneros-Heredia, D. F., Vieira, J., Kohn, S., Gavilanes, G., Lynch, R. L., Hamilton, P. S., Maynard, R. J. (2019). “A new glassfrog (Centrolenidae) from the Chocó-Andean Río Manduriacu Reserve, Ecuador, endangered by mining. PeerJ, 7, e6400. [link]

IUCN SSC Amphibian Specialist Group. (2020). “Nymphargus manduriacu.” The IUCN Red List of Threatened Species 2020: e.T149692574A149692615. https://dx.doi.org/10.2305/IUCN.UK.2020-3.RLTS.T149692574A149692615.e Accessed on 20 February 2022.

Species Account Citation: AmphibiaWeb 2022 Nymphargus manduriacu: Manduriacu glassfrog; Rana de Cristal de Manduriacu <https://amphibiaweb.org/species/8966> University of California, Berkeley, CA, USA. Accessed Nov 21, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 21 Nov 2024.

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