Description
Ameerega shihuemoy is a small to medium-size frog for its genus, with adult females having a snout to vent length from 21.5 to 25.7 millimeters and males having a smaller size range of 19.2 to 21.8 millimeters. The head is typically narrower than the body or about as wide, and its width is 29 to 33% of body length. The greatest width of the head is at the jaw articulation rather than at the eyes. In the profile, the snout is bluntly rounded or pointed and in the dorsal and ventral view it is typically rounded but can range from truncate to bluntly pointed. The slightly posterolaterally-directed nostrils are located near the tip of the snout and are visible from below and from the front but not from above. The canthus rostralis is short and protrudes. The loreal region is flat or slightly concave and vertical. The distance between the eyes is wider than the upper eyelid. The eye length is shorter than snout length, and the distance from the center of the nostril to the eye is 60 to 87% of eye length. The tympanums are distinct and is 35 to 60% of the size of each eye. The skin texture on the dorsal surface of the head, body, and hind limbs is noticeably coarse and granular. The texture of the skin on the ventrum, forelimbs, and sides of the head and body is smooth or almost smooth. The ventrolateral surfaces of the feet are also relatively smooth (Serrano-Rojas et al. 2017).

The hands are moderately large, and relative finger lengths go from IV > I > II > III with fingers I, II, and IV having similar lengths when adpressed to the point that finger I can appear shorter or longer than finger II. Also, when adpressed, the weakly to moderate finger discs overlap. The disc of the third finger is 1.2 – 1.8 times the width of the phalanx below it. The large, round outer metacarpal tubercle is located at the base of the palm, and the smaller, round inner metacarpal tubercle is located at the base of the first finger. One well-developed, prominent subarticular tubercle can be found on fingers I and II, two on fingers III and IV. There are no supernumerary tubercles, finger keels, or metacarpal folds on the hands (Serrano-Rojas et al. 2017).

The tibia length is 47 to 54% of snout-vent length. There is a large inner metatarsal fold situated on the distal half of the tarsus and extending to the inner metatarsal tubercle. There is no outer metatarsal fold. Both the inner and outer metatarsal tubercles are low with rounded surfaces. The outer metatarsal tubercle is larger than the inner. The relative toe lengths are IV > III > V > II > I with the first toe reaching the base of the subarticular tubercle on the second toe. There is slight webbing near the base of the toes on toes II, III, and IV. The toe discs are moderately enlarged, being wider than the finger discs. Moderately raised subarticular tubercles are present with one each on toes I and II, two each on toes III and V, and three on toe IV. There are no supernumerary tubercles or fringes on the foot (Serrano-Rojas et al. 2017).

At stage 25, Ameerega shihuemoy tadpoles have a total length range of 15.0 – 18.8 mm. The body is globular, ovoid in the dorsal view, and compressed in the lateral view. From the dorsal view the snout is rounded. The nostrils are small, oval, and located dorsolaterally. They do not have any projections. The small eyes are also dorsolaterally directed. A small oral disc composed of papillae that are laterally notched, conical, and simple, surrounds the anteroventrally located mouth. Ther anterior labium does not have marinal papillae but one complete row of papillae can be found on the posterior labium. The two anterior papillae are the same overall width but the second has a medial gap. The three posterior papillae are complete, and the first two are of equal length, but the third is shorter. The anterior jaw sheath has reduced serration and a medial indentation. The serrated posterior jaw sheath is V-shaped. The long lateral process extends past the lower jaw. The labial tooth row formula is 2(2)/3(1). There is a single spiracle on the left side (sinistral) located just anterior to the middle of the body. The tail musculature is at its highest where it meets the body and is the same height as the body. The dorsal tail fin does not extend onto the body. Both tail fins are concave in shape and have rounded posterior ends. They reach their maximum height at the last third of the tail (Serrano-Rojas et al. 2017).

Ameerega shihuemoy looks similar to A. altamazonica, A. boliviana, A. hahneli, A. ignipedis, A. petersi, A. picta, A. pongoensis, A. pulchripecta, A. simulans, A. smaragdina, and A. yungicola but can be differentiated from all Ameerga except for A. boliviana, A. simulans, A. smaragdina, some A. pongoensis, and most A. petersi by the lack of calf, thigh, and axillary flash marks. Ameerega shihuemoy also has dorsolateral lines that range in color from cream to light orange that differentiate it from all other species except A. picta. Ameerega shihuemoy’s belly is blue with a reticulated black patterning that differentiates it from A. boliviana, A. petersi, and A. smaragdina (Serrano-Rojas et al. 2017).

Vocalization also helps to differentiate Ameerega shihuemoy from other species. There is a longer duration between the calls of Ameerega shihuemoy (Mean = 1042.5 milliseconds, standard deviation = 186.6 milliseconds) than in comparative species (A. simulans, A. picta, A. hahneli, A. boliviana, A. yungicola, and A. macero). Ameerega shihuemoy also has a clearly higher dominant frequency (Mean = 4672.7 Hz, Standard Deviation = 251.0 Hz) than morphologically similar species (Serrano-Rojas et al. 2017).

Live adult individuals have a blackish colored dorsum, showing clear granulation and coppery-brown hues towards the middle of the back that turn starkly black near the top edge of the flanks. A clear cream, coral, or bright orange dorsolateral line starts at the groin from a coral or bright orange spot located on the upper thigh and hip. This line continues slantwise, curving over the eye and connecting around the snout. This stripe is flanked by darker black coloration on either side. Below the stripe, on the flanks, the coloration varies from metallic bluish green to mostly black. There is also a pale white-cream stripe along the upper lip that begins between the eye and nostril and continues backwards underneath the eye and tympanum until just after the base of the upper arm. The dorsal surfaces of the arms and legs are bronze-brown in color with hues of black and green. All surfaces on the underside of the animal are blue with a retitculated black patterning, however some individuals have black ventrums with blue reticulations (Serrano-Rojas et al. 2017).

Adult specimens in preservative lose much of their coloration, as the blue ventral coloring and orange spot and stripe fade to gray. This loss of coloration can make the black reticulation seen in life difficult to see (Serrano-Rojas et al. 2017).

Live tadpoles are dark brown in color with black spotting. The ventral side is translucent such that the intestines are clearly visible through the skin, but becomes somewhat pigmented toward the tail. Furthermore, the caudal musculature only has weak coloration and the tail fin is transparent, although small and irregular clusters of melanophores occur along the tail (Serrano-Rojas et al. 2017).

Tadpole specimens in preservative have dark gray dorsums with transparent bellies through which the intestines are somewhat visible. The caudal musculature is creamy white accented by nonuniform gray specks and the fins are also moderately transparent (Serrano-Rojas et al. 2017).

Variation in individuals of this species comes from coloration, as the color of the dorsolateral line may vary from cream to bright orange, the amount of greenish coloration on the flanks and limbs may vary, and the belly may be black with blue reticulations (Serrano-Rojas et al. 2017).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Peru

View distribution map in BerkeleyMapper.

Ameerega shihuemoy has been found in nine localities in the Manu Province of the Madre de Díos region of southeastern Peru within an elevational range of 340 to 850 meters. Six localities are in the Amarakaeri Communal Reserve, the other three occur in the buffer zone of the Manu Biosphere Reserve, specifically Erika lodge, the Manu Learning Centre, and Aguas Calientes, Shintuya. This species occurs in premontane forest (Serrano-Rojas et al. 2017).

Life History, Abundance, Activity, and Special Behaviors
This species is typically found in low disturbance forest near impermanent bodies of water in the wet season and rocky riparian areas during the dry season. Individuals are generally active at twilight in the early evening or morning. Typical shelters are crevices in rocks and gaps in roots. When individuals are inactive at night they rest on low vegetation at heights above ground of 0.1 to 0.5 meters (Serrano-Rojas et al. 2017).

The species authority conducted a habitat selection analysis for the species to determine which structural variables were key indicators of the absence or presence of these frogs near streams. They found that the presence of large rocks, leaf litter cover, canopy cover, number of potential refuges, stream flow, and presence of a still body of water were the six variables that best modeled frog habitation near streams (Serrano-Rojas et al. 2017).

Males call year-round, with calling activity concentrated during the early evening but also occurring in the early morning. Calling occurs out in the open, where males perch on leaf litter, rocks, or other woody detritus. The males of this species give an advertisement call of sequential chirping pulsed notes. The dominant frequency of the calls ranges between 4478.9 to 4909.6 Hz, the duration of the notes ranges from 84 to 109 milliseconds, and the notes are repeated at a rate of 0.8 to 1.0 notes per second, with 8 pulses per note. The species also has a territorial defense call composed of three quick notes in series, with the first note being longer than the others. The duration of the first note is 87.2 ± 2.5 milliseconds, the second is 69.4 ± 2.6 milliseconds, and the third is 72.8 ± 2.8 milliseconds (Serrano-Rojas et al. 2017).

Seasonal and permanent streams are both sites for reproduction activity. Females lay eggs covered with a translucent orange mucilage in small nesting sites near streams. Males provide parental care by guarding eggs and transporting tadpoles. Two clutches with 22 and 25 eggs, respectively, were found in June and July. One clutch was abandoned by the father after becoming dirty and dry, and containing insect larvae, suggesting that insect larvae may be potential predators of A. shihuemoy. The other clutch developed normally and tadpoles were assumed to be transported at stage 22 (Serrano-Rojas et al. 2017).

Tadpoles are exotrophic and benthic. Generally, tadpoles can be found in slow, shallow streams or in still water alongside streams. While total time until metamorphosis is unknown, it’s suggested that development from stages 13 to 22 lasts twenty days, stages 26 to 38 lasts four days, and stages 40 to 46 (transformation complete) lasts seven days (Serrano-Rojas et al. 2017).

Ameerega shihuemoy metamorphs and tadpoles have been found in sympatry with A. macero metamorphs in slow, shallow streams (Serrano-Rojas et al. 2017).

Trends and Threats
The habitat of this species is subjected to threats from agriculture, gold mining, and logging, as well as potential legislation legitimizing the construction of the Nuevo Eden-Boca Manu-Boca Colorado road. Illegal construction of this road has already commenced, exacerbating the listed human disturbance threats to the species. The road’s route would go through the buffer zones between Manu National Park and Amakaeri Communal Reserve, likely leading to habitat deterioration within the protected regions. This in turn could lead to population declines and decreased geographical range for the species, as it’s known from some localities along the Madre de Dios River within the buffer zone between the two parks (Serrano-Rojas et al. 2017).

Possible reasons for amphibian decline

General habitat alteration and loss
Habitat modification from deforestation, or logging related activities
Intensified agriculture or grazing
Disturbance or death from vehicular traffic
Mining
Habitat fragmentation

Comments
The species authority is: Serrano-Rojas, S. J., Whitworth, A., Villacampa, J., Von May, R., Gutiérrez, R. C., Padial, J. M., Chaparro, J. C. (2017). “A new species of poison-dart frog (Anura: Dendrobatidae) from Manu province, Amazon region of southeastern Peru, with notes on its natural history, bioacoustics, phylogenetics, and recommended conservation status.” Zootaxa, 4221(1): 071-094

Maximum Likelihood analysis of the 16S ribosomal RNA gene found Ameerega shihuemoy was sister to a clade composed of A. altamazonica, A. macero, A. rubriventris, and two undescribed Ameerega species from Peru and Brazil (Serrano-Rojas et al. 2017).

The species name, “shihuemoy” (pronounced shee-way-moy), means "poison dart frog" in Harakmbut, the language of the aboriginal Amarakaeri people, who live in the same areas as the newly discovered frog (Serrano-Rojas et al. 2017).

References

Serrano-Rojas, S. J., Whitworth, A., Villacampa, J., Von May, R., Gutiérrez, R. C., Padial, J. M., Chaparro, J. C. (2017). ''A new species of poison-dart frog (Anura: Dendrobatidae) from Manu province, Amazon region of southeastern Peru, with notes on its natural history, bioacoustics, phylogenetics, and recommended conservation status.'' Zootaxa, 4221(1), 71-94.

Species Account Citation: AmphibiaWeb 2018 Ameerega shihuemoy <https://amphibiaweb.org/species/8569> 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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