Description
Ameerega pepperi is a medium sized frog of which the two males in the original description both measured 28.6 and females ranged from 30.8 - 34.4 mm. They have some characteristics that describe Ameerega species including having no webbing between digits present and granular dorsal skin. The head is narrower than the body with the widest part being between the jaw articulation and the tympanum. From the lateral view the snout is sloping, from the dorsal view the snout is bluntly rounded, and from the ventral side the snout appears truncated. The nostrils are directed posterolaterally and located on the tip of the snout, where they can be seen from the dorsal and ventral views. The canthus rostralis is sloped and rounded. The eyes bulge outwards from the face with a pupil that is slightly rounded and also horizontally elliptical. The circular tympanum is visible and lacks a supratympanic fold. The dorsal skin is granular with the hind limbs being more granular in texture and the forelimbs lacking granulation. The skin is smooth on the ventral side and on some areas of the head. The digits lack supernumerary tubercles, lateral fringes, and basal webbing. The hands are small and on the palms there is a large circular outer metacarpal tubercle on the median base. There are no metacarpal tubercles on the base of finger I. The fingers have widened discs and relative lengths of I = II = IV < III. Finger III has an enlarged disc. Fingers III and IV have two subarticular tubercules, whereas fingers I and II only have one. The hindlimbs are short, small, and lack tarsal tubercles. There are moderate-sized inner and outer metatarsal tubercles that are protuberant and round. The relative toe lengths are I < II < V < III < IV. Toes I and II have slight expansions that create discs smaller than the fingers, however toes III – V have expanded discs that are 1.5 times the size of the adjacent phalanx. Toes III, IV, and V have two subarticular tubercles and toes I and II only have one (Brown and Twomey 2009).

The most notable characteristic to distinguish A. pepperi from similar species is the red, orange, or yellow coloration on the dorsal side of this species. Ameerega pepperi has a dorsolateral stripe whereas A. parvula and A. bilinguis lack this distinct patterning. Both A. cainarachi and A. macero are smaller in size than A. pepperi. The largest variation between this species and closely related species is the mate calling patterns heard from these species. Whereas A. pepperi has a series of burst notes that are modulated by frequency, A. cainarachi has a regular chain of notes that can be heard, A. macero has a series of peeps that are very intense, A. bassleri has a chorus of whistles repeated for several minutes, and A. yoshina produces more notes per second than A. pepperi (Brown and Twomey 2009).

Ameerega pepperi are characterized by their black dorsal coloration with red, orange or yellow patterning depending on the location of the individual. This patterning is more vivid and clustered near the head and becomes less dense near the rear. They have two yellow dorsolateral stripes that originate near the eye and end near the groin, where they are slightly wider than by the eye. They also have a yellow labial stripe that begins near the nares. The limbs are either black or a dark green color with small patches of tan or olive. The hind legs also contain femoral spots that are yellow in color. In contrast, the forearms contain yellow coloration that stretches up toward the mouth. The ventral side has a dark blue coloration with many black streaks and splotches. The irises are black in color as well. When preserved in alcohol, the species remains very similar in color, although the red and yellow colorations on the dorsal side often change to a black color and an silver-white color, respectively (Brown and Twomey 2009).

The largest variation between individuals is dorsal coloration, which is tied to geographic location. The populations in the southern part of their range have more red on their dorsal side and the populations in the north have more orange or yellow on their dorsal side near the head. This variation creates a gradient of color change throughout their range (Brown and Twomey 2009).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Peru

View distribution map in BerkeleyMapper.

Ameerega pepperi is found in the upper Huallaga Valley to the southern boarder San Martín at elevations between 380 m up to 1000 m. Individuals are most likely to be found on the eastern side of Río Huallaga although specimens have been found on the western side in San Francisco and Huicungo as well. Although no specimens have been documented from between those sites, it is likely that they inhabit that area based on to ecological surveys of the habitat. Ameerega pepperi is found in premontane forests and are most likely to be found in the areas surrounding streams (Brown and Twomey 2009).

Life History, Abundance, Activity, and Special Behaviors
Ameerega pepperi is found in premontane forests not more than 30 m away from a stream. They can survive in altered habitats only if there is still a stream present that has not lost a source of shade. These frogs spend the daylight hours hiding among the boulders that sit alongside the streams (Brown and Twomey 2009).

The mating call of A. pepperi is a series of whistle-like sounds or “retarded trill” that gets produced at a rate of 0.9 - 1.3 notes per second. Each call produces a dominant frequency of 2970 Hz and note duration is for 130 - 220 ms with a lag of 560 - 1030 ms in between. Calling activity for this species happens most frequently around dusk when the males have reached a preferable position on an elevated rock or log (Brown and Twomey 2009).

Once a call has been made, courtship and mating takes place among the leaf litter on the ground. The female produces clutches of 22 - 44 eggs at a time, which are guarded by the males until they hatch around eighteen days later. Tadpoles develop in streams that have a clay-like sediment that the tadpoles can easily bury themselves into, especially when the weather becomes hotter. These tadpoles take approximately five to six weeks to reach full development (Brown and Twomey 2009).

Trends and Threats
Ameerega pepperi has experienced slight amounts of habitat loss in certain areas throughout their range (Brown and Twomey 2009).

Possible reasons for amphibian decline

General habitat alteration and loss

Comments
The species authority is: Brown, J. L., Twomey E. (2009). “Complicated histories: three new species of poison frogs of the genus Ameerega (Anura: Dendrobatidae) from north-central Peru.” Zootaxa 2049:1-38

Ameerega pepperi belongs to the A. bassleri clade. It is most closely related to A. bassleri and is more distantly related to both A. ignipedis and A. yoshina (Brown and Twomey 2009).

The species was named after Canadian conservationist Mark Pepper who is responsible for a greater understanding of poison frog biogeography and taxonomy (Brown and Twomey 2009).

It is suggested that the cause of speciation between A. pepperi and similar larger, more colorful species like A. bassleri and A. yoshina is differences in behavior and vocal mating calls. However, the only areas that A. pepperi and its sister species A. bassleri have been found together occurs in Juanjui, which suggests that geographic separation may also be an important factor in the speciation of these frogs (Brown and Twomey 2009).

References

Brown, J. L., and Twomey, E. (2009). ''Complicated histories: three new species of poison frogs of the genus Ameerega (Anura: Dendrobatidae) from north-central.'' Zootaxa, 2049, 1-38.

Species Account Citation: AmphibiaWeb 2016 Ameerega pepperi <https://amphibiaweb.org/species/7276> University of California, Berkeley, CA, USA. Accessed Jan 5, 2025.

Citation: AmphibiaWeb. 2025. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 5 Jan 2025.

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