Los Amigos Leaf Frog
Species Description: Santa-Cruz, R. von May, A. Catenazzi, C. Whitcher, E. López Tejeda, and D.L. Rabosky. 2019. A new species of terrestrial-breeding frog (Amphibia, Strabomantidae, Noblella) form the Upper Madre de Dios watershed, Amazonian Andes and lowlands of southern Peru. Diversity 11: 0145.
© 2019 Alessandro Catenazzi (1 of 42)
Noblella losamigos has a snout-vent length range of 9.74 - 13.6 mm for females and 9.16–11.40 mm for males. Its head is narrower than the body and slightly wider than long. The snout appears short and round from a dorsal view, but appears almost flat in the profile view. The lips are rounded and the species does not have postrictal tubercles. The nostrils don’t bulge out from the head and are located near the snout. From a dorsal view, the canthus rostralis appears slightly curved and in the profile it appears rounded. The lores are flat. It possesses a large eye that is 46% the length of its head. The diameter of the eye is 1.8 times the distance of the eye from the nostril and its upper eyelid width is 62% the interorbital distance. A short supratympanic fold covers the upper quarter of the tympanic annulus, which is visible below the skin. A tympanic membrane is present as well. The species does not have cranial crests (Santa-Cruz et al. 2019).
Its dorsal skin ranges from smooth to a fine shagreen texture. There are tiny tubercles on the upper eyelid and dorsal surface of the head. There are no observable discoidal or dorsolateral folds. A protuberant cloaca is present and the cloacal region exhibits several small tubercles. Skin texture on the ventrum and gular regions range from smooth to finely areolate. The skin on the belly and the flanks is smooth. A pectoral fold is present but difficult to observe (Santa-Cruz et al. 2019).
On the arms, there are no observable ulnar tubercles. Supernumerary palmar tubercles are observable. The palmar tubercle is a flat oval and double the size of the thenar tubercle, which appears elongated. The subarticular tubercles appear similar to calluses and are flat both in ventral and lateral views. Non-protruding subarticular tubercles are not present. The largest subarticular tubercles are located at the base of the fingers. Each digit tip is rounded and ends in papillae. Additionally, each finger has narrow lateral fringes. When adpressed, the relative finger lengths are: 3 > 2 > 4 > 1. The second finger is consistently at least as long as the first finger. The fourth finger only has two phalanges. The species has T-shaped and pointed terminal phalanges. The species does not have nuptial pads. (Santa-Cruz et al. 2019).
The length of the hindlimb is moderate, as the tibia is 51% of the snout-vent length and the foot is 43% of the snout-vent length. Tubercles are not present on the upper and posterior areas of the hindlimb. Additionally, there are no observable tubercles on the outer surface of the tarsus and the heels do not exhibit tubercles. However, a short, fold-like tubercle is present on the ventral region of the foot. The inner metatarsal tubercle appears as an oval, is of higher relief, and is about the same size as the conically shaped, rounded outer metatarsal tubercle. The subarticular tubercles are difficult to distinguish and are not clearly seen from the dorsal view. Each toe possesses narrow lateral fringes and does not exhibit basal webbing. The third, fourth, and fifth toes are pointed and the tips of the second, third, fourth, and fifth toes have slightly expanded disks with grooves and papillae. The tip of the fifth toe is smaller than the the third and fourth toes tips. When adpressed, the relative toe lengths are 4 > 3 > 5 > 2 > 1 (Santa-Cruz et al. 2019).
Despite exhibiting many of the defining characteristics of its genus, N. losamigos can be distinguished from other species of its genus by its size, digit morphology, tarsal tubercle, skin texture, suprainguinal spots, facial mask pattern, and lack of an observable tympanum. The snout vent length of N. losamigos is larger than that of N. pygmaea and smaller than that of N. coloma, N. duellmani, N. heyeri, N. lynchi, N. lochites, N. madreselva, N. personina, P. bagrecito, P. glauca, P. chirihampatu, and P. usurpator. Unlike N. losamigos, which has two phalanges on finger IV, Noblella duellmani, N. thiuni, N. coloma, N. heyeri, N. lynchi, N. madreselva, N. pearsonina, N. peruviana, and N. pygmaea have three phalanges on their fourth fingers. There is a short, fold-like tubercle on the underside of the tarsal region in N. losamigos. A similar tubercle can be found on N. ritarasquinae and P. glauca, and N. peruviana and N. heyeri. However, in N. lochites and N. myrmecoides, the tubercle extends across the ventral side of the tarsal region. A longer tarsal tubercle is found in P. usurpator, P. chirihampatu, N. thiuni, N. personina, N. lynchi, and N. coloma and N. carrascoicola has a subtly observable tubercle. A small, sickle-shaped tubercle is observable in P. bagrecito. No tubercle or tarsal fold is observable in N. duellmani, N. madreselva, and N. pygmaea. Noblella pygmaea has a small, rounded tubercle. While N. losamigos has smooth to shagreen doral skin, N. duellmani, N. madreselva, N. lynchi, N. personina, and N. pygmaea have small tubercles or pustules on the dorsal surface. Additionally, whereas N. losamigos display suprainguinal spots, P. chirihampatu and P. glauca exhibit suprainguinal stripes. The facial mask of N. losamigos is disrupted by a dark brown lateral band containing cream spots stretching along the flanks from the snout tip to near the insertion point of the thighs. In contrast, N. duellmani has a narrow, dark brown post-orbital stripe, N. pygmaea have a broad gray dorsolateral stripe stretching from the upper eyelid to the thigh insertion, and N. personina does not have a lateral dark band. Lastly, N. losamigos does not have an observable tympanum, which helps differentiate it from of N. carrascoicoa, N. duellmani, N. madreselva, N. myrmecoides, N. ritarasquinae, N. thiuni, Psychrophrynella bagrecito, Psychrophrynella chirihampatu, Psychrophrynella glauca, and Psychrophyrnella usurpator, which all have a clearly observable tympanum (Santa-Cruz et al. 2019).
In life, dorsal coloration varies between ocher gold and light brown. An interorbital bar and dark brown, irregularly-shaped dorsal mark is present on most specimens. Specimens without the dorsal mark exhibit a light middorsal line that stretches from the body’s middle to the cloaca. Ventral coloration varies between transparent gray to black. The size and number of cream colored flecks that appear on all specimens’ hands, thighs, throat, venter, and feet varies. Some males present a black coloration from the throat to the middle of the ventral surface. Circular suprainguinal marks can be found on some specimens. Dark inguinal spots are present. Though some specimens have speckled forelimb patterns, others have a dark brown stripe resembling a wristband. Most specimens have a dark facial mask with variation in mask shape and size. Additionally, most specimens have one to three cream colored flecks on their upper lips, one of which is below the eyes. A lateral line stretching from the snout tip to the point of insertion of the thigh merges with the facial mask in some specimens. If this merging is present, the line is typically interrupted into blotches by lighter flank colors. (Santa-Cruz et al. 2019).
In preservative, the golden brown dorsum is marked by irregular dark brown marks on the head and body. Its forelimbs are cream with dark brown, wristband shaped stripes running across. Unlike the forelimbs, the wristband shaped stripes aren’t visible on the hind limbs of some specimens but display irregularly patterned tiny dark bars. Spots of cream cover parts of the dark brown facial mask and lateral band. The lower flanks are also dark brown. The species has a dark gray iris. Small cream-colored spots occasionally appear on the mainly dark gray ventral side (Santa-Cruz et al. 2019).
Noblella losamigos vary in body size, shape, and coloration. Both body size and shape vary in relation to elevation. Body size is directly related to elevation, i.e. higher elevation correlates with larger body sizes of males and females. Morphological variation is smaller in lower elevations while higher variability in morphology is observed of specimens in higher elevations. In terms of coloration and pattern, some male specimens have a black strip that stretches from the throat to midway on the ventral surface. Additionally, while some specimens display speckled forelimb patterns, others exhibit a dark brown strip with resemblance to a wristband. The majority of specimens have a dark facial mask that varies in size, shape, and number of cream colored flecks on the upper lip. Lastly, a lateral line from the snout point to the thigh insertion is present in some specimens (Santa-Cruz et al. 2019)
Distribution and Habitat
Noblella losamigos is found in southern Peru at elevational ranges of 240 – 1490 m. More specifically, the species is found in the Los Amigos and Kosñipata Valleys, at Cocha Cashu Biological Station near Pakitza in the Manu National Park lowlands, and around the Manu Learning Centre of the Andean piedmont. The lowland Amazon rainforest is located at the lower bound and montane forest on the Andes’ eastern slopes is located at the upper bound. Noblella losamigos’ distribution is more dense in the floodplain forest at the Amazon lowland locality, but the species can also be found in the leaf litter in terra firme, bamboo, and palm swamp forests (Santa-Cruz et al. 2019).
Life History, Abundance, Activity, and Special Behaviors
The species is a direct developer. In colder temperatures, the species may lose mobility and become easy targets for predators (von May et al. 2019)
Trends and Threats
Logging and mining contribute to habitat loss and modification. Additionally, its small body size poses a higher risk of thermal stress. However, based on IUCN criteria, the species authority recommends a categorization of “Least Concern” because portions of its distribution overlaps with the protected areas of Tambopata National Reserve, Amarakaeri Communal Reserve, and Manu National Park and because the species can be found in pristine and secondary forests (Santa-Cruz et al. 2019).
Relation to Humans
No known relation to humans (Santa-Cruz et al. 2019).
Possible reasons for amphibian decline
General habitat alteration and loss
Santa-Cruz, R., von May, R., Catenazzi, A., Whitcher, C., López Tejeda, E., Rabosky, D.L. (2019). “A New Species of Terrestrial-Breeding Frog (Amphibia, Strabomantidae, Noblella) from the Upper Madre De Dios Watershed, Amazonian Andes and Lowlands of Southern Peru.” Diversity 9: 145.
The phylogenetic tree was constructed by Bayesian analysis of 16S, 12S, COI, RAG1, and Tyr gene fragment DNA sequences with Phrynopus peruanus as the tree root. Noblella losamigos was placed in a clade with southern Peruvian Noblella species and several members of Psychrophrynella. Its closest relative is N. pygmaea and an undescribed species (Santa-Cruz et al. 2019).
The species epithet is a reference to the species type locality: Los Amigos Biological Station and Conservation Consession located on the lower Los Amigos River watershed (Santa-Cruz et al. 2019).
Noblella losamigos sp. n. is the only species in the genus Noblella that inhabits both lowland and montane rainforest, covering an elevational range of 1250 m, and the only species in the “southern clade” of Noblella (likely to represent Noblella sensu stricto) that inhabits the lowland Amazon rainforest” (Santa-Cruz et al. 2019).
This species was featured as News of the Week on September 2, 2019:
With global warming underway, it is unclear if amphibians of the lowland tropics will be able to cope. A recent study by von May et al (2019) reports critical thermal limits of 56 species of sympatric lowland Amazonian frogs in Peru. Small, directly developing strabomantids, such as newly described Noblella losamigos (Santa-Cruz et al 2019), appear to be at the highest risk of thermal stress whereas hylid and microhylid frogs more effectively tolerate higher temperatures. In von May and colleagues' work, they estimate that 4% of lowland rainforest frogs studied will experience temperatures exceeding their thermal tolerances, and fully 25% might be moderately affected under a hypothetical 3°C increase in environmental temperature (Written by David B. Wake).
Santa-Cruz R., von May R., Catenazzi A., Whitcher C., López Tejeda E., L. Rabosky D. (2019). ''A New Species of Terrestrial-Breeding Frog Amphibia, Strabomantidae, Noblella) from the Upper Madre De Dios Watershed, Amazonian Andes and Lowlands of Southern Peru.'' diversity, 11(9), 145. [link]
von May R., Catenazzi A., Santa-Cruz R., S. Gutierrez A., Moritz C., L. Rabosky D. (2019). ''Thermal physiological traits in tropical lowland amphibians: Vulnerability to climate warming and cooling.'' PLOS One, 14(8), 18. [link]
Written by: Leighton Pu (2020-02-24)
Edited by: Ann T. Chang (2020-02-27)
Species Account Citation: AmphibiaWeb 2020 Noblella losamigos: Los Amigos Leaf Frog <https://amphibiaweb.org/species/9077> University of California, Berkeley, CA, USA. Accessed Apr 13, 2021.
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Citation: AmphibiaWeb. 2021. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 13 Apr 2021.
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