The specific epithet, “mayeri,” honors General Sinclair James Mayer from the Sistema Defesa, Indústria e Academia division of the Brazilian Army. He played an instrumental role in making the expedition to Pico da Neblina possible (Fouquet et al. 2023).

Description
Neblinaphryne mayeri is a small-bodied, semi-fossorial frog with a snout-vent length of 14.0 - 19.2 mm in males and 15.9 - 33.1 mm in females. The head is very slightly longer than wide and narrower than the body. The short snout is rounded in the dorsal and lateral views. The oval nostrils are small and do not protrude. The distance between the nostrils is about equal to the distance from the nostril to the eyes. The canthus rostralis is somewhat concave. The oval pupil is horizontal. The eye diameter is slightly less than twice the distance from the nostril to the eye. The upper eyelid is a little less than two-thirds of the interorbital distance. There is no tympanic membrane or annulus visible. The frontoparietal region is smooth and there are no cranial crests. There are no enlarged tubercles or folds on the head. The subgular vocal sacs can be conspicuous in some males and absent in others. The dorsal skin is finely granular. There are no dorsolateral or discoidal folds. The throat is finely granular but the belly is areolate. There is no cloacal sheath. The thenar tubercle is oval and smaller than the round palmer tubercle. The robust fingers are short and thin without lateral fringes or webbing. The fingertips are rounded to slightly pointed on fingers I, II, and IV and do not expand or have discs or grooves. The third finger is mucronated. Finger I is slightly shorter than finger II with the relative length of the fingers being I < II < IV < III. The subarticular tubercles of the fingers are round, but do not project, and have a formula of 1 - 1 - 2 - 2. The fingers slightly flatten on the ventral side and the skin is transparent on the tips. There are no nuptial pads. The thigh length is very slightly longer than the tibia length, and about equal to the foot length. The flat inner metatarsal tubercle is oval and slightly smaller than the prominent, round outer metatarsal tubercle. Like the fingers, the toes are fully developed and lack lateral fringes and webbing. The toes tips do not expand with toes I and V being rounded or pointed and toes II - IV being mucronated. The relative length of the toes is I < II < III < V < IV with toe V only being slightly longer than toe III. The round subarticular tubercles are small, flat, and rounded with a formula of 1 - 1 - 2 - 3 - 2. Also like the fingers, the toes are slightly flattened on the ventral surface and transparent on the tips. Neither the palms or the pes have supernumerary tubercles (Fouquet et al. 2023).

DIAGNOSIS:

At the time of the species description, N. mayeri was the only member of its family. The family Neblinaphrynidae can be differentiated from the rest of the Brachycephaloidea (terrorana) superfamily, which is a part of, by osteological. More specifically, most other Brachycephaloidea families that can be found in the Pantepui biogeographical region, have spatulate terminal phalanges, while Neblinaphrynidae have terminal phalanges that are pointed. Additionally, the highly vestigial, or lacking, state of the septomaxillae (snout region) in Neblinaphrynidae is another unique character. This family can be further distinguished from Adelaphrynidae by the presence of fully developed fingers (Adelaphrynidae have a reduced fourth finger), with mucronate (pointy) tips on the second and third fingers and on the second, third and fourth toes only (Adelaphrynidae having all of its toes and fingers with mucronate tips), the absence of lateral grooves (Adelophrynidae having lateral grooves), the presence of two subarticular tubercles on the fourth finger (Adelaphrynidae having only a single hump-shaped tubercle), and the absence of vomerine teeth (present in Adelaphrynidae). Neblinaphryne can be differentiated from the genera Ceuthomantis, Dischidodactylus and Pristimantis by having mucronate (pointy) tips on the second and third fingers and on the second, third and fourth toes only (compared to rounded tips for the three genera), and by having the tensor fasciae latae muscle originating anteriorly on the iliac shaft (vs. originating posteriorly or in the middle of it for the three other genera). It can further be distinguished from Ceuthomantis and Dischidodactylus by its iliacus externus muscle originating anteriorly on the iliac shaft (vs. originating on the posterior half of the iliac shaft or on the posterior three-fourths of the iliac shaft), and from Dischidodactylus by the lack of vomerine teeth (vs. present). Compared to more distantly related families in the Hyloidea superfamily, Neblinaphrynidae has seven differentiating characteristics: 1) absence to highly vestigial septomaxillae, 2) frontoparietal region is smooth and absence of cranial crest, 3) the vomer bone is free of contact with any other bone and doesn’t have a dentigerous process, 4) the third finger has a mucronate tip, 5) the second, third and fourth toes have mucronate tips, 6) the iliacus externus muscle originates anteriorly and extends in parallel alongside the entire length of the iliac shaft, 7) the tensor fasciae latae muscle originates anteriorly on the iliac shaft and is immediately posterior to the sacral diapophyses (Fouquet et al. 2023).

COLORATION:

In life, this species has a brown dorsal coloration, with some individuals having irregular blotches of bluish-gray and red on dorsal and lateral surfaces of the head, body and limbs. They may present with a yellow transversal bar under the supratympanic fold. The paracloacal area has yellow marks that might vary in position and size and, possibly extending to the posterior part of the thighs. The background coloration of the ventrum is a diffuse yellow that varies in extent, in some individuals covering the belly, upper arm and thighs, and in others limited to a few specks. There may also be bluish flecks on the throat, ventral surface of the hind limbs, and flanks. The iris is dark brown. After being preserved in 70% ethanol for 5 years, the general coloration didn’t change a lot except for discolored blotches on dorsum, arms, and legs. Those blotches varied from light gray to light blue. The dorsal limbs are dark brown as are the throat, ventral surface of the arms, tibia, and feet. The ventral surface of the chest and thighs is light brown. The skin at the finger articulations is lighter. The paracloacal marks and bluish flecks become light gray and white, respectively (Fouquet et al. 2023).

VARIATION:

There does not appear to be sexual size dimorphism. Vocal sacs and slits are variable in males. In both sexes, irregular blotches may be found on the dorsal surface as well as a transverse yellow bar under the supratympanic fold. The size and extent of paraclocal marks also varies. In preservative, light gray dorsolateral and mid-dorsal lines can be found in some specimens as well as lines on the anterior part of the arms (Fouquet et al. 2023).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Brazil

View distribution map in BerkeleyMapper.

This species is endemic to the Pico da Neblina massif, in Pantepui region of Brazil. More specifically, specimens have been found in Parque Nacional do Pico da Neblina, Santa Isabel do Rio Negro, Amazonas State, Brazil. It is found from 2013 - 2995 m a.s.l. in elevation, with the highest elevations corresponding to the summit of Pico da Neblina, Brazil’s highest mountain in the State of Amazonas. The majority of specimens have been collected above 2600 m elevation. These individuals were found more frequently on steep rocky slopes but also open grassy habitats with scattered short trees (Fouquet et al. 2023).

Life History, Abundance, Activity, and Special Behaviors
Neblinaphryne mayeri is described as a semi-fossorial species. This trait is supported by the fact that of the 32 type specimens, only one was not found under rocks. That individual was captured using a pitfall trap. Furthermore, the mucronated and pointy finger and toe tips as well as metatarsal tubercle morphology suggests fossoriality. Individuals were often found clustered in groups (Fouquet et al. 2023).

No calls were heard from this species during the researchers’ field season in 15 - 23 November 2017 (Fouquet et al. 2023).

At the time of the species description, the reproductive behavior, development mode, interactions with predators and preys or intraspecific interactions hadn’t been documented yet (Fouquet et al. 2023).

Larva
Brachycephaloidea, the superfamily that N. mayeri is part of, is direct-developing (Fouquet et al. 2023).

Trends and Threats
The species authority recommends that N. mayeri be given a “Critically Endangered” status on the IUCN red-list due to its extremely limited range (less than 96 square km), and presence only at high elevations. Climate change is probably the main threat to this species. Species living at high elevations are particularly vulnerable to changing microclimates, as they have nowhere to retreat to with warming temperatures. Amphibians are particularly vulnerable to these slight changes in microclimate as their basic physiology is dependent on environmental temperatures and humidity. Among other species in Brachycephaloidea, shifts in altitudinal distribution have already been observed. However frogs like N. mayeri, that live at high elevations have nowhere to retreat to in search of cooler temperatures, which may lead to extinction (Fouquet et al. 2023).

Another threat that N. mayeri may face is the human introduction of pathogens, for example chytridiomycosis. Human introduced pathogens may be particularly harmful to this species as they are considered “immunologically naïve” communities due to their isolation from humans. This second threat lead the species authority to wonder the philosophical question if these Lost Worlds, a reference to the story by the same name written by Sir Arthur Conan Doyle, should ever be discovered (Fouquet et al. 2023).

Possible reasons for amphibian decline

Disease
Climate change, increased UVB or increased sensitivity to it, etc.

Comments

PHYLOGENETIC RELATIONSHIPS:

Neblinaphyne mayeri, on the basis of Bayesian Inference of combined mitogenetic (nearly complete genome) and nuclear (a total of 5607 base pairs from POMC, RAG1, TYR, NCX1, CXCR4, and SLC8A3) DNA is the sister taxon to all Brachycephaloidea except for Ceuthomantidae, which is the next most closely related family. That divergence occurred more than 45 Ma. However, when only nuclear data was analyzed, N. mayeri was estimated to diverge from all Brachycephaloidea except Ceuthomantidae about 55 Ma. When only mitochondrial data was analyzed, N. mayeri formed a clade with Ceuthomantidae, which was sister to the rest of Brachycephaloidea, and diverged about 53 Ma (Fouquet et al. 2023).

OTHER INTERESTING INFORMATION:

Along with Caligophrynidae, Neblinophrynidae is thought to have diverged from the rest of Brachycephaloidea over 45 million years ago (Fouquet et al. 2023).

Neblinaphyne mayeri was described alongside Caligophryne boylei in 2023, both taxa were described as a new family, genus, and species, which has not happened since 2003 (Fouquet et al. 2023).

The discovery of both N. mayeri and C. doylei, point to the high, and largely unexplored diversity of the Pantepui region, deeply rooted in the tree of life. Due to high elevations, and dangerous conditions this region has largely been unexplored by humans. At the same time human caused climate change is threatening this area, making it increasingly inhospitable for high altitude species (Fouquet et al. 2023).

References
Fouquet A., Kok, P. J. R., Recoder, R. S., Prates, I., Camacho A., Marques-Souza S., Ghellere J. M., McDiarmid R. W., and Rodrigues M.T. (2023). Relicts in the mist: Two new frog families, genera and species highlight the role of Pantepui as a biodiversity museum throughout the Cenozoic. Molecular Phylogenetics and Evolution, 191, 107971 [link]

Species Account Citation: AmphibiaWeb 2024 Neblinaphryne mayeri <https://amphibiaweb.org/species/9833> 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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