Description
Brachycephalus leopardus is a miniature species of saddleback toad that ranges between 9.7 - 11.9 mm in snout-vent length. The body is robust in appearance and takes on a bufoniform, or toad-like, shape. As such, the head is a bit wider than it is long, and it constitutes 32% of the snout-vent length. The snout is short, not quite reaching the length of the eye diameter, and when viewed from the dorsal and lateral angles it appears to be somewhat truncated. The nostrils protrude slightly from the snout and are angled anterolaterally. The loreal region is slightly indented into the face. The lips are not quite flush to the ventral side of the head, giving them a slightly sigmoidal appearance when viewed from the lateral angle. The eyes also protrude slightly when viewed from the dorsal and lateral view, and the eye diameter constitutes 36% of the length of the head. Neither the canthus rostralis nor the tympanum are distinct, and the vocal sac lacks external expansion. The dorsum is smooth, lacking the warts or co-ossifications present in members of the same genus and family. The head, chin, arms, and legs all lack the granular texture that is present on the lateral sides and belly. The granular portions are covered in large glandular warts that are circular in shape. The upper arms are approximately equal in length to the forearms, and both are thin relative to the robust body. The lengths of the fingers adhere to the following scheme IV < I < II < III, with fingers I and IV thought to be vestigial and significantly shorter than II and III. The tips of fingers II and III are pointed, compared to the round tips of finger I. The subarticular tubercles are absent, as are the inner and outer metacarpal tubercles. The hind limbs are short and more proportionately robust than the forelimbs. The length of the thigh equates to 35% of the snout-vent length, while the length of the tibia equates to 84% of the thigh length. The lengths of the toes are all relatively short, and they adhere to the following scheme V < II < III < IV. Toes II and III are reduced while toe I is not visible externally and toe V is thought to be vestigial due to its extreme reduction. The subarticular tubercles and inner metatarsal tubercles are absent whereas the outer metatarsal tubercle takes the shape of a large, distinct ovoid (Ribeiro et al. 2015).

DIAGNOSIS:

The smooth dorsum of Brachycephalus leopardus can help distinguish it from the more verrucose-backed members of its genus. The lack of dermal co-ossification on its dorsum sets it apart from members of the B. ephippium group, and the bufoniform shape sets it apart from members of the B. didactylus group, which tend to follow a more leptodactyliform body plan and are smaller in size on average. The small dark spots on the dorsal portion of the head, arms, legs, and thorax combined with the larger dark spots on its sides are unique to B. leopardus and can set it apart from all other members of Brachycephalus (Ribeiro et al. 2015).

COLORATION:

In life, B. leopardus expresses a bright aposematic orange coloration across the dorsum and limbs. The sides of the body shift towards a more yellow hue that continues across the ventrum as well. Minute dark spotting is apparent throughout the dorsum as well as the extremities. The sides of the body are spattered with the larger dark spots that resemble that of its namesake, the leopard. The iris is completely black. In preservative, the dorsum fades to a cream color with the sides and belly fading to a pale cream. Both the miniscule spots on most of the body as well as the larger spots on the side remain visible in preservative (Ribeiro et al. 2015).

VARIATION:

The coloration of the lateral and ventral parts of the body may vary in how much yellow is present on different individuals. The small and large spots may also be expressed at variable densities between individuals (Ribeiro et al. 2015).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Brazil

View distribution map in BerkeleyMapper.

Like many others in its genus, B. leopardus is restricted to high elevation cloud forest biomes and is found at two Brazilian localities. Specifically, they can be found in the region known as Morro dos Perdidos in the municipality of Guaratuba within the Brazilian state of Paraná, and at Serra do Araçatuba in the municipality of Tijucas do Sul within the same state. At Morro dos Perdidos, it is found at elevations around 1400 - 1420 meters above sea level, and at Serra do Araçatuba, it is found at around 1640 meters above sea level (Bornschein et al. 2019).

Life History, Abundance, Activity, and Special Behaviors
Brachycephalus leopardus is active during the day and can be found amongst the leaf litter in these cloud forests (Ribeiro et al. 2015).

Calling adult males were never found calling on top of the leaf litter (Ribeiro et al. 2015).

Mating pairs of B. leopardus can be found performing axillary amplexus (Ribeiro et al. 2015).

Members of the genus are noted to have a relatively low reproductive rate (Pie et al. 2018).

It has been proposed that for B. rotenbergae, a relative of B. leopardus, the bright orange coloration may contribute to the crypsis of the species in addition to being an aposematic signal to potential predators. Many leaves, seed pods, and mushrooms found in the leaf litter habitats of Brachycephalus species share a similar color and size, implying that the bright orange coloration may not be as conspicuous against the forest floor as one may assume. As B. leopardus and B. rotenbergae are similar in color and habitat, this observation may apply to both species, as well as others in the genus that share these traits (Nunes et al. 2021).

Trends and Threats
As of 2023, the IUCN Red List has not yet assessed this species; however, Bornschein et al. (2019) analyzed the Brachycephalus species using the IUCN Red List criteria with newer locality information and concluded this species should be listed as Endangered (criteria B1ab(i,iii)+2ab(ii,iii)).

Brachycephalus leopardus is threatened by deforestation to clear space for monocrop agriculture, urban projects, and pastures that decrease the available habitat range for this species and others (Ribeiro et al. 2015, Bornschein et al. 2019). Recent research has revealed that deforestation and habitat degradation affect at least 20 Brachycephalus species. Agricultural and urban projects can also increase the risks for soil contamination and introduction of invasive species. Soil contamination can be particularly damaging for amphibians like B. leopardus that have permeable skin (Bornschein et al. 2019). The excessive use of its habitat for cattle ranching also may damage the condition of the leaf litter that B. leopardus lives in. Even small amounts of bovine trampling may be enough to disrupt the leaf litter and the ecosystems that are housed within it, which could suggest that B. leopardus may benefit from stricter enforcement of environmental protection laws in the region (Ribeiro et al. 2015). For these reasons, it has been suggested that B. leopardus be added to the IUCN Red List as an endangered species (Bornschein et al. 2019).

Possible reasons for amphibian decline

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

Comments
Brachycephalus leopardus was described as a new species based on morphology by Ribeiro et al. (2015). The species description was criticized for using insufficient morphological characters, having no osteological data, and disregarding known sexual dimorphism in the genus along with data management issues (Condez et al. 2017). However, the validity of the species was supported by Bayesian methods on mitochondrial genes (Firkowski et al. 2016), and later Bayesian analysis of 16S mtDNA found B. leopardus is sister to the clade formed by B. brunneus, B. curupira,, and B. izecksohni (Pie et al. 2018).

The Brachycephalus genus is broken up into three sub-groups, which are named after exemplars of each group. The subgroups are as follows: the B. ephippium group located in southeastern Brazil, the B. pernix group located in southern Brazil, and the B. didactylus group, which was previously known as the genus Psyllophryne and contains the “flea toads”. Brachycephalus leopardus has been placed into the B. pernix group, which also includes B. pernix, B. brunneus, B. izecksohni, B. ferruginus, and B. pombali (Ribeiro et al. 2015).

At higher latitudes, there is a tendency for members of the B. pernix group to be found at lower altitudes (Pie et al. 2018).

ETYMOLOGY:

Brachycephalus leopardus is named after the feline genus, Leopardus, due to the resemblance of its dark lateral spotting to the iconic pattern of members of the Leopardus genus (Ribeiro et al. 2015).

References
Bornschein, M. R., Pie, M. R., & Teixeira, L. (2019). Conservation status of Brachycephalus toadlets (Anura: Brachycephalidae) from the Brazilian Atlantic Rainforest. Diversity, 11(9), 150. [link]

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Condez, T. H., Monteiro, J. P., & Haddad, C. F. (2017). Comments on the current taxonomy of Brachycephalus (Anura: Brachycephalidae). Zootaxa, 4290(2), 395. [link]

Firkowski, C. R., Bornschein, M. R., Ribeiro, L. F., & Pie, M. R. (2016). Species delimitation, phylogeny and evolutionary demography of co-distributed, montane frogs in the southern Brazilian Atlantic Forest. Molecular Phylogenetics and Evolution 100, 345-360 [link]

Nunes, I., Guimarães, C. S., Moura, P. H., Pedrozo, M., Moroti, M. de, Castro, L. M., Stuginski, D. R., & Muscat, E. (2021). Hidden by the name: A new fluorescent pumpkin toadlet from the Brachycephalus ephippium Group (Anura: Brachycephalidae). PLOS ONE, 16(4). [link]

Pie M. R., Ribeiro L. F., Confetti A. E., Nadaline M. J., Bornschein M. R. 2018. A new species of Brachycephalus (Anura: Brachycephalidae) from southern Brazil. PeerJ 6:e5683 [link]

Ribeiro, L. F., Bornschein, M. R., Belmonte-Lopes, R., Firkowski, C. R., Morato, S. A. A., & Pie, M. R. (2015). Seven new microendemic species of Brachycephalus (Anura: Brachycephalidae) from Southern Brazil. PeerJ, 3. [link]

Species Account Citation: AmphibiaWeb 2023 Brachycephalus leopardus <https://amphibiaweb.org/species/8341> University of California, Berkeley, CA, USA. Accessed Apr 19, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 19 Apr 2024.

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