Description
Scinax faivovichi is moderate-sized, slender-bodied frog with male specimens that ranged from 16.2 - 18.8 mm in snout-vent length, and females ranged from 18.8 - 20.6 mm (sample size was 29 specimens, 23 males and 6 females). Their heads are longer than wide. In the profile view, they have a protruding snout, and from the dorsal view they have a subacuminate snout. Also, in the middle of their pronounced, well-defined canthus rostralis, these frogs have a warty protuberance. Their internarial distance is less than their eye–nostril distance and eye diameter, and their eye diameter is less than their eye–nostril distance. The species has protruding eyes and a concave region between their eyes and nostrils, the loreal region. They possess a V-shaped indentation between their protuberant nostrils. They have a distinct circular tympanum, which has a diameter that is about half the length of the diameter of their eye. There is a weak supratympanic fold from their shoulder to their tympanic region. They have a discrete subgular vocal sac, a big round tongue, and vomerine teeth in two clusters between their moderate-sized, elliptical choanae (Brasileiro et al. 2007).

They have slender arms, with forearms that are somewhat stout, but smaller than their hands. Their outer metacarpal tubercule is cordiform, the inner metacarpal tubercule is elliptical, and subarticular tubercules are single and rounded. They do not have webbed fingers. Their finger lengths in order from shortest to longest are I < II < IV < III. The length of their tibia is greater than that of their thigh, and the sum of their thigh and tibia is about the same as their snout vent length. Their feet are characterized by a round inner metatarsal tubercule, a divided outer metatarsal tubercule, and rounded single subarticular tubercules. Their toe lengths from shortest to longest are I < II < V < III < IV. The formula for their foot webbing is I - II 2⁺ 3⁺ III 2⁻ 3⁺ IV 3⁺ − 2 V. Their dorsal and ventral skin texture is somewhat rough, or rugose (Brasileiro et al. 2007).

One feature that distinguishes this species from all others in the S. perpusillus species group is that its head that is longer than wide. It also has a unique V-shaped indentation between its nostrils, and a brown undersurface on its tarsus and foot. It is smaller than S. alcatraz, S. arduous, S. littoreous, and S. v-signatus. Each of the species in the species group differs from S. faivovichi in additional ways. Scinax alcatraz has a less protruding snout, a less triangular head, less prominent eyes, a less defined canthus rostralis, a less ornamented dorsum, in addition to lacking both a concave loreal region and dark stripes on arms. Scinax arduous has more prominent eyes, a less protruding snout, and more rugose dorsal skin texture. Scinax atratus has a thicker body, less prominent eyes, a less pronounced canthus rostralis, more rugose dorsal skin, and it lacks the dark stripes on its forearms and the gular region with dark spots. Scinax littoreous has a less pronounced canthus rostralis, smoother dorsal skin, less developed finger disks, a less concave loreal region, has white spots on venter as opposed to brown ones, lacks stripes on its arms and forearms, and has a less ornamented dorsum. Scinax melloi differs in that it is smaller, has smoother skin on its back, a more keratinized inner metacarpal tubercule, a less protruding snout, less prominent eyes, and a smaller head. Scinax peixotoi has a thicker body, less prominent eyes, a less protruding snout, a less pronounced canthus rostralis, and has a silvery dorsum as opposed to a brown one. Scinax v-signatus has a larger wider head, a less pronounced canthus rostralis, more rugose dorsal skin, and a V-shaped dark mark on its dorsal side. Scinax perpusillus has a thicker body, a less protruding snout, and more rugose dorsal skin than S. faivovichi (Brasileiro et al. 2007).

In life, the color of this species’ dorsal side is greenish-beige and possesses metallic hues. In addition, they have a dark brown interorbital bar. They have a dark brown line on their canthus rostralis, upper eyelids, and supratympanic fold. They also have a thick bright stripe running down their back. One to two brown bars run posteriorly from the edge of each eye to the inguinal region. A concealed part of their shanks are adorned with yellow flash color spots. They have a golden iris, with a horizontally oriented black bar (Brasileiro et al. 2007).

In preservative, the color of this species’ dorsal side ranges from creamy to brown. They may or may not have a well-defined interorbital bar, or stripe down their back. In addition, they may or may not have a thick canthus rostralis line or dorsolateral stripes. The pigmentation of the brown bars on the dorsum of their arms also differs amongst individuals. They possess stripes on their thighs running from knee to inguinal region that vary in pigment intensity and location on the thigh. Their throat has dark spots that may appear together in patches. The undersides of their hands, fingers, arms, and thighs are white, while the undersides of their tibiae feet and toes are brown (Brasileiro et al. 2007).

They display sexual dimorphism, with larger females that lack vocal sacs and vocal slits, and possess a darker colored dorsal side than males (Brasileiro et al. 2007).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Brazil

View distribution map in BerkeleyMapper.

The species is endemic to Brazil. Within the borders of Brazil, the species is restricted to 24-hectacres in the Ilha de Porcos Pequena, a privately-owned island covered by native preserved Atlantic Forest, at elevations of 0 - 80 m asl (Brasileiro 2008).

Life History, Abundance, Activity, and Special Behaviors
They are nocturnal and abundant on hot, rainy nights. Males could be heard calling from bromeliad leaves in April, October, and December, but less activity was heard in April. Calling males were positioned with their bodies vertical and head directed skyward (Brasileiro et al. 2007).

Females are also commonly found perched upon bromeliads in their natural range. Like the others in its S. perpusillus species group, these frogs rely on the bromeliad plants for breeding. Tadpoles of this species can be found in the pools of water that form within bromeliads. Researchers found tadpoles during October and December, and thus noted that this suggests their breeding season may align with the early summer rains of September or October (Brasileiro et al. 2007).

Trends and Threats
Although S. faivovichi is found at high density within its range, that range is small and isolated. As a result, they face the threat of extinction due to habitat changes or disturbances. Additionally, the island does not have any legal conservation status under federal law leading to the IUCN Redlist classification of this species as “Critically Endangered” (Brasileiro et al. 2007, Brasileiro 2008).

Possible reasons for amphibian decline

General habitat alteration and loss
Habitat modification from deforestation, or logging related activities

Comments
The species authority is: Brasileiro, Cinthia A.; Oyamaguchi, Hilton M.; Haddad, Celio F. B. “A New Island Species of Scinax (Anura; Hylidae) from Southeastern Brazil.” Journal of Herpetology, Vol:41, Iss:2, 271-275.

Scinax faivovichi belongs to the Scinax perpusillus species group that includes eight other species besides Scinax faivovichi: Scinax alcatraz, Scinax atratus, Scinax arduous, Scinax littoreus, Scinax melloi, Scinax perpusillus, Scinax v-signatus, and Scinax peixotoi (Brasileiro et al. 2007).

The species was named after Julian Faivovich, whom made major contributions to the systematic of the frog family Hylidae, including the genus Scinax (Brasileiro et al. 2007).

References

Brasileiro, C. (2008). Scinax faivovichi. The IUCN Red List of Threatened Species 2008: e.T136140A4248952. http://dx.doi.org/10.2305/IUCN.UK.2008.RLTS.T136140A4248952.en. Downloaded on 21 Feb. 2017.

Brasileiro, C. A., Oyamaguchi, H. M., and Haddad, C. F. B. (2007). ''A new island species of Scinax (Anura: Hylidae) from southeastern Brazil.'' Journal of Herpetology, 41, 271-275.

Species Account Citation: AmphibiaWeb 2017 Scinax faivovichi <https://amphibiaweb.org/species/6929> 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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