Description
Crossodactylodes itambe is a flat-bodied frog in which males have the snout-vent length ranges of 14.0- 17.6 mm and female snout-vent length range is 13.5 - 18.0 mm. The snout is short, appearing round from the dorsal view and sloping from the lateral view. The nostrils are swollen and directed laterally. The eyes are prominent and are located antero-laterally. The species doesn’t have vomerine teeth or a tympanum. Males have hypertrophied forearms. The inner metacarpal tubercle is weakly developed. The first finger is shorter than the second. The toes and fingers don’t have any type of webbing or fringes but fingers two, three, and four have discs on them and the toes are moderately expanded. Males have clusters of spines on their thumbs and lack vocal sacs and vocal slits. The species' cloacal flap is simple. The dorsal skin is coarsely granular (Barata et al. 2013).

DIAGNOSIS:

At the time of the species description, there were only four members of the species, including C. itambe. Crossodactylodes itambe is different from Crossodactylodes izecksohni because C. izecksohni has a slightly bigger body size and has no marks on the dorsal surface of the hand and body. Crossodactylodes izecksohni’s thumbs are stronger than the thumbs of C. itambe. Crossodactylodes itambe has a weakly developed inner metacarpal tubercle, longer hand length, and darker (black) eyes than C. izecksohni. The lack of a vocal sac in C. itambe differentiates it from C. pintoi and C. bokermanni. Additionally, compared to C. pintoi, C. itambe has a more simple cloacal flap. Crossodactylodes bokermanni is different from C. itambe because C. bokermanni have a vocal slit, the discs on the fingers are truly expanded, and there are marks on the body and legs (Barata et al. 2013). A fifth species, Crossodactylodes septentrionalis, was also described in the same year as C. itambe (Teixeira et al. 2013). Crossodactylodes itambe lacks a dorsolateral fold, and black stripe, band, and bars, which are present in C. septentrionalis (Santos et al. 2020).

COLORATION:

The dorsum and the venter colors are dark brown to light brown, but vary by time of day. During the daytime, they are uniformly dark brown to black. During the nighttime, they’re light brown with dark marble color patterns on top of the arms and legs. In some individuals, the color pattern has light brown rectangles with small white spots or rectangles that are spread in the dorsum, legs, and arms. On the foot and on the hand, its color is darker than the rest of the body. In preservative, the coloration varies from dark gray and black (Barata et al. 2013).

VARIATION:

Crossodactylodes itambe doesn’t have any sexual dimorphism in their snout-vent length. Sex can be determined by males having spines on the thumbs, which varies from having 6 - 16 spines. Additionally, males have stronger forearms than females. The coloration is similar amongst both males and females (Barata et al. 2013).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Brazil

View distribution map in BerkeleyMapper.

Crossodactylodes itambe is only known from one location in the Atlantic rainforest of Brazil (Barata et al. 2018). Specifically, they are found in rocky areas in open fields of southeastern Parque Estadual do Pico do Itambe at an altitude of 1836 to 2062 m above sea level (Barata et al. 2013).

Life History, Abundance, Activity, and Special Behaviors
Crossodactylodes itambe are the most active at nighttime (Barata et al. 2013) and are observed in bromeliads where they spend most of their life (Barata et al. 2013, 2018). Precisely, this species is only found in Vriesea medusa, which is a night blooming bromeliad with a limited distribution. Elevation is also believed to play role in the abundance of the C. itambe as more individuals were found in larger V. medusa at higher elevations (Barata et al. 2018).

Vriesea medusa has large rosettes and is capable of holding a large amount of water in its tanks. This allows C. itambe to avoid dessication, predators, and competitors (Barata et al. 2018). This stable water source also makes reproduction possible as C. itambe are oviparous and lay egg masses on the leaves of the plant (Barata et al. 2013). The larger bromeliad tank also holds more nutrients for the growth of tadpoles (Barata et al. 2018).

Males mainly call from inside bromeliads with their body only somewhat submerged under water while maintaining their head above. They produce three calls that superficially sound like squeaking, chirping, and creaking with creaking to be their most common call. The creaking call has two components with the combined components lasting 469 - 662 ms, having a call rate of 56 - 63 calls per minute, and a dominant frequency of 2261 - 2649 Hz (Santos et al. 2020).

While the bromeliad provides some protection, C. itambe still encounters invertebrate threats. Generally, these invertebrates are small spiders that go after the young offspring and small adults. When it is time for breeding, the frogs tend to avoid areas where threat may be perceived (Barata et al. 2018).

Trends and Threats
The area where C. itambe occurs, Estadual do Pico do Itambe is a protected area. However, fires, while not common, are still a threat to the species population as it may cause a decline of nearby bromeliads populations possibly resulting in extinction of the itambe species (Barata et al. 2018).

Possible reasons for amphibian decline

General habitat alteration and loss

Comments

PHYLOGENETIC RELATIONSHIPS:

Bayesian analysis of two mtDNA sequence fragments (that cover 12S, 16S, tRNA, Valine, COI and cytb) and three nDNA genes (POMC, RAG-1, and Tyr) found that C. itambe is sister to C. septentrionalis. The next most closely related species is C. izeckaohni. However, C. pintoi was not included in this analysis because it is only known from specimens collected in 1909 (Santos et al. 2020).

ETYMOLOGY:

The species epithet “itambe” is in reference to the location in which this species of frog was collected, Parque Estadual do Pico do Itambé, which is in the State of Minas Gerais. Itambé also means “sharp rock” in the Tupi-Guarani language (Barata et al. 2013).

References

Barata I. M., Silva E. P., Griffiths R. A. (2018). “Predictors of abundance of a rare bromeliad-dwelling frog (Crossodactylodes itambe) in the Espinhaço Mountain Range of Brazil.” Journal of Herpetology, 1, 52(3), 321–326. [link]

Barata, I.M., Santos, M.T.T., Leite, F.S.F, Garcia, P.C.A. (2013) “A new species of Crossodactylodes (Anura: Leptodactylidae) from Minas Gerais, Brazil: first record of genus within the Espinhaço Mountain Range.” Zootaxa, 3731.4 (2013) 552–560. [link]

Santos M.T.T., Barata I.M., Ferreira R.B., Haddad C.F.B., Gridi-Papp M., de Carvalho T.R. (2021). “Complex acoustic signals in Crossodactylodes (Leptodactylidae, Paratelmatobiinae): a frog genus historically regarded as voiceless.” Bioacoustics, 31, 1-16. [link]

Santos, M.T.T., Maghalhães, R.F., Ferreira, R.B., Vittorazzi, S.E., Dias, I.R., Leite, F.S.F., Lourenço, L.B., Santos, F.R., Haddad, C.F.B, Garcia, P.C.A. (2020). "Systematic revision of the rare bromeligenous genus Crossodactylodes Cochran 1938 (Anura: Leptodactylidae: Paratelmatobiinae).” Herpetological monographs 34(1), 1–38. [link]

Teixeira M Jr, Recoder RS, Amaro RC, Damasceno RP, Cassimiro J, Rodrigues MT (2013). "A new Crossodactylodes Cochran, 1938 (Anura: Leptodactylidae: Paratelmatobiinae) from the highlands of the Atlantic Forests of southern Bahia, Brazil." Zootaxa 3702: 459-472. [link]

Species Account Citation: AmphibiaWeb 2022 Crossodactylodes itambe: Itambe's bromeliad frog <https://amphibiaweb.org/species/8089> University of California, Berkeley, CA, USA. Accessed Nov 15, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 15 Nov 2024.

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