Amazon Milk Frog

Males 77 mm, females 88 mm. The dorsum is dark brown with large khaki-green to light brown spots. The legs, arms and fingers have darker brown bars with cream borders. The snout is rounded. There is a large khaki-green triangle between the eyes pointing in the direction of the snout. The dorsum has large tubercles. The iris is golden with a black Maltese cross centered on the pupil. There is a vocal sac on each side of the head. Lima et al.(2005)Similar species: Osteocephalus taurinus can be distinguished from T. resinifictrix because it does not have a khaki-green dorsum or a Maltese cross in the eye. Lima et al.(2005)It is known on the upper Amazonas and the river Itacoai as "sapo canoeiro", meaning boatman frog because it croaks imitate the tapping of the oars against the side of the canoes. Lima et al.(2005)For more information on the call site and advertisement calls of T. resinifictrix, click the "view video" button above.Click here (http://amphibiaweb.org/refs/pdfs/Phrynohyas_resinifitrix.pdf) to download a .pdf of Hödl's (1991) paper describing the film.

In Brazil, this species occurs throughout the Reserva Florestal Adolpho Ducke. Lima et al. (2005)It is primarily found in primary forest. It will occupy this canopy unless it descends to a calling site, a large water-filled tree holes. (Hodl 1991)

The species is arboreal and nocturnal. Males call only from water filled tree holes, at heights between 2 and 32 m. Calling seems to only occur during rainless, cloudless nights. Calls can travel long distances through the use of the rain forest low-frequency sound window. Lima et al.(2005)Reproduction occurs mainly in the rainy season between November and May. Clutches of about 2500 eggs form a gelatinous mass that floats near the surface of water or adheres to the inner wall of the tree holes. Tadpoles develop until metamorphosis in the tree holes. Tadpoles have dark brown dorsums and light colored bellies. They feed on conspecific eggs and vegetable detritus. Lima et al.(2005)A typical call by T. resinifictrix consists of three notes similar in spectral composition. The notes have clear harmonic structures with sound energy distribution over a wide range of frequencies. At the first note of the call, there is a maximum intensity at the sixth harmonic (1300 Hz) and also increased intensities at the fourth (867) and fifths (1083) as well. The first harmonic is 216.6 Hz. Calls were separated by approximately 15.8 s and consisted of a series of 1 to 6 notes. The variable call rate was highest at the beginning of the night, and lowest at the end of the night. The mean duration of a note was 307 ms and the mean internote interval lasted 633 ms.

The Amazon Milk frog (Trachycephalus resinifictrix) is a large hylid tree frog (males 65-77 mm, females 86-100 mm snout-vent length) that inhabits primary forests in eastern Suriname, central Guyana, French Guiana and Amazonian Colombia, Ecuador, Peru, Bolivia, and Brazil at altitudes up to 450 m asl. The nocturnal T. reinifictrix is rarely seen because it lives entirely arborally, in rain water-filled tree holes (phytotelmata) in the forest canopy at heights between 2-32 m (6-100 feet) and seldom comes to ground level. The genus so named because of a milky white secretion it makes when threatened.This species is also sometimes called the mission golden eyed-tree frog for its golden iris, with a black Maltese cross centered on the pupil; and the boatman frog, "sapo canoeiro", because its croaks sound like oars against the side of a canoe (Lima et al. 2005).Their call can be heard at Fonozoo (http://www.fonozoo.com/fnz_detalles_registro_amphibia.php?id=76136&tipo_registro=1)

From their water-filled tree cavities males make loud, broadly-broadcasting calls from their large vocal sacs on cloudless nights, to attract females. Breeding occurs mostly in the rainy season, August-September and April-June. During breeding males have nuptial pads on the insides of their thumbs.Females lay up to 2500 small black eggs in a jelly mass on the top of the water or on the walls of the cavity.Dark brown on top with light-colored bellies, the tadpoles eat algae and plant detritus and conspecific eggs (opportunistic oophagy) as they develop in the tree cavity.In captivity, the tadpoles finished metamorphosis about 10 weeks after eggs were laid.Adults are insectivores (Mignet 2015; Lima et al. 2007; La Marca et al. 2010).

Recent work revealed that T. resinifictrix included a cryptic new species, T. tschudi, also a canopy dweller and morphologically very similar, but recognizable by its distinct call frequency (Gordo et al. 2013)

Amazon milk frogs are commonly seen in zoological institutions and have been bred in captivity for decades.Mignet (2015) gives detailed description of breeding fundamentals and life stages, geared especially for zoos, aquariums and captive breeding programs.

Note: This species was previously placed within the genus Phrynohyas. Phrynohyas was recently synonymized with Trachycephalus (Faivovich, et al., 2005).

The Mission golden-eyed tree frog or Amazon milk frog (Trachycephalus resinifictrix) is a large species of arboreal frog native to the Amazon Rainforest in South America. It is sometimes referred to as the blue milk frog due to a sticky, milk-like substance that they produce when feeling threatened. It was first discovered along the Maracanã River in Brazil. This species was previously within the genus Phrynohyas, which was recently synonymized with Trachycephalus.