Description
Measuring 30.5 to 42.0 mm from snout to vent, Adelphobates galactonotus is one of the largest poison frogs in the Amazon rainforest. Its skin is mostly smooth with the exception of the granular posterior belly and ventral surfaces of the thighs. This frog has a short snout. The eye is twice as big as the round tympanum. The tarsal tubercle is well developed. There are large discs on its fingers. Its hindlimb is about ⅓ longer than the body (Hoogmoed and Avila-Pires 2012, Silverstone 1975).

DIAGNOSIS:

Adelphobates galactonotus has sometimes been mistaken for Dendrobates tinctorius, colloquially called the dyeing poison frog. However, A. galactonotus has a tarsal tubercle that is absent in D. tinctorius (Silverstone 1975). Additionally, the dyeing poison frog is marginally larger reaching 50 mm, and is only found north of the Amazon River. While the dyeing frog does exhibit polymorphism, it is most commonly a variant of blue and/or yellow with black spots scattered about or with dorsal lines. Parental care of tadpoles is observed in both A. galactonotus and D. tinctorius (Walls 1994).

COLORATION:

Adelphobates galactonotus is notable for its vibrant colors and pattern variations (Hoogmoed and Avila-Pires 2012). In life, a high degree of variation in coloration is exhibited within A. galactonotus, but it is most commonly recognized as having vibrant yellow-orange-red color on dorsum that can reach around the flanks. Sometimes the bright colors can nearly encompass the entire body of the frog excluding the seat patch and underside of thighs, which remains black. Occasional speckled or spotted black coloring can cover the majority of the dorsal surface of the head, body. Its hind limbs and forelimbs often have black pigmentation unevenly creeping from the ventral side to the feet and toes. Some have colored spots that match the back on the belly (Hoogmoed and Avila-Pires 2012).

In preservative, the dorsum color ranges from yellow to orange to red or from white to light blue, with different amounts of black to completely black, and even black with blue to green dots (Hoogmoed and Avila-Pires 2012).

VARIATION:

According to Hoogmoed and Avila-Pires (2012) there is no regularity in the pattern or color distribution throughout the known range of this species. However, specimens from the area of the Estação Científica Ferreira Penna, Pará region displayed orange backs with black dots and spots. Seven kilometers away in Posto, an individual had a uniform orange body without spotting. White morphs, also known as “Moonshine”, have been found in the wild as well as red, pale orange, yellow, black (all of the previous found in Pará), and yellow with black spots in Mato Grosso (Hoogmoed and Avila-Pires 2012). Most displayed black ventral bellies, however, one specimen was found with light spots on the throat and ventral surface of the calves (Silverstone 1975). Currently localized morphs include orange, red, black with tiny red spots, black with large peach colors areas, yellow, yellow with black vermiculations, light blue, dark grayish blue to black, black with blue to green spots, black with white spots and lines, black with cream color. The “Moonshine” morph is well known in the pet trade but uncommon in the wild (Hoogmoed and Avila-Pires 2012). In captivity, red morphs tend to be bright red when metamorphosing, but become darker with increased age and all are black ventrally (Overkamp 2009). It is unknown if different color morphs relate to differences in the toxicity of their skin (Hoogmoed and Avila-Pires 2012).

This species exhibits sexual dimorphism in the males as having noticeably larger discs of the fingers than the females. Additionally, female A. galactonotus are generally larger than the males (Silverstone 1975, Hoogmoed and Avila-Pires 2012).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Brazil

	View distribution map in BerkeleyMapper.
	View Bd and Bsal data (2 records).

Adelphobates galactonotus is endemic to the states of Pará and Tocantins in Brazil; it has also been seen as far east as the state of Maranhão. This poison frog is known to exist only south of the Amazon River, mainly in Pará in the lowland forests. At an altitude between sea level around 355 to 600 meters in Serra de Carajás, the distribution of A. galactonotus falls in the Belém, Xingu, and Tapajós areas of endemism (Silva et al. 2005). This region is located between the Tapajós River and Teles Pires River in the west and the Atlantic coast in the east, south to extreme northern Mato Grosso and northern Tocantins, and east to São Luis in Maranhão (Barreto et al. 2011).

Life History, Abundance, Activity, and Special Behaviors
Being mostly terrestrial, A. galactonotus lives within the Amazon rainforest among the leaf litter on the forest floor where humidity is high or in freshwater marshes. Frog populations are commonly found near fallen trees. Some congregate in sun patches on the forest floor and have been observed in open spaces. This species has also been found in agricultural areas and seems tolerant of human disturbance; they were also found in areas that have recently been slashed and burned, suggesting tolerance for such areas. However, A. galactonotus is not generally an abundant species regardless of time of year (Hoogmoed and Avila-Pires 2012).

Adelphobates galactonotus “gather” but not in large numbers, near and around Brazil nut pods, which can contain water. They use these nut pods to deposit tadpoles. After hatching, the male carries a maximum of two tadpoles on his back at a time to place in a water pool for development and metamorphosis (Hoogmoed and Avila-Pires 2012).

Its diet in natural environments comprises entirely of small invertebrates, and it derives the toxins on its skin from its food. Brightly colored variations of A. galactonotus do not increase vulnerability to predators; therefore, geographic variation is independent of predation (Rojas et al. 2015).

Larva
Adelphobates galactonotus tadpoles at Gosner stages 31 and 37 have an average total length of 38.17 millimeters with a standard deviation of 2.70 millimeters. The body is relatively flat, though it becomes more rounded dorsally and globular laterally. Its eyes are positioned anterolaterally with a diameter ranging from 0.09 to 0.11 milimeters. The snout has a softly circular shape, and the nostrils are oval-shaped. The A. galactonotus tadpole has a front-facing oral disc with elongated papillae and tooth rows inside. It has a U-shaped upper jaw sheath and a V-shaped lower jaw sheath. The spiracle is positioned lateroventrally and is deeper than it is long. It opens at around the middle third of the body with its inner wall is fused to the body. The vent tube is medial. This tadpole has a significant amount of musculature in its tail. The dorsal and ventral fins are parallel to its tail muscles. Its lateral lines are imperceptible (Santos et al. 2018).

The tadpoles of A. galactonotus are morphologically similar to A. castaneoticus and A. quinquevittatus. While the snouts of A. galactonotus tadpoles are rounded, A. castaneoticus tadpoles have short snouts and A. quinquevittatus have sloped snouts. Adelphobates galactonotus tadpoles have a visible oral disc; meanwhile, A. castaneoticus discs are less detectable. Additionally, A. galactonotus tadpoles are larger than A. castaneoticus tadpoles (Santos et al. 2018).

In life, A. galactonotus tadpoles are black with slightly lighter tails and fins. In preservative, the tadpoles are greyer with small black spots scattered throughout their bodies. The tail appears browner, and the dorsal region may have yellow spots during Gosner stage 43 (Santos et al. 2018).

Tadpoles can be found in rainy forests as well as fragmented landscapes that include pastures, highways, and urban areas (Santos et al. 2018).

Trends and Threats
Population trends are assumed to be stable and the species is considered “Least Concern” by the IUCN Red List. The species has a wide distribution, presumed large population and is unlikely to decline (IUCN 2023). Current threats include, but are not limited to, forest deforestation, logging, fire, urban development, agricultural lands, and the international pet trade - all of the species kept in captivity stem from illegal exports. Despite its population trend, the populations in the state of Tocantins are threatened by the man-made Tucuruí Lake hydroelectric project and the planned hydroelectric plants that are soon to follow. Gold mining in the upper Tapajós and Teles Pires Rivers, and a new large project is projected to begin soon in the Volta Grande area of the Xingu River threatens the frog populations in the immediate and surrounding areas (Hoogmoed and Avila-Pires 2012, IUCN 2023).

Relation to Humans
This species is likely smuggled for international pet trade. However, frogs have been successfully bred in captivity to produce morph colorations not seen in nature (IUCN 2023).

Possible reasons for amphibian decline

Habitat modification from deforestation, or logging related activities
Mining
Intentional mortality (over-harvesting, pet trade or collecting)

Comments

PHYLOGENETIC RELATIONSHIPS:

The species was previously known as Dendrobates galactonotus

This species was featured as News of the Week on January 6, 2020:

Bright colors may serve to warn predators that potential prey are toxic, so one might predict that predators are the main factor driving diversification in warning signals. However, several studies of color polymorphisms in poison frogs suggest otherwise. In one study, Jeckel et al. (2019) found Adelphobates galactonotus from two localities with distinct color morphs did not differ in their toxin profiles or palatability. They suggest the color difference is unlikely to have evolved from predation pressures and instead be a product of parental imprinting and sexual selection, as was found in Oophaga pumilio by Yang et al. (2019) [News of the Week Nov 11, 2019]. In another, Rojas et al. (2019) reconstructed the evolution of color in >200 individuals of A. galactonotus and found that transitions between color morphs have occurred several times. Using mtDNA and a SNP matrix, they found population structure was mostly explained by geographic distance (not color), and that population sizes were relatively small. Rojas et al suggest that genetic drift likely played a role shaping the current diversity of colors in this species. Finally, a study by Lawrence et al. (2019) [News of the Week October 28, 2019] suggest that a suboptimal warning signal in Dendrobates tinctorius arose through drift. These studies mark a shift in how evolutionary biologists are thinking about signal diversity in toxic animals. (Rebecca Tarvin)

References
Grant, T., Frost, D. R., Caldwell, J. P., Gagliardo, R., Haddad, C. F. B., Kok, P. J. R., Means, D. B., Noonan, B. P., Schargel, W. E., and Wheeler, W. C. (2006). Phylogenetic Systematics of Dart-Poison Frogs and Their Relatives (Amphibia: Athesphatanura: Dendrobatidae). American Museum of Natural History, 2006(299), 1-262. [link]

Hoogmoed, M.S. and Avila-Pires, T.C.S. (2012). Inventory of color polymorphism in populations of Dendrobates galactonotus (Anura: Dendrobatidae), a poison frog endemic to Brazil. Phyllomedusa, 11, 95–115. [link]

IUCN SSC Amphibian Specialist Group & Instituto Boitatá de Etnobiologia e Conservação da Fauna. 2023. Adelphobates galactonotus. The IUCN Red List of Threatened Species 2023: e.T55185A173863084. https://dx.doi.org/10.2305/IUCN.UK.2023-1.RLTS.T55185A173863084.en. Accessed on 01 November 2024.

Mediros, L. A. D., Gentil, E., Kaefer, I. L., and Cohn-Haft, M. (2024). Distribution and diversification of Adelphobates, emblematic poison frogs from Brazilian Amazonia. Anais Da Academia Brasileira De Ciências, 96(1), e20230659. [link]

Rojas, D., Stow, A., Amézquita, A., Simões, P. I., Lima, A. P. (2015). No predatory bias with respect to colour familiarity for the aposematic Adelphobates galactonotus (Anura: Dendrobatidae). Behaviour 152, 1–21. [link]

Santos, D. L., Dantas, S. P., and Nomura, F. (2018). The tadpole of Adelphobates galactonotus (Steindachner, 1864)(Amphibia, Anura, Dendrobatidae). Zootaxa, 4422(2), 287-290. [link]

Species Account Citation: AmphibiaWeb 2024 Adelphobates galactonotus: Splash-Backed Poison Frog <https://amphibiaweb.org/species/1631> University of California, Berkeley, CA, USA. Accessed Nov 24, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 24 Nov 2024.

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