The polka-dot tree frog (''Boana punctata''), also known as the dotted tree frog, is a
frog
A frog is any member of a diverse and largely Carnivore, carnivorous group of short-bodied, tailless amphibians composing the order (biology), order Anura (ανοὐρά, literally ''without tail'' in Ancient Greek). The oldest fossil "proto-f ...
species in the
family
Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...
Hylidae
Hylidae is a wide-ranging family of frogs commonly referred to as "tree frogs and their allies". However, the hylids include a diversity of frog species, many of which do not live in trees, but are terrestrial or semiaquatic.
Taxonomy and s ...
found in much of South America and also in
Trinidad and Tobago
Trinidad and Tobago (, ), officially the Republic of Trinidad and Tobago, is the southernmost island country in the Caribbean. Consisting of the main islands Trinidad and Tobago, and numerous much smaller islands, it is situated south of ...
. It is fairly small with a snout–to–
vent
Vent or vents may refer to:
Science and technology Biology
*Vent, the cloaca region of an animal
*Vent DNA polymerase, a thermostable DNA polymerase
Geology
*Hydrothermal vent, a fissure in a planet's surface from which geothermally heated water ...
length of .
Its natural
habitat
In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical ...
s are
subtropical or tropical dry forest
The tropical and subtropical dry broadleaf forest is a habitat type defined by the World Wide Fund for Nature and is located at tropical and subtropical latitudes. Though these forests occur in climates that are warm year-round, and may receive ...
,
subtropical or tropical moist lowland forest
Tropical and subtropical moist broadleaf forests (TSMF), also known as tropical moist forest, is a subtropical and tropical forest habitat type defined by the World Wide Fund for Nature.
Description
TSMF is generally found in large, discont ...
, subtropical or tropical
swamp
A swamp is a forested wetland.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p. Swamps are considered to be transition zones because both land and water play a role in ...
s, subtropical or tropical moist
montane forest
Montane ecosystems are found on the slopes of mountains. The alpine climate in these regions strongly affects the ecosystem because temperatures fall as elevation increases, causing the ecosystem to stratify. This stratification is a crucial f ...
, swamps, freshwater
marsh
A marsh is a wetland that is dominated by herbaceous rather than woody plant species.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p Marshes can often be found at ...
es, intermittent freshwater marshes, rural gardens,
urban area
An urban area, built-up area or urban agglomeration is a human settlement with a high population density and infrastructure of built environment. Urban areas are created through urbanization and are categorized by urban morphology as cities, t ...
s, and heavily degraded former forests. It is not considered threatened by the
IUCN
The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...
.
Pigmentation and skin fluorescence
In 2017, several polka-dot tree frogs collected in the
Santa Fe Province
The Province of Santa Fe ( es, Provincia de Santa Fe, ) is a Provinces of Argentina, province of Argentina, located in the center-east of the country. Neighboring provinces are from the north clockwise Chaco Province, Chaco (divided by the 28th ...
in Argentina were the first
amphibian
Amphibians are tetrapod, four-limbed and ectothermic vertebrates of the Class (biology), class Amphibia. All living amphibians belong to the group Lissamphibia. They inhabit a wide variety of habitats, with most species living within terres ...
, amongst more than 6,000 species of frog, identified as naturally
fluorescent
Fluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation. It is a form of luminescence. In most cases, the emitted light has a longer wavelength, and therefore a lower photon energy, tha ...
.
Among land-living
vertebrate
Vertebrates () comprise all animal taxa within the subphylum Vertebrata () ( chordates with backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the phylum Chordata, ...
s, it had only been confirmed earlier in certain
parrot
Parrots, also known as psittacines (), are birds of the roughly 398 species in 92 genera comprising the order Psittaciformes (), found mostly in tropical and subtropical regions. The order is subdivided into three superfamilies: the Psittacoid ...
s (as opposed to fish and invertebrates where fluorescence is relatively widespread).
[ A few months later, fluorescence was discovered in the closely related '']Hypsiboas atlanticus
''Boana atlantica'' is a small-sized species of tree frog in the family Hylidae. It is endemic to the Atlantic Forest from Pernambuco to Bahia in northeastern Brazil. It is a very abundant species inhabiting primary and secondary forest and for ...
'', and in 2019 it was discovered in the distantly related pumpkin toadlet
The pumpkin toadlet (''Brachycephalus ephippium''), or Spix's saddleback toad, is a small and brightly coloured species of frog in the family Brachycephalidae. This diurnal species is endemic to southeastern Brazil where it is found among leaf ...
(''Brachycephalus ephippium'') and red pumpkin toadlet
''Brachycephalus pitanga'', the red pumpkin toadlet, is a small and brightly coloured species of anuran in the family Brachycephalidae. It is endemic to Atlantic rainforests in São Paulo state of southeastern Brazil, and only known from four lo ...
(''B. pitanga''). In 2020, it was confirmed that fluorescence is relatively widespread among frogs and other amphibians.
When exposed to ultra-violet light, the skin
Skin is the layer of usually soft, flexible outer tissue covering the body of a vertebrate animal, with three main functions: protection, regulation, and sensation.
Other cuticle, animal coverings, such as the arthropod exoskeleton, have diffe ...
of the polka-dot tree frog emits a bright green fluorescent glow. The discovery was made accidentally when the researchers checked the skin secretions of the frog under UV light. They expected only a faint red fluorescence, because the frog skin contains biliverdin
Biliverdin (latin for green bile) is a green tetrapyrrolic bile pigment, and is a product of heme catabolism.Boron W, Boulpaep E. Medical Physiology: a cellular and molecular approach, 2005. 984-986. Elsevier Saunders, United States. It is the ...
, a green tetrapyrrolic bile
Bile (from Latin ''bilis''), or gall, is a dark-green-to-yellowish-brown fluid produced by the liver of most vertebrates that aids the digestion of lipids in the small intestine. In humans, bile is produced continuously by the liver (liver bile ...
pigment
A pigment is a colored material that is completely or nearly insoluble in water. In contrast, dyes are typically soluble, at least at some stage in their use. Generally dyes are often organic compounds whereas pigments are often inorganic compo ...
responsible for its dull mottled browny-green colour. The surprising green fluorescence is attributed to hyloin compounds, mainly hyloin-L1, hyloin-L2 and hyloin-G1.[ These fluorescent molecules, in the dihydroisoquinolinone family and derived from the ]isoquinoline
Isoquinoline is a heterocyclic aromatic organic compound. It is a structural isomer of quinoline. Isoquinoline and quinoline are benzopyridines, which are composed of a benzene ring fused to a pyridine ring. In a broader sense, the term isoquin ...
(a benzene
Benzene is an organic chemical compound with the molecular formula C6H6. The benzene molecule is composed of six carbon atoms joined in a planar ring with one hydrogen atom attached to each. Because it contains only carbon and hydrogen atoms, ...
ring fused to a pyridine
Pyridine is a basic heterocyclic organic compound with the chemical formula . It is structurally related to benzene, with one methine group replaced by a nitrogen atom. It is a highly flammable, weakly alkaline, water-miscible liquid with a d ...
ring), in an alkaloid
Alkaloids are a class of basic, naturally occurring organic compounds that contain at least one nitrogen atom. This group also includes some related compounds with neutral and even weakly acidic properties. Some synthetic compounds of similar ...
protecting mucous membrane
A mucous membrane or mucosa is a membrane that lines various cavities in the body of an organism and covers the surface of internal organs. It consists of one or more layers of epithelial cells overlying a layer of loose connective tissue. It is ...
, have been identified in the lymph
Lymph (from Latin, , meaning "water") is the fluid that flows through the lymphatic system, a system composed of lymph vessels (channels) and intervening lymph nodes whose function, like the venous system, is to return fluid from the tissues to ...
tissue, skin and glandular secretions of the frog.[ Because it is linked to secretions from skin glands, they can also leave fluorescent markings on surfaces where they have been.][
The fluorescence intensity represents about 18−29% of the luminosity under twilight conditions and is suspected to play a possible role in the communication, camouflage and mating of the frog.][
]
References
{{DEFAULTSORT:Boana Punctata
punctata
Amphibians of Argentina
Amphibians of Bolivia
Amphibians of Brazil
Amphibians of Colombia
Amphibians of Ecuador
Amphibians of French Guiana
Amphibians of Guyana
Amphibians of Paraguay
Amphibians of Peru
Amphibians of Suriname
Amphibians of Trinidad and Tobago
Amphibians of Venezuela
Amphibians described in 1799
Fluorescence
Taxonomy articles created by Polbot