''Scarthyla vigilans'' (Maracaibo Basin treefrog) is a species of

frog A frog is any member of a diverse and largely semiaquatic group of short-bodied, tailless amphibian vertebrates composing the order (biology), order Anura (coming from the Ancient Greek , literally 'without tail'). Frog species with rough ski ...

in the family

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 ...

. It is found in northern

Colombia Colombia, officially the Republic of Colombia, is a country primarily located in South America with Insular region of Colombia, insular regions in North America. The Colombian mainland is bordered by the Caribbean Sea to the north, Venezuel ...

(Caribbean lowlands,

Magdalena Valley The Magdalena River (, ; less commonly ) is the main river of Colombia, flowing northward about through the western half of the country. It takes its name from the biblical figure Mary Magdalene. It is navigable through much of its lower reaches, ...

, and eastern

llanos The Llanos ( Spanish ''Los Llanos'', "The Plains"; ) is a vast tropical grassland plain situated to the east of the Andes in Colombia and Venezuela, in northwestern South America. It is an ecoregion of the tropical and subtropical grasslands, ...

), northern

Venezuela Venezuela, officially the Bolivarian Republic of Venezuela, is a country on the northern coast of South America, consisting of a continental landmass and many Federal Dependencies of Venezuela, islands and islets in the Caribbean Sea. It com ...

(

Maracaibo Basin The Maracaibo Basin, also known as Lake Maracaibo natural region, Lake Maracaibo depression or Lake Maracaibo Lowlands, is a foreland basin and one of the eight natural regions of Venezuela, found in the northwestern corner of Venezuela in South A ...

Falcón Falcón State (, ) is one of the 23 States of Venezuela, states of Venezuela. The state capital is Coro, Venezuela, Coro. The state was named after Juan Crisóstomo Falcón. History Early history Present day Falcón State was first explored ...

, Coastal Range, high Llanos and

Orinoco Delta The Orinoco Delta is a vast river delta of the Orinoco River, located in eastern Venezuela. Location The Orinoco Delta is one of the eight natural regions of Venezuela. It covers the whole of Delta Amacuro State and a few square kilometers o ...

), and

Trinidad Trinidad is the larger, more populous island of the Republic of Trinidad and Tobago, the country. The island lies off the northeastern coast of Venezuela and sits on the continental shelf of South America. It is the southernmost island in ...

. Although generic allocation of this species has been controversial, molecular data have now confirmed its close relationship with '' Scarthyla goinorum'' and placement in that genus. Indeed, adults are very similar to ''Scarthyla goinorum''; however, the male advertisement call and

tadpole A tadpole or polliwog (also spelled pollywog) is the Larva, larval stage in the biological life cycle of an amphibian. Most tadpoles are fully Aquatic animal, aquatic, though some species of amphibians have tadpoles that are terrestrial animal, ...

s are clearly distinct.

Description

''Scarthyla vigilans'' are small frogs, with a maximum size of in

snout–vent length Snout–vent length (SVL) is a morphometric measurement taken in herpetology from the tip of the snout to the most posterior opening of the cloacal slit (vent)."direct line distance from tip of snout to posterior margin of vent" It is the mos ...

. The body is elongate and slender. The head is as wide as the body and longer than it is wide. The snout is long and acuminate. The eyes are moderately large and protuberant. The tympanum is distinct although partly obscured by the diffuse supratympanic fold. The fingers and toes are slender and bear small round discs. The fingers lack webbing while the toes are webbed. Night-time coloration is lime green with indistinct stripes; the ventral parts are transparent. During the day, the coloration is more contrasting. Males have a single subgular

vocal sac The vocal sac is the flexible Biological membrane, membrane of skin possessed by most male frogs and toads. The purpose of the vocal sac is usually as an amplification of their mating or advertisement call. The presence or development of the voca ...

. The male advertisement call resembles a cricket chirp (and can be mistaken as such) and has very low intensity. The tadpoles have short, globular body and moderately long tail. The maximum total length is .

Habitat and conservation

''Scarthyla vigilans'' occurs in open environments of lowlands, including flooded grasslands, degraded areas with low vegetation, and shallow standing water. Breeding takes place in standing water and swamps. Its maximum altitude is about

above sea level Height above mean sea level is a measure of a location's vertical distance (height, elevation or altitude) in reference to a vertical datum based on a historic mean sea level. In geodesy, it is formalized as orthometric height. The zero level ...

, although most records are from lower elevations. It is a very common but

nocturnal Nocturnality is a ethology, behavior in some non-human animals characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnality, diurnal meaning the opposite. Nocturnal creatur ...

, small, and inconspicuous species. The call is relatively low and easily masked by other calling frogs. It is adaptable and not facing any known threats. It is present in some protected areas.

References

{{Taxonbar, from=Q1610368 vigilans Amphibians of Colombia Amphibians of Trinidad and Tobago Amphibians of Venezuela Amphibians described in 1971 Taxonomy articles created by Polbot