''Hyperolius nitidulus'' is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

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 ...

from the family

Hyperoliidae The Hyperoliidae, or sedge frogs and bush frogs, are a large family of small to medium-sized, brightly colored frogs which contains more than 250 species in 19 genera. Seventeen genera are native to sub-Saharan Africa. In addition, the monotypic ...

. It is found on the West African

savanna A savanna or savannah is a mixed woodland-grassland (i.e. grassy woodland) ecosystem characterised by the trees being sufficiently widely spaced so that the canopy does not close. The open canopy allows sufficient light to reach the ground to ...

s between Guinea and Mali in the west and Nigeria and Cameroon in the east. Common name plain reed frog has been coined for it.

Description

''Hyperolius nitidulus'' are medium-sized reed

frogs A frog is any member of a diverse and largely carnivorous group of short-bodied, tailless amphibians composing the order Anura (ανοὐρά, literally ''without tail'' in Ancient Greek). The oldest fossil "proto-frog" ''Triadobatrachus'' is ...

with a rather blunt snout. Males vary is size between and on average weight about one gram. Females are larger and heavier than males, their body size can vary between with an average weight of about two grams before laying eggs. This species has a large

choana The choanae (singular choana), posterior nasal apertures or internal nostrils are two openings found at the back of the nasal passage between the nasal cavity and the throat in tetrapods, including humans and other mammals (as well as crocodilia ...

, which is not hidden beneath edge of mandible like in most ''Hyperolius'' species. They have a relatively large tongue which is broad and shaped like a heart. Their dorsal view is roundish and sometimes a bit pointy. From a lateral view their body is flattened but some have a round truncate. The position of the naris is slightly close to snout tip than to the eye. Skin is laterally smooth and with small warts. Body is slender and half cylindrical with thin limbs. They have extra skin folds that are used to hide their feet while aestivating during dry conditions. Fingers and toes have circummarginal discs. Males have a median subgular

vocal sac The vocal sac is the flexible 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 vocal sac is one way o ...

which is used for calling. During their juvenile stage their color is beige with a darker lightly flanked stripe at the side from snout to vent. As an adult they exhibit metachrosis (change in color), this color change is based on many factors such temperature, humidity. During the night the uniformly color is beige and during the day the color can vary between yellow and orange with spots. During the dry season the juveniles become white as they

aestivate Aestivation ( la, aestas (summer); also spelled estivation in American English) is a state of animal dormancy, similar to hibernation, although taking place in the summer rather than the winter. Aestivation is characterized by inactivity and a ...

the skin in the inside of their limbs becomes red due to the underlying capillary network.

Diet

Adults are insectivores, usually consuming taxa such as ''

Drosophila ''Drosophila'' () is a genus of flies, belonging to the family Drosophilidae, whose members are often called "small fruit flies" or (less frequently) pomace flies, vinegar flies, or wine flies, a reference to the characteristic of many species ...

'', ''

Musca Musca () is a small constellation in the deep southern sky. It was one of 12 constellations created by Petrus Plancius from the observations of Pieter Dirkszoon Keyser and Frederick de Houtman, and it first appeared on a celestial globe in dia ...

'', ''

Phormia ''Phormia regina'', the black blow fly, belongs to the Calliphoridae, blow fly family Calliphoridae and was first described by Johann Wilhelm Meigen. The black blow fly's wings are specialized with a sharp bend. These flies are also have well-de ...

'', '' Lucilia'', and ''

Calliphora ''Calliphora'' is a genus of blow flies, also known as bottle flies, found in most parts of the world, with the highest diversity in Australia. The most widespread species in North America area ''Calliphora livida'', '' C. vicina'', and '' C. vo ...

''.

Reproduction

Breeding normally occurs during wet season, that is May–October. During mating season males will migrate to temporary ponds and at times stay there and wander between ponds. Males on average stay for several days or even weeks, while females only visit the ponds only for

oviposition The ovipositor is a tube-like organ used by some animals, especially insects, for the laying of eggs. In insects, an ovipositor consists of a maximum of three pairs of appendages. The details and morphology of the ovipositor vary, but typical ...

. While in the ponds males begin calling between dusk and midnight. Males have two distinct calls; one call is used for mating to attract females, and the second call is used as a territorial call.

Mating call A mating call is the auditory signal used by animals to attract mates. It can occur in males or females, but literature is abundantly favored toward researching mating calls in females. In addition, mating calls are often the subject of mate choic ...

is fairly short metallic that can last from 0.16 to 0.24 seconds with an average frequency of 2.04–3.43

Kilohertz The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), equivalent to one event (or cycle) per second. The hertz is an SI derived unit whose expression in terms of SI base units is s−1, meaning that one h ...

; the frequency varies depending on the size of the frog. Territorial call sounds like a “croak”; it is deeper than the mating call and lasts for a longer period of time. On average each calls can last from 0.28 to 0.36 seconds with a frequency of 0.98–2.0

. Males tend to become aggressive when defending their small calling territories. The female deposits her eggs in the water, attaching the clutch underwater where there is vegetation at the bottom of the pond. Females have the ability to lay 94–800 eggs per clutch. Females are able to produce several clutches during one mating season. Nonetheless, clutch size will decrease when multiple clutches are laid. There is no parental care. Eggs are white with a dark brown animal pole. Two to fives days after the egg were laid the embryos start to hatch as are free-swimming

tadpole A tadpole is the larval stage in the biological life cycle of an amphibian. Most tadpoles are fully aquatic, though some species of amphibians have tadpoles that are terrestrial. Tadpoles have some fish-like features that may not be found i ...

s. The tadpole development may take longer because it is dependent on water temperature. Free-living larvae stay in the vegetation areas at the edge of the pond and feed of algae. During this period the larvae are at high risk of many predators such as

dragonfly A dragonfly is a flying insect belonging to the infraorder Anisoptera below the order Odonata. About 3,000 extant species of true dragonfly are known. Most are tropical, with fewer species in temperate regions. Loss of wetland habitat threate ...

and beetle larvae,

turtle Turtles are an order of reptiles known as Testudines, characterized by a special shell developed mainly from their ribs. Modern turtles are divided into two major groups, the Pleurodira (side necked turtles) and Cryptodira (hidden necked tu ...

s, and most fish. The tadpole stage lasts six to eight weeks, before the tadpoles

metamorphose Metamorphosis is a biological process by which an animal physically develops including birth or hatching, involving a conspicuous and relatively abrupt change in the animal's body structure through cell growth and differentiation. Some insec ...

. For the frog to mature completely it requires about two months.

Habitat

''Hyperolius nitidulus'' inhabit margins of swamps, rivers and lakes in savanna, grassland and bushland habitats. It is a very adaptable species that also occurs in many human-modified areas, such as cultivated land, towns, and gardens.

Survival during dry season

''Hyperolius nitidulus'' live in an environment with a wet season that can be cold and humid, and an extremely hot and dry season. During the hot and dry season the frog is dependent on water therefore it has special adaptations to survive the extreme climate. ''Hyperolius nitidulus'' is known for its unique aestivation behavior during the hot and dry season. During dry season ''Hyperolius nitidulus'' do not seek shelter or hide, instead, they fully expose themselves to the sun by sitting on dry plants to reduce rapid water loss and can remain in this sitting position for months without food or water. The juveniles only move when they are in serious danger. They sit with their legs held tightly to the body and feet hidden under their skin folds. During this period, since there is no food or water intake, the juvenile frog does not urinate or defecate. The body stores all nitrogenous waste as urea in body fluids and purines. As the hot weather increases the dorsal skin of the frog becomes white due to the presence

iridophores Chromatophores are cells that produce color, of which many types are pigment-containing cells, or groups of cells, found in a wide range of animals including amphibians, fish, reptiles, crustaceans and cephalopods. Mammals and birds, in contr ...

that can reflect light like a mirror since they are filled with purines crystals. Juveniles are the only ones that survive a dry season because most adults cannot adapt to the changes in living condition and die. Juveniles born in the first 2/3 of the wet season have enough time to mature and reproduce in the same season. These juveniles must mature quickly and use all their energy for growth and reproduction, which prevents them from preparing for the dry season that lies ahead; they will die when dry season begins due to the lack of energy. Juveniles that are born in the last third of the wet season take their time maturing and prepare themselves for the dry season. These last juveniles do not reproduce, instead, they allocate all their resources to energy storage to be able to survive the dry season and hope to reproduce the following wet season.

References

{{Taxonbar, from=Q1944139 nitidulus Frogs of Africa Amphibians of Cameroon Amphibians of the Central African Republic Amphibians of West Africa Amphibians described in 1875 Taxa named by Wilhelm Peters Taxonomy articles created by Polbot