{{short description|Species of frog}} {{speciesbox | image = | status = LC | status_system = IUCN3.1 | status_ref = <ref name="iucn status 16 November 2021">{{cite iucn |author=IUCN SSC Amphibian Specialist Group |date=2017 |title=''Hyperolius nitidulus'' |volume=2017 |article-number=e.T16794889A16813897 |doi=10.2305/IUCN.UK.2017-2.RLTS.T16794889A16813897.en |access-date=16 November 2021}}</ref> | taxon = Hyperolius nitidulus | authority = Peters, 1875 | synonyms = }}
'''''Hyperolius nitidulus''''' is a species of frog from the family Hyperoliidae. It is found on the West African savannas between Guinea and Mali in the west and Nigeria and Cameroon in the east.<ref name="iucn status 16 November 2021" /><ref name=frost>{{cite web |url=http://research.amnh.org/vz/herpetology/amphibia/Amphibia/Anura/Hyperoliidae/Hyperolius/Hyperolius-nitidulus |title=''Hyperolius nitidulus'' Peters, 1875 |author=Frost, Darrel R. |year=2015 |work=Amphibian Species of the World: an Online Reference. Version 6.0 |publisher=American Museum of Natural History |access-date=2 December 2015}}</ref> Common name '''plain reed frog''' has been coined for it.<ref name="iucn status 16 November 2021" />
==Description==
''Hyperolius nitidulus'' are medium-sized reed frogs with a rather blunt snout. Males vary in size between {{convert|23|and|29|mm|abbr=on}} and on average weight about one gram.<ref name="Bubac"/> Females are larger and heavier than males, their body size can vary between {{convert|24|and|32|mm|abbr=on}} with an average weight of about two grams before laying eggs.<ref name="life cycle">{{cite journal|last1=Lampert |first1=Kathrin |last2=Linsenmair |first2=Eduard K. |title=Alternative life cycle strategies in the West African reed frog ''Hyperolius nitidulus'': the answer to an unpredictable environment?|year=2002 |journal=Oecologia |volume=130 |issue=3 |pages=364–372 |doi=10.1007/s00442-001-0821-4|pmid=28547042 |s2cid=6446076 }}</ref> This species has a large choana, which is not hidden beneath edge of mandible like in most ''Hyperolius'' species.<ref name=taxonomic /> They have a relatively large tongue which is broad and shaped like a heart. Their dorsal view is roundish and sometimes a bit pointy.<ref name=taxonomic /> 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.<ref name=taxonomic>{{cite journal|last=Rödel|first=Mark-Oliver|author2=Sandberger|title=The taxonomic status of ''Hyperolius spatzi'' Ahl, 1931 and ''Hyperolius nitidulus'' Peters, 1875 (Amphibia: Anura: Hyperoliidae)|journal=Bonn Zoological Bulletin|date=November 2010|volume=57|issue=2|pages=177–188 |url=http://biostor.org/reference/136996}}</ref> 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.<ref name=Bubac /> Males have a median subgular vocal sac which is used for calling.<ref name=alternative /> 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.<ref name="6 corrected">{{cite journal |last1=Schmuck |first1=R. |last2=Linsenmair |first2=Eduard K.|title=Adaptations of the reed frog ''Hyperolius viridiflavus'' (Amphibia: Anura: Hyperoliidae) to its arid environment, II |journal=Journal of Comparative Physiology B |year=1986 |volume=158 |issue=5 |pages=542–548|doi=10.1007/BF00692561|s2cid=31036567 }}</ref> During the night the uniformly color is beige and during the day the color can vary between yellow and orange with spots.<ref name=taxonomic /> During the dry season the juveniles become white as they aestivate 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'', ''Musca'', ''Phormia'', ''Lucilia'', and ''Calliphora''.<ref name="life cycle" />
==Reproduction==
Breeding normally occurs during wet season, that is May–October.<ref name=alternative /><ref name="6 corrected" /> 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. While in the ponds males begin calling between dusk and midnight.<ref name=alternative /><ref name="6 corrected" /> 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 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 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 Kilohertz.<ref name="life cycle" /><ref name=alternative /> Males tend to become aggressive when defending their small calling territories.<ref name=alternative />
The female deposits her eggs in the water, attaching the clutch underwater where there is vegetation at the bottom of the pond.<ref name=alternative /> Females have the ability to lay 94–800 eggs per clutch.<ref name="enrivoment 1" /> Females are able to produce several clutches during one mating season. Nonetheless, clutch size will decrease when multiple clutches are laid.<ref name="enrivoment 1" /> There is no parental care. Eggs are white with a dark brown animal pole.<ref name=alternative /> Two to fives days after the egg were laid the embryos start to hatch as are free-swimming tadpoles.<ref name=alternative>{{cite thesis |last=Lampert |first=Kathrin P. |title=Alternative life history strategies in the West African reed frog, ''Hyperolius nitidulus'' |year=2001 |type=Ph.D. thesis |publisher=Bayerischen Julius-Maximilians-Universität Würzburg |url=https://d-nb.info/966000757/34 }}</ref> 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.<ref name="life cycle" /><ref name="6 corrected" /> During this period the larvae are at high risk of many predators such as dragonfly and beetle larvae, turtles, and most fish. The tadpole stage lasts six to eight weeks, before the tadpoles metamorphose. For the frog to mature completely it requires about two months.<ref name="enrivoment 1" />
==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.<ref name="iucn status 16 November 2021" />
==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.<ref name=Bubac>{{cite web|last=Bubac|first=Christine|title=Hyperolius nitidulus|url=http://amphibiaweb.org/cgi/amphib_query?where-genus=Hyperolius&where-species=nitidulus|access-date=9 November 2013}}</ref><ref name=taxonomic /> 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.<ref name="6 corrected" /> 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.<ref name="enrivoment 1">{{cite journal |last=Kobelt |first=Frank |author2=K.E Linsenmair |title=Adaptation of the reed frog ''Hyperolius viridiflavus'' (Amphibia, Anura, Hyperoliidae) to its arid environment |journal=Oecologia |year=1986 |volume=68 |issue=4 |pages=533–541 |doi=10.1007/bf00378768 |jstor=4217879|pmid=28311709 |s2cid=20785118 }}</ref> 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 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.<ref name="iucn status 16 November 2021" /><ref name=alternative /> Juveniles born in the first 2/3 of the wet season have enough time to mature and reproduce in the same season.<ref name=Bubac /> 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.<ref name="life cycle" /> 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.<ref name=taxonomic />
==References== {{Reflist|30em}}
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nitidulus Category:Frogs of Africa Category:Amphibians of Cameroon Category:Amphibians of the Central African Republic Category:Amphibians of West Africa Category:Amphibians described in 1875 Category:Taxa named by Wilhelm Peters Category:Taxonomy articles created by Polbot