Hyperolius nitidulus
| Hyperolius nitidulus | |
|---|---|
| Conservation status | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Amphibia |
| Order: | Anura |
| Family: | Hyperoliidae |
| Genus: | Hyperolius |
| Species: | H. nitidulus |
| Binomial name | |
| Hyperolius nitidulus Peters, 1875 | |
Hyperolius nitidulus is a species of frogs from the Hyperoliidae family.This species can be found in dry savannas, moist savanna, subtropical or tropical dry shrubland, subtropical or tropical moist shrubland, subtropical or tropical dry lowland grassland, subtropical or tropical seasonally wet or flooded lowland grassland, subtropical or tropical high-altitude grassland, rivers, swamps, freshwater lakes, intermittent freshwater lakes, freshwater marshes, intermittent freshwater marshes, arable land, pastureland, rural gardens, urban areas, water storage areas, ponds, open excavations, irrigated land, seasonally flooded agricultural land, canals and ditches.[1]
Appearance
Hyperolius Nitidulus are medium-sized reed frogs with a rather blunt snout. Males vary is size between 23mm and 29mm and on average weight about one gram.[2] Females are larger and heavier than males, their body size can vary between 24mm to 32mm with an average weight of about two grams before laying eggs.[3] This species has a large Choana, which is not hidden beneath edge of mandible like in most Hyperolius species.[4] The have a fairly larger tongue that which broad and shaped like a heart. Their dorsal view is roundish and sometimes a bit pointy.[4] 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.[4] 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. Finger and toes have circummarginal disc.[2] Males have a median subgular vocal sac which is used for calling.[5]
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.[6] During the night the uniformly color is beige and during the day the color can vary between yellow and orange with spots.[4] 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. Hyperolius Nitidulus is mostly found in the Savannas of Western Africa, South of Sahara, and Grasslands. Adults are insectivores they usually consumed species such: Drosophila, Musca, Phormia, Lucilia and Calliphora.[3]
Biology
Breeding normally occurs during wet season that are the months of May through October.[5][6] 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.[5][6] Males have two distinct calls; one call is used for mating to attract females the second call is used as a territorial call. Mating call is fairly short metallic that can last from 0.16–0.24 seconds with an average frequency of 2.04–3.43 Kilohertz however; the frequency varies depending on the size of the frog. Territorial call sounds like a “croak” it is deeper than the mating call and for longer periods of time. On average each calls can last from 0.28–0.36 seconds with a frequency of 0.98–2.0 Kilohertz.[3][5] Males tend to become aggressive when defend their small calling territories.[5]
Mating
The females deposits her eggs in the water, she attaches the clutch under the water where there is vegetation at the bottom of the pond.[5] Females have the ability to lay 94–800 eggs per clutch.[7] Females are able to produce several clutches during one mating season. Nonetheless, clutch size will decrease when multiple clutches are laid.[7] Hyperolius Nitidulus is a species that show no parental care. Eggs from Hyperolius Nitidulus are distinguished by a white color with a dark brown animal pole.[5]
Hatching
Two to fives days after the mother laid the egg the embryos start to hatch as are free-swimming tadpoles.[5] 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.[3][6] During this period the larvae are at high risk of many predators such as dragonfly larvae, beetle larvae and turtles and most fish. The tadpole stage can last from six up to eight weeks before the tadpoles metamorphose to an adult frog. For the frog to mature completely it requires about two months.[7]
Survival during dry season
Hyperolius Nitidulus lives in an environment, which has a wet season that can be cold and humid, and an extremely hot and dry season.[2][4] 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.[6] The juveniles only move when they are in serious danger. They seat with their legs held tightly to the body an feet hidden under their skin folds.[7] During this period since there is no food or water in take the juvenile frog does not urinate or defecate. The body stores all nitrogenous waste, which are stored 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 for the most part are the only ones that survive a dry season most adult cannot adapt to the changes in living condition so they die.[1][5] Surviving a d[6] ry season is very critical for juveniles therefore they must prepare before the season starts.[5][7] Juveniles born in the first 2/3 of the wet season have enough time to mature and reproduce in the same season.[2] Once these early season juveniles mature they have the ability to reproduce within the same season. Since these juveniles must mature quickly and used all their energy for growth and reproduction it prevents them from preparing for the dry season that lies ahead. These juvenile will die when dry season begins due to the lack of energy.[3] 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.[4] The season in which they reproduce all their energy is used therefore they cannot survive the next dry season.[2]
References
- ↑ 1.0 1.1 "Hyperolius nitidulus". 2004. Retrieved 30 November 2013.
- ↑ 2.0 2.1 2.2 2.3 2.4 Bubac, Christine. "Hyperolius nitidulus". Retrieved 9 November 2013.
- ↑ 3.0 3.1 3.2 3.3 3.4 Lampert, Kathrin; Linsenmair (15 May 2001). "Alternative life cycle strategies in the West African reed frog Hyperolius nitidulus: the answer to an unpredictable environment?" (130). pp. 364–372.
- ↑ 4.0 4.1 4.2 4.3 4.4 4.5 Rödel, Mark- Oliver; Sandberger (November 2010). "The taxonomic status of Hyperolius spatzi Ahl, 1931 and hyperolius Nitidulus, 1875 (Amphibia: Anura: Hyperoliidae)". Bonn Zoological Bulletin 57 (2): 177–188.
- ↑ 5.0 5.1 5.2 5.3 5.4 5.5 5.6 5.7 5.8 5.9 Lampert, K (2001). "Alternative life history strategies in the West African reed frog, Hyperolius nitidulus". Bayerischen Julius-Maximilians-Universität Würzburg.
- ↑ 6.0 6.1 6.2 6.3 6.4 6.5 Schmuck, R; Linsenmair (1986). "Adaptations of the Reed Frog Hyperolius viridiflavus (Amphibia: Anura: Hyperoliidae) to its arid environment, II.". Journal of Comarative Physiology B 158 (5): 542–548.
- ↑ 7.0 7.1 7.2 7.3 7.4 W, Geise; K.E Linsenmair (1986). "Adaptation of the reed frog Hyperoliu Viridiflavus (Amphibia, Anura, Hyperoliidae) to its Arid Environment". Oecologia 68 (4): 542. doi:10.1007/bf00378768.