Nyctibatrachus major | |
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Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Amphibia |
Order: | Anura |
Family: | Nyctibatrachidae |
Genus: | Nyctibatrachus |
Species: | N. major |
Binomial name | |
Nyctibatrachus major Boulenger, 1882 | |
Range of N. major; reports of the species from Maharashtra are probably erroneous [2] | |
Synonyms [3] | |
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Nyctibatrachus major, the Malabar night frog, large wrinkled frog, or Boulenger's narrow-eyed frog [3] is a species of frog in the family Nyctibatrachidae, commonly known as the robust frogs. It was described in 1882 by the zoologist George Albert Boulenger, and is the type species of the genus Nyctibatrachus . It is a large frog for its genus, with an adult snout–vent length of 31.5–52.0 mm (1.24–2.05 in) for males and 43.7–54.2 mm (1.72–2.13 in) for females. It is mainly brownish to greyish in colour, with a dark greyish-brown upperside, a greyish-white underside, and light grey sides. It also has a variety of grey or brown markings. When preserved in ethanol, it is mostly greyish-brown to grey, with whitish sides. Sexes can be told apart by the presence of the femoral glands (bulbous glands near the inner thigh) in males.
The species is endemic to the Western Ghats mountain range of India, where it is found in Kerala, Tamil Nadu, and Karnataka. Adults inhabit fast-moving forest streams at elevations of up to 900 m (3,000 ft) and have highly specific habitat requirements. Adults are mostly found in or near water and are nocturnal; subadults can be found during both the night and day. Its diet mainly consists of other frogs and insect larvae. Over a period of several days or weeks, females lay multiple small clutches of eggs on leaves and rocks overhanging water; tadpoles drop into the water below on hatching. The species is currently classified as being vulnerable on the IUCN Red List owing to its small and fragmented range and ongoing habitat degradation. Threats to the species include habitat loss, increased human presence near the streams it inhabits, and possibly nitrate pollution caused by fertiliser overuse.
The zoologist George Albert Boulenger formally described the species as Nyctibatrachus major in 1882 on the basis of twelve type specimens from what he referred to as "Wynaad" and "Malabar", creating the genus Nyctibatrachus in the same publication. [4] [5] N. major was subsequently designated as the type species of Nyctibatrachus in 1942 by the American herpetologist George Myers. [6] [7] In 1910, zoologist Nelson Annandale described the species Rana travancorica on the basis of specimens collected from Travancore, presumably because of the shape of the pupils in these specimens, which was typical of the genus Rana . [8] [9] This species was synonymised with N. major by the herpetologist Raghavan Pillai in 1978, as he found the shape of the pupil to be a variable characteristic in preserved specimens. [9] Although this synonymisation was disputed by the herpetologist Sushil Dutta in 1997, it has since been found to be valid and R. travancorica is currently treated as a synonym of N. major. [3] [5] In 2011, the herpetologist Sathyabhama Biju and colleagues re-examined the specimens from which the species was described, and concluded that several of these actually represented species distinct from N. major; they then designated an adult female collected from "Malabar" as the lectotype to avoid subsequent taxonomic uncertainty and ensure that the genus Nyctibatrachus could be tied to a single type species. [5]
There are no subspecies of N. major. [3] It is currently treated as one of 34 species in the night frog genus Nyctibatrachus, in the family Nyctibatrachidae, commonly known as the robust frogs. [7] According to a 2017 study by the herpetologist Sonali Garg and colleagues, within the genus, it is sister (most closely related) to a clade (group of organisms descending from a common ancestor) formed by N. acanthodermis and N. gavi . These three species are further sister to a clade formed by N. grandis and N. sylvaticus . The clade of these five species is sister to N. radcliffei , and these six species are sister to N. indraneili . [10] [11] A study from 2014 found a slightly different relationship, with major being sister to gavi, and acanthodermis being sister to that clade. [12] The following cladogram shows relationships within this clade based on a phylogeny from the 2017 study by Sonali Garg and colleagues: [10]
The species had its DNA barcoded in 2010. This barcoding allows unknown specimens of the frog to be identified accurately with even small tissue samples, which could help resolve taxonomic uncertainties and aid conservation efforts for the species. The development of species-specific microsatellite markers could offer tools for assessing genetic variation and population dynamics, further informing conservation strategies for this species. [13]
Nyctibatrachus major is a large species of night frog, with an adult snout–vent length of 31.5–52.0 mm (1.24–2.05 in) for males and 43.7–54.2 mm (1.72–2.13 in) for females; other species in the "large" group of Nyctibatrachus range in size from 41 to 77 mm (1.6 to 3.0 in). [5] [14] The upperside is dark greyish-brown, with variable light grey and dark brown markings, and the underside is greyish-white. The lores (area between the eyes and nostrils) and area around the tympanum (external ear) are dark brown, with a dark grey stripe between the eyelids, and the irises are dark brown. The sides of the belly are light grey, mottled with white and dark grey, and the groin is dark brown. The limbs are brown with pale diagonal bands. When preserved in 70% ethanol, the colour of the upperside changes to greyish-brown, marked variably with pale and dark brown. The colour of the band between the eyelids changes to faint grey, and the underside and sides become whitish, the latter marked with black spots. [5] Males and females are broadly similar in their external appearance, but can be distinguished by the presence of the femoral glands (bulbous glands near the inner thigh) in males. [14] Like other frogs in the genus, it has two rows of vomerine teeth along each vomerine ridge and a bluish-black liver that can be seen through the skin of the underside. [5] Male frogs also have two vocal sacs, [4] which are seen as an internal pair of slits at the back of the lower jaw. The sacs expand towards the sides and to a large size when inflated. [5]
The species may be confused with several other species in its genus, namely N. dattatreyaensis , N. humayuni , N. indraneili , N. jog , N. karnatakaensis , N. petraeus and N. vrijeuni . It can be distinguished from these species by its large size; well-developed toe and finger discs; the absence of a groove on the third finger disc; the presence of a groove on the fourth toe disc; conspicuous wrinkling and glandular protrusions on the skin of the upperside; medium-sized webbing between the fingers; and a prominent Y-shaped ridge from the upper lip to the nostrils. [5]
Tadpoles of the species are mainly black, with a brown body, brown underside of head, and a mostly white tail. There are two long pale marks on the lower back, and the tail has darks bands near the front. Tadpoles have a maximum length of 5.2 cm (2.0 in), of which one-half to two-thirds is the tail. Their heads and bodies are roughly egg-shaped and somewhat flattened, and the mouth is small with no teeth. After reaching a length of 1.5–1.9 cm (0.59–0.75 in), tadpoles have only a tail stump and begin metamorphosing; they can be distinguished from adults by the lack of grooves on the fingers. [15]
Advertisement calls consist of solitary notes 0.05 seconds long, delivered around 20 seconds apart. The calls are mainly delivered in a frequency band of 0.6–1.9 kHz, the frogs modulating calls significantly at the higher end of this range, although some calls are also delivered at a frequency of around 2.43 kHz. [16]
The species is endemic to the Western Ghats of southern India, where it is found in Kerala, Tamil Nadu, and Karnataka. [15] It was previously thought to also occur in Maharashtra, but those records are likely erroneous. [2] Adults inhabit fast-moving streams in evergreen deciduous forest, secondary forest, and forest edge at elevations of 0–900 m (0–2,950 ft). [1] [15] They prefer undisturbed forest, [17] and generally are not found in highly degraded habitats [1] or in open areas near the boundary of a forest. [18] In particular, streams inhabited by adults are slightly acidic (pH of 6.0–6.5), [14] with low temperatures (18–24.5 °C (64–76 °F)), low light intensities, and low concentrations of calcium carbonate, as well as high levels of dissolved oxygen. [17] Tadpoles also have highly specific requirements for their microhabitat, preferring streams with low air and water temperatures, low light intensity and dense canopy cover, high humidity, and large amounts of leaf litter. [18] Tadpoles have been found at elevations up to 825 m (2,700 ft). [15]
Adults are mostly nocturnal and spend most of their time in aquatic environments, most commonly being seen on rocks near water. During the day, adults typically conceal themselves below rocks, but subadults are more active. When disturbed or threatened, they scramble through the mud of the streambed and stay underwater for some time before coming to the surface again. [15] Other observers have found that they rarely bury themselves in mud or try to exit the water and hide in nearby undergrowth. [9]
Nyctibatrachus major mainly feeds on insect larvae and other frogs. It consumes insects like dragonflies in the genus Ophiogomphus , beetles in the genera Psephenus and Enochrus and the families Dytiscidae and Haliplidae, true bugs in the genus Neides , and springtails in the genus Sminthurinus . Frogs that N. major feeds on include Fejervarya limnocharis , Euphlyctis cyanophlyctis , and Micrixalus saxicola ; the especially high rates at which the species predates F. limnocharis and E. cyanophlyctis may be due to the fact that all of these species share the same microhabitat. [19]
The species' life cycle and breeding behaviour are poorly known. Females with mature eggs have been collected from May to June; tadpoles have been collected in October. [15] Femoral glands are only present in males and seem to show subtle seasonal variation, being longer proportional to total body length from February to September (before and during the monsoon) than from October to January (after the monsoon). This may indicate that these glands have a reproductive function and aid in amplexus (mating). [14] Males also have extremely small testes proportional to their body size, although the reasons for this are unclear. [16] The sperm of the species is rather distinctive, with a loosely coiled, S-shaped head and an unusually thin tail. [20]
Mature eggs are pigmented and have an outer diameter of 4.1 mm (0.16 in). Immature eggs are smaller and colourless. Females possess egg cells undergoing several stages of maturity at any time; this suggests that they lay multiple small clutches of eggs over several days or weeks, instead of one large clutch at once. [16] Eggs are laid on leaves and rocks overhanging water, after which the males guard them until they hatch and the tadpoles fall into the water below. [15] Tadpoles metamorphose into froglets by 98 days. [21]
Nyctibatrachus major is classified as being vulnerable on the IUCN Red List due to its small and fragmented range and ongoing habitat degradation. [1] It is threatened by habitat loss caused by factors such as deforestation, wood and timber harvesting, and conversion of land for agricultural use. It is also threatened by the construction of check dams, road construction, and an increase in tourism in its range. Adults and tadpoles of N. major are highly sensitive to changes in their microhabitat. [17] [18] Consequently, increased human activities that alter their habitat may lead to declines in the species' population, as has occurred in the related N. aliciae . [18]
The species may also be threatened by nitrate pollution caused by overuse of fertilisers. Due to habitat fragmentation, many of the streams the frog inhabits are adjacent to farms that experience high levels of nitrogen-based fertilizer use, leading to elevated nitrate concentrations in the water. The LC50 (concentration at which 50% of exposed tadpoles die) for nitrates in the species is 2,510 micrograms (μg) per litre over a 30-day period; nitrate concentrations in streams with N. major tadpoles have been collected vary from 110 to 6,000 μg per litre. Even sub-lethal concentrations of nitrates in the water lead to adverse effects such as paralysis, restlessness, abnormal swimming patterns, and swollen body parts. [21] [22]
Philautus is a genus of shrub frogs in the family Rhacophoridae from Asia. Some species in this genus are now considered extinct by IUCN, while others are widespread and abundant. The taxonomy of the group is unclear, with many poorly described species.
Nyctibatrachus is a genus of frogs endemic to the Western Ghats of southwestern India. Their common name is night frogs. Their scientific name also means "night frog", in reference to their habits and dark color. They are the only extant members of the monotypic subfamily Nyctibatrachinae. Currently, 35 species belong to Nyctibatrachus.
Micrixalus saxicola is a species of frog in the family Micrixalidae, found in forest streams in the Western Ghats of India.This frog has a brown colored dorsum and a white ventral side with irregular white specks on its dark brown throat and chest. Its smooth skin and cryptic coloration allow it to blend into its surroundings while resting or calling. The males of the species are territorial, and will use calling, foot tapping, and foot flagging to warn off competition. M. saxicolais is described by the IUCN as a vulnerable species due to habitat loss, fragmentation, and human interference.The frog also threatened by infection by the fungus Batrachochytrium dendrobatidis.
Indirana semipalmata is a species of frog endemic to the Western Ghats region of southern India. They are small frogs, reaching lengths of about 36 mm (1.4 in) from snout to vent. The species breeds during the monsoons, laying their eggs on moist rocks and tree bark. Their tadpoles are terrestrial – hatching, feeding, and undergoing metamorphosis without ever entering any standing bodies of water.
Nyctibatrachus beddomii is a species of frog in the family Nyctibatrachidae.
Nyctibatrachus deccanensis is a species of frogs in the family Nyctibatrachidae. It is endemic to the southern Western Ghats in Tamil Nadu and Kerala states, India. Its natural habitats are tropical moist lowland forests, moist montane forests, and rivers. It is threatened by habitat loss.
The Bombay night frog, also known as Abdulali's wrinkled frog, Abdulali's night frog or Humayun's wrinkled frog, is a species of frog in the family Nyctibatrachidae. It is endemic to the Western Ghats of Maharashtra state, India. The species is found near torrential hill streams in tropical moist evergreen and semi-evergreen forests, a habitat that is threatened by habitat loss and pollution. Its name honours Humayun Abdulali, an Indian biologist.
The giant wrinkled frog is a species of frogs in the family Nyctibatrachidae endemic to the Western Ghats of India in the Kudremukh region. Its natural habitats are tropical moist lowland forests and rivers. It is threatened by habitat loss.
Nyctibatrachus minimus is a species of frogs in the family Nyctibatrachidae. It is the smallest known frog in the genus Nyctibatrachus and was recently discovered from Kurichiyarmala in the Western Ghats or Wayanad, Kerala.
The Dattatreya night frog is a species of frog in the family Nyctibatrachidae first described in the Shola forests around the Dattatreya Peeta in the Chikkamagaluru district of Karnataka. It is still known only from this part of the Western Ghats, India.
Nyctibatrachidae is a small family of frogs found in the Western Ghats of India and in Sri Lanka. Their common name is robust frogs. Recognition of Nyctibatrachidae as a family is fairly recent. These frogs were previously placed in the broadly defined family Ranidae, which was more recently divided into three subfamilies: Lankanectinae, Nyctibatrachinae, and Astrobatrachinae.
The spinular night frog, also known as the spinular wrinkled frog, is a species of frog in the family Nyctibatrachidae, commonly known as the robust frogs. It was described in 2011 as one of 12 new species in its genus by the herpetologist Sathyabhama Das Biju and his colleagues. A large frog for its genus, it has an adult male snout–vent length of 52.9–66.2 mm (2.08–2.61 in). It has a brownish-grey back, a grey underside, dark brown limbs, and dark grey feet. When preserved in ethanol, it is black above with greyish-brown undersides. The species is endemic to the Western Ghats of India, where it is known from the states of Kerala and Tamil Nadu, where the specimens used to describe the species were originally collected. It is found under rocks in streams in forests. The species has not been assigned a conservation status by the IUCN.
The Jog night frog or Jog's night frog is one of 34 species of nocturnal frogs in the genus Nyctibatrachus. It is found exclusively in the Western Ghats, India, and both sexes share the responsibility of watching over the eggs.
Nyctibatrachus manalari, the Manalar night frog, is a species of frog in the robust frog family Nyctibatrachidae. It was described in 2017, along with six other species in its genus, by the herpetologist Sonali Garg and her colleagues. A small frog, it has an adult male snout–vent length of 13.1–15.4 mm (0.52–0.61 in). It is mainly reddish-brown in color, with a pale patch on the snout, lighter undersides, and dark brown horizontal lines on the limbs. When preserved in ethanol, it is mostly grey to greyish-brown, with grayish-white undersides.
Nyctibatrachus mewasinghi, also known as Mewa Singh's night frog or the Peruvannamuzhi wrinkled frog, is a species of frog in the robust frog family Nyctibatrachidae. It was described in 2017 by the herpetologist Keerthi Krutha and her colleagues. A small frog, it has an adult snout–vent length of 21.4–23 mm (0.84–0.91 in). It is mainly light greyish-brown above and off-white below, with a triangular light brown patch on the snout, light brown limbs with off-white undersides, and dark grey fingers and toes. It has scattered greyish-brown spots on the throat and the underside of the limbs. When preserved in ethanol, it has a more faded colour.
Nyctibatrachus robinmoorei, also known as Robin Moore's night frog or the Tirunelveli wrinkled frog, is a species of frog in the family Nyctibatrachidae, commonly known as the robust frogs. It was described in 2017, along with six other species in its genus, by the herpetologist Sonali Garg and her colleagues. A small frog, it has an adult male snout–vent length of 12.2–13.4 mm (0.48–0.53 in). It is mainly reddish-brown, with a light grey underside, light orangish-brown bands running from the eyes to the middle of the back, light brown limbs, and darker brown hands and feet. When preserved in ethanol, it is mostly brown, with light greyish-white undersides and light greyish-brown limbs.
Nyctibatrachus radcliffei, also known as Radcliffe's night frog or the Thiashola wrinkled frog, is a species of frog in the robust frog family Nyctibatrachidae. It was described in 2017, along with six other species in its genus, by the herpetologist Sonali Garg and her colleagues. A medium-sized frog for its genus, it has an adult male snout–vent length of 32.8–38.3 mm (1.29–1.51 in). It is mainly reddish-brown, with a light flesh-red coloured underside, light brown limbs, and dark grey hands and feet. When preserved in ethanol, it is mostly dark grey, with grayish-white undersides.
Nyctibatrachus sabarimalai, also known as the Sabarimala night frog or Sabarimala wrinkled frog, is a species of frog in the family Nyctibatrachidae, commonly known as the robust frogs. It was described in 2017, along with six other species in its genus, by the herpetologist Sonali Garg and her colleagues. A small frog, it has an adult male snout–vent length of 12.3–13.2 mm (0.48–0.52 in). It is mainly brown, with a dark brown back, a greyish-white underside, light brown bands running from the eyes to the middle of the back, light brown limbs, and light grey hands and feet. When preserved in ethanol, it is mostly grey, with greyish-white undersides and light grey limbs.
The femoral gland is a specialised gland found in some male frogs that plays a role in chemical communication and reproductive signalling. Particularly prominent within the frog family Mantellidae, these glands are located on the underside of the hindlimbs, usually on the inner thighs or shanks. Femoral glands can be identified by their swollen appearance and distinct colouration, which differ from the surrounding skin. Femoral glands are classified into four distinct morphological types, varying from minute granular structures to conspicuous patches characterised by large granules and prominent central indentations.
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