Atelopus elegans (Boulenger 1882)

Atelopus elegans is a small to medium toad that exhibits sexual dimorphism. Adult males have a snout-vent length range of 22 - 24 mm and adult females have snout-vent length range of 33 - 36 mm. The difference in weight between the sexes is also significant, with males weighing an average of 0.61 g and females averaging 2.78 g (Velalcázar Guerrero 2014). The head is small, approximately one third the length of the body, and is smooth and flat. This species has a round snout from the dorsal view, with a slightly protruding lower jaw from a lateral view, ending in a blunt point. The canthus rostralis is distinct at the nostril level but not fleshy. The loreal region is vertical but not concave. The eyelid is not fleshy. There is no visible tympanum or eardrum. The body is smooth, long, thin, and relatively flat to the ground in resting position (Boulenger 1882, Peters 1973).The forelimb is slender and long. When the forearm is adpressed posteriorly along the body, the palm reaches the vent. The palms have deep, fleshy folds and low, rounded tubercles. The hands have full, fleshy webbing that almost obscure the first finger and is deeply incised between the second, third, and fourth fingers. The fourth finger is considerably longer than the second and reaches beyond the penultimate joint of the third (Peters 1973). The hind limb is also long and slender. When adpressed anteriorly along the body, the tibiotarsal articulation reaches the area between the loreal region and the posterior margin of the eye. When the hind limbs are held at right angles to the body, the heels overlap. The foot is fleshy with deep grooves or folds. The planter tubercles are weak and indistinct; the outer metatarsal tubercle is poorly defined, and the inner is nearly indistinguishable. The webbing on the foot is also thick and fleshy. The first and second digits are enclosed, except for their tips. The rest of the toes are fully webbed with shallow incisions. Along the fourth toe the webbing extends to the tip as a fringe. The fifth toe is longer than the third. There are no distinct subarticular tubercles (Peters 1973).At Gosner stage 25, A. elegans larvae have a total length range of 6.2 – 6.7 mm, with a body length range of 2.6 – 2.8 mm. The body has an average width of 1.8 mm, is oval from a dorsal and lateral views, and is flattened ventrally. The snout is round, both from the dorsal view and in the profile. There is noticeable constriction of the body at the eyes and at the spiracle. Circular nostrils with incomplete rims are present about half the distance from the tip of the snout to the eyes and located dorsolaterally. The internarial distance is slightly smaller than the interorbital distance. The dorsal eyes are directed dorsolaterally and the space between them is twice the eye diameter. The spiracle is sinistral and located almost two-thirds of the body length posteriorly from the snout. The spiracle has a dorsally directed free tube with the diameter of the opening being equal to the tube length. The vent tube does not protrude from the end of the body. The tail length range is 3.6 – 3.9 mm or about 58% of the total length. The caudal musculature is robust at the base but begins to evenly narrow after one-third the distance from the body. The tail is generally rounded with a dorsal tail fin that begins at the level of the body and is 40% of the tail height. The ventral fin begins just posterior to the vent tube. The ventral mouth has surrounding labia that form a complete oral disc with a width of 1.8 mm. Larvae have 37 marginal papillae arranged in uniserial rows on the dorsal and ventral region. The ventral region has a gap on the most posterior portion of the lip. No submarginal papillae are present at stage 25 but they become visible in later stages. The labial tooth formula is 2/3 with complete rows of anterior and posterior teeth that are equal in length. The jaw sheaths are also equal in length and have serrated inner margins. The upper beak is somewhat concave and the lower is V-shaped. Larvae possess both long and short-cusped teeth as well as teeth with no cusps. Posterior to the mouth there is an abdominal sucker that is 44% of the total length. The distinguishable abdominal sucker is composed of a stripe of large, protruding cells. By stage 43, when the tail fin height has also decreased, the abdominal sucker is no longer present (Marcillo-Lara et al. 2020). Atelopus longirostris and A. balios are the most similar species within A. elegans’ range. Atelopus longirostris displays a tan dorsal color with yellow markings and a white ventral coloration, which differs from that of A. elegans. Atelopus longirostris can also be distinguished from A. elegans by the prominent extension protruding from the snout that is absent in A. elegans. Atelopus balios is similar to A. elegans in coloration, however, where A. elegans has interdigital webbing that almost entirely covers the thumb, A. balios has a free and visible thumb that protrudes from the webbing membrane (Ron et al. 2018).Unique larval color patterning of tan with brown, yellow, and black markings distinguishes larval specimens of A.elegans from larvae of other species within the Atelopus genus. The presence of short-cusped teeth in A. elegans also differentiate it from the A. palmatus, which have stronger, long-cusped teeth (Marcillo-Lara et al. 2020). In life, adult A. elegans ranges in color from brilliant yellow to a dark olive green. Clearly defined black spots are always present on the back and limbs. The ventrum of A. elegans is yellow, with orange on the bottoms of the feet and toes. Atelopus elegans has a black eye with a light-yellow ring around the pupil (Ron et al. 2018). A black stripe is present beginning at the tip of the snout and continuing through the eye along the full extent of both sides of the body to the groin (Boulenger 1882).In preservative, the dorsal ground color of adults is white with a pattern of black or brownish parallel stripes that begin posterior to the eyelid and are joined by bars as it extends to the cloaca. The dorsal strips are connected by vermiculations or lateral bars at irregular intervals or separated by additional lengthwise stripes or by light spots with brown borders or by brown spots with white borders. In most individuals, there is a solid white line that runs from the eye to the groin along the dorsolateral line. Below the white line is a dark bar that begins at the snout, crosses the canthus laterally, through the eye, and continues to the groin. There is no pigment on the lateral or ventral surfaces below this dark line. The dorsal surfaces of the limbs and feet have dark brown to black mottling, streaks, and strips, similar to the body. The ventral surfaces of the limbs are uniformly yellowish white (Peters 1973). In life, A. elegans larvae have unique coloration patterns that can be used to distinguish them from larvae of other species. The body of larval A. elegans is dark tan with brown and dark yellow spots and some black markings. The dark yellow spots can be found around the eyes and top of the snout, while no brown or black markings are found in this area. The black markings are always larger than the brown or mustard yellow spots. The tail is tan and has brown spots mostly on the dorsal surface while black marks can be found at the anterior part of the tail and the posterior margins of the tail musculature. The spiracle has some mustard spots at the base. The heart and some blood vessels can be seen ventrally, and the abdominal sucker and mouth are transparent. The lower abdomen is colored and patterned similarly to the dorsum. When preserved, the color and patterning largely remain the same but the mustard spots fade. The spiracle becomes unpigmented. While the abdominal sucker remains transparent, the ventrum becomes tan (Marcillo-Lara et al. 2020). In life, metamorphs at stage 41 begin to develop golden dorsolateral strips that become more defined and turn cream colored at stage 43 (Marcillo-Lara et al. 2020). Adult A. elegans exhibit sexual size dimorphism (Velalcázar Guerrero 2014). There are color differences between the Gorgona Island population and the Ecuadorian populations (Ron et al. 2018). Between Gosner stages 30 - 35 larvae have visible submarginal papillae that are not present in lower stages (Marcillo-Lara et al. 2020).The species authority is: Boulenger, G. A. (1882). "Account of the reptiles and batrachians collected by Mr. Edward Whymper in Ecuador in 1879–80." Annals and Magazine of Natural History. Series 5. 9: 457–467.The genus Atelopus is a monophyletic group within the family Bufonidae. Atelopus has been demonstrated to be monophyletic through many studies, but the detailed interspecific, intraspecific, and intergeneric relationships within Atelopus are poorly understood. This is partially due to extreme morphological similarities between species, making collection and identification difficult. More so, nearly all of the more than 100 species within the genus Atelopus have suffered severe population decline and many species are now thought to be extinct, thus making collection and sample obtention difficult, if not impossible for many species (Lötters et. al. 2011).The lowland Gorgona Island population was originally named as a separate species, Atelopus gracilis, by Thomas Barbour in 1905 because it is geographically separate and has a different coloration (Ron et al. 2018). More work is needed to determine this population’s placement. The species epithet “elegans” is derivative of the Latin “elegans”, which translates to “elegant” or “handsome”, and was named as such in reference to the smooth and unblemished nature of the skin of this species (Ron et.al. 2018).The species was originally described as Phryniscus elegans (Boulenger 1882), and other synonyms include Atelopus gracilis (Barbour 1905) and Atelopus varius elegans (Cochran and Goin 1970).

Atelopus elegans inhabits humid tropical rainforests in northwest Ecuador including the following provinces: Esmeraldas, Imbabura, Pichincha, Santo Domingo de los Tsachilas, and Cotopaxi. In the last ten years the species has only been observed within the province of Esmeraldas with apparent disappearance from all other historical locations, particularly in the central part of the country (Flechas et al. 2017). This species can be found in elevations of 300 to 1140 meters above sea level in Ecuador (IUCN 2019). A separate population is also found at sea level in the lowlands of Gorgona Island off the coast of Columbia. There is some dispute on whether to include the Gorgona Island population within this species or to consider it a separate species (Atelopus gracilis) or subspecies (Marcillo-Lara et al. 2020).

Overall, this species is decreasing in numbers. The population in Gorgona Island, Columbia is currently stable, but the population in Ecuador has experienced significant declines. It was previously listed as “Critically Endangered” by the IUCN in 2004 and 2010. The IUCN status was changed to “Endangered” in 2019, likely due to the stable population in Columbia. Surveys of the Gorgona Island population in 2003, 2007, and 2010 indicate the species occurs in abundant numbers. In Ecuador, the species has not been seen throughout the majority of its former range for at least the past 10 years and is assumed to be locally extinct except for one population within the Esmeralda province (IUCN 2019).The major threats facing A. elegans are habitat loss and infection from the chytrid fungus Batrachochytrium dendrobatidis (Bd). In Ecuador, the forests where this species can be found are declining in quality and area due to agriculture, logging, mining and expanding human settlements. Throughout its Ecuadorian range, only 23.9 percent of the original vegetative cover remains undisturbed (IUCN 2019). Occurrence of Bd in the Ecuador populations is uncertain, but samples from museum specimens detected evidence of infection dating back to at least 2000. Bd fungus has been found in individuals inhabiting Gorgona Island, off the coast of Columbia, since 2000 where the population suffered an initial decline related to the infection but has since recovered and remains stable although chytrid fungus is still present in many individuals. From 2007 to 2012, the Gorgona Island population did not show any declines and incidence of Bd infection decreased steadily (Flechas et al. 2015). The remaining population is characterized by a bacterial community present on the skin that shows resistance to the fungus, which may increase resilience. This population may also be less susceptible to Bd due to its low elevation habitat which is less favorable for Bd growth (Flechas et al. 2012). The impact of the Bd infection on the Ecuador population is unknown.A range-wide population estimate is unknown and there are no current population monitoring systems in place. The last population survey to occur took place in 1994 in the province of Cotopaxi. The current assumed extent of occurrence is 4,287 square kilometers within two locations: Esmeraldas province in Ecuador and Gorgona Island off Columbia (IUCN 2019). Although serious declines have been reported in Ecuador, the Gorgona Island population appears to be abundant and remains stable after recovery following declines due to chytrid fungus (Gomez-Hoyos 2017).Captive breeding was attempted in Ecuador during a 2011 - 2012 study as ex situ management for proactive conservation of A. elegans. A total of three males and seventeen females were collected from a riverbank in Durango, Province of Esmeraldas, Ecuador resulting in the first successful oviposition event in captivity for the species (Coloma and Almeida-Reinoso 2012). Another captive colony of A. elegans has been studied under the Balsa de los Sapos initiative at the Pontifical Catholic University of Ecuador for conservation purposes (Ron et al. 2018).

Mature adults have been found in open areas (paddocks) adjacent to forests, in secondary growth forests, flooded areas and in riverbank vegetation. At night, they have been known to perch on leaves in the canopy (IUCN 2019). An adult female was observed walking during the day along a stream. However, very little information is available on their use of micro-habitats (Coloma and Almeida-Reinoso 2012). Very few population surveys have been conducted for A. elegans over the past 10 years, but the greatest abundance has been found on Gorgona Island, Colombia, which may be a different species, Atelopus gracilis. In 2012, at the Parque Nacional Natural (PNN) Gorgona, 123 individuals were observed during a distance sampling study for population density, and A. elegans was estimated to have a density of 0.01 individuals/m2 (Gomez-Hoyos et al. 2017). Near Durango, Esmeraldas Province in Ecuador, eight individuals were found in 2009 by a field party from the Museum of Zoology of Ecuador (Ron et al. 2011). For a 2011 - 2012 study 20 adults were found along a riverbank in Durango, Province of Esmeraldas, Ecuador (Coloma and Almeida-Reinoso 2012).In 2012, an ex situ breeding experiment was conducted using four males and 17 females. Only one female laid a clutch, and only after being stimulated by Human Chorionic Gonadotropin hormone. The clutch of eggs was laid the next day under a stone and produced 300 tadpoles (Coloma and Almeida-Reinoso 2012).Larvae of A. elegans are gastromyzophorus, having an abdominal sucker, which is an ecomorphological trait used to keep their position in torrential fresh-water streams and rivers (Altig and Johnson 1989).

Atelopus elegans (Boulenger)

Phryniscus elegans Boulenger, 1882a:155 [type locality: Tanti, Ecuador, 2000 feet]; 1882b:464, fig. 1.

Atelopus elegans.—Boulenger, 1894:375; 1898:119.—Peracca, 1904:22.

A.[telopus] elegans.—Nieden, 1926:81.

Atelopus [elegans] elegans.—Rivero, 1963:109.

HOLOTYPE.—British Museum (Natural History), one female.

DESCRIPTION.—Snout from above rounded, not ending in point; distinct angle in canthus at nostril level; canthus and upper eyelid not fleshy, dorsum of head smooth and flat. Snout from side with distinct projection, ending in blunt point, extending beyond symphysis of lower jaw; loreal region vertical, not concave. Head dorsally and laterally smooth, without spines, warts, or pustules. Body slender, skin completely smooth.

Forelimb long, slender; when laid back along body, palm reaches anus. Webbing fleshy, enclosing and almost completely obscuring first digit; full webbing between first and second digits; web extends to tips of other digits but is deeply incised between them. Fourth digit extending beyond level of penultimate joint of third; considerably longer than second digit. Palm of hand fleshy, with deep folds; palmar tubercle low, rounded; plantar tubercle weak and indistinct.

Hind limb long, slender; when brought forward along body, tibiotarsal articulation reaches points between loreal region and posterior margin of eye; heels overlap when tibiofibulae are parallel to femora at right angles to body. Hind foot with thick, fleshy webbing; first and second digits almost totally enclosed, with only their tips distinguishable; other digits with full webbing that is shallowly incised, and extends to tip of fourth digit as fringe only. Fifth toe longer than third. Sole of foot quite fleshy with deep grooves or folds, no clearly defined subarticular tubercles; outer metatarsal tubercle poorly defined, inner metatarsal tubercle almost indistinguishable.

COLOR IN ALCOHOL.—Dorsal ground color white, with more or less regular pattern of brownish or black consisting of parallel stripes beginning on eyelid, where they may be joined by bar between eyes, and extending to just short of anus, which is usually in isolated spot of brown narrowly separated from stripes. Dorsal stripes irregularly connected by vermiculations and lateral bars, or separated by additional stripes running lengthwise, by light spots surrounded by brown borders, or by brown spots surrounded by white. Solid white line from eye to groin along dorsolateral line in most individuals, bordered below by dark line beginning at tip of snout, passing along lateral area of canthus, and continuous from eye to groin. No pigment on sides or belly below this lateral dark streak. Dorsal areas of limbs and feet mottled, streaked, and striped with dark brown to black, as body; ventral areas of appendages unicolor yellowish white.

COLOR IN LIFE.—Unknown, but several specimens are very yellowish in ground color, indicating that this might be the living color.

Atelopus elegans és una espècie d'amfibi que viu a Colòmbia i a l'Equador.

Es troba amenaçada d'extinció per la pèrdua del seu hàbitat natural.

Atelopus gracilis ist eine Amphibienart aus der Familie der Kröten (Bufonidae).

The elegant stubfoot toad or Pacific jambato frog (Atelopus elegans) is a species of toad in the family Bufonidae found in lowlands and Andean slopes of northwest Ecuador to 1,140 m (3,740 ft) asl and on the Gorgona Island, off southwest coast of Colombia. It was described by George Albert Boulenger in 1882 based on a specimen collected by Edward Whymper. It is known in Spanish as rana jambato del Pacífico or simply jambato del Pacífico.

Atelopus elegans o rana jambato del Pacífico es una especie de anfibios de la familia Bufonidae. Habita en la Isla Gorgona (Colombia) y el noroeste de Ecuador. Su hábitat natural incluye bosques tropicales o subtropicales secos y a baja altitud, montanos secos, y ríos. Está amenazada de extinción por la pérdida de su hábitat natural.

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Atelopus elegans Atelopus generoko animalia da. Anfibioen barruko Bufonidae familian sailkatuta dago, Anura ordenan.

Atelopus elegans est une espèce d'amphibiens de la famille des Bufonidae.

Atelopus elegans é uma espécie de sapo da família Bufonidae. Ele é endêmico na Colômbia e Equador. Seu habitat natural são as florestas úmidas das terras baixas e de montanhas, em áreas tropicais e subtropicais, e rios. Está ameaçado pela perda do seu habitat.

Atelopus elegans (tên tiếng Anh là Rana Jambato Del Pacífico) là một loài cóc thuộc họ Bufonidae. Loài này có ở Colombia và Ecuador. Môi trường sống tự nhiên của chúng là rừng ẩm vùng đất thấp nhiệt đới hoặc cận nhiệt đới, vùng núi ẩm nhiệt đới hoặc cận nhiệt đới, và sông ngòi. Chúng hiện đang bị đe dọa vì mất nơi sống.

Международное научное название

Atelopus elegans (Boulenger, 1882)

Синонимы Охранный статус
Систематика
на Викивидах
Изображения
на Викискладе ITIS 207212NCBI 1979394

Элегантный арлекин^[1] (Atelopus elegans) — вид жаб рода Atelopus из семейства Bufonidae.

Описание

Длина тела самцов 21–23 мм, самок — 31–35 мм^[2]. Окраска тела тёмно-коричневая с красновато-коричневыми продольными полосами. Иногда от глаз до паха проходят белые продольные полосы^[3].

Распространение

Этот вид встречается на северо-западе Эквадора в провинциях Эсмеральдас, Имбабура и Пичинча на высоте от 300 до 1140 м над уровнем моря, а также на небольшом колумбийском острове Горгона^[3], который находится в 30 км от колумбийского тихоокеанского побережья.

Вид обитает в низменных и предгорных влажных тропических лесах^[2], не найден в деградированных средах обитания. Нерестится в потоках.

Примечания

Элегантный арлекин (Atelopus elegans) — вид жаб рода Atelopus из семейства Bufonidae.