Ecnomiohyla rabborum

Last updated

Rabbs' fringe-limbed treefrog
Ecnomiohyla rabborum.jpg
Status iucn3.1 CR.svg
Critically endangered, possibly extinct  (IUCN 3.1) [1]
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Amphibia
Order: Anura
Family: Hylidae
Genus: Ecnomiohyla
Species:
E. rabborum
Binomial name
Ecnomiohyla rabborum
Mendelson, Savage, Griffith, Ross, Kubicki, and Gagliardo, 2008
Ecnomiohyla rabborum distribution map.jpg
El Valle de Antón in Panama, the native location of the species
This adult male in the Atlanta Botanical Garden (named Toughie by his handlers) was the last known surviving member of its species until his death on September 26, 2016. Ecnomiohyla rabborum 2.jpg
This adult male in the Atlanta Botanical Garden (named Toughie by his handlers) was the last known surviving member of its species until his death on September 26, 2016.

Ecnomiohyla rabborum, commonly known as Rabbs' fringe-limbed treefrog, is a possibly extinct species of frog in the family Hylidae. They were relatively large frogs that inhabited the forest canopies of central Panama. Like other members of the genus Ecnomiohyla , they were capable of gliding by spreading their enormous and fully webbed hands and feet during descent. The males of the species were highly territorial and would guard water-filled tree holes used for breeding. They were also the ones responsible for guarding and caring for the young, including providing food. They were the only known species of frog where the tadpoles derived nutrition by feeding on the skin cells of their fathers.

Contents

The species was discovered in 2005 and formally described in 2008 by a team of herpetologists led by Joseph R. Mendelson III. It was named in honor of the conservationists and herpetologists George B. Rabb and Mary S. Rabb. It was officially listed as Critically Endangered by the International Union for Conservation of Nature and Natural Resources (IUCN) by 2009. It is believed that the species became extinct in the wild mainly because of an epidemic of Batrachochytrium dendrobatidis in its native range. Despite the efforts of several conservation teams, captive breeding programs all failed. The last known female of the species died in 2009. She was survived by two other individuals, both males. On February 17, 2012, one of the two was euthanized at Zoo Atlanta in Georgia due to failing health. [2] The last known surviving member of the species, an adult male named Toughie, resided at the Atlanta Botanical Garden until his death September 26, 2016. [3]

Description

Ecnomiohyla rabborum was a relatively large frog. The snout-vent length (SVL) of males averaged between 62 and 97 mm (2.4 and 3.8 in), while in females it was between 61 and 100 mm (2.4 and 3.9 in). The head was wider than the body and flattened at the top. The snout was moderately long with nostrils protruding from the sides near the tip. Viewed from the top, the snout was more or less elliptical in shape. The canthal ridge was concave (curves outward) and had thick and rounded edges. The loreal regions were similarly concave. The tympana was smaller in diameter than the eyes and slightly inclined. Smooth glandular structures (known as the supratympanic fold) extended over the tympana from the eyes to the edges of the lower jaw. The tongue was round, and the species possessed narrowly spaced ovoid groups of pre-vomerine teeth. [4]

The arms were short and stout with very large hands. There were no skin folds on the wrists, though a scalloped fringe of skin was present from the elbows to just below the discs on the fourth fingers. The fingers were all relatively short with large flattened discs on the tips. The discs on the second, third, and fourth fingers were about the same diameter as the tympana. Small protrusions known as tubercles were present on the underside of the hands. On the first finger, the tubercles on the tipmost joints were elliptical in shape. On the second and third fingers, the tubercles below the finger joints (subarticular tubercles) were smaller than that on the fourth fingers. There were no tubercles on the palms of the hands though elongated flat tubercles were present behind the bases of the inner fingers (the "thumbs"). Numerous small and round tubercles were also present in between the joints of the fingers. The fingers were more or less fully webbed. [4] [5]

The hind limbs were slender and of moderate length. Like the hands, the feet were very large. When resting, the heels of the legs barely overlapped each other. If stretched forward up the length of the body, the tibiotarsal articulation (the "ankle") would reach beyond the eyes. Like the arms, a fringe of scalloped skin also extended from the heel to the base of the foot on each leg, continuing as a low ridge to the base of the disc of the fifth toe. The toes, like the fingers, possessed flattened discs at the tips, though they were slightly smaller in diameter. The tubercles on the tipmost joints of the fifth toes were larger than all of the other subarticular tubercles on the toes. Interspersed between them were numerous small and conical tubercles. The toes were also fully webbed. [4] [5]

The skin of E. rabborum was granular in texture and predominantly a mottled brown. The upper surfaces of the limbs was also mottled brown while the rear surfaces of the thighs were a pale yellow. The chin and upper chest was distinctively brown, though the rest of the underside of the body was mostly white speckled with irregular brown spots. The eyelids and upper surfaces of the limbs and back were studded with green flecks, the appearance and positions of which could be changed by the animal voluntarily (metachrosis). The irises of the eyes was uniformly reddish brown. [4] [5]

During the breeding season, adult males of the species were characterized by greatly enlarged upper arms (humerus) with a bony ridge covered by skin and black keratinized spines. Spines were also present on the upper surface of the area just before the thumbs. These spines were likely used during amplexus. [4] [5]

Taxonomy

Ecnomiohyla rabborum is classified under the genus Ecnomiohyla of the treefrog subfamily Hylinae, family Hylidae. [6] It was first described in 2008 by a team of herpetologists consisting of Joseph R. Mendelson III, Jay M. Savage, Edgardo Griffith, Heidi Ross, Brian Kubicki, and Ronald Gagliardo. During its discovery in 2005, it was initially misidentified by the team as Ecnomiohyla fimbrimembra , but Kubicki recognized it as a new species. [7] The type specimens were raised in captivity. They were obtained from tadpoles collected by Griffith and Ross from an area near El Valle de Antón, Coclé, Panama on July 15, 2005. [4]

The generic name Ecnomiohyla comes from Greek ecnomios ("marvelous" or "unusual") and Hylas, the companion of Hercules. [4] [8] [9] The specific name is in honor of the conservationists and herpetologists George B. Rabb and Mary S. Rabb. [10]

Distribution

Ecnomiohyla rabborum was known only from the cloud forests of the Pacific-facing slopes of the mountains above the town of El Valle de Antón in central Panama, between the provinces of Coclé and Panamá. Its range had an area of less than 100 km2 (39 sq mi) at altitudes of 900 to 1,150 m (2,950 to 3,770 ft). [11] [5] [12] However, it has not been observed in the area since 2007. [7]

Ecology and biology

Ecnomiohyla rabborum, like other members of the genus, lived in the forest canopy. They were nocturnal and fed on insects. [5] When threatened, they were capable of gliding through the air by leaping from their perch and fully stretching their massive webbed hands and feet. [4] They could also steer the direction of their descent. [7] [10] In observations, they were known to glide for a distance of 9 m (30 ft). [4]

The males of the species were highly territorial, defending water-filled tree holes used for breeding. [10] The advertising calls of E. rabborum males consisted of "warm up" owl-like calls of three to five notes immediately followed by a single "grrrrrck", which some called a barking sound. [13] The calling bouts happened only at night and lasted for about one to two minutes, with the intervals longer at the beginning and gradually becoming shorter. Aside from attracting females, the calls may also have served to warn off competing males. Mating occurred throughout the year, though the calls seem to have intensified two to three days before or after a full moon and during the peak mating season from mid-March to May. [4]

Females laid their eggs inside the water-filled tree holes, attached to the wood or bark just above the waterline. After laying their eggs, the females left while the males remained to guard them. Males may have mated more than once, and a single tree hole could contain an egg clutch of 60 to 200 eggs. The eggs would hatch into large tadpoles with dorsoventrally flattened bodies and short, blunt snouts. The eyes were situated on top and directed towards the sides. They were not visible when the tadpole was viewed from below. The nostrils were situated about two thirds of the way between the eyes and snout. The mouth was small and located at the bottom of the tip of the snout. Small papillae were present along the sides of the upper lip and along the entire margin of the lower lip. The beaks were robust and with small serrations. The spiracle opened on the middle of the left side of the body. The tail was slender with fins that did not extend to the body. The tadpoles were predominantly pale brown in color. At the time when the legs first appeared, they had a snout to vent length of roughly 25 to 27 mm (0.98 to 1.06 in). [4] The tadpoles were so large and numerous that at times, there appeared to be more tadpoles than water in the tree holes. [10]

E. rabborum was remarkable in that the males appeared to provide nutrition to the tadpoles directly. During the day, the males backed into the tadpole-filled water of the tree holes and remained in that half-submerged state until night. During this time, the tadpoles swam around them, rasping small pieces of skin from their fathers' backs and eating them. [14] This was the first observed instance of any frog species doing this, though it was similar to the way some female caecilians feed their young. [4] [10]

Conservation

Zoosporangia of Batrachochytrium dendrobatidis (visible as small globular bodies attached to an arthropod at the top and on algae at the bottom) Batrachochytrium dendrobatidis.jpg
Zoosporangia of Batrachochytrium dendrobatidis (visible as small globular bodies attached to an arthropod at the top and on algae at the bottom)

At the time of its collection, the herpetologists who later described Ecnomiohyla rabborum were already aware of the encroaching threat of the chytrid fungus Batrachochytrium dendrobatidis (colloquially referred to by biologists as "Bd") in Panama. [4] The fungus causes an infectious amphibian disease called chytridiomycosis, which has been linked to the massive decline and extinction of amphibian species in certain parts of the world; including the Americas, Australia, and New Zealand. Infected amphibians can display a wide variety of symptoms, usually including lethargic and abnormal behavior, convulsions, peeling skin, ulcers, and hemorrhaging; eventually resulting in death. [15] The origin of the disease is unknown, but there is speculation that it may have been introduced throughout the world via importation of the African clawed frog ( Xenopus laevis ). [16]

In 2006, in the hopes of saving the species, the then undescribed specimens of E. rabborum that teams of herpetologists collected were sent to captive breeding facilities in the El Valle Amphibian Conservation Centre (EVACC), Zoo Atlanta, and the Atlanta Botanical Garden. However, these efforts ultimately proved to be futile. The frogs thrived in these facilities but never mated. The last female died in 2009 in the Atlanta Botanical Garden.

In an essay regarding the rapid extinctions of amphibians happening around the world, Joseph R. Mendelson III, the Curator of Herpetology in Zoo Atlanta and one of the scientists who first described E. rabborum, stated that herpetologists in the last 20 years are becoming "forensic taxonomists". Species are now being described just before or even after they have already gone extinct. On the situation of E. rabborum, he comments:

It appears that nature has run its course before three teams of dedicated people were able to determine the needs of these frogs in order for them to reproduce. To have been a part of one of those teams has been a frustrating and sad experience. [10]

Two males in Zoo Atlanta and Atlanta Botanical Garden survived until February 17, 2012, when one of them had to be euthanized to prevent suffering after a decline in health and to preserve valuable genetic material. [17] Though the frog could have been allowed to die naturally, amphibians decompose rapidly. If it had died during the night when no personnel were present, it could have proven impossible to extract genetic material. [18] The Deputy Director of the Zoo, Dwight Lawson commented:

This is the second time in my career that I have literally seen one of the very last of its kind die and an entire species disappear forever with it. It is a disturbing experience, and we are all poorer for it. The ongoing amphibian extinction crisis has taken a rich diversity of animals from us, and more effort and resources are desperately needed to halt the losses. [17]

The last known observation of the frog in the wild was that of a single male heard calling (but not seen) in 2007. [7] [19] At the time of its last survey in 2009, the IUCN classified E. rabborum as Critically Endangered. [11] [20] [21] More recent estimates deem the species effectively extinct in the wild. [12] [22] A single adult male named Toughie at the Atlanta Botanical Garden was the last known survivor of the species until his death. [17]

See also

Related Research Articles

<i>Hemiphractus</i> Genus of amphibians

Hemiphractus is a genus of frogs, the horned treefrogs, in the family Hemiphractidae. These overall brownish frogs have a pointed snout and a casque on the head. They are nocturnal, relatively rare and native to humid lowland and highland forests in northern South America and Panama, where typically found on the ground or at relatively low levels in vegetation.

<i>Ecnomiohyla</i> Genus of amphibians

Ecnomiohyla, commonly known as fringe-limbed treefrogs or marvelous frogs, is a genus of frogs in the family Hylidae. This genus was erected in 2005 following a major revision of Hylidae. The ten original species in this genus were previously placed in the genus Hyla. The generic name Ecnomiohyla comes from Greek ecnomios and Hylas, the companion of Hercules.

<i>Indirana semipalmata</i> Species of amphibian

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.

<span class="mw-page-title-main">Panamanian golden frog</span> Species of amphibian

The Panamanian golden frog, also known as Cerro Campana stubfoot toad and other names, is a species of toad endemic to Panama. Panamanian golden frogs inhabit the streams along the mountainous slopes of the Cordilleran cloud forests of west-central Panama. While the IUCN lists it as Critically Endangered, it may in fact have been extinct in the wild since 2007. Individuals have been collected for breeding in captivity in a bid to preserve the species. The alternative common name, Zetek's golden frog, and the epithet zeteki both commemorate the entomologist James Zetek.

<i>Triprion spinosus</i> Species of amphibian

Triprion spinosus, also known as the spiny-headed tree frog, spiny-headed treefrog, spinyhead treefrog, coronated treefrog, and crowned hyla, is a species of frog in the family Hylidae. It has a spotty distribution in Panama, Costa Rica, Honduras, and southern Mexico. Previously in its own monotypic genus Anotheca Smith, 1939, it was transferred to the genus Triprion in 2018.

Charadrahyla nephila is a species of frog in the family Hylidae. It is endemic to Mexico and occurs in the Sierra de Juárez and Sierra Mixe in the northern Oaxacan highlands; there is also a questionable record from the Sierra de los Tuxtlas, Veracruz. Prior to its description, it was mixed with Hyla chaneque. The specific name nephila is derived from Greek nephos ("cloud") and philia ("fondness"), referring to the cloud forest habitat of this species. Common name Oaxacan cloud-forest treefrog has been coined for it.

<span class="mw-page-title-main">Cope's brown treefrog</span> Species of frog

Cope's brown treefrog or fringe-limbed treefrog is a species of frog in the family Hylidae. It is found in Costa Rica, Nicaragua, and Panama. Its natural habitats are subtropical or tropical moist lowland forests and subtropical or tropical moist montane forests. It is threatened by habitat loss.

Ecnomiohyla thysanota, also known as Cerro Mali treefrog, is a species of frog in the family Hylidae. It is endemic to Panama where it is known from its type locality, Cerro Malí in eastern Serranía de Darién, near the border to Colombia, where it might also occur. This arboreal species is only known from a single specimen, the holotype.

<i>Agalychnis lemur</i> Species of amphibian

Agalychnis lemur, the lemur leaf frog or lemur frog, is a species of frog in the subfamily Phyllomedusinae. It is found in Costa Rica, Panama, and adjacent northwestern Colombia. It is classed as Critically Endangered and threatened by the fungal disease chytridiomycosis.

Sarcohyla cembra, also known as the Southern Sierra Madre treefrog, is a species of frog in the family Hylidae. It is endemic to Mexico. Until recently, it was only known from two male specimens: one from its type locality on the Pacific slopes of the Sierra Madre del Sur mountains, Pochutla District, Oaxaca, and another one from Sierra de Yucuyacua south-east of Llano de Guadalupe, in north-west Oaxaca. The two locations are about 172 km (107 mi) apart. After having not been seen after 1993, it was feared that the species might be extinct. However, the species was rediscovered in field surveys in 2011–2012, extending its range with a new locality about 10 km north of the type locality.

Plectrohyla tecunumani is a species of frogs in the family Hylidae. It is endemic to the Sierra de los Cuchumatanes in western Guatemala. Its specific name refers to Tecun Uman, the Guatemalan national hero. Common name cave spikethumb frog has been coined for it.

Telmatobius pefauri is a species of frog in the family Telmatobiidae. It is endemic to extreme northern Chile. It was already feared that this species is extinct, but recent research has suggested that the species is extant at several localities in the Arica y Parinacota Region, albeit at low numbers. Furthermore, morphological and genetic data suggest that Telmatobius zapahuirensis is a synonym of Telmatobius pefauri. Common name Arico water frog has been coined for this species.

<i>Nannophrys guentheri</i> Extinct species of amphibian

Nannophrys guentheri is an extinct species of frog in the family Dicroglossidae. It was endemic to Sri Lanka. The species was first identified in 1882 by George Boulenger and named after the German-born British zoologist Albert Günther. It is not known where in Sri Lanka the specimens were found.

George Bernard Rabb was an American zoologist, and the former director of the Brookfield Zoo from 1976 until 2003. Rabb's pioneering work led the zoo toward its current position as a conservation center, a concept Rabb has championed for zoos everywhere. He joined Brookfield Zoo in 1956 as curator of research. Rabb created the zoo's Education Department and was instrumental in the use of naturalistic exhibitry to provide visitors with environmental immersion experiences throughout the zoo. Rabb had affiliations with conservation associations worldwide and is a respected spokesman on wildlife conservation issues. He won the 1996 Heini Hediger Award, 1997 Silver Medal, and 2008 Lifetime Achievement Award.

<span class="mw-page-title-main">Toughie (frog)</span> Last known Rabbs fringe-limbed treefrog (died 2016)

Toughie was the last known living Rabbs' fringe-limbed treefrog. The species, scientifically known as Ecnomiohyla rabborum, is thought to be extinct, as the last specimen—Toughie—died in captivity on September 26, 2016.

<i>Rheohyla</i> Genus of amphibians

Rheohyla is a genus of frogs in the family Hylidae. As currently recognized, it is monotypic, containing only Rheohyla miotympanum, also known as the small-eared hyla or small-eared treefrog. However, the nominal species likely is a complex of more than one species. It is endemic to eastern and central Mexico. The generic name refers to streams, the breeding habitat of this frog. The specific name is derived from Greek meion, a diminutive prefix, together with Greek tympanon (='drum') and refers to the small tympanum.

Ecnomiohyla sukia, the shaman fringe-limbed tree frog, is a frog in the family Hylidae. It is endemic to Costa Rica. It has been observed between 400 and 1000 meters above sea level.

<span class="mw-page-title-main">Tapir Valley tree frog</span> Species of amphibian

The Tapir Valley tree frog is a species of frog in the family Hylidae only found in the area of the Costa Rican Tapir Valley Nature Reserve.

References

  1. IUCN SSC Amphibian Specialist Group (2019). "Ecnomiohyla rabborum". IUCN Red List of Threatened Species . 2019: e.T85341796A54357363. doi: 10.2305/IUCN.UK.2019-1.RLTS.T85341796A54357363.en . Retrieved 18 November 2021.
  2. "Rare frog dies, one of only two left in the world". WKYT News. 2012-02-17. Archived from the original on 2013-10-04. Retrieved 2012-02-17.
  3. Bo Emerson (28 September 2016). "Rare frog goes extinct, despite Atlanta's rescue efforts". The Atlanta Journal-Constitution. Archived from the original on 11 October 2016. Retrieved 28 September 2016.
  4. 1 2 3 4 5 6 7 8 9 10 11 12 13 Joseph R. Mendelson III; Jay M. Savage; Edgardo Griffith; Heidi Ross; Brian Kubicki; Ronald Gagliardo (2008). "Spectacular new gliding species of Ecnomiohyla (Anura: Hylidae) from Central Panama". Journal of Herpetology. 42 (4): 750–759. doi:10.1670/08-025R1.1. S2CID   20233879.
  5. 1 2 3 4 5 6 ARKive. "Rabbs' fringe-limbed treefrog (Ecnomiohyla rabborum)". Wildscreen. Archived from the original on 2012-08-25. Retrieved March 9, 2012.
  6. Frost, Darrel R. (2014). "Ecnomiohyla rabborum Mendelson, Savage, Griffith, Ross, Kubicki, and Gagliardo, 2008". Amphibian Species of the World: an Online Reference. Version 6.0. American Museum of Natural History. Retrieved 26 January 2015.
  7. 1 2 3 4 Joseph R. Mendelson III (2011). "Shifted baselines, forensic taxonomy, and Rabbs' fringe-limbed treefrog: the changing role of biologists in an era of amphibian declines and extinctions" (PDF). Herpetological Review. 42 (1): 21–25.
  8. Julián Faivovich; Célio F.B. Haddad; Paulo C.A. Garcia; Darrel R. Frost; Jonathan A. Campbell; Ward C. Wheeler (2005). "Systematic review of the frog family Hylidae, with special reference to Hylinae: phylogenetic analysis and taxonomic revision". Bulletin of the American Museum of Natural History. 294 (294): 1–240. CiteSeerX   10.1.1.470.2967 . doi:10.1206/0003-0090(2005)294[0001:SROTFF]2.0.CO;2. S2CID   83925199.
  9. Charles W. Myers; Richard B. Stothers (2006). "The myth of Hylas revisited: the frog name Hyla and other commentary on Specimen medicum (1768) of J. N. Laurenti, the "father of herpetology"". Archives of Natural History. 33 (2): 241–266. doi:10.3366/anh.2006.33.2.241.
  10. 1 2 3 4 5 6 Robert W. Hansen, ed. (2011). "About our cover: Ecnomiohyla rabborum". Herpetological Review. 42 (1): 3.
  11. 1 2 Joseph R. Mendelson III & Ariadne Angulo (2009). Ecnomiohyla rabborum . In: IUCN 2011. IUCN Red List of Threatened Species. Version 2011.2. Retrieved March 9, 2012.
  12. 1 2 Zoo Atlanta. "Rabbs' Fringe-Limbed Treefrog". Atlanta Fulton County Zoo. Archived from the original on December 22, 2011. Retrieved March 9, 2012.
  13. Mendelson III, Joseph R. (October 10, 2016). "A Frog Dies in Atlanta, and a World Vanishes With It". New York Times. Retrieved 11 October 2016.
  14. "Ecnomiohyla rabborum Mendelson, Savage, Griffith, Ross, Kubicki, and Gagliardo 2008". Amphibians of Panama. Smithsonian Tropical Research Institute, Smithsonian Institution. Archived from the original on March 3, 2016. Retrieved March 12, 2012.
  15. Amphibian Diseases Research Group. Amphibian Chytridiomycosis: An Informational Brochure (PDF). California Center for Amphibian Disease Control (CCADC). Archived from the original (PDF) on 2011-08-13. Retrieved 2012-03-12.
  16. M.E.T. Scioli (February 21, 2012). "Goodbye, Ecnomiohyla rabborum, we hardly knew ye". Science is the Belief in the Ignorance of Experts. Archived from the original on 2013-02-01. Retrieved March 12, 2012.
  17. 1 2 3 Zoo Atlanta (February 17, 2012). "It's Leap Year. Remember the Rabbs' tree frog". Atlanta Fulton County Zoo. Archived from the original on May 24, 2012. Retrieved March 12, 2012.
  18. John R. Platt (February 21, 2012). "Extinction Looms for Rare Frog Species, Now Down to 1 Individual". Extinction Countdown. Scientific American. Retrieved March 12, 2012.
  19. Andrew C. Revkin (May 19, 2011). "The Many Forces Driving Extinction". Opinion Pages. The New York Times. Retrieved March 12, 2012.
  20. "Extinction Crisis Continues Apace". International Union for Conservation of Nature and Natural Resources. November 3, 2009. Retrieved March 12, 2012.
  21. Louise Gray (November 3, 2009). "Flying frog and mountain mouse among new species in danger of going extinct". The Telegraph. Archived from the original on November 6, 2009. Retrieved March 12, 2012.
  22. Peter H.J. Maas (2012). "Last stand in captivity or cultivation: successes and failures". The Sixth Extinction Website. Archived from the original on February 15, 2012. Retrieved March 12, 2012.

"Rabbs' Fringe-limbed Treefrog Declared Extinct." Rabbs' Fringe-limbed Treefrog Declared Extinct. RiVista, n.d. Web. 22 Nov. 2016. <http://www.reptilesmagazine.com/Rabbs-Fringe-limbed-Treefrog-Declared-Extinct-trending/>.