Ecnomiohyla rabborum, commonly known as Rabbs' fringe-limbed treefrog, is a possibly extinct species of frog in the family Hylidae.

Like other members of the genus Ecnomiohyla, they were capable of gliding by spreading their enormous and fully webbed hands and feet during descent.

[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.

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.

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).

[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.

[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.

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.

[10] 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.

[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.

[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.

[4] Females laid their eggs inside the water-filled tree holes, attached to the wood or bark just above the waterline.

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.

[4][10] 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.

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).

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".

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.

[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.

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.

[12][22] A single adult male named Toughie at the Atlanta Botanical Garden was the last known survivor of the species until his death.