The Jamaican Ibis, Jamaican Flightless Ibis or Clubbed-wing Ibis (Xenicibis xympithecus) is an extinct

Extinction

In biology and ecology, extinction is the end of an organism or of a group of organisms , normally a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point...

 bird species of the ibis subfamily uniquely characterized by its club-like wings. It is the only species in the genus Xenicibis, and one of only two flightless

Flightless bird

Flightless birds are birds which lack the ability to fly, relying instead on their ability to run or swim. They are thought to have evolved from flying ancestors. There are about forty species in existence today, the best known being the ostrich, emu, cassowary, rhea, kiwi, and penguin...

 ibis genera, the other being the genus Apteribis

Apteribis

Apteribis is an extinct genus of flightless birds in the ibis subfamily that was endemic to the Hawaiian Islands in the Pacific Ocean.-Distribution:...

endemic to Hawaii

Hawaii

Hawaii is the newest of the 50 U.S. states , and is the only U.S. state made up entirely of islands. It is the northernmost island group in Polynesia, occupying most of an archipelago in the central Pacific Ocean, southwest of the continental United States, southeast of Japan, and northeast of...

.

Description

The species was first described in 1977 based on postcranial bone elements excavated in a cave deposit at Long Mile Cave

Long Mile Cave

Long Mile Cave, sometimes known locally as Pick'ny Mama Cave or Hell's Gate Cave, is a palaeontological and palaeoanthropological site in the Cockpit Country of north-western Jamaica.-Description:...

, Jamaica

Jamaica

Jamaica is an island nation of the Greater Antilles, in length, up to in width and 10,990 square kilometres in area. It is situated in the Caribbean Sea, about south of Cuba, and west of Hispaniola, the island harbouring the nation-states Haiti and the Dominican Republic...

, by H. E. Anthony in 1919–1920. At the time, it was presumed to be flightless based on the incomplete coracoid; its flightlessness was confirmed after a humerus

Humerus

The humerus is a long bone in the arm or forelimb that runs from the shoulder to the elbow....

 of the same species was found in the Swansea Cave

Swansea Cave

Swansea Cave is a cave and palaeontological site in the Saint Catherine Parish of south-eastern Jamaica.-Description:The site lies on private land in the Worthy Park district at an altitude of 385 m above sea level and is surrounded by forest and sugarcane cultivation. The geology is white...

, Jamaica. New fossil finds from two locations, including the Red Hills Fissure

Red Hills Fissure

Red Hills Fissure is a palaeontological site at the Red Hills in Saint Andrew Parish of south-eastern Jamaica.-Description:The Red Hills Fissure is a karstic solutional feature, with a vertical extent of about 8 m and a maximum width of 3 m, that was exposed by road construction in 1988...

, show that the bird has a unique modification of the carpometacarpus

Carpometacarpus

The carpometacarpus is the fusion of the carpal and metacarpal bone, essentially a single fused bone between the wrist and the knuckles. It is a smallish bone in most birds, generally flattened and with a large hole in the middle. In flightless birds, however, its shape may be slightly different,...

 rendering it club-like. The metacarpal is enlarged and bowed distally with thickened walls, while the ulna

Ulna

The ulna is one of the two long bones in the forearm, the other being the radius. It is prismatic in form and runs parallel to the radius, which is shorter and smaller. In anatomical position The ulna is one of the two long bones in the forearm, the other being the radius. It is prismatic in form...

 and radius

Radius (bone)

The radius is one of the two large bones of the forearm, the other being the ulna. It extends from the lateral side of the elbow to the thumb side of the wrist and runs parallel to the ulna, which exceeds it in length and size. It is a long bone, prism-shaped and slightly curved longitudinally...

 have been modified as well. This was a large ibis, weighing about 2 kg (70 oz).

Clubbed wing function

Ornithologists speculate that the wings were used as weapons, in the manner of a club

Club (weapon)

A club is among the simplest of all weapons. A club is essentially a short staff, or stick, usually made of wood, and wielded as a weapon since prehistoric times....

 or flail

Flail (weapon)

The flail is a hand weapon derived from the agricultural tool.The handle is attached to the striking part of a weapon by a flexible chain or cord...

, similar to the adaptations found in some mantis shrimp

Mantis shrimp

Mantis shrimp or stomatopods are marine crustaceans, the members of the order Stomatopoda. They are neither shrimp nor mantids, but receive their name purely from the physical resemblance to both the terrestrial praying mantis and the shrimp. They may reach in length, although exceptional cases of...

s (Stomatopoda: Gonodactyloidea) that possess a club-like distally inflated dactyl used to strike prey and other shrimps. However, among birds, this adaption appears to be unique. Adaptations of the wing to fight in birds is an example of contingency in which various bird species find different solutions to the same problem based in chance.

Distribution

The Jamaican Ibis was endemic to Jamaica. Bones have been excavated from several caves, including the Long Mile Cave, the Swansea Cave, the Jackson's Bay Cave

Jackson's Bay Cave

Jackson's Bay Cave is a very large cave system on the Portland Ridge in Clarendon near the south coast of Jamaica. It is considered to be one of the most beautiful in the Caribbean...

 and the Red Hills Fissure. Bones from Cuba

Cuba

The Republic of Cuba is an island nation in the Caribbean. The nation of Cuba consists of the main island of Cuba, the Isla de la Juventud, and several archipelagos. Havana is the largest city in Cuba and the country's capital. Santiago de Cuba is the second largest city...

 claimed to be of this genus were later identified as those of a Limpkin

Limpkin

The Limpkin , Aramus guarauna, is a bird that looks like a large rail but is skeletally closer to cranes. It is the only extant species in the genus Aramus and the family Aramidae. It is found mostly in wetlands in warm parts of the Americas, from Florida to northern Argentina...

. Jamaica and Cuba have always been separated by the sea, so it is improbable that a flightless species could reach the other islands.