Jamaican Ibis | |
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Conservation status | |
Scientific classification | |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Aves |
Order: | Pelecaniformes |
Family: | Threskiornithidae |
Subfamily: | Threskiornithinae |
Genus: | Xenicibis |
Species: | X. xympithecus |
Binomial name | |
Xenicibis xympithecus |
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The Jamaican Ibis, Jamaican Flightless Ibis[1] or Clubbed-wing Ibis[2] (Xenicibis xympithecus) is an extinct bird species of the ibis subfamily uniquely characterized by its club-like wings.[3] It is the only species in the genus Xenicibis,[1] and one of only two flightless ibis genera,[2][3] the other being the genus Apteribis endemic to Hawaii.[2][4]
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The species was first described in 1977 based on postcranial bone elements excavated in a cave deposit at Long Mile Cave, Jamaica, by H. E. Anthony in 1919–1920.[1][5] At the time, it was presumed to be flightless based on the incomplete coracoid;[1] its flightlessness was confirmed after a humerus of the same species was found in the Swansea Cave, Jamaica.[5][6] New fossil finds from two locations, including the Red Hills Fissure, show that the bird has a unique modification of the carpometacarpus rendering it club-like.[3] The metacarpal is enlarged and bowed distally with thickened walls, while the ulna and radius have been modified as well. This was a large ibis, weighing about 2 kg (70 oz).[3]
Ornithologists speculate that the wings were used as weapons, in the manner of a club or flail,[3] similar to the adaptations found in some mantis shrimps (Stomatopoda: Gonodactyloidea) that possess a club-like distally inflated dactyl used to strike prey and other shrimps.[7] However, among birds, this adaption appears to be unique.[3] 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.[3][8]
The Jamaican Ibis was endemic to Jamaica. Bones have been excavated from several caves, including the Long Mile Cave,[1] the Swansea Cave,[6] the Jackson's Bay Cave[9] and the Red Hills Fissure.[3] Bones from Cuba claimed to be of this genus[10] were later identified as those of a Limpkin. Jamaica and Cuba have always been separated by the sea, so it is improbable that a flightless species could reach the other islands.[5]