The Jamaican ibis, Jamaican flightless ibis
Description
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 1919–20.
[Suárez, William (2001) "Deletion of the flightless ibis Xenicibis from the fossil record of Cuba" . Caribbean Journal of Science 37 (1–2): 109–110] At the time, it was presumed to be flightless based on the incomplete
coracoid;
its flightlessness was confirmed after a
humerus of the same species was found in the
Swansea Cave, Jamaica.
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.
The
metacarpal is enlarged and bowed
distally with thickened walls, while the
ulna and radius have been modified as well. From its maximum femur diameter of 8.7 mm, it has been estimated that the Jamaican Ibis weighed about 2 kg (70 oz).
Clubbed wing function
speculate that the wings were used as weapons, in the manner of a club or flail,
similar to the adaptations found in some
(Stomatopoda: Gonodactyloidea) that possess a club-like distally inflated dactyl used to strike prey and other shrimps.
Among birds, this adaption seems unique.
In birds, adaptations of the wing that are advantageous in the context of fighting represent an example of contingency in which species find different solutions to the same problem as a result of random variations.
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
and the Red Hills Fissure.
Bones from
Cuba claimed to be of this genus
were later identified as those of a
limpkin. Jamaica and Cuba have never been linked, so it is improbable that a flightless species could reach a different island.
