"Embryological Evidence Identifies Wing Digits in Birds as Digits 1, 2, and 3" Koji Tamura, Naoki Nomura, Ryohei Seki, Sayuri Yonei-Tamura, and Hitoshi Yokoyama Science 11 February 2011: Vol. 331 no. 6018 pp. 753-757 DOI: 10.1126/science.1198229 Abstract: The identities of the digits of the avian forelimb are disputed. Whereas paleontological findings support the position that the digits correspond to digits one, two, and three, embryological evidence points to digit two, three, and four identities. By using transplantation and cell-labeling experiments, we found that the posteriormost digit in the wing does not correspond to digit four in the hindlimb; its progenitor segregates early from the zone of polarizing activity, placing it in the domain of digit three specification. We suggest that an avian-specific shift uncouples the digit anlagen from the molecular mechanisms that pattern them, resulting in the imposition of digit one, two, and three identities on the second, third, and fourth anlagens. Cheers!! --Mikko
Fossils of the genus Leptoptilos from the Pleistocene of Liang Bua, Flores, Indonesia, belong to a new species of giant marabou stork, Leptoptilos robustus sp. nov. This giant bird, estimated at 1.80 m in length, was similar in dimensions to extant Leptoptilos dubius, except for the tibiotarsus. An evolutionary lineage is proposed in which a volant L. dubius-like ancestor in the Middle Pleistocene evolved into the Late Pleistocene L. robustus on Flores, with a concomitant reduction of the ability to fly and an increase in body size. The large body size and terrestrial lifestyle of L. robustus are responses to an unbalanced, insular environment with abundant prey items and a lack of mammalian carnivores, and emphasize the extraordinary nature of the Homo floresiensis fauna.
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