We haven’t had enough fossil penguins here, so let me rectify that deficiency. Below the fold you’ll find a reconstruction of Waimanu, a 61-62 million year old penguin that was discovered in New Zealand.
Oh, and Carl Zimmer has posted a photo of the bird with its skin and feathers on.
Reconstruction of Waimanu
(composite of W. manneringi
and W. tuatahi
, based on original art
by Chris Gaskin ©Geology Museum, University of Otago). ca, caudal vertebrae; ce, cervical
vertebrae; cm, carpometacarpus; cr, coracoid; fb, fibula; fe, femur; fu, furcula; hu, humerus; sk,
skull, md, mandible; oc, os coaxae; ra, radius; sc, scapula; sy, synsacrum; ti, tibiotarsus; tm,
tarsometartarsus; ul, ulna. In the wing, the dorsal view (left ulna, radius, carpometacarpus) and
ventral view (humerus) are combined.
This penguin-like bird is strongly adapted for wing-propelled diving, and it appears in the fossil record only 3-4 million years after the K/T boundary. Either it was remarkable precocious, or as the authors favor, the radiation of modern birds occurred well before the extinction of the dinosaurs. They estimate that the neornithine radiation began 90-100 million years ago, in the late Cretaceous. The end of the Cretaceous must have been an interesting time in the skies—the archaic bird groups, the modern neornithines, and the pterosaurs all overlapped in time, and shared many of the same environments.
click for larger image
Fossil record and phylogeny of ornithurine birds with the stratigraphy of Waipara region and
geological settings for Waimanu
. Solid line shows geological ranges of taxa with first and last
occurrences shown by squares. Dashed line shows postulated phylogeny compiled from literature. Grey circles indicate possible initial divergence times for
clades; known fossils (squares) show constraints on ages. Early divergences within the Carinatae
could be older, and we have conservatively placed them later in the Cretaceous to give only one
long ghost-lineage between Ambiortus
and the early Carinatae. The placement of Waimanu
Sphenisciformes is evaluated by the cladistic analysis described in the text; see also Supplementary
Information Figure 4. TH, Thanetian; SE, Selandian; DA, Danian; MA, Maastrichtian; CA,
Campanian, SA; Santonian, CO, Coniacian; TU, Turonian; CE, Cenomanican; AL, Albian; AP,
Aptian; BA, Barremian; HA, Hauterivian; VA, Valanginian; BE, Berriasian.
Slack KE, Jones CM, Ando T, Harrison GL, Fordyce RE, Arnason U, Penny D (2006) Early Penguin Fossils, plus Mitochondrial Genomes, Calibrate Avian Evolution. Mol Biol Evo, preprint in advance of publication.