The BBC appears to have ignored the 300,000 year caveat that the study’s abstract included
BBC writer Leila Battison too casually trumpeted certainty, where certainty is debatable, by synopsizing the research team’s finding into:
Many early bird species suffered from the same catastrophic extinction as the dinosaurs, new research has shown.
The meteorite impact that coincided with the disappearance of the dinosaurs 65 million years ago, also saw a rapid decline in primitive bird species.
Only a few bird groups survived through the mass extinction, from which all modern birds are descended.
The fossil deposits, in North and South Dakota and Wyoming in the US, and Saskatchewan in Canada, date from the last 1.5 million years of the Cretaceous period.
More precise dating places the bird fossils to within 300,000 years of the extinction event – a very short period on geological timescales.
These fossils had been studied before, but they have been “shoehorned” into modern groups on the basis of their overall similarity.
Dr Longrich and his team have reanalysed and reclassified these important fossil fragments, using features of the shoulder joint to assign the fossils to modern and ancient groups.
These findings show for the first time a diversity of archaic birds alive, right up until the end of the Cretaceous.
This would mean that the archaic birds went extinct abruptly 65 million years ago, and that modern birds must have descended from just a few groups that survived the event.
© 2011 Leila Battison, Old fossils solve mystery of earliest bird extinction, BBC News (20 September 2011) (extracts)
“Not so fast!” (as ESPN’s Lee Corso often chides his prognosticating colleagues on College GameDay)
The fossil study’s abstract makes a considerably less inflated claim about its findings than the BBC’s popularization does:
[I]t remains unclear whether archaic birds became extinct gradually over the course of the Cretaceous or whether they remained diverse up to the end of the Cretaceous and perished in the K–Pg mass extinction.
Here, we describe a diverse avifauna from the latest Maastrichtian of western North America, which provides definitive evidence for the persistence of a range of archaic birds to within 300,000 y of the K–Pg boundary.
A total of 17 species are identified, including 7 species of archaic bird, representing Enantiornithes, Ichthyornithes, Hesperornithes, and an Apsaravis-like bird.
None of these groups are known to survive into the Paleogene, and their persistence into the latest Maastrichtian therefore provides strong evidence for a mass extinction of archaic birds coinciding with the Chicxulub asteroid impact.
© 2011 Nicholas R. Longrich, Tim Tokaryk, and Daniel J. Field, Mass extinction of birds at the Cretaceous–Paleogene (K–Pg) boundary, Proceedings of the National Academy of Sciences [PNAS] 108(37): 15253-15257 (13 September 2011) (paragraph split)
Two substantial interpretive errors in the BBC’s review of the findings
First, the abstract’s statement — “provides definitive evidence for the persistence of a range of archaic birds to within 300,000 y of the K–Pg boundary” — is not the same as the BBC’s claim that — “These findings show for the first time a diversity of archaic birds alive, right up until the end of the Cretaceous.”
I certainly agree with BBC author Battison that 300,000 years is a short time, geologically speaking. But it is equally a long enough time to question her use of the word “abruptly,” especially when compared to an asteroid impact that was virtually instantaneous. A third of a million years is long enough to allow pre-asteroid mechanisms to account for the absence of archaic bird species after the K-Pg (K-T) boundary.
Second, Battison’s statement that, “Dr Longrich and his team have reanalysed and reclassified these important fossil fragments,” should have alerted her to the fact that the team’s findings will almost certainly be challenged.
Paleontologists don’t take kindly to someone reclassifying pre-existing work in order to bolster a perspective they already find questionable.
The moral? — Don’t believe much of what you read about science in the popular press
The media’s ignorance and sensation-seeking make for sizeable errors.