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Dino Farts and Fleas
May 16, 2012
As if to balance all the publications about the
futuristic gadgets of our
information age, there have been two recent articles about
dinosaurs. No, these articles aren't about
Kodak, or the
music industry (at least Kodak is trying to modernize its
business model), it's about those hefty creatures that dominated
Earth's ecosystem many millions of years before
man arrived to take over the planet.
Children of my generation were fascinated by dinosaurs, and there were many dinosaur books published for children. My friends and I used to make drawings of dinosaurs based on the many images in those books. In those days of monochrome television with just a few channels, there wasn't much else to keep ourselves entertained. We read a lot of books, since there wasn't anything to distract us from reading.
The first article, in the April 24, 2012, issue of Current Biology,[1] doesn't address dinosaurs directly, but rather some giant
fleas that appear to have lived by sucking dinosaur
blood.[1-5] One thing about
nature, if there's an
ecological niche, there will be a
species to fill it. Fleas are associated with
birds, which are the
genetic relics of the dinosaurs. There had been no evidence of flea parasitism of dinosaurs, although many
fossils of fleas from
ages closer to the present, the
Eocene (34-56 million years ago) and
Oligocene (23-34 million year ago), have been discovered.[1]
Fossil evidence for fleas has been sparse in the
Mesozoic (65-250 million years ago), which is the time when dinosaurs dominated both the
land and
seas.[1] One preoccupation of
entomologists is the
mouth parts of the insects that they study, since these tell a lot about the insect's feeding adaptation. Unfortunately, no clear fossil images of mouth parts had been found for fleas in the Mesozoic.[1]
The paper in Current Biology, by authors from the
Capital Normal University (
Beijing,
China) and the
Chinese Academy of Sciences, presents fossils of two primitive flea species from the
Jurassic (145.5-199.6 million years ago) and the
Cretaceous (65.5-145.5 million years ago) in
Inner Mongolia.[1] These fleas had large bodies, and, more interestingly, they had long
serrated stylets that seem to be adapted for piercing tough and thick
skin. This demonstrates the likelihood that such fleas were adapted to feed on their contemporaneous
feathered dinosaurs, and the flying dinosaurs, the
pterosaurs.[1]
This ancient flea, Pseudopulex jurassicus, lived about 165 million years ago.
It was a about an inch long, which is ten times larger than the dog fleas of today.
(Illustration by Wang Cheng, Oregon State University))
George Poinar, Jr., an
emeritus professor of
zoology at
Oregon State University and an international expert in ancient and extinct insects, thinks that these fleas are a distinct flea
lineage; that is, modern fleas did not evolve through such a form. Poinar, who studied fleas in
amber from 40-50 million years, wrote a commentary on the
Chinese paper in the same issue of the journal.[2] The species, which have been named Pseudopulex jurassicus and Pseudopulex magnus, had long
claws that allowed them to effectively grasp their host while feeding.[Oregon]
In a
previous article (Cow Farts and Beefy Burps, March 16, 2011), I wrote how
methane is
about twenty times more potent a greenhouse gas than
carbon dioxide; and that cattle farming is responsible for 18% of
greenhouse gases.[6]
The culprits here are
cattle, since the
methanogenic bacteria in their
digestive systems produce large quantities of methane. Cattle expel 95% of this gas through
burping, and 5% through
flatulence. We have a lot of cattle on the Earth, today, but there were a lot of dinosaurs,much larger, around in the Mesozoic.
Another paper in Current Biology,[7] this one in the May 8, 2012 issue, examines the idea that dinosaur flatulence may have had a major affect on Earth's climate of their time.[7-11]
Sauropods, such as the
Apatosaurus (a.k.a., Brontosaurus), the long-necked, long-tailed herbivores of the Mesozoic, were likely to have hosted
microbial methanogenic symbionts, since these are an efficient means for digestion of
vegetation via
fermentation.[7, 9]
Sauropods weighed about twenty tons, and they lived together in herds of a few tens per square kilometer.[10] Unlike cows, Sauropods bacteria likely populated the hindguts, and methane was released through flatulence, not burping.[11] As
David Wilkinson of
John Moores University (Liverpool, UK), one of the authors of the study, told the
BBC,
"Cows today produce something like 50-100 [million metric tons] per year. Our best estimate for Sauropods is around 520 [million metric tons]"[9]
Wilkerson admits, however, that this estimate may be off by a factor of 2. "There are a lot of educated guesses."[11]
Present day methane production is about 500 million netric tons per year. This is from natural sources and human activity, such as cattle farming for
meat and
milk.[9] Before the
Industrial Revolution, global methane production was only 181 million tons per year.[10]
The Mesozoic was much warmer than today, about 10°
C (18°
F) warmer, but the Sauropods contributed only about 1°C of this.[9, 11] Other dinosaur species would have added to this total, as would sources such as rotting vegetation.[9]
Climate modeling indicates that methane existed in 4-5 times higher concentrations in the Mesozoic than now.[8]
References:
- Tai-ping Gao, Chung-kun Shih, Xing Xu, Shuo Wang and Dong Ren, "Mid-Mesozoic Flea-like Ectoparasites of Feathered or Haired Vertebrates," Current Biology, vol. 22, no 8 April 24, 2012, pp. 732-735.
- Current Biology, vol. 22, no. 8 (April 24, 2012), pp. R278-R280.
- David Stauth, "Jurassic pain: Giant “flea-like” insects plagued dinosaurs," Oregon State University Press Release, May 1, 2012.
- Brid-Aine Parnell, "Dinosaurs were Drained of blood by Gigantic Horror Fleas," Register (UK), May 2, 2012.
- Giant 'flea-like' insects plagued dinosaurs 165 million years ago, Science Blog, May 1, 2012.
- Christopher Matthews, "Livestock a major threat to environment-Remedies urgently needed," Food and Agriculture Organization of the United Nations (Rome, November 26, 2006).
- David M. Wilkinson, Euan G. Nisbet and Graeme D. Ruxton, "Could methane produced by sauropod dinosaurs have helped drive Mesozoic climate warmth?" Current Biology, vol. 22, no. 9 (May 8, 2012), pp. R292-R293.
- David J. Beerling, Andrew Fox, David S. Stevenson and Paul J. Valdes, "Enhanced chemistry-climate feedbacks in past greenhouse worlds," Proc. Natl. Acad. Sci., vol. 108 no. 24 (June 14, 2011), pp. 9770-9775.
- Dinosaur gases 'warmed the Earth', BBC News, May 7, 2012.
- Dinosaurs passing wind may have caused climate change, Telegraph (UK), May 7, 2012.
- Michael Marshall, "Sauropod farts warmed the planet," New Scientist, May 7, 2012.
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