83 posts · 35,508 views
this blog covers evolution, ecology, animal behavior, genetics, ornithology, parrots and birds in general along with stories about other animals, mental illness, atheism and politics.
GrrlScientist
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- March 12, 2010
- 12:59 PM
- 20 views
Gender-Bending Chickens: Mixed, Not Scrambled
by GrrlScientist in Living the Scientific Life (Scientist, Interrupted)
tags: evolution, evolutionary biology, gynandromorph, bilateral gynandromorph bird, half-sider, mixed-sex chimaera, sex determination, molecular biology, genetics, developmental biology, endocrinology, birds, chicken, Gallus gallus, ornithology, bpr3.org/?p=52,peer-reviewed research, peer-reviewed paper, journal club
Half-sider.
Almost exactly one year ago, hundreds of American birders
were thrilled by sightings and photographs of this remarkable
Northern Cardinal, or Redbird, Cardinalis cardinalis,
photographed in Warrenton, VA.
Image: DW Maiden, 2 March 2009.
I'll never forget the first time I saw a bilateral gynandromorph. I was a bird-crazy teenager reading my way through a stack of avicultural publications when I spied the strangest bird I'd ever seen on the cover of one magazine: an eclectus parrot that was very precisely divided down the middle: one side was rich scarlet and the other was brilliant emerald. Because eclectus parrots are sexually dimorphic -- females are red and males are green -- this remarkable bird was easily identifiable as being composed of both sexes, one on each side.
Even though this was the first time I'd ever seen a gynandromorph, these mysterious birds do pop up from time to time. For example, bird watchers occasionally run across them in the wild (see above photograph) and poultry farmers sometimes find them in their flocks: it is estimated that roughly one in 10,000 domestic chickens -- another sexually dimorphic species -- is a gynandromorph.
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Zhao, D., McBride, D., Nandi, S., McQueen, H., McGrew, M., Hocking, P., Lewis, P., Sang, H., & Clinton, M. (2010) Somatic sex identity is cell autonomous in the chicken. Nature, 464(7286), 237-242. DOI: 10.1038/nature08852
- March 10, 2010
- 03:50 PM
- 27 views
Ancient DNA Isolated from Fossil Eggshells May Provide Clues to Eggstinction of Giant Birds
by GrrlScientist in Living the Scientific Life (Scientist, Interrupted)
tags: evolution, evolutionary biology, ancient DNA, aDNA, molecular biology, molecular ecology, archaeology, paleontology, fossil eggshell, extinct birds, giant moa, Dinornis robustus, elephant birds, Aepyornis maximus, Mullerornis, Thunderbirds, Genyornis, bpr3.org/?p=52,peer-reviewed research, peer-reviewed paper, journal club
Elephant bird, Aepyornis maximus, egg
compared to a human hand with a hummingbird egg balanced on a fingertip.
To conduct my avian research, I've isolated and sequenced DNA from a variety of specimens, such as blood, muscle, skin and a variety of internal organs, dry toepads from long-dead birds in museum collections, feathers, the delicate membranes that line the inside of eggs, and even occasionally from bone. But I was surprised to learn that avian DNA can also be extracted directly from fossilized eggshells -- eggshells that completely lack eggshell membranes.
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Charlotte L. Oskam, James Haile, Emma McLay, Paul Rigby, Morten E. Allentoft, Maia E. Olsen, Camilla Bengtsson, Gifford H. Miller, Jean-Luc Schwenninger, Chris Jacomb, Richard Walter, Alexander Baynes, Joe Dortch, Michael Parker-Pearson, M. Thomas P. Gilb. (2010) Fossil avian eggshell preserves ancient DNA. Proc. R. Soc. B. info:/10.1098/rspb.2009.2019
- February 12, 2010
- 02:30 PM
- 91 views
Faith-Based Birding 201: Fraudulent Photos and Federal Funding
by GrrlScientist in Living the Scientific Life (Scientist, Interrupted)
tags: faith-based birding, mass hysteria, endangered species, extinct species, conservation, politics, Ivory-billed Woodpecker, Campephilus principalis, IBWO, ornithology, birds, bpr3.org/?p=52,peer-reviewed research, peer-reviewed paper
The Cornell Lab of Ornithology has posted a reward of $50,000
to be given to anyone who can provide "video, photographic, or
other compelling information and lead a project scientist to a
living wild Ivory-billed Woodpecker."
Mass hysteria is that strange psychological phenomenon where a group of people experience the same hallucination at the same time. Such hallucinations include observing statues or paintings of the Virgin Mary either bleeding or crying at certain times of the year. But mass hysteria is not limited to religious fanatics. During the past five years, there has been a marked increase in what I refer to as "faith-based birding," where groups of people believe they've seen the Ivory-billed Woodpecker, Campephilus principalis, a large bird that has been extinct in the US for more than 50 years.
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Dalton, R. (2010) Still looking for that woodpecker. Nature, 463(7282), 718-719. DOI: 10.1038/463718a
- February 8, 2010
- 03:10 PM
- 83 views
Racehorse Research Identifies Speed Gene
by GrrlScientist in Living the Scientific Life (Scientist, Interrupted)
tags: evolutionary biology, molecular biology, Thoroughbred race horses, horses, aerobic capacity, muscle development, myostatin, MSTN, myostatin-suppressing C variant, myostatin-suppressing T variant, Horse Genome Project, Equinome, bpr3.org/?p=52,peer-reviewed research, peer-reviewed paper
Emerging from the mist is Rachel Alexandra, a champion American Thoroughbred who excels at winning both long and short distance races.
Image: Rob Carr, 2009, Associated Press [larger view]
If you've worked at or been around a racetrack very much, as I have, you'll quickly realize that everyone there has their own pet idea for picking winners. Horse breeders have always relied on pedigree analysis and studying the horse's conformation to predict whether a particular racehorse is better suited for running short or longer distances. But this is an inexact science that can waste valuable time, money and sometimes, horses. Which makes one wonder whether modern molecular biology can be applied to the challenge of identifying specific genes that make a particular horse better suited to running sprints or distances?
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Hill, E., Gu, J., Eivers, S., Fonseca, R., McGivney, B., Govindarajan, P., Orr, N., Katz, L., & MacHugh, D. (2010) A Sequence Polymorphism in MSTN Predicts Sprinting Ability and Racing Stamina in Thoroughbred Horses. PLoS ONE, 5(1). DOI: 10.1371/journal.pone.0008645
- February 5, 2010
- 10:10 AM
- 120 views
Fossil Feather Colors Really ARE Written In Stone
by GrrlScientist in Living the Scientific Life (Scientist, Interrupted)
tags: evolutionary biology, paleontology, taphonomy, plumage color, feathers, color, melanin, eumelanin, phaeomelanin, dinosaurs, theropod, paravian, avialae, fossils, Anchiornis huxleyi, ornithology, birds, bpr3.org/?p=52,peer-reviewed research, peer-reviewed paper
New research reveals that recently-described 155-million-year-old Anchiornis huxleyi,
a woodpecker-like dinosaur the size of a modern-day domesticated chicken,
had black-and-white spangled wings and a rusty red crown.
Image: Michael DiGiorgio, Yale University [larger view]
Fig. 4. Reconstruction of the plumage color of the Jurassic troodontid Anchiornis huxleyi. The tail is unknown specimen BMNHC PH828, and reconstructed based on the complete specimen previously described. Color plate by Michael A. Digiorgio.
Ever since dinosaurs were discovered, scientists, artists and children everywhere have speculated about what they really looked like. Fossilized bones, skin impressions and recently, feathers, provide a basic mental image of these animals' appearances, but these materials also leave important questions unanswered, basic questions such as what color were dinosaurs?
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Li, Q., Gao, K., Vinther, J., Shawkey, M., Clarke, J., D'Alba, L., Meng, Q., Briggs, D., Miao, L., & Prum, R. (2010) Plumage Color Patterns of an Extinct Dinosaur. Science. DOI: 10.1126/science.1186290
Vinther, J., Briggs, D., Clarke, J., Mayr, G., & Prum, R. (2009) Structural coloration in a fossil feather. Biology Letters, 6(1), 128-131. DOI: 10.1098/rsbl.2009.0524
- February 1, 2010
- 01:19 PM
- 103 views
Fetid Fish Revise Understanding of Fossil Formation
by GrrlScientist in Living the Scientific Life (Scientist, Interrupted)
tags: evolutionary biology, paleontology, fossils, fossilization, fossil forensics, Taphonomy, taxonomy, zoology, deep time, paleoceanography, amphioxus, Branchiostoma lanceolatum, lamprey, Lampetra fluviatilis, chordates, bpr3.org/?p=52,peer-reviewed research, peer-reviewed paper
Three rotting Amphioxus heads.
A sequence of images showing how the characteristic features of the body of amphioxus, a close living relative of vertebrates, change during decay. Colours are caused by interference between the experimental equipment and the light illuminating the specimens.
Image: Mark Purnell, Rob Sansom, Sarah Gabbott, University of Leicester.
[larger view]
DOI: 10.1038/nature08745
How do you know what something looks like when you've never seen it before? This is the question that paleontologists deal with every day: describing the appearance of ancient animals based on incomplete information gathered from small fossilized fragments of those animals. As if that is not difficult enough, they also use this incomplete information about physical appearances to build family trees that describe the evolution of these animals.
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Sansom, R., Gabbott, S., & Purnell, M. (2010) Non-random decay of chordate characters causes bias in fossil interpretation. Nature. DOI: 10.1038/nature08745
Donoghue, P., & Purnell, M. (2009) Distinguishing heat from light in debate over controversial fossils. BioEssays, 31(2), 178-189. DOI: 10.1002/bies.200800128
- January 30, 2010
- 02:45 PM
- 122 views
Newly Described Bird-like Dinosaur Predates Archaeopteryx by 63 Million Years
by GrrlScientist in Living the Scientific Life (Scientist, Interrupted)
tags: evolutionary biology, convergent evolution, paleontology, taxonomy, zoology, basal birds, theropods, dinosaurs, ornithology, birds, Alvarezsauroidea, Haplocheirus sollers, Maniraptora, Archaeopteryx, bpr3.org/?p=52,peer-reviewed research, peer-reviewed paper
A Newly Discovered Basal Alvarezsauroid Theropod from the Early Late Jurassic.
Artwork: Portia Sloan [larger view]
DOI: 10.1126/science.1182143
A long-standing scientific debate focuses on the origins of birds: did they evolve from reptiles or dinosaurs? Currently, most scientists think that birds are modern dinosaurs, but because small hollow bones like those of birds and small dinosaurs don't fossilize well, the early fossil record for birds is sparse. However, a new dinosaur species unearthed in China's Gobi Desert strengthens the dinosaur-bird hypothesis and may also provide valuable clues as to how flight evolved.
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Choiniere, J., Xu, X., Clark, J., Forster, C., Guo, Y., & Han, F. (2010) A Basal Alvarezsauroid Theropod from the Early Late Jurassic of Xinjiang, China. Science, 327(5965), 571-574. DOI: 10.1126/science.1182143
- January 28, 2010
- 02:39 PM
- 130 views
Orange Stripey Dinosaurs? Fossil Feathers Reveal Their Secret Colors
by GrrlScientist in Living the Scientific Life (Scientist, Interrupted)
tags: evolutionary biology, fossils, feathers, plumage color, color, dinosaurs, theropods, Sinosauropteryx, Sinornithosaurus, birds, Confuciusornis, melanosomes, phaeomelanosomes, eumelanosomes, keratinocytes, SEM, scanning electron microscopy, 10.1038/nature08740, bpr3.org/?p=52, peer-reviewed research, peer-reviewed paper
Reconstruction of two Sinosauropteryx, sporting their orange and white striped tails.
Artwork by Chuang Zhao and Lida Xing [larger view]
DOI: 10.1038/nature08740
While looking at museum dioramas that feature dinosaurs, I often overhear people asking "How do they know what color dinosaurs were?" The truth is that artists and scientists they didn't know -- until now. A new paper was just published in Nature that carefully examines fossilized plumage and comes to an interesting conclusion: scientists can identify at least some of the original colors in ancient feathers.
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Zhang, F., Kearns, S., Orr, P., Benton, M., Zhou, Z., Johnson, D., Xu, X., & Wang, X. (2010) Fossilized melanosomes and the colour of Cretaceous dinosaurs and birds. Nature. DOI: 10.1038/nature08740
- January 26, 2010
- 08:59 AM
- 142 views
Migratory Monarch Butterflies See Earth's GeoMagnetic Field
by GrrlScientist in Living the Scientific Life (Scientist, Interrupted)
tags: evolutionary biology, behavioral ecology, biochemistry, biophysics, magnetoreception, photochemical mechanism, cryptochromes, geomagnetic fields, butterflies, Monarch Butterfly, Danaus plexippus, birds, migration, Cryptochrome, bpr3.org/?p=52,peer-reviewed research, peer-reviewed paper
Every autumn, millions of monarch butterflies, Danaus plexippus, each weighing less than one gram (one US penny weighs 2.5 grams), migrate nearly 4000 kilometers (3000 miles) between their summer breeding grounds in the United States and their wintering areas either in southern California or in the mountains of Mexico (Figure 1).
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Gegear, R., Foley, L., Casselman, A., & Reppert, S. (2010) Animal cryptochromes mediate magnetoreception by an unconventional photochemical mechanism. . Nature. DOI: 10.1038/nature08719
- January 22, 2010
- 11:51 AM
- 163 views
Colorful Tits Produce Speedier Sperm
by GrrlScientist in Living the Scientific Life (Scientist, Interrupted)
tags: evolution, evolutionary biology, evolutionary ecology, plumage color,carotenoid-based colour, carotenoids, lipid peroxidation, oxidative stress, sperm motility, sperm quality, sperm velocity, birds, ornithology, Great Tit, Parus major, bpr3.org/?p=52,peer-reviewed research, peer-reviewed paper
Great Tit, Parus major.
Image: Luc Viatour, Creative Commons/Wikipedia [larger view]
In some species of birds, males are more brightly colored than females. This phenomenon is due to female choice: females choose to mate with males that have the brightest plumage colors and most elaborate ornaments. But these characters are more than mere glitzy advertising, they are an example of honest signals because the brightest plumage and most elaborate ornaments are worn only by those males who have managed to procure enough resources necessary to grow them. But what is the link between plumage brightness and male quality? According to a newly published study of Great Tits, Parus major, males with more intensely colored breast plumage produce faster and more motile sperm.
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Helfenstein, F., Losdat, S., Møller, A., Blount, J., & Richner, H. (2010) Sperm of colourful males are better protected against oxidative stress. Ecology Letters, 13(2), 213-222. DOI: 10.1111/j.1461-0248.2009.01419.x
- January 15, 2010
- 04:59 PM
- 174 views
Doing It For the Kids: The Evolution of Migration
by GrrlScientist in Living the Scientific Life (Scientist, Interrupted)
tags: evolutionary biology, behavioral ecology, life history, migration, long-distance migration,birds,ornithology,bpr3.org/?p=52,peer-reviewed research, peer-reviewed paper
White-rumped sandpiper, Calidris fuscicollis, chicks on Bylot Island, Nunavut, Canada.
Image: Laura McKinnon [larger view]
I recently told you about research that used new microtechnology to document the incredible journey of Arctic Terns, a small bird species that annually migrates from its wintering area in Antarctica to its breeding colonies in Arctic and sub-Arctic regions of Europe, Asia, and North America. But Arctic Terns are not the only birds that migrate extremely long distances: many birds, particularly shorebirds, regularly travel tens of thousands of kilometers between their wintering and breeding territories every year.
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McKinnon, L., Smith, P., Nol, E., Martin, J., Doyle, F., Abraham, K., Gilchrist, H., Morrison, R., & Bety, J. (2010) Lower Predation Risk for Migratory Birds at High Latitudes. Science, 327(5963), 326-327. DOI: 10.1126/science.1183010
- January 13, 2010
- 04:55 PM
- 145 views
Fly Me to the Moon: The Incredible Migratory Journey of the Arctic Tern
by GrrlScientist in Living the Scientific Life (Scientist, Interrupted)
tags: evolutionary biology, behavioral ecology, migration, microtechnology, geolocator, natural history, biological hotspots, longest migration, seabirds, Arctic Tern, Sterna paradisaea, bpr3.org/?p=52,peer-reviewed research, peer-reviewed paper
Arctic Tern, Sterna paradisaea, Iceland.
Image: Arthur Morris, Birds as Art, 2007 [larger view].
Canon 400mm f/5.6L lens (handheld) with the EOS-1D Mark III. ISO 200. Evaluative metering +1/3 stop: 1/1000 sec. at f/5.6 in Manual mode. Manual Flash with Better Beamer at 1:1.
For decades, it was widely suspected that a small seabird, the Arctic Tern, Sterna paradisaea, migrates an estimated 40,000 km each year -- the longest migratory journey of any animal.
"This is a mind-boggling achievement for a bird of just over 100 grams," says the study's first author Carsten Egevang, a seabird researcher with the Greenland Institute of Natural Resources.
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Egevang, C., Stenhouse, I., Phillips, R., Petersen, A., Fox, J., & Silk, J. (2010) Tracking of Arctic terns Sterna paradisaea reveals longest animal migration. Proceedings of the National Academy of Sciences. DOI: 10.1073/pnas.0909493107
- January 7, 2010
- 07:59 AM
- 190 views
Darwin's Finches Develop Immunity to Alien Parasites
by GrrlScientist in Living the Scientific Life (Scientist, Interrupted)
tags: evolutionary biology, immunology, immune response, antibodies, parasite, avian pox virus, Poxvirus avium, nest fly, Philornis downsi, birds, ornithology, Darwin's Finches, Medium Ground Finch, Geospiza fortis, Ecuador, Galapagos Islands, bpr3.org/?p=52,peer-reviewed research, peer-reviewed paper
A male Medium Ground Finch, Geospiza fortis, sits on a tree branch in Ecuador's Galapagos Islands.
Image: Jen Koop.
People often view the Hawaiian islands as a tropical paradise, the ideal vacation site, but you wouldn't agree with this assessment if you happen to be a bird. According to a federal report published last year in the United States, nearly all of Hawaii's birds are in danger of becoming extinct due to habitat destruction, competition from imported species and of course, infections by alien disease organisms. In short, this tropical paradise is an ecological disaster area.
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Huber, S., Owen, J., Koop, J., King, M., Grant, P., Grant, B., & Clayton, D. (2010) Ecoimmunity in Darwin's Finches: Invasive Parasites Trigger Acquired Immunity in the Medium Ground Finch (Geospiza fortis). PLoS ONE, 5(1). DOI: 10.1371/journal.pone.0008605
- June 2, 2009
- 09:09 PM
- 501 views
Post-Traumatic Embitterment Disorder: The Newest Mental Illness?
by GrrlScientist in Living the Scientific Life (Scientist, Interrupted)
tags: Post-Traumatic Embitterment Disorder, Posttraumatic Stress Disorder, Adaptation disorder, stress reaction, Adjustment disorder, Negative life events, psychology, behavior, psychiatry, peer-reviewed paper
[larger view]
In this economy, nearly everyone has experienced unemployment, bankrupture, foreclosure, divorce, or some combination thereof. But roughly 1-2% of these people become so stressed out by these losses that "they can barely function other than to ruminate about their circumstances," according to Dr. Michael Linden, the German psychiatrist who described and named Post-Traumatic Embitterment Disorder (PTED). Read the rest of this post... | Read the comments on this post...... Read more »
Linden, M. (2003) Posttraumatic Embitterment Disorder. Psychotherapy and Psychosomatics, 72(4), 195-202. DOI: 10.1159/000070783
- April 5, 2009
- 10:06 PM
- 474 views
Human Eyes Speak Volumes to Birds
by GrrlScientist in Living the Scientific Life (Scientist, Interrupted)
tags: Eurasian Jackdaw, Corvus monedula, body language, behavior, peer-reviewed paper
Eurasian Jackdaw, Corvus monedula.
This is the smallest species of corvid (crows and ravens).
Image: Wikipedia [larger view].
Those of you who go birding will know what I am talking about when I say that birds are so capable of reading human body language that they know when we are looking at them, which frequently causes them to hide from our gaze. However, this capacity has never before been scientifically studied in birds, until now, that is. Read the rest of this post... | Read the comments on this post...... Read more »
Auguste M.P. von Bayern, & Nathan J. Emery. (2009) Jackdaws Respond to Human Attentional States and Communicative Cues in Different Contexts. Current Biology, 19(7). DOI: 10.1016/j.cub.2009.02.062
- March 25, 2009
- 03:15 PM
- 541 views
Evolution of Squeaker Catfishes in Africa's Lake Tanganyika
by GrrlScientist in Living the Scientific Life (Scientist, Interrupted)
tags: evolutionary biology, speciation, species flocks, molecular phylogeny, behavioral ecology, Synodontis species, squeaker catfish, cuckoo catfish, Lake Tanganyika, peer-reviewed paper
False Cuckoo Catfish, also known as the Dwarf Lake Synodontis, Synodontis lucipinnis [Siluriformes: Mochokidae]. Endemic to Lake Tanganyika in Zambia.
Image: Destination Tanganyika [larger view].
One of the groups of fishes that I worked with as an aquarist for nearly my entire life are the synodontids, often known as "squeaker catfish" for their ability to make high-pitched sounds. These medium- to large-sized African catfishes are attractive, long-lived and intelligent, and many species in this genus exhibit a variety of distinctive breeding behaviors. For example, S. multipunctatus is the only fish documented to practice brood parasitism: it sneaks its eggs in with those of mouthbrooding cichlids in Lake Tanganyika, and its larvae grow faster than those of the host and feed on them. Add that to a fascinating evolutionary history, which is still being deciphered, and you have a very interesting group of fishes. Read the rest of this post... | Read the comments on this post...... Read more »
DAY, J., BILLS, R., & FRIEL, J. (2009) Lacustrine radiations in African Synodontis catfish . Journal of Evolutionary Biology, 22(4), 805-817. DOI: 10.1111/j.1420-9101.2009.01691.x
- March 22, 2009
- 09:52 PM
- 543 views
Genetic Compatibility Drives Mate Choice in Gouldian Finches
by GrrlScientist in Living the Scientific Life (Scientist, Interrupted)
tags: evolutionary biology, mate choice, sex determination, genetic compatibility, behavioral ecology, Gouldian Finch, Erythrura gouldiae, peer-reviewed paper
Image: Sarah Pryke, Macquarie University.
People often worry that our increasing medical and technological prowess will allow humans to routinely choose the sex of our babies, along with a suite of other characteristics. But according to a remarkable and elegant new study, female Gouldian finches, Erythrura gouldiae, have long been choosing the sex of their chicks -- based on the plumage color of the father's head. Not only that, but this study shows that biologists have underestimated the role of female choice in determining the sex of their offspring. Read the rest of this post... | Read the comments on this post...... Read more »
Pryke, S., & Griffith, S. (2009) Genetic Incompatibility Drives Sex Allocation and Maternal Investment in a Polymorphic Finch. Science, 323(5921), 1605-1607. DOI: 10.1126/science.1168928
- January 27, 2009
- 03:09 PM
- 665 views
Meet the Great Speciators: The White-Eyes
by GrrlScientist in Living the Scientific Life (Scientist, Interrupted)
tags: evolution, speciation, diversification rate, Zosterops, White-eyes, ornithology, birds, molecular phylogeny, South Pacific Islands
The Splendid (Ranongga) White-eye, Zosterops splendidus,
endemic to Ranongga Island in the Solomon Islands archipelago.
This species' home range is smaller than Manhattan Island.
Image: Chris Filardi [larger view].
For many decades, the white-eyes (Family: Zosteropidae) were known as the "Great Speciators" in honor of their apparent ability to rapidly give rise to new species while other birds in the same areas showed little or no diversification. But the Great Speciator hypothesis could only ever be indirectly inferred -- until now, that is. According to a paper that was just published by my postdoctoral colleagues, Rob Moyle and Chris Filardi, this group of diminutive birds apparently does evolve faster than any other avian group on earth.
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Robert G. Moyle, Christopher E. Filardi, Catherine E. Smith, & Jared Diamond. (2009) Explosive Pleistocene diversification and hemispheric expansion of a ‘‘great speciator’’. Proceedings of the National Academy of Sciences, 106(4).
- December 24, 2008
- 01:58 PM
- 636 views
What Parrots Tell us About the Origin and Evolution of Birds
by GrrlScientist in Living the Scientific Life (Scientist, Interrupted)
tags: parrots, Psittaciformes, evolution, molecular phylogeny, ornithology, Neornithes
Red-crowned Amazon parrot, Amazona viridigenalis, at Elizabeth Street Parrotry, Brownsville, Texas.
Image: Joseph Kennedy, 7 April 2008 [larger view].
Nikon D200, Kowa 883 telescope TSN-PZ camera eyepiece 1/750s f/8.0 at 1000.0mm iso400.
One of the most contentious issues among scientists who study the evolution of birds is identifying precisely when the modern birds (Neornithes) first appeared. This is due to conflicts between the fossil record and molecular dating methodologies. For example, fossils support a Tertiary radiation whereas molecular dating methodologies suggest that the birds radiated in the early Cretaceous. But there is another way to address this discrepancy. Because the evolution of parrots and cockatoos reflects the evolution of Aves themselves, studying the psittaciformes offers compelling insights into this mystery. Further, because psittaciformes generally are not migratory and because they tend to occupy discrete ranges, their ancient patterns of diversification are easier to discern than for many other taxonomic orders of birds that have dispersed widely. Read the rest of this post... | Read the comments on this post...... Read more »
T. F. Wright, E. E. Schirtzinger, T. Matsumoto, J. R. Eberhard, G. R. Graves, J. J. Sanchez, S. Capelli, H. Muller, J. Scharpegge, G. K. Chambers.... (2008) A Multilocus Molecular Phylogeny of the Parrots (Psittaciformes): Support for a Gondwanan Origin during the Cretaceous. Molecular Biology and Evolution, 25(10), 2141-2156. DOI: 10.1093/molbev/msn160
- December 19, 2008
- 03:55 PM
- 622 views
Dinosaurs: A Bunch of Mister Moms
by GrrlScientist in Living the Scientific Life (Scientist, Interrupted)
tags: evolution, behavioral ecology, parental care, egg incubation, dinosaurs, birds
The Oviraptorid dinosaur, Citipati osmolskae,
on a nest of eggs that was unearthed in the Gobi desert
of Mongolia by the American Museum of Natural History.
Image: Mick Ellison, American Museum of Natural History.
Oviraptors ("egg seizer") were given their name because their fossil remains were first discovered on top of a pile of eggs. Because of their close proximity to clutches of dinosaur eggs, it was initially assumed that these dinosaurs were eating them. However, in his 1924 paper, their discoverer Henry Fairfield Osborn cautioned the scientific community by writing that the name Oviraptor "may entirely mislead us as to its feeding habits and belie its character." Read the rest of this post... | Read the comments on this post...... Read more »
D. J. Varricchio, J. R. Moore, G. M. Erickson, M. A. Norell, F. D. Jackson, & J. J. Borkowski. (2008) Avian Paternal Care Had Dinosaur Origin. Science, 322(5909), 1826-1828. DOI: 10.1126/science.1163245
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