Total Pageviews

Tuesday, September 13, 2016

Speaking of Geologic Time Periods Ending in E: Indian Fossils and the Spread of Primate-Like Animals: India's Island Days

      Well-preserved bones of rat-sized creatures excavated in an Indian coal mine may come from close relatives of the first primate-like animals, Iowa, USA, researchers describe.



     A set of two dozen limb fossils, dating to about 54.5 million years ago during the Eocene, raises India’s profile as a possible hotbed of early primate evolution, says biologist Dr. Rachel Dunn. 




      Bones from Vastan coal mine in Gujarat, India’s westernmost state, indicate that these small tree-dwellers resembled the first primates from as early as 65 million years ago, the scientists report in the October 2016 Journal of Human Evolution.



     These discoveries add to previously reported jaws, teeth and limb bones of four ancient primate species found in the same mine. “The Vastan primates probably approximate a common primate ancestor better than any fossils found previously,” says paleontologist and study co-author Dr. Kenneth Rose of Johns Hopkins University.




     The Vastan animals were about the size of living gray mouse lemurs and dwarf lemurs, weighing roughly 150 to 300 grams (about half a pound), the investigators estimate. 




      Most Vastan creatures possessed a basic climbing ability unlike the more specialized builds of members of the two ancient primate groups that gave rise to present-day primates, the researchers say. One of those groups, omomyids, consisted of relatives of tarsiers, monkeys and apes. 




       The other group, adapoids, included relatives of lemurs, lorises and bushbabies. The Indian primates were tree-dwellers but could not leap from branch to branch like lemurs or ascend trees with the slow-but-sure grips of lorises, the new report concludes.




      Vastan primates probably descended from a common ancestor of omomyids and adapoids, the researchers propose. India was a drifting landmass headed north toward a collision with mainland Asia when the Vastan primates were alive. Isolated on a huge chunk of land, the Indian primates evolved relatively slowly, retaining a great number of ancestral skeletal traits, the researchers propose.




      “It’s possible that India played an important role in primate evolution,” says evolutionary anthropologist Dr. Doug Boyer of Duke University. In 2010, a team led by Boyer reported that a roughly 65-million-year-old fossil found in southern India might be a close relative of the common ancestor of primates, tree shrews and flying lemurs (which glide rather than fly and are not true lemurs).




     One possibility is that primates and their close relatives evolved in isolation on the island continent of India between around 65 million and 55 million years ago, Dr. Boyer suggests. Primates then spread around the world once India joined Asia by about 50(?) million years ago.




     This is a controversial idea. An increasing number of scientists suspect primates originated in Asia. Chinese primate fossils dating to 56 million to 55 million years ago are slightly older than the Vastan primates. The Chinese finds show signs of having been omomyids.

      And in at least one respect, Dr. Boyer says, some of the new Vastan fossils may be more specialized than their discoverers claim. Vastan ankle bones, for instance, look enough like those of modern lemurs to raise doubts that the Indian primates were direct descendants of primate precursors.




      Dr. Dunn, however, regards the overall anatomy of the Vastan fossils as “the most direct evidence we have” that ancestors of early primates lacked lemurs’ leaping abilities, contrary to what some researchers have argued. 

Your thoughts? Omo or Ada? Or?
Steph

P.S. My oldest peach tree is loaded with fruit this year! They are just ripening now.





29 comments:

  1. Replies
    1. Fun Seinfeld clip, Paul.

      Innocent peaches?

      Delete
  2. If we were near you, we'd bake you a peach pie.

    ReplyDelete
    Replies
    1. Yum, Joanne! I am freezing a bunch and making jam. And passing on some of the bounty to friends and neighbors.

      Delete
  3. Thanks for the link to this, WW. It is much more accessible with my new higher speed internet connection.
    I like concepts like this one where the imagination can almost see the processes that were at work. Thanks.
    The bone (femur?) pics seem to refer to extant gray mouse and dwarf lemurs, but they are 3 inches long, almost cat size. I must have missed something.

    ReplyDelete
    Replies
    1. Welcome, Mendo Jim. The femur figure is misleading; I believe the femur on the left is actual size and the one on the right is enlarged to show detail. The authors have posted images of bones found to this online virtual fossil "repository."

      So, the actual size of these fossil femurs is likely closer to 2 inches.

      Delete
  4. Replies
    1. jan, you are really out there today. . .

      Mordor macula--great name. I am seeing red.

      Delete
    2. Graffiti here. Graffiti way out there.

      Local newscasters had an unfortunate mix-up this week reporting nuclear tests in North Dakota and pipeline issues in North Korea. . .

      Delete
    3. No, there hasn't been a nuclear weapons incident in North Dakota in nine years.

      Delete
    4. ... Though ND has considerably more nuclear firepower than DPRK.

      Delete
    5. Commenting in nuclear-free Canadian to acknowledge that some of ND's nukes are based less than a mile from the border?

      Delete
  5. Speaking of time periods ending in "e," if all NPR puzzle-doers were geniuses like Mendo Jim and jan, , or genius/geologists like Scientific Steph, a correct answer to Will Shortz’s puzzle this week could be these seven epochs, which are very “well-known” to geniuses.

    LegoLamentsThatSuchEpochsAreNotSoWellKnownToBarryPaulAndLego

    ReplyDelete
    Replies
    1. Lego, e-pochs(pox), huh? Is that like getting chicken pox over the internet?

      --Emily Varicella--

      Delete
  6. Parse your thumbnail, Steph: Tarse, Tarsier, Tarsiest? (Am I a Tarsier parsier now?)

    ReplyDelete
    Replies
    1. Thank heavens for consonants. . .πŸ˜†

      We most definitely need a word/puzzle lover at NPR on Sundays!

      Delete
  7. Testing:
    πŸŒπŸŒŽπŸŒπŸŽΉπŸ˜‡πŸ˜•πŸŒ‰πŸŽΆπŸ’€

    ReplyDelete
    Replies
    1. Aha! Wake up, Blaine and PC, the Philistines are upon you!

      Delete
    2. These are great, Paul. I did fiddle around with some settings; wonder if I enabled pictographs πŸ˜‰. Cool bridge.

      Delete
  8. Anyone know much about "Cyonara," a lambda-cyhalothrin pesticide? A lawn service is using it to control bugs in our neighborhood. The name, though "clever," sounds ominous. . .

    ReplyDelete
    Replies
    1. Here's the product web page, and here's the MSDS. Don't drink it, don't put it in your fish tank.

      Delete
    2. Thanks, jan. Hope our local bees and cicadas will not be affected.

      Delete
    3. Just a curious observation:
      I did a quick count of the "states registered" and got 48. The missing 2? You guessed it -- AK & HI. Any hypotheses?

      Delete
    4. That is curious, Paul. Hawaii has a very, very active anti-GMO and anti-pesticides faction. Guessing the bugs don't flourish in Alaska so there's little need?

      Delete
  9. New post on "Antikytherian Mechanism Shipwreck Revisited: Human Skeleton Over 2,000 Years Old Discovered at Site" is now up.

    ReplyDelete