Wednesday, July 8, 2020

SearchResearch Challenge (7/8/20): Gomphotheres... in Panama?

The other day I was thinking about gomphotheres, as one does on nice spring afternoons... 

... remember them?  They're a kind of elephant-like animal that lived in North America during the Pleistocene?  We mentioned them in an earlier SRS post about avocado seed dispersal.  

I remembered that they were native to North America (or Siberia, depending on how far you want to go back in time).  They were widespread in North America during the Miocene and Pliocene epochs.  That's all well and good, but then I read a fascinating article about this that pointed out how they were ALSO in South America. 

But I knew that day in the day (that is, during the Miocene) North and South America were separate continents separated by a lot of ocean.  

When you put all that together, you have to ask yourself:  How does a gomphothere get from North America to South America if they're separate continents?  

American continents just before the Miocene

I looked up the geohistory of Panama and found that it emerged from the sea about 3M years ago.  

If Panama didn't exist until around 3M years ago, how did gomphotheres get from one to the other?   Did they swim?  (THAT seems unlikely.)  

Remember that the Miocene ran from  23 to 5 million years ago, while the Pliocene ran from 5 to 2.5 million years ago.  

So if Panama emerged as a land bridge between North and South America about 3M years ago, that gives the gomphotheres 500,000 years to wander from North into South America.   

That makes sense.  That's a lot of time, they could have easily migrated from point A to point B in half-a-million years.  

And... IIRC, armadillos are native to South America, but now they're all over Mexico and parts of the US Southwest. 

Interesting.  So.. did they come north when the Panamanian land bridge formed?  Did they come north while the gomphotheres went south?  

Naturally, I'm thinking about these (apparently) disjointed observations, and thinking to myself that the emergence of the Panamanian land bridge must have had huge biological consequences.  SURELY someone has written about this, right?  I'd like to read more about this mega-event--but how?  

This line of thinking leads to two key questions that I think you'll find interesting (I certainly do!)... 

1.  The emergence of the Panama Isthmus must have been a big deal biologically.  If I was to do a search for this, what would be the best term for this?  There MUST be a specialty term that I could use to search for more information.  What would that term (or phrase) be? 

Another apparently disjoint observation that actually links into this in an interesting way... 

Screw fly (which leads to screw worms).  

I remember reading that screw worms (Cochliomyia hominivoraxwere a major problem for livestock in the United States.  They're terrible pests--the adult females lay eggs on hosts (typically cattle or sheep), the larvae hatch and start munching away on the living animals.  Sometimes this even happens to humans.  

However, in a hugely successful agricultural science program, screwflies have been functionally extinct in the US since the late 1960s.  

2.  Once you've figured out the answer to the first Challenge, can you figure out the connection between the answer to Challenge #1 and the eradication of screw worms in the US?  

I know it seems disconnected, but once you figure it out, you'll be as amazed as I was upon learning this little story.  Sometimes these things really do work out.  

Let us know how you find the answers to these Challenges!  Post your discoveries in the comments. 


Search on! 


  1. Perhaps this is cheating, for #1. I knew of the "event" but couldn't think of the name. I searched for [american biota exchange] which found me what I was looking for, the Wikipedia article on "Great American Interchange"

    1. It's good you knew that... but I'm really curious how other people (who don't know about GABI) will discover it!

  2. For #2, I searched for ["screw worm" OR "Cochliomyia hominivorax" "south america"] (I copied the genus and species from this blog post, hence the capitalization). The first result ( says that eradication was based on releasing lots of sterile males. It wasn't immediately clear to me why eradication went to the Darién gap and then stopped, as mentioned on that page. With ctrl+f "eradication" I saw and clicked on the link to a paper, "Screwworm eradication in North and Central America." Just from the abstract, I see that the eradication program moved from the US southward. I was already familiar with the gap (although not it's name) , and not surprised that there wasn't much interest on continuing to eradicate further south once they got to that point.

  3. I always thought the "Great American Interchange" was the cloverleaf on 101 between Lawrence and San Tomas Expressways.

  4. [panama animals moving between north south america] did the trick. Adding the word paleontology didn't do anything.

  5. Good Morning/day!

    Again, something new and interesting.

    I started with [Panama Isthmus (this part not on my query: "also historically known as the Isthmus of Darrienn (Istmo de Darién) from Wikipedia" origin] also read there: This event (Panama Isthmus formation) is known in paleontology as the Great American Interchange.

    Is considered one of the most important geologic, oceanographic, and biogeographic events ever Biogeographic, new for me." research shows that the closure happened much earlier, as much as 23 million years ago...""..."The separation of the Pacific Ocean and what would become the Caribbean Sea by the Isthmus has been called 'The Great American Schism'..."

    From Nasa: Panama: Isthmus that Changed the World

    [ The Great American Schism]

    PDF:The Great American Schism: Divergence of Marine Organisms After the Rise of the Central American Isthmus "Adaptive divergence can be seen in life history parameters..."

    [define adaptive divergence]

    With [Isthmus of Panama history]

    On Historic Routes

    With [Great American Interchange] first went to Wikipedia and noticed the golden star. Therefore, went to read it using Google Translate. There learned that species that went North to South were more successful than those coming to the North.

    [screw worms eradication around(3) Panama isthmus]

    America’s Never-Ending Battle Against Flesh-Eating Worms"...A transcontinental screwworm barrier has been in place for 50 years...The man who came up with the scheme, and believed in it most passionately, was Edward F. Knipling..." Also in connection with DDT and later to not use pesticides

    Then, searched on Wikipedia [ Isthmus of Tehuantepec] just to learn

    Isthmus of Tehuantepec

    Curious things I learned yesterday:
    a. There is a statue of Benito Juarez in The United States
    b. 1984 is the book is the most borrowed book in the NY Public Library
    c. A song in Karate Kid, was rejected first from being part of Rocky III. You're the Best out, Eye of the Tiger in.

    1. Searched on YouTube with [Panama isthmus formation] some videos. The one of PBS talks about similarities between Hawaii and Panama

      Also searching found what tombolo is

    2. Searched [animales Sur Norte Istmo Panama]

      First result is: El Gran Intercambio Biótico Americano. GABI

      GABI PDF

      There are other good links from NatGeo and BBC

      Fauna prehistórica del norte y sur de América se topó en Costa Rica Animals from North and South found each other in Costa Rica.

      With [Formacion Istmo Panama]

      La nueva versión de cómo se formó el Istmo de Panamá (2019) *In my queries I don't use accents like in Panamá.

      "...En un estudio reciente publicado en la revista Scientific Reports, los científicos de la Universidad de Cardiff propusieron que el Istmo no nació solo del proceso tectónico, sino que también podría haberse beneficiado en gran medida del crecimiento de los volcanes..."

      To find more data and also information in English [David Buchs Panama Isthmus formation]

      Out of topic. And related to previous SRS Challenges. I just found this. Only available for free is the abstract. It is very interesting.
      Native American gene flow into Polynesia predating Easter Island settlement I'm almost sure Dr. Russell already read it. And in case not, here it is.

    3. This weekend, I watched the movie Pearl in Paradise. And in there, it is mentioned some national flower. And of course, the next morning, SRS for it.

      Fiji: The national flower is tagimaucia (Medinilla waterhousei) and that also helped me to discover that many countries and states have a national flower or a flower emblem. Also made me remember our SRS Challenge about anthems. I didn't know in Mexico it is Dahlia. And also didn't know that Dahlia had such an incredible history. I'm sure Dr. Russell, will love it, if he didn't know it already. And maybe in a future we have another SRS about flowers

      Finally, just found this
      The secrets of the mysterious Culper Spy Ring Influenced the birth of the US. It sounds interesting. I'll watch later

    4. Searched on YouTube [ Screw worm eradication]

      Eradication of the Screwworm

      USDAAPHIS Just found it. No description but few minutes have been interesting

  6. 1) [emergence of the Panama Isthmus must have been a big deal biologically]

    Finds: Formation of the Isthmus of Panama. Technical discussion which I could not follow very well. However, way down the page is the Section INTERCONTINENTAL DISPERSALS OF TERRESTRIAL ANIMALS in which we see "The Great American Biotic Interchange is characterized by a surge in successful dispersals in both directions" Under SUMMARY is this key phrase, "Establishing how and when the Isthmus of Panama formed is crucial for understanding the greatest “natural experiment” ever"

    2) [eradication of screw worms in the US? ] finds finds this excellent article A Short History of the Screwworm Program. Another great "natural experiment."

    This is/was a fascinating trip into (my) unknown territory

  7. off topic, but check the SF/GGB shots…
    off planet

    1. Those photos are REALLY impressive. I didn't bother to try and take any because I figured the moon would wash it out. I'm impressed.

    2. Dr. Russell, Remmij and here more Neowise photos with Northern Lights

  8. This comment has been removed by the author.


    Wow this is really cool!! Im very interested in new ways to use genetic engineering to rid human life of the impacts of pests on our selfs and our livestock. It reminds me of other similar programs to decrease mosquito populations using sterilized individuals.

  10. I also see that Ramon also posted the same article. I'm trying out your challenges, because I'm an educator looking for ways to engage my students in improving their search and research skills, thank you for maintaining your blog.

    1. Glad to help out. You might be interested in checking out the online course for even MORE search/research skills!

    2. Oh yeah.. I also should point you to my book, The Joy of Search. Find info about it at

  11. Thanks for the Answer, Dr. Russell. It was as you mentioned, very interesting, with lots of knew knowledge and with some more to SRS on our time.

    About those other topics:

    I have been watching Washington TV Series and learning a lot. The first surprises were: Washington was with the British and that there were Half Kings. Today, YouTube suggested this video.

    The Many U.S. Presidents Before George Washington

    George Washington was the first U.S. president under the current United States Constitution, but he wasn’t the country’s first president....The first president of the United States under the Articles of Confederation was John Hanson from Maryland.

    This is really how Presidents are counted in The United States? My guess is not because as mentioned on the video was not really a United States, so George Washington is the first

    I still need to read about the kings and watch episodes 2 & 3 of the TV Series.

    On second topic, searching about Our Lady of Mount Carmel, found about this:

    Bell Gable while reading:

    Btw, while I was reading George Washington's article on Wikipedia, noticed a different color star. The bronze one is a featured article. Do you know what the other color means?

    George Washington