# A question about Brontosaurus

**URL:** <https://boards.straightdope.com/t/a-question-about-brontosaurus/554083>\
**Category:** Cecil's Columns/Staff Reports\
**Created:** [September 17, 2010, 2:11pm UTC](https://boards.straightdope.com/t/a-question-about-brontosaurus/554083 "2010-09-17T14:11:17Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![DrumBum](https://avatars.discourse-cdn.com/v4/letter/d/e79b87/32.png) [@DrumBum](https://boards.straightdope.com/u/DrumBum)\
**Post date:** [September 17, 2010, 2:11pm UTC](https://boards.straightdope.com/t/a-question-about-brontosaurus/554083/1 "2010-09-17T14:11:17Z")

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In the [recent column](http://www.straightdope.com/columns/read/371/is-it-true-the-brontosaurus-never-really-existed) , regarding the Brontosaurus ,Cecil’s says

> [@](#):
>
> …when it was pretty firmly established that the brontosaurus was the same species as the apatosaurus,

I thought that Brontosaurus and Apatosaurus are the same genus. Am I mistaken ?  
.

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**Author:** ![Floater](https://avatars.discourse-cdn.com/v4/letter/f/dc4da7/32.png) [@Floater](https://boards.straightdope.com/u/Floater)\
**Post date:** [September 17, 2010, 3:24pm UTC](https://boards.straightdope.com/t/a-question-about-brontosaurus/554083/2 "2010-09-17T15:24:13Z")

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I’m afraid you are. They are the same species.

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**Author:** ![Irishman](https://avatars.discourse-cdn.com/v4/letter/i/b487fb/32.png) [@Irishman](https://boards.straightdope.com/u/Irishman)\
**Post date:** [September 17, 2010, 4:03pm UTC](https://boards.straightdope.com/t/a-question-about-brontosaurus/554083/3 "2010-09-17T16:03:54Z")

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Yes, you are wrong.

To rephrase the column, first Apatasaurus was found and named. Then Marsh discovered a set of bones, found a head for it, and determined that the collective set was similar to Apatasaurus, but different enough to warrant being a new species. Thus he named it Brontosaurus.

Eventually other scientists uncovered the funny business with the head and determined that the “Brontosaurus” was just another set of Apatasaurus bones with the wrong head on it.

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**Author:** ![DrumBum](https://avatars.discourse-cdn.com/v4/letter/d/e79b87/32.png) [@DrumBum](https://boards.straightdope.com/u/DrumBum)\
**Post date:** [September 17, 2010, 4:18pm UTC](https://boards.straightdope.com/t/a-question-about-brontosaurus/554083/4 "2010-09-17T16:18:01Z")

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IANA Biologist but the first critter unearthed was called _Apatosaurus ajax_ and the second, bigger one was called _Brontosaurus excelsus_. Now they are called _Apatosaurus ajax_ and \*Apatosaurus excelsus \*.

I guess I was confused since this would suggest that they are of the same genus but are two different species.

High school biology was a long time ago. :smack:  
.

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**Author:** ![Darwins\_Finch](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darwins_finch/32/20304_2.png) [@Darwins\_Finch](https://boards.straightdope.com/u/Darwins_Finch)\
**Post date:** [September 17, 2010, 4:44pm UTC](https://boards.straightdope.com/t/a-question-about-brontosaurus/554083/5 "2010-09-17T16:44:20Z")

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> [@DrumBum](#):
>
> IANA Biologist but the first critter unearthed was called _Apatosaurus ajax_ and the second, bigger one was called _Brontosaurus excelsus_. Now they are called _Apatosaurus ajax_ and \*Apatosaurus excelsus \*.
> 
> I guess I was confused since this would suggest that they are of the same genus but are two different species.
> 
> High school biology was a long time ago. :smack:  
> .

_Brontosaurus_ was, indeed, a different species from the previously-described _Apatosaurus_. As you note, the original was _A. ajax_, while the second was _B. excelsus_. When _Brontosaurus_ was synonymized with _Apatosaurus_, the species epithets were retained, so _B. excelsus_ became _A. excelsus_.

So, contrary to Cecil and the previous posters, you are correct - the animal previously classified as Brontosaurus is now in the same genus as _Apatosaurus ajax_, but is of a different species.

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**Author:** ![Irishman](https://avatars.discourse-cdn.com/v4/letter/i/b487fb/32.png) [@Irishman](https://boards.straightdope.com/u/Irishman)\
**Post date:** [September 17, 2010, 5:55pm UTC](https://boards.straightdope.com/t/a-question-about-brontosaurus/554083/6 "2010-09-17T17:55:02Z")

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Okay, thank you for the correction.