# Do all mammals have tribosphenic design molars? **URL:** \ **Category:** Factual Questions\ **Created:** [May 22, 2006, 2:46am UTC](https://boards.straightdope.com/t/do-all-mammals-have-tribosphenic-design-molars/357698 "2006-05-22T02:46:38Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![Jebus\_H.Christ](https://avatars.discourse-cdn.com/v4/letter/j/6a8cbe/32.png) [@Jebus\_H.Christ](https://boards.straightdope.com/u/Jebus_H.Christ)\ **Post date:** [May 22, 2006, 2:46am UTC](https://boards.straightdope.com/t/do-all-mammals-have-tribosphenic-design-molars/357698/1 "2006-05-22T02:46:38Z")
Do all mammals have reallly have tribosphenic design molars? From wikipedia > [@](#): > > The tribosphenic design appears in all species of mammals. What about Tachyglossidaes including the Echidna which seems to have no teeth? [http://en.wikipedia.org/wiki/Tachyglossidae](http://en.wikipedia.org/wiki/Tachyglossidae) [http://en.wikipedia.org/wiki/Molar\_(tooth)](http://en.wikipedia.org/wiki/Molar_(tooth)) ---
**Author:** ![John\_Mace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_mace/32/185_2.png) [@John\_Mace](https://boards.straightdope.com/u/John_Mace)\ **Post date:** [May 22, 2006, 2:58am UTC](https://boards.straightdope.com/t/do-all-mammals-have-tribosphenic-design-molars/357698/2 "2006-05-22T02:58:12Z")
> [@Jebus H. Christ](#): > > [http://en.wikipedia.org/wiki/Molar\_(tooth)](http://en.wikipedia.org/wiki/Molar_(tooth)) This is the link you want: [http://en.wikipedia.org/wiki/Molar\_(tooth)](http://en.wikipedia.org/wiki/Molar_%28tooth%29) It’s also the link from which your quote was taken. You owe me one. πŸ˜‰ ---
**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:** [May 22, 2006, 3:02am UTC](https://boards.straightdope.com/t/do-all-mammals-have-tribosphenic-design-molars/357698/3 "2006-05-22T03:02:34Z")
> [@Jebus H. Christ](#): > > Do all mammals have reallly have tribosphenic design molars? The tribospehnic design is thought to be primitive (i.e., plesiomorphic) in mammals, but has been modified by various lineages. You can see all manner of variations in molar structure [here](http://animaldiversity.ummz.umich.edu/site/topics/mammal_anatomy/tooth_diversity.html). ---
**Author:** ![Jebus\_H.Christ](https://avatars.discourse-cdn.com/v4/letter/j/6a8cbe/32.png) [@Jebus\_H.Christ](https://boards.straightdope.com/u/Jebus_H.Christ)\ **Post date:** [May 22, 2006, 3:35am UTC](https://boards.straightdope.com/t/do-all-mammals-have-tribosphenic-design-molars/357698/4 "2006-05-22T03:35:21Z")
> [@John Mace](#): > > This is the link you want: [http://en.wikipedia.org/wiki/Molar\_(tooth)](http://en.wikipedia.org/wiki/Molar_%28tooth%29) > > It’s also the link from which your quote was taken. > > You owe me one. πŸ˜‰ Thanks. ---
**Author:** ![Jebus\_H.Christ](https://avatars.discourse-cdn.com/v4/letter/j/6a8cbe/32.png) [@Jebus\_H.Christ](https://boards.straightdope.com/u/Jebus_H.Christ)\ **Post date:** [May 22, 2006, 3:53am UTC](https://boards.straightdope.com/t/do-all-mammals-have-tribosphenic-design-molars/357698/5 "2006-05-22T03:53:03Z")
Another mammal question: > [@](#): > > Deep in their bones, all mammals are related. The earliest known mammals were the morganucodontids, tiny shrew-size creatures that lived in the shadows of the dinosaurs 210 million years ago. They were one of several different mammal lineages that emerged around that time. All living mammals today, including us, descend from the one line that survived. Were morganucodontids the line that survived? ---
**Author:** ![Jebus\_H.Christ](https://avatars.discourse-cdn.com/v4/letter/j/6a8cbe/32.png) [@Jebus\_H.Christ](https://boards.straightdope.com/u/Jebus_H.Christ)\ **Post date:** [May 22, 2006, 3:54am UTC](https://boards.straightdope.com/t/do-all-mammals-have-tribosphenic-design-molars/357698/6 "2006-05-22T03:54:33Z")
> [@Jebus H. Christ](#): > > Another mammal question: > > Were morganucodontids the line that survived? That is from National Geographic. [http://magma.nationalgeographic.com/ngm/0304/feature1/index.html?fs=www7.nationalgeographic.com](http://magma.nationalgeographic.com/ngm/0304/feature1/index.html?fs=www7.nationalgeographic.com) ---
**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:** [May 22, 2006, 4:27am UTC](https://boards.straightdope.com/t/do-all-mammals-have-tribosphenic-design-molars/357698/7 "2006-05-22T04:27:15Z")
> [@Jebus H. Christ](#): > > Were morganucodontids the line that survived? Nope. They only lasted through about the middle of the Jurassic. The sister clade to Morganucidontidae split into Docodonta and Symmetridonta; the latter lineage is the one that survived to produce cats and rats and elephants. ---
**Author:** ![John\_Mace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_mace/32/185_2.png) [@John\_Mace](https://boards.straightdope.com/u/John_Mace)\ **Post date:** [May 22, 2006, 4:29am UTC](https://boards.straightdope.com/t/do-all-mammals-have-tribosphenic-design-molars/357698/8 "2006-05-22T04:29:08Z")
> [@Darwin's Finch](#): > > the latter lineage is the one that survived to produce cats and rats and elephants. No unicorns? πŸ™‚