Chubutensis versus Angustidens Teeth

[AlexMcCarthyWX]

Hey everyone,

Is there any good way to tell the difference between a C. chubutensis and C. angustidens tooth, especially the smaller ones?

[mrieder79]

Chubtensis has less pronounced cusps. Sometimes they almost seem to be mere bumps in the enamel near the root. Google the two species and after awhile you will be able to see the difference. Angustidens has far more pronounced cusps. Chubtensis also seems to be broader, but that is not as distinct.

The tooth in my avatar is a chubtensis. You can barely see the cusps.

Edited July 9, 2016 by mrieder79

[sixgill pete]

Also, angusteidens is an Oligocene to possibly early miocene tooth. chubutensis is an early miocene tooth that occupied a very very short geologic time period.

[siteseer]

With chubutensis it has always seemed to me a matter of splitting hairs. When a species is established based on its lateral cusplets being a little smaller than another species (angustidens) which itself has cusplets a little smaller than its ancestor (auriculatus - this name to account for all the Mid-Late Eocene names that have been proposed) you might wonder where the dividing line is in terms of some kind of measurement. What we have to remember is that each scientific name is an official proposal to define remains that belong together. Names can change and often do and sometimes we see things in teeth that seem out of chronologic order. I have seen Late Oligocene Carcharocles teeth with no cusplets, seemingly a tooth from the distant future. Is that an early megalodon or just an angustidens that experienced sort of a genetic burp and did not develop the cusplets as was normal for the species. A tooth like that reminds us that we are seeing one lineage of ancestors and descendants with auriculatus being a descendant of unserrated-toothed ancestors while also being an ancestor to angustidens. Individual teeth can be a little thicker or thinner or follow less of a regular shape for their tooth positions. Anyone who has ever cooked knows that the finished product can be slightly to noticeably different a few times out of many even when you always try to be faithful to the recipe.

C. angustidens seems like more of a definable species because it has consistently smaller lateral cusplets than auriculatus along with it being a little flatter overall. As Sixgill Pete noted, it also seems to be largely an Oligocene species though a few Late Eocene-Early Oligocene teeth (auriculatus or chubutensis?) or Late Oligocene-Early Miocene teeth (angustidens or chubutensis?) might generate disagreement with no clear answer. Some rare Middle Miocene and even Late Miocene Carcharocles teeth have weak lateral cusplets. We can wonder if these teeth represent a late-surviving population of chubutensis, or perhaps more likely, a megalodon tooth exhibiting a trait of its ancestors no longer expressed in most of the population.

Because Carcharocles teeth are noticeably larger than other sharks of its time particular across the Miocene and into the Pliocene, small differences across that time seem more significant. We don't give different names to hammerhead teeth that have serrated edges. It's seen as a variation within a species. The name chubutensis may have a useful place in how we see change in Carcharocles teeth across time but we also have to keep in mind that we can just as easily call those teeth "early megalodon."

Hey everyone,

Is there any good way to tell the difference between a C. chubutensis and C. angustidens tooth, especially the smaller ones?