Can you help me differentiate these "Makos"

[PolskiByk]

Here is a photo 15 various Mako teeth I have collected at Calvert Cliffs.   I have been sticking them in a baggy marked Makos, but now I want to display them with the correct labels.   The Isurus vs. Cosmopolitodus hastalis thing is confusing for a newbie, as is correctly identifying Broad vs. Narrow vs. Longfin.  (Are there others besides these three types Makos at Calvert?) 

 

Does anyone want to take a stab at identifying these, or tell me what features I should look for to differentiate them? 

Thanks!

 

 

[Miocene_Mason]

Here’s ones I am pretty confident are Carcharodon hastilis (which is the most recent revision). The others I’m either not sure or are different species. I’ll PM you some excerpts from a book that can help you with the remaining. It’s rather technical so be ready for that

BTW a few other “makos” are found at the cliffs, depending on what you call a “Mako”. Ex. Carcharomodus escheri is extremely rare by occasionally found (it is probably very closely related to Isurus)

Edit: silly me, forgetting to add photos. Here:

[ynot]

For identification purposes it would help to show the teeth from front, back and side.

Also put a scale (ruler preferred) in at least one picture, please.

 

I think most of Your teeth are lower teeth (Isurus or Carcharodon), which are hard to determine species (because they all look similar)

[HoppeHunting]

I agree with Mason’s assessment. Another way you can usually distinguish hastalis vs. Isurus is by pinching the tooth at the center of the root. Isurus will typically have a thicker root as opposed to the generally flat teeth of C. hastalis. As mentioned above, however, the lower teeth of these two species are very similar, so this test is usually only effective on uppers. I also believe that when looked at from a side view Isurus teeth tend to have more curvature, a bit like that of a Sand Tiger tooth, while hastalis are usually straight/flat. Hope this helped.

[Cam28]

21 hours ago, WhodamanHD said:

Here’s ones I am pretty confident are Carcharodon hastilis (which is the most recent revision). The others I’m either not sure or are different species. I’ll PM you some excerpts from a book that can help you with the remaining. It’s rather technical so be ready for that

BTW a few other “makos” are found at the cliffs, depending on what you call a “Mako”. Ex. Carcharomodus escheri is extremely rare by occasionally found (it is probably very closely related to Isurus)

Edit: silly me, forgetting to add photos. Here:

 

Seriously now even the species name "Hastalis" isn't safe, let alone the muddy mess of the genus? Think we should all just call it the gw ancestor, call it a day lol

 

& When/where was the genus Carcharomodus created? I know now it seems popular to call all the mega sharks of the Meg lineage "Otodus" but all these lamniform revisions seem exhausting 

[Miocene_Mason]

18 minutes ago, Cam28 said:

 

Seriously now even the species name "Hastalis" isn't safe, let alone the muddy mess of the genus? Think we should all just call it the gw ancestor, call it a day lol

 

& When/where was the genus Carcharomodus created? I know now it seems popular to call all the mega sharks of the Meg lineage "Otodus" but all these lamniform revisions seem exhausting 

No they didn’t change the species name (I’ll blame that on spell check). Tis indeed a muddy mess! Carcharomodus is a new genus created this year (I think), escheri was previously thought of as one of the Makos or Carcharodon, until they recently found a skeleton. Escheri is mainly found in northwest Europe, but is occasionally found elsewhere. It’s lightly serrated and resembles the European version of hastalis (hastalis seems to vary regionally). It’s an example of convergent evolution with the GW. Neither Carcharodon nor Carcharomodus are part of the Megalodon line. Megalodon is subsumed under Otodus now (which is in my opinion way less cool than Carcharocles) as is angustidens, auriculatus, chubutensis (and sokolovi If you believe in it). This development comes after the finding of meglolamna, and means (in some sciencey way in which I do not understand) makes Otodus a paraphyly unless Carcharocles is part of it, which would make it an invalid clade. All a bunch of complicated taxonomy which just boils down to “we are not yet sure what’s what”. Then there’s the lumper/splitter stuff (“how many slices can you get out of a loaf of bread”).