Hexanchus or Echinorhinus?

[dinoshark]

i went out hunting last weekend back around sharktooth hill in bakersfield and found this 95% complete tooth with a unique two-cusped crown. the root and the tooth in general is very flat - but i'm on the fence if this is a hexanchus or an echinorhinus tooth, or something else. those two are the most similar options, but still there are differences with each. i find there to be slightly more resemblance to an echinorhinus, but would really love to hear everyone's thoughts. the tooth is 2.1 cm in slant length, just under an inch. what do folks think? 

 

lingual

 

 

labial

 

 

here's a similar hexanchus tooth from the web, but there is additional cusp: 

 

and here's an example of similar echinorhinus tooth labial side - difference is there are mesial cusps pointing the opposite way, which my tooth lacks: