See discussion here about Odonteus liebecki vs. Odonteus thoracicornis:



Mine looks similar, that is, there is a bit of a carina on the clypeus. Following Harpootlian's key (for SC), this would seem to point to Odonteus thoracicornis. I was basing my ID way back then on published images showing that major male thoracicornis has prominent pronotal horns. Maybe that's not reliable? See Phil's image, identified as Odonteus thoracicornis, "a reasonably minor male, the pronotal horns can be quite a bit larger"


Funny to be revisiting these after all this time. I'm really not sure about my 2005 ID of Odonteus liebecki now, though Phil H confirmed it at the time. Maybe this is one of those where species-level ID is just very iffy without dissection.