Stump Borer from US Virgin Islands

Subject: large beetle
Location: west end of St Thomas, USVI
November 29, 2016 5:26 pm
Hi, Bugman.
I live in the US Virgin Islands. After coming home today, I noticed a large (about 9 cm long) brownish-black beetle hiding in a notch in the outside of our balcony railing. I was hoping I could get a better photo if it came out from its hiding spot after dark, but it hasn’t moved yet. I tried identifying it going on the assumption that it’s a stag beetle, but I’ve been going in circles trying to pinpoint the species. Can you help me?
Signature: Stumped on St Thomas

Stump Borer
Stump Borer

Dear Stumped on St Thomas,
This is NOT a Stag Beetle.  It is a Prionid or Stump Borer in the tribe Mallodonini.  I greatly resembles the Hardwood Stump Borer,
Mallodon dasystomus, a North American species that is known to range as far south as Columbia.  It might be the same species as this Prionid from Puerto Rico.  The site Insectoid has a checklist of species from the Caribbean.  According to the Worldwide Cerambycidae Photo Gallery, Hovorodon bituberculatum  is found on St Thomas.  The mandibles on your individual indicate it is a male.  We would advise that you steer clear of those mandibles as they look like they might do some damage.

Hi, Daniel.
Thank you for all the information. He’s still in his spot on our railing, and looking more and more like the male Hovorodon bituberculatum. I agree that his mandibles look strong and sharp and I will definitely stay out of their way.

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