Okay, so I found my own solution, but I thought I would post it here in case anyone else has a similar problem.
I was using the recent posts shortcode, so I had to (on the server side of things) edit the file ttpv-recentpost-shortcode.php. The line I had to change was:
$output_str .= "<li>";
I changed it to
$output_str .= '<li style="list-style-type: none;">';
I tried changing it at the div level above it to see if it would inherit from my stylesheet, which didn’t work, I also tried changing the ul tag, which didn’t work.