Image of banded tun

Description:

I found a nice, clean, empty shell of Tonna sulcosa, Banded Tun, at University Beach, Corpus Christi, Texas. At first I did not recognize it and thought it was a cassid, perhaps in the genus Semicassis, but a colleague (Dr. Wes Tunnell, thanks!) suggested looking into Tonnidae. The shell is easily recognizable by its tan spiral banding on a white shell, and the dark protoconch. I will take better photos, including of the protoconch (which is not perfect), and post them here later. Wikipedia has a great plate that shows the dark protoconch: https://en.wikipedia.org/wiki/Tonna_sulcosa (although the shell I found is more elongate). What caught me by surprise is that I could not recognize the shell, thinking it was a local species, but in the back of my mind I had seen it before. It turns out this species is originally from the Indo-West Pacific, not from the Gulf of Mexico! I do not think it represents an invasive species. The shell I found is in good condition, so it is most likely that someone bought it in a store and dropped it (accidentally or intentionally) in nearby the water. Or maybe someone who knows I often walk on the beach was trying to pull a prank on me? The dimensions of the shell are 100.68 x 69.67 x 54.94 mm.