I'm a professor of aquatic ecology at Purdue University, West Lafayette, Indiana (USA). I have sampled freshwater fishes in Costa Rica for nearly 15 years. I had an opportunity to sample at Palo Verde in July 2023, and I caught a loricariid in the genus Pterygoplichtys using a cast net that I have not seen before. It's obviously introduced in Costa Rica and may even be invasive in the area I sampled given its local abundance there. P. pardalis has been reported from Costa Rica in the past, but I just can't see this as that species. Yes, the spots on the venter look like it could be P. pardalis. However, the dorsal coloration and light spots in the pectoral and pelvic fins are not a good fit for that species. Based on dorsal patterning of light spots, some of which are triangular, I think it is most likely P. ambrosettii. I am curious to see what others think. If it is P. ambrosettii, I can't find any previous observations of this species in Costa Rica. It's not recognized by FishBase or Eschmeyer's Catalog of fishes as occurring in Costa Rica, either. The overall coloration is not terribly consistent with other photos of the species, although this may reflect the heavily tannin-stained water in which I found the fish (i.e., it may exhibit this more "washed out" coloration in water with very low visibility and light penetration). On the other hand, maybe I just haven't come across similar photos of this species yet.
Any thoughts?
Very best,
Reuben R. Goforth, Ph.D.
