ok all, here is the info and "answer":
- you've all learned quite a bit and made the best guesses possible! perhaps (as xander included in his guess) it's also somewhat of a track record of putting up "exotic" representatives from a pretty small family overall.
- i sent this photo to richard the day before posting it as well; i came across it through a connection to some colleagues and am in the process of finding out more details. so no, i unfortunately don't have this fish (not that we really have space for it anywhere, haha), and this is another researcher in the photo.
- the fish is, in all likelihood, a crocodile gar "type III" - gator x longnose cross. they do look pretty different from the juveniles we have pictured on LEP.net and primitivefishes.com, but as fish age (particularly in wild conditions) they will look quite different. the croc II is a good example of long-term tracking of pattern changes in a hybrid.
- the fish in the photo would be a naturally occurring example of a gar hybrid, and this is definitely one project (of many) that we would like to tackle in the near future (finding out more about these fish and how consistently they occur and where).
- in terms of diagnoses, it basically looks like a gator in terms of pattern, but the jaws are a little too long (yet too short for a big longnose). the fins are slightly different, but the head is really the giveaway (fins can be quite variable). it truly is an impressive specimen...i hope to get back to Shedd Aquarium to check on theirs in the near future too.
onward to the next one - and thanks to all for their excellent responses!--
--solomon