While I've heard reports of putative Corydoras hybrids, I have never seen any direct evidence of interspecific mating until this past week.
My main tank has a variety of corys - Corydoras panda, C. punctatus, C. arcuatus, C. aeneus, a probable C. trilineatus and another species whose identity I don't know. While I started off with several C. trilineatus, I only have one left. And apparently it's a female.
A few days ago, in a rainy week, one day after doing a water change, I noticed the trilineatus in the t-position that corys adopt while mating - with a panda. She then swam off grasping at least one egg (probably more) between her ventral fins.
While they clearly mated, I have no idea if the eggs would have been fertile. Regardless, I would be very surprised to find any fry. When she tried to place an egg, the rummynoses realised what she was doing, and proceeded to chase her around, hoping for some more eggs, I presume. Even though I tried to distract them by feeding them, the odds of eggs remaining unfound in that tank are probably pretty slim