Egg found?

Question

Egg Found   Hi!
I have a painted turtle and a red eared slider in the same tank, and they seem to be getting along fine with each other.  Today, I found an odd shaped stone at the bottom of the tank.  I pick it up, and I am very positive it is an egg!  I didn't notice it til today, so I am not quite sure how long it has been there!  I Googled pictures of red eared slider or painted turtle eggs, and the pictures match my egg!  I am very confused as to how a red eared slider and a painted turtle produced an egg, I didn't even know they were opposite sexes!  I did some research, and it is extremely rare and almost impossible for these two different species to produce offspring! All I want to know is if the baby inside the egg is still alive after sitting at the bottom of the take for about a day or two, and if I should bother trying to care for it.  I am getting ready to put some dirt in a container and bury the egg in it, because I at least know that much about turtle eggs!
Thank you for your time!
-Carlee
P.S. I live in Michigan, and I am also confused as to why the egg has been laid in such a cold time of the year!

Answer
Carlee,   Your research is impeccable. Yes, it is an egg. First we will start with the sexing of your baby's. Take a good look at the front claws. If they are long and the tail is long(kinda) and thin. It is a male. If your nails are short and the tail is stubby or they are laying egg..lol they are female. As far as different species reproducing, this will not happen. Water turtles have been known to mate with other similar species of water turtles but, not able to reproduce. The egg you have is infertile and they always will be, sorry. The laying out of season, remember they are in captivity now and even though they have their body clocks and know when to lay sometimes if all the conditions are right this can happen. This is more common in young turtles. So don't worry everything is fine. A little info real quick. Had this been fertile it would stay at the bottom of the tank. You would set a spot up with sand for them to bury it in until they were born. Good Luck, Tina