I've only seen a mud darter once, one that Nate Tessler caught and I pictured it. I would say it seems to look the same as my pictures but I also question why it wouldn't be a large female orangethroat. I do think your fish is a mud darter but if someone knows a definate reason why it is a mud and not a female orangethroat I would like to hear or see why. Here is a pic of each from my collection...
Mud Darter from the Wisconsin River, WI
Mud_Darter1_from_the_Wisconsin_River_south_of_Sauk_Prairie_WI_05_08_07_by_BZ.jpg 175.78KB
1 downloads
Female Orangethroat Darter from headwater of Big Darby Creek, OH
female_orange_throat_darter1_Big_Darby_Creek_headwaters_4_8_06_by_JZ.jpg 123.65KB
2 downloads
Edit: I'm not sure the range fits to be a mud darter, that might make me lean toward orangethroat, I'll try to do a little more looking around.