Of the otters I have killed the tail was as long as the body and similar to the picture and been dark brown I don’t think it’s a otter. But have been wrong beforeAfter some quick Google fu, I'm leaning Kangaroo.
Muskrat pelts typically don't have tails
Otters are long even body and short more triangular tail.
Wallaby are smaller and are generally short round shape like a plat.