It's usually easy but this one has me doubting, has me stumped a little. These two are CCB siblings and both are large, approx. 6". They molted at about the same time as far as the last molt goes, I didn't keep up with number of molts. One shows some characteristics of not being mature yet, it has a more narrow carapace, lighter color, a little plumpish looking and much lighter telson, the telson is a little small too. But telson color varies enough that I've seen adults with that color telson also. So I'm not absolutely sure it's mature yet. Any opinions?