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39 DIAGNOSTIC FEATURES AND DESCRIPTION This crayfish goes under the name of Calico, Papershell or Mud crayfish. Mud crayfish is seen in older literature and this name describes its preferred habitats which are slow moving streams, sloughs, roadside ditches and ponds which are often mud- bottomed. Irrespective of the name used, its markings are not really distinctive. The adults are often a darker mud brown color like that in the photo above. Juveniles like that in the photograph beginning this section tend to show the best coloration which is a mottled light brown. From above, this color pattern provides good camouflage. I have noticed that these crayfish often show a purplish tinge on the bottom of the chelae as this photo shows. As with all crayfishes, their color is the lightest and brightest after a molt which steadily gets darker as algae and crud build up on their carapace. The key identification character of the species is the shape of the first pleopod of a Form I male. This one is quite distinctive from other Nebraska crayfishes in that the corneous tip is short and sharply curved with an almost 90 degree bend. Form II pleopods retain this sharp curve. The two halves of the aureola of the Calico crayfish come close together but do not touch. There is room for two rows of punctuations in the gap between them. The rostrum of the Calico crayfish is broad at the base and tapers towards a terminal spine. It is deeply dished and there are no side spines like those on the Northern crayfish. The chelae or claws of the Calico crayfish are slim with thin, delicate fingers. Just visible in this photo is a row of setae that line the inside edge of the fixed finger. The moveable finger always has an excision or cutout near the base with an opposing tubercle on the fixed finger.