Mictaceans: Mictacea

Mictaceans (mik-tah-SEE-ans) resemble long, slender shrimps. They range in length from 0.078 to 0.14 inches (2 to 3.5 millimeters). This species does not have a shieldlike carapace covering the head and segmented thorax. However, a plate does cover the head and the first segment of the thorax, which is tightly joined with the head. The head plate covers the sides of head and the bases of the mouthparts. Mictaceans may or may not have stalked eyes. The first pair of thoracic limbs is associated with the mouth. The remaining seven pairs are used for swimming. Pairs 1 through 5, or 2 through 6, are branched, or biramous (BY-ray-mus). Gills are absent. The abdomen is six-segmented. The first five abdominal segments have pairs of uniramous (YU-neh-RAY-mus) or unbranched appendages called pleopods (PLEE-oh-pawds). At the end of the abdomen is a pair of slender biramous appendages called uropods (YUR-oh-pawds). In between the uropods is a slender, taillike segment called the telson. The telson and uropods do not join together to form a fanlike tail.