Genus Mecistocephalus Newport, 1843

Diagnosis.

Mecistocephalids with at least 45 leg-bearing segments. Two clypeal plagulae, separated by a mid-longitudinal stripe. Spiculum usually present. Buccae with setae at least in the posterior half. Posterior alae of the labrum smooth. Coxosternum of the first maxillae divided, with a mid-longitudinal suture. Coxosternum of the second maxillae undivided; groove from the metameric pore reaching the lateral margin of the coxosternum. Telopodites of the second maxillae well developed, overreaching those of the first maxillae; pretarsus present. Forcipular trochanteroprefemur with a distal tooth and often with another tooth at approximately mid-length. Sternal sulcus of trunk segments furcate or not. Last leg-bearing segment: Coxopleura usually without a macropore distinct from other pores; legs usually as slender in males as in females, with or without one or two short apical spines (Uliana et al. 2007).