7.3.1. Class and order Protura (proturans)

Proturans are small, delicate, elongate, mostly unpigmented hexapods, lacking eyes and antennae, with entognathous mouthparts consisting of slender mandibles and maxillae that slightly protrude from the mouth cavity. Maxillary and labial palps are present. The thorax is poorly differentiated from the 12-segmented abdomen. Legs are five-segmented. A gonopore lies between segments 11 and 12, and the anus is terminal. Cerci are absent. Larval development is anamorphic, that is with segments added posteriorly during development. Protura either is sister to Collembola, forming Ellipura in a weakly supported relationship based on entognathy and lack of cerci, or is sister to all remaining Hexapoda. (See also Box 9.2)


  The extant Hexapoda

Chapter 7