Fig. 21

Evolutionary scenario of morphological characters of the centipede forcipule (including characters listed by Edgecombe [55] and Haug et al. [28]). Note that the phylogenetic positions of Lithobiomorpha and Craterostigmomorpha are ambiguous (compare Benavides et al. [58]). A (Chilopoda) First trunk segment appendages transformed into forcipules housing venom glands. Three specific types of coeloconica sensilla. Complete tarsungular suture present. Ca and Cl present in the cuticle of the tarsungulum (without any gradient). Moderate sclerotized tarsungulum. Venom gland opening located subterminally and opening dorsally. Joints of telopodite positioned medially. B (Scutigera coleoptrata): Coxosternite medially unfused (potentially plesiomorphic). Coxosternite with four elongate spine-bristles and a corresponding spine-bristle on the forcipular trochanteroprefemur (see Fig. 2B). C (Pleurostigmophora): Coxosternite medially fused featuring a suture. Significantly shorter forcipular femur and tibia. Coxal apodemes on the forcipules. Incomplete tarsungular suture. Strongly sclerotized tarsungulum and joints. Joints of telopodite positioned laterally. D (Lithobius forficatus): Porodont on the lateral part of the forcipular dental margin (see Fig. 4B). Ca as tarsungular gradient. Two differently radiodense layers at the tarsungular tip. E (Phylactometria): Rigid forcipules (pleurite arching over the coxosternite, sclerotized hinge joint between coxosternite and trunk). Na and Zn present in the tarsungular cuticle. F (Epimorpha): Coxosternite medially fused without visible suture. Shared lateral joints from trochanteroprefemur to tarsungulum. Zn present in the tarsungulum featuring a gradient. G (Geophilomorpha): Zn (potentially plesiomorphic) or Cl present in the tarsungulum featuring a gradient