SEM images, mouthparts of P. heisei. (A) mandibles, dorsal view; (B) right mandible, mentum and part of maxilla, ventral view; (C–D) labrum-epipharynx, ventral view. Abbreviations: at, apical tooth; bs, basistipes, ca, cardo; clc, curved longitudinal concavity; lml, lamella; lp, labial palp; lr, labrum; mpb, mandibular protuberance; mt, mentum; pll, plate-like lobe; ppf, palpifer; sat, subapical tooth; smdj, secondary mandibular joint.