K. Sekiya & R. Machida


Kaoru Sekiya PDF
Ryuichiro Machida Sugadaira Montane Research Center, University of Tsukuba,
Sugadaira Kogen, Ueda, Nagano 386-2204, Japan


Formation of the entognathy of Dicellurata, Occasjapyx japonicus (Enderlein, 1907) (Hexapoda: Diplura, Dicellurata)


The development of the entognathy in Dicellurata was examined using Occasjapyx japonicus (Enderlein, 1907). The formation of entognathy involves rotation of the labial appendages, resulting in a tandem arrangement of the glossa, paraglossa and labial palp. The mandibular, maxillary and labial terga extend ventrally to form the mouth fold. The intercalary tergum also participates in the formation of the mouth fold. The labial coxae extending anteriorly unite with the labial terga, constituting the posterior region of the mouth fold, the medial half of which is later partitioned into the admentum. The labial appendages of both sides migrate medially, and the labial subcoxae fuse to form the postmentum, which posteriorly confines the entognathy. The entognathy formation in Dicellurata is common to that in another dipluran suborder, Rhabdura. The entognathy of Diplura greatly differs from that of Protura and Collembola in the developmental plan, preventing homologization of the entognathies of Diplura and other two entognathan orders.


Entognatha, comparative embryology, mouth fold, admentum, postmentum