A giant Jurassic hunter: the earliest dipluran and its implications for hexapod body pattern evolution

Abstract

Abstract Hexapoda comprises the hyperdiverse insects and three cryptic, early-diverging lineages, Protura, Collembola, and Diplura, that are key to understanding the hexapod body pattern but remain extremely rare as fossils. Here, we report the earliest dipluran, Sinojapyx giganteus gen. et sp. nov., from the Middle Jurassic Daohugou Biota (approx. 165 Mya). Its ectognathous mouthparts challenge the conventional view that all non‑insect hexapods are entognathous, providing solid evidence that entognathy evolved independently at least three times. The pincer‑like cerci of Sinojapyx are symmetrical and lack denticles, representing a transitional state preceding the sophisticated predatory appendages of extant japygoids. Exceeding 5 cm in body length and equipped with robust mandibles and pincer-like cerci, this giant soil dweller occupied the apex of the soil food web in the Jurassic, filling a niche typically held by scorpions or centipedes today. This discovery not only bridges a major gap in the dipluran fossil record but also offers critical insights into the ancestral body pattern of non‑insect hexapods and soil trophic networks in the Jurassic.