 |
| Sinojapyx giganteus Wang, Cai, Sánchez-García, Sendra & Huang, 2026 Palaeoecological reconstruction by Jie Sun. |
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.
Keywords: diplura, hexapod evolution, mouthpart, entognathy, grasping apparatus
 |
| General habitus of Sinojapyx giganteus (holotype, NIGP205729) from the Middle Jurassic Daohugou Bed. (A) Counterpart, inner view of dorsal aspect. (B) Part, inner view of ventral aspect. (C) Line drawing based on the part with reference to the counterpart; scale bar, 5 mm. |
Systematic palaeontology
Superclass: Hexapoda Latreille, 1825
Class: Diplura Börner, 1904
Superfamily: Japygoidea Lubbock, 1873
Family: Sinojapygidae fam. nov.
Type genus: Sinojapyx gen. nov.
Diagnosis. Body size gigantic, exceeding 5 cm (more than twice the length of typical extant Japygoidea, which are usually < 2 cm); head nearly triangular; mouthparts ectognathous, robust mandibles with large teeth and laciniae lacking pectinate laminae; maxillary and labial palps multi-segmented; abdominal segment IX strongly elongated; segment VIII−X not more sclerotized than the rest of abdomen, with urosternite X partly fused to the pleurite; pincer-like cerci equal, devoid of teeth and denticles.
Genus: Sinojapyx gen. nov.
Type species: Sinojapyx giganteus sp. nov.
Etymology. The prefix, ‘Sino-,’ refers to China. ‘Japyx’ denotes the type genus of the family Japygidae. The gender is masculine.
Sinojapyx giganteus sp. nov.
Etymology. The specific epithet is derived from the Latin word ‘gigante’ which means ‘giant.’ The gender is masculine.
 |
| Phylogenetic and evolutionary context of Diplura. (A) Phylogeny of Diplura showing the phylogenetic placement of Sinojapyx giganteus and Ferrojapyx vivax. (B) Evolutionary context of the cerci in Diplura. |
 |
| Palaeoecological reconstruction of Sinojapyx giganteus, illustrated by Jie Sun. |
Yehao Wang; Chenyang Cai; Alba Sánchez-García; Alberto Sendra and Diying Huang. 2026. A Giant Jurassic Hunter: the Earliest dipluran and Its Implications for hexapod body pattern evolution. Proc. R. Soc. B. 293 (2080): 20261207. DOI: doi.org/10.1098/rspb.2026.1207 [07 Oct 2026]
