A new genus of Insecta based on egg structure from the Late Cretaceous Klikov Formation of the Czech Republic

Pages	183–193
DOI	10.37520/jnmpnhs.2025.011
Keywords	Fossil insect egg, Late Cretaceous, Czech Republic
Citation	HEŘMANOVÁ, Zuzana a KVAČEK, Jiří. A new genus of Insecta based on egg structure from the Late Cretaceous Klikov Formation of the Czech Republic. Journal of the National Museum (Prague), Natural History Series. Prague: National Museum, 2025, 194(1), 183–193. DOI: https://doi.org/10.37520/jnmpnhs.2025.011. ISSN 1802-6842 (print), 1802-6850 (electronic). Also available from: https://www.nm.cz/en/periodicals/journal-of-the-national-museum-prague-natural-history-series/194-1/a-new-genus-of-insecta-based-on-egg-structure-from-the-late-cretaceous-klikov-formation-of-the-czech-republic

Journal of the National Museum (Prague), Natural History Series | 2025/194/1

A new genus, Regentus gen nov., is established here based on species originally described as Spirellea trebecensis, hence the new combination Regentus trebecensis (Knobloch et Mai,1986) comb. nov. The material was collected and prepared by E. Knobloch from the Klikov Formation, from fluvial lacustrine sediments of upper Turonian – Santonian age, located in the South Bohemian Basins, Czech Republic. Regentus trebecensis fossils are broadly elliptical in outline, hollow inside, with a ribbed surface. Their apical end shows ridges irregularly arranged, pointing towards the tip; the ridges on the basal end form an irregular star-shaped structure. The wall of the fossil shows regular perforations arranged in two parallel rows leading from the inside to the surface. Regentus trebecensis was originally described as a seed, related to recent Stemonaceae Caruel. R. trebecensis resembles Stemonaceae seeds in shape and longitudinally ribbed surface. However, R. trebecensis lack an aril and uniseriate or vesicular hairs originating from hilum, raphe or micropyle, the characteristic for Stemonaceae seeds. The presence of perforations in the fossil wall precludes its interpretation as a fruit or seed. The shape and structure of the perforations resemble aeropyles of insect eggs, particularly the air-containing meshwork of insect eggs (e.g. Phasmatodea, Lepidoptera); this led us to interpret the studied fossils as insect eggs. The diversity of insect eggs resembling seeds is high, although no insect group with features exactly matching the fossil material has yet been identified.

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