Palaeontinidae
| Order | Hemiptera |
| Age | ~170–125 Ma (Jurassic–Early Cretaceous) |
| Wingspan | Up to ~15 cm |
| Diet | Plant sap (piercing-sucking mouthparts) |
| Fossil Sites | Karatau, Yixian |
The Palaeontinidae were large hemipteran insects that superficially resembled enormous cicadas. Living during the Jurassic and into the Early Cretaceous, they had wingspans reaching up to 15 cm and were among the largest Hemiptera ever known. Their piercing-sucking mouthparts were used to feed on the sap of gymnosperm trees.
Description
Palaeontinids had broad wings held roof-like over the body, much as modern cicadas hold their wings. The wing venation was distinctive and well-preserved in limestone and shale fossils from Karatau in Kazakhstan and other Jurassic deposits. Some species had wingspans of 12-15 cm — roughly three to four times the size of the largest modern cicadas.
Like all Hemiptera, palaeontinids had piercing-sucking mouthparts (a rostrum or "beak"), which they used to penetrate plant tissues and feed on sap. Their large size suggests they fed on sizable gymnosperm trees, which would have provided an abundant sap supply.
Ecology
As plant sap feeders, palaeontinids occupied a similar ecological niche to modern cicadas and large plant-feeding bugs. Given their size, they would have been conspicuous members of Jurassic forest communities and likely produced sounds, as modern cicadas do, though there is no direct fossil evidence of sound-producing structures.
Decline and Extinction
Palaeontinids declined during the Early Cretaceous and went extinct by the mid-Cretaceous. Their disappearance may be linked to the rise of flowering plants and the decline of the gymnosperm forests on which they depended. Modern cicadas (family Cicadidae), which are not closely related to palaeontinids despite superficial similarities, rose to prominence later.