Rare fossil insect (Zekuforma maculata sp. nov) from the Tibetan plateau unveils adaptive innovations and extinction mechanisms

Ecological adaptive radiation drives evolutionary innovation, yet intrinsic constraints and environmental stressors may dictate its limits. Heteroptera, repeatedly colonized aquatic realms, but their major terrestrial lineage Pentatomomorpha remained confined to land for least 230 million years. We shatter this paradigm with the first semi-aquatic Pentatomomorpha, Zekuformidae fam. nov., an Early Miocene semi-aquatic fossil from Tibetan Plateau. Convergent, it evolved trimerous antennae (extremely short) and subapically inserted pretarsal claws for water-land transitions, yet lacked key adaptations such as hydrodynamic body shapes, elongate legs for propulsion, and hydrophobic setae. Mid-Miocene aridification from Tibetan uplift extinguished its wetland habitat, dooming this "evolutionary dead-end." This discovery reveals four independent aquatic origins in Heteroptera, exposing how selection and constraint govern ecological transitions.