Overview
- An international team led by Prof. Chenyang Cai and Erik Tihelka formally described Chosha praecursor and published the study in Nature on August 26, 2026.
- The fossils come from calcareous claystone concretions in the Tesnus Formation of the Marathon Uplift in western Texas and preserve fine anatomical detail that had been missed in earlier work.
- Chosha retains six thoracic legs and an ovipositor but also shows segmented abdominal appendages and paddle‑like rear limbs, features that record intermediate steps between crustacean ancestors and modern insects.
- Sediment and anatomical evidence place Chosha in near‑shore, deltaic settings and support a prolonged semi‑aquatic, amphibious lifestyle at the water–land interface rather than an abrupt shift to full terrestrial life.
- Phylogenetic analysis groups Chosha with two other Paleozoic hexapods in a stem insect clade, substantially closing the roughly 80‑million‑year gap between molecular‑clock dates and the early insect body‑fossil record and providing a new calibration point for studies of terrestrialization.