Protocoleoptera

The Protocoleoptera are the earliest beetles in the fossil record.
"The oldest stem-group coleopterid is early Permian, 280 mya (million years ago)... true Coleoptera did not appear until the Triassic 230mya".

Interpreting the early fossil record of beetles has been difficult because their forewings are modified as elytra. So no wing veins are visible. Wing veins are the main way insect specialists classify insects.

 References 

 Other sources 
 Arnol'di L.V. et al 1977. Mesozoic Coleoptera. transl. 1991. Simthsonian Inst. Libraries & U.S. National Science Foundation, Washington D.C.
 Crowson R.A. 1981. The biology of the Coleoptera. London: Academic Press.
 Ponomarenko A.C. 2003. Ecological evolution of beetles (Insecta: Coleoptera). Acta Zoologica Cracoviensia 46 (suppl.) 316–328.

Category:Beetles