First Australian amber fossil of Podonominae (Diptera: Chironomidae) from the late Middle Eocene

Abstract

A non-biting midge of the cosmopolitan family Chironomidae (Podonominae) is recorded in amber from the Anglesea Coal Measures, southeastern Australia. The new morphotype is likely a new species but is not formally described here because of insufficient diagnostic character states. To date, only five amber deposits in the Northern Hemisphere have yielded fossils of Podonominae, making our discovery the first amber-hosted representative of the group from the Southern Hemisphere. The single adult male individual has been assigned to the subfamily Podonominae, and shows similarities to the Austrochlus cluster group including small size, the lack of veins R2 + 3, and the distally located cross-vein m-cu. Synchrotron X-ray microtomographic imaging reveals some internal structures of the wing musculature and brain capsule, highlighting the taphonomic significance of this unique specimen. Maria Blake* [ maria.paulsen@monash.edu ], School of Earth, Atmosphere and Environment, 9 Rainforest Walk, Monash University, Clayton, Victoria, 3800, Australia Enrique Peñalver [ e.penalver@igme.es ], Instituto Geológico y Minero de España, CSIC, Valencia, Spain Jeffrey D. Stilwell [ jeffrey.stilwell@monash.edu ], School of Earth, Atmosphere and Environment, 9 Rainforest Walk, Monash University, Clayton, Victoria, 3800, Australia, and Australian Museum, Australian Museum, 1 William Street, Sydney, NSW 2010, Australia Joseph J. Bevitt [ jbv@ansto.gov.au ], Australian Centre for Neutron Scattering, Australian Nuclear Science and Technology Organisation, Lucas Heights, New South Wales, Australia Daniel J. Bickel [ Dan.Bickel@australian.museum ] Australian Museum, 1 William Street, Sydney, New South Wales, 2000, Australia.