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| Telmatomyia talbragarica Baranov, McCurry, Amaral, Beattie & Trewick, 2025 Artwork by Valentyna Inshyna |
Highlights:
• This discovery is the oldest Southern Hemisphere record of Chironomidae.
• Podonominae rapidly dispersed from Siberia in Jurassic, or of Gondwana origin.
• Fossil has a unique suction disc—for survival in turbulent environments’.
Abstract
Podonominae, a group of non-biting midges within the Chironomidae family, serves as an important biogeographical model. For a long time, it was believed that Podonominae originated in Northern Gondwana and later spread to Laurasia. However, because the oldest known fossils of this group come from the Jurassic period in Eurasia more recent interpretations have suggested a Laurasian origin.
We present the oldest record of Podonominae from Gondwana, specifically from the Tithonian age (Jurassic) in Australia. This discovery is also the oldest Chironomidae fossil found in the Southern Hemisphere and suggests that Podonominae likely originated in Gondwana. The new fossil represents a highly specialized form of Podonominae, adapted to living in the littoral zones of large lakes. It has adaptations to this environment that are unique amongst Podonominae, and similar to those found in some modern marine Chironomidae species such as Telmatogetoninae.
Graphical abstract
Keywords: Biogeography, Diptera, Podonominae, Jurassic, Gondwana
Systematic palaeontology
Chironomidae (Newman, 1834).
Podonominae Thienemann and Edwards in Thienemann, 1937.
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| Telmatomyia talbragarica (AM F141771), female pupa. A) Habitus B) Terminal disk; C) Terminal disk, with enhanced contrast. |
Telmatomyia gen. nov.
Differential diagnosis.
Diagnosis. Pupa: can be distinguished from any other representative of Chironomidae by its very large size (> 9 mm), almost round thoracic horns with plastron occupying about 70 %–80 % of it, and uniquely modified abdominal segments 8 and 9, which form an oval terminal disc with a suture like articulation between the segments, wider than long, apparently without fringe of terminal setae (although there are setae looking marks around the terminal disk.
Etymology: Telmatomyia, is from the Greek “Telmato-” adjective, “of stagnant water” reflecting the lacustrine nature of the habitat at Talbragar, and “myia” – Greek for “fly”.
Telmatomyia talbragarica sp.nov.
Etymology: from Talbragar formation.
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| Reconstruction of the lake shore of Talbragar Fossil Fish Bed, depicting several Telmatomyia talbragarica pupae attached to a rock underwater. Pair of Orthogonikleithridae fishes are patrolling the waters of the lake, while Rhoetosaurus brownei is approaching the lakeshore, by the grove of “Agathis” jurassica. Artwork by Valentyna Inshyna, used with permission. |
Viktor Baranov, Matthew R. McCurry, André P. Amaral, Robert Beattie and Steven A. Trewick. 2025. The Oldest Gondwanan non-biting midge (Diptera, Chironomidae, Podonominae) sheds light on the Historical Biogeography of the Clade. Gondwana Research. DOI: doi.org/10.1016/j.gr.2025.09.001 [8 October 2025]
