title: Specialized proteinine rove beetles shed light on insect-fungal associations in the Cretaceous.
abstract: Insects and fungi have a long history of association in shared habitats. Fungus-feeding, or mycophagy, is remarkably widespread in beetles (Coleoptera) and appears to be a primitive feeding habit that preceded feeding on plant tissues. Numerous Mesozoic beetles belonging to extant fungus-associated families are known, but direct fossil evidence elucidating mycophagy in insects has remained elusive. Here, we report a remarkable genus and species, Vetuproteinus cretaceus gen. et sp. nov., belonging to a new tribe (Vetuproteinini trib. nov.) of the extant rove beetle subfamily Proteininae (Staphylinidae) in Mid-Cretaceous Burmese amber. The mouthparts of this beetle have a markedly enlarged protruding galea bearing an apparent spore brush, a specialized structure we infer was used to scrape spores off surfaces and direct them into the mouth, as in multiple modern spore-feeding beetles. Considering the long evolutionary history of Fungi, the Mid-Cretaceous beetles likely fed on ancient Basidiomycota and/or Ascomycota fungi or spore-producing organisms such as slime moulds (Myxomycetes). The discovery of the first Mesozoic proteinine illustrates the antiquity of the subfamily, and suggests that ancestral Proteininae were already diverse and widespread in Pangaea before the supercontinent broke up.
authors.affiliation: Key Laboratory of Economic Stratigraphy and Palaeogeography, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, People's Republic of China cycai@nigpas.ac.cn.|State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, People's Republic of China.
authors.forename: Chenyang
authors.identifier: 0000-0002-9283-8323
authors.initials: C
authors.lastname: Cai
authors.affiliation: Integrative Research Center, Field Museum of Natural History, 1400 S Lake Shore Drive, Chicago, IL 60605, USA.
authors.forename: Alfred F
authors.identifier: 0000-0001-9885-6306
authors.initials: AF
authors.lastname: Newton
authors.affiliation: Integrative Research Center, Field Museum of Natural History, 1400 S Lake Shore Drive, Chicago, IL 60605, USA.
authors.forename: Margaret K
authors.identifier: 0000-0003-0061-9981
authors.initials: MK
authors.lastname: Thayer
authors.affiliation: Landcare Research, New Zealand Arthropod Collection, Private Bag 92170, Auckland, New Zealand.
authors.forename: Richard A B
authors.initials: RA
authors.lastname: Leschen
authors.affiliation: State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, People's Republic of China.
authors.forename: Diying
authors.initials: D
authors.lastname: Huang
mesh_terms: D000818:Animals; D005075:Biological Evolution; D001517:Coleoptera / Q000033:anatomy & histology* / Q000145:classification; D005580:Fossils; D005658:Fungi
keywords: Burmese amber; Coleoptera; Cretaceous; Proteininae; Staphylinidae; mycophagy