title: Cretaceous environmental changes led to high extinction rates in a hyperdiverse beetle family.
abstract: BACKGROUND
  As attested by the fossil record, Cretaceous environmental changes have significantly impacted the diversification dynamics of several groups of organisms. A major biome turnover that occurred during this period was the rise of angiosperms starting ca. 125 million years ago. Though there is evidence that the latter promoted the diversification of phytophagous insects, the response of other insect groups to Cretaceous environmental changes is still largely unknown. To gain novel insights on this issue, we assess the diversification dynamics of a hyperdiverse family of detritivorous beetles (Tenebrionidae) using molecular dating and diversification analyses.
  
  
  RESULTS
  Age estimates reveal an origin after the Triassic-Jurassic mass extinction (older than previously thought), followed by the diversification of major lineages during Pangaean and Gondwanan breakups. Dating analyses indicate that arid-adapted species diversified early, while most of the lineages that are adapted to more humid conditions diversified much later. Contrary to other insect groups, we found no support for a positive shift in diversification rates during the Cretaceous; instead there is evidence for an 8.5-fold increase in extinction rates that was not compensated by a joint increase in speciation rates.
  
  
  CONCLUSIONS
  We hypothesize that this pattern is better explained by the concomitant reduction of arid environments starting in the mid-Cretaceous, which likely negatively impacted the diversification of arid-adapted species that were predominant at that time.
authors.affiliation: INRA - UMR 1062 CBGP (INRA, IRD, CIRAD, Montpellier SupAgro), Campus de Baillarguet, Montferrier-sur-Lez, 34988, France. kergoat@supagro.inra.fr.
authors.forename: Gael J
authors.initials: GJ
authors.lastname: Kergoat
authors.forename: Patrice
authors.initials: P
authors.lastname: Bouchard
authors.forename: Anne-Laure
authors.initials: AL
authors.lastname: Clamens
authors.forename: Jessica L
authors.initials: JL
authors.lastname: Abbate
authors.forename: Hervé
authors.initials: H
authors.lastname: Jourdan
authors.forename: Roula
authors.initials: R
authors.lastname: Jabbour-Zahab
authors.forename: Gwenaelle
authors.initials: G
authors.lastname: Genson
authors.forename: Laurent
authors.initials: L
authors.lastname: Soldati
authors.forename: Fabien L
authors.initials: FL
authors.lastname: Condamine
mesh_terms: D000818:Animals; D044822:Biodiversity; D005075:Biological Evolution; D001517:Coleoptera / Q000145:classification / Q000235:genetics*; D005580:Fossils; D007313:Insecta / Q000235:genetics; D010802:Phylogeny