Archaic sap beetles (Coleoptera: Nitidulidae) as Cretaceous pollinators

Abstract

Kateretidae have been considered a family of generalist (as a whole) fossil pollinator beetles after the description of many fossil species in this taxon from the Upper Cretaceous Kachin amber together with pollen grains from their host plant. But the placement of this group of fossils in Kateretidae remained tentative because some definite characters to be observed in the fossils (e.g., maxillae and genitalia) were almost inaccessible by conventional methods. A recent paper proposed to include most of these fossil “kateretid” genera and species in the newly erected family Apophisandridae among Cucujoidea. The description of the two new genera and species Diopsiretes corniger gen. et sp. nov. and Cornuturetes elaphus gen. et sp. nov. from the same deposit, and the use of synchrotron light to describe the first cited species, combined with the examination of new photographic material of the type of Apophisandra ammytae, allowed us to better define this peculiar group of fossils. We attempt to demonstrate their placement in an extinct basal subfamily in Nitidulidae (Apophisandrinae stat. nov.), with some partially shared plesiomorphic characters of both Kateretidae and Nitidulidae: Epuraeinae, and with a series of convergent morphological characters also shared with other extant anthophagous nitidulids including Nitidulinae: Mystropini and Meligethinae. As such, all the fossil species from the Kachin amber initially described in Kateretidae and recently moved to Apophisandridae, should be included in Nitidulidae: Apophisandrinae.