The Bee Fauna of Eocene Fushun Amber (Hymenoptera

The now inaccessible amber deposits of the Fushun coalfield (Guchengzi Formation; Ypresian) represent the only diverse record of Paleogene arthropods from northeastern Asia. Among the wealth of inclusions recovered from the mines before they were closed and filled, only five specimens of bees were discovered. Meager as they are, these samples provide an important paleogeographical point of reference for piecing together the fauna of forest-dwelling bees during and after the Early Eocene Climatic Optimum. Three species in two genera are recorded, one species representing a new extinct genus and tribe of Megachilinae related to Glyptapini, Ctenoplectrellini (here including Aspidosmia Brauns), and perhaps Dioxyini, and the other two species comprising a new genus of the eusocial corbiculate tribe Melikertini (Apinae). The early-diverging tribes of Megachilinae—Glyptapini, Ctenoplectrellini, and the new tribe, all possessing a distinct metatibial scopa—are briefly reviewed. Glyptosmia Engel, n. gen., with Glyptosmia hemiaspis Engel, n. sp., is the sole member of Glyptosmiini Engel, n. tribe. Although it somewhat resembles species of the genus Ctenoplectrella Cockerell (from Baltic, Bitterfeld, Oise, and Rovno ambers), Glyptosmia also shares distinctive traits of Glyptapini (areolate propodeum) and even the cleptoparasitic Dioxyini (tuberculate metanotum). The tribe can be distinguished by the bare compound eyes, dense mesosomal punctation, tuberculate metanotum, areolate propodeum, flattened mesoscutellum with a sinuate apical margin, and characteristically thickened metatibial spurs, among other characters. Two species of the corbiculate bee tribe Melikertini are described, both of the genus Thyreomelikertes Engel, n. gen. Thyreomelikertes lacks the facial protuberances found in genera such as Aethemelikertes Engel, Haidomelikertes Engel, Amelikertotes Engel, or Succinapis Engel and is superficially similar to Melissites Engel or Mochlomelikertes Engel, Breitkreuz, and Ohl, with its long, flattened, and trapezoidal mesoscutellum somewhat reminiscent of the latter genus. The genus is also noteworthy for the putatively plesiomorphic retention of relatively developed grooves on the outer surface of the mandible and dense mesosomal pubescence. The two included species, Thyreomelikertes electrosinicus, n. sp., and T. kongi, n. sp., can be distinguished by size and the development of setae on the meso- and metatibiae. All the individuals are morphologically workers, and so, like all other melikertines, Thyreomelikertes was social and, based on the phylogenetic position of the tribe, presumably lived in anchored eusocial colonies. By contrast, G. hemiaspis was likely a free-living solitary species. The species from Fushun amber are described, figured, and compared with other species of Cenozoic and living bees. The mandibular structure of Thyreomelikertes is unique among Melikertini and permits a fuller description of the diversity of structural homologies across corbiculate bee mandibles

Apoidea · Biology · Fauna · Hymenoptera · Zoology · Ecology · Fossil Insects in Amber · Geology · Insect and Arachnid Ecology and Behavior · Paleontology · Plant and animal studies

• A Monograph of the Baltic Amber Bees and Evolution of the Apoidea (Hymenoptera)

  Open Access•Michael S Engel•Bulletin of the American Museum…•2001

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