A Polypore Fungus Beetle from the Early Cretaceous of France.

Beetles first appear in the fossil record in the Early Permian. And by the Triassic were already beginning to dominate Insect faunas, with many modern groups in existence by the end of the Cretaceous. However the majority of Beetle groups were defined from extant species, and many are hard to differentiate in the fossil record because of this, with the result that many fossil Beetle groups are not well studied, and fossil collections in museums and universities often include many undescribed Beetles.

In a paper published in the journal Acta Palaeontologica Polonica on 9 August 2013, Carmen Soriano of the European Synchrotron Radiation Facility, DarrenPollock of the Department of Biology at Eastern New Mexico University, Didier Néraudaeu of Géosciences Rennes and the Centre national de la recherche scientifique, Andre Nel of the MuséumNational d’Histoire Naturelle and Paul Tafforeau, also of the European Synchrotron Radiation Facility, describe a Polypore Fungus Beetle from Early Cretaceous Amber from Archingeay-Les Nouillers in the Charente-Maritime Department in southwest France.

The amber is opaque, as is the majority of amber from the Early Cretaceous of France (and Mesozoic amber in general). However it has proven possible to build up three-dimensional models of Insects trapped in such amber using X-ray synchrotron microtomography. This method enables the fossil to be examined at any angle desired, and even for internal features, not usually available to palaeoentomologists, to be examined.

The new Beetle is named Synchrotronia idinineteena, where ‘Synchrotronia’ refers to the European Synchrotron Radiation Facility in Grenoble, where the specimen was detected and reconstructed, and ‘idinineteena’ refers to the beamline in which the specimen was detected and imaged (ID19). It is a 3.2 mm long, 1.4 mm wide Beetle with a narrow head and lateral eyes close to the antennae. Based upon careful examination of the limbs of the specimen it was possible to place it within the Tribe Holostrophini, which is in the Subfamily Eustrophinae of the Family Tetratomidae (Polypore Fungus Beetles). This is not only the oldest known member of the Family Tetratomidae, it is the first Mesozoic fossil to be assigned to the group at all.

3D reconstruction of the holotype of Synchrotronia idinantinensis. Specimen tomographied in beamline ID19 of the ESRF, at 30keV and 5.06 μ voxel size. Scale bar 2 mm. Soraino et al. 2014.

In modern times the Tribe Holostrophini is largely restricted to north and east Asia, with only a single species found in Europe. The Beetles feed on wood rotting Fungi, which would be a plausible diet for a Cretaceous Beetle found in amber (which is preserved tree resin). The specimen is about 140 million years old, dating to a time when the climate was extremely warm, and the amber is believed to have been produced by a Gymnosperm tree living in a warm, humid, estuarine forest.

See also…

A new species of Scarab Beetle from Hardap Province, Namibia.

There are currently eight species of Scarab Beetles in the genus Scapanoclypeus, which is known from Namibia and western South Africa. They are placed within a group of Tanyproctine Scarabs which are found only in Africa.

A new species of Scarab Beetle from the Elandsberg Mountains of the Western Cape, South Africa.                                                    Scarab Beetles of the genus Trichostetha occur across southern Africa, reaching their greatest diversity in...

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