A recent paper published in the October issue of Cretaceous Research describes an exciting newly discovered fossilized beetle. The fossil representatives of the new beetle are not commonly found or well studied, making this an especially interesting find. The authors, David Peris and Enrico Ruzzier, claim that this beetle does not fit into the current classification system and outlined new criteria for sorting certain families of beetles into groups.
Mordellidae is a family of beetles which includes approximately 2400 living species. There are two main subfamilies; Ctenidiinae with only a single species, and Mordellinae which holds the remaining species. The newly found species was classified as a Mordellidae because of its wedge-shaped body, well developed coxal plates (a hardened area where the hip joint is formed), and a ridge of spines on the outer surface of the hind, lower leg. According to several specialists in the field spine ridges are the most important feature for separating the Modellinae family into more specific taxonomical groups. These ridges present in various lengths, directions, and numbers depending on the species.
The fossil found in the Peñacerrada I outcrop in Spain was the first Spanish beetle ever described in amber. Amber, fossilized resin from trees produced during the Tertiary period, is a very successful medium for preserving bugs. The fossil was dated to the Albian, a period in the early Cretaceous. This was the most primitive beetle studied thus far in Cretaceous amber. The specimen was found to have unique characteristics undescribed in other similar species. Because of these characteristics a new tribe – a taxonomic unit between subfamily and genus – called the Mediumiugamiini was created to accommodate for these differences.
There are still representatives of Mordellidae in the world today. Living, adult Mordellidae can be found living on herbaceous flowers or on dead or dying trees. Larvae typically feed on rotting wood and on fungi. The group is also known as the “tumbling flower beetles” because of the irregular movements they exhibit when escaping predators.
Peris, D., & Ruzzier, E. (2013). A new tribe, new genus, and new species of Mordellidae (Coleoptera: Tenebrionoidea) from the Early Cretaceous amber of Spain. Cretaceous Research, 45, 1-6. Retrieved from: http://www.sciencedirect.com/science/article/pii/S0195667113001110
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