Monday 13 January 2014

A fossil Cockroach from the earliest Late Carboniferous of the Ningxia Hui Autonomous Region of northwestern China.

Cockroaches (Blattodea or Blattida) are highly successful non-metamorphic Insects (i.e. their young resemble the adults, there is no distinctive larval stage with a separate morphology) related to Termites and Mantises. Cockroaches are found across the globe, but are most numerous and diverse in the tropics. They are large Insects, with few species reaching sexual maturity while less than a centimeter in length, and some large tropical species reaching around 10 cm in length. The forewings of Cockroaches are modified to provide a protective covering for their hindwings and bodies. The earliest Cockroaches appear in the fossil in the Late Carboniferous, becoming abundant by the end of the period. 

In a paper published in the Journal of Systematic Palaeontology on 11 December 2012, Zhijun Zhang of the Department of Palaeontology at the Geological Museum of ChinaJoerg Schneider of the Department of Palaeontology at the Technische Universität Bergakademie Freiberg and Youchong Hong of the Beijing Museum of Natural History describe a new species of fossil Cockroach from the earliest Late Carboniferous of the Ningxia Hui Autonomous Region of northwestern China.

The new species is named Qilianiblatta namurensis, where 'Qilianiblatta' means Cockroach from the Qilianshan Mountains and 'namurensis' means 'from the Namurian' the earliest Stage of the Late Carboniferous (overlapping the latest Mississippian and earliest Pennsylvanian in American reckoning). The species is described from one whole and one partial right forewing, the intact specimen being about 25 mm in length. Wings, particularly forewings, are typically considered to be enough for taxonomic assignment in palaeoentomology, as wing venation is highly distinctive in Insects. 

Qilianiblatta namurensis, right forewing. Photograph (A) and line drawing (B). Zhang et al. (2012).

The specimens come from the Xiaheyan Village Insect Site, in Zhongwei County in the Qilianshan Mountains, close to the Great Wall of China. This site has produced over 3000 Insect specimens from seven different orders, and is one of the oldest significant Insect producing fossil sites known.

The approximate location of the Xiaheyan Village Insect Site.  Zhang et al. (2012).

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