At last, a Pennsylvanian stem-stonefly (Plecoptera) discovered
1 Key Laboratory of Insect Evolution and Environmental Changes, College of Life Science, Capital Normal University,105 Xisanhuanbeilu, Beijing, 100048, China
2 40 rue d'Aveillans, La Motte d'Aveillans, 38770, France
3 Department of Bioagricultural Sciences and Pest Management, Colorado State University, Fort Collins, CO 80523, USA
4 Department of Biology, Mississippi College, Clinton, MS 39058, USA
BMC Evolutionary Biology 2011, 11:248 doi:10.1186/1471-2148-11-248Published: 31 August 2011
Stem-relatives of many winged insect orders have been identified among Pennsylvanian fossils (Carboniferous Period). Owing to their presumed 'basal' position in insect phylogeny, stoneflies were expected to occur at this period. However, no relative has ever been designated convincingly.
In this paper, we report specimens belonging to a new fossil insect species collected from the Tupo Formation (Pennsylvanian; China). The wing venation of Gulou carpenteri gen. et sp. nov. exhibits character states diagnostic of the order Plecoptera, but lack character states shared by unequivocal representatives of the order. Derived from this identification, the delimitation of the fossil species is ascertained based on comparison of several extant stonefly species. This comparative analysis allowed a trait present in G. carpenteri gen. et sp. nov., but rarely occurring in extant species, to be documented and highlighted as atavistic. Affinities of taxa formerly proposed as putative stem-stoneflies are reconsidered in the light of the new discovery.
Gulou carpenteri gen. et sp. nov. is considered the only genuine Plecoptera reported from the Pennsylvanian. Continuing efforts on the systematics of Pennsylvanian winged insects indicate a fauna more diverse than previously appreciated. It suggests that insects already had a long, yet undocumented, history by this time.