New fossil ephialtitids elucidating the origin and transformation of the propodeal-metasomal articulation in Apocrita HymenopteraReport as inadecuate

New fossil ephialtitids elucidating the origin and transformation of the propodeal-metasomal articulation in Apocrita Hymenoptera - Download this document for free, or read online. Document in PDF available to download.

BMC Evolutionary Biology

, 15:45

First Online: 13 March 2015Received: 23 July 2014Accepted: 24 February 2015DOI: 10.1186-s12862-015-0317-1

Cite this article as: Li, L., Shih, C., Rasnitsyn, A.P. et al. BMC Evol Biol 2015 15: 45. doi:10.1186-s12862-015-0317-1


BackgroundApocrita has a special structure that its first abdominal segment has been incorporated into the thorax as the propodeum. The remaining abdomen, metasoma, is connected to this hybrid region via a narrow propodeal-metasomal articulation forming a -wasp waist-, which serves an important function of providing maneuverability, flexibility and posture for oviposition. However, the origin and transformation of the propodeal-metasomal articulation are still vague. Ephialtitidae, as the basal group of Apocrita from the Early Jurassic to the Early Cretaceous, have shown various types of propodeal-metasomal articulations.

ResultsThis study describes and illustrates two new genera with three new species, Acephialtitia colossa gen. et sp. nov., Proephialtitia acanthi gen. et sp. nov. and P. tenuata sp. nov., collected respectively from the Early Cretaceous Yixian Formation at Liutiaogou and the Middle Jurassic Jiulongshan Formation at Daohugou, both in Inner Mongolia, China. These genera are assigned to the Ephialtitidae based on their complete wing venation, e.g. 2r-rs, 2r-m, 3r-m and 2 m-cu always present in the forewings and Rs, M and Cu in the hind wings. These new fossil ephialtitids have well-preserved propodeal-metasomal articulations indicating metasoma is broadly attached to propodeum.

ConclusionThe broad articulation between the propodeum and metasoma in basal Ephialtitidae, likely passed on from a still more basal family Karatavitidae, suggests three separate pathways of the transformation of the -wasp waist- in three different derived lineages leading from Ephialtitidae to: i Kuafuidae and further to the remaining Apocrita, ii Stephanidae, and iii Evanioidea. In addition, the demise of ephialtitid wasps lagging behind the flourishing of angiosperms suggests that ephialtitid extinction might have been mainly driven by competition with numerous new taxa eg. the abundant Cretaceous xylophilous Baissinae and Ichneumonoidea appeared just before or-and soon after the J-K boundary.

KeywordsNew genera Jiulongshan formation Daohugou Yixian formation Liutiaogou Inner Mongolia Electronic supplementary materialThe online version of this article doi:10.1186-s12862-015-0317-1 contains supplementary material, which is available to authorized users.

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Author: Longfeng Li - Chungkun Shih - Alexandr P Rasnitsyn - Dong Ren



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