Rediscovery of the Mathieu collection of Carboniferous (Pennsylvanian)–Permian (Cisuralian) arthropods from the Kaiping Coalfield (northeastern China)

Numerous arthropods (e.g. branchiopods, insects) collected during the first half of the 20th century by F.-F. Mathieu within the Pennsylvanian–Cisuralian (Moscovian–Asselian) succession of the Zhaogezhuang colliery (Hebei Province, China), romanised notably as Chao Ko Chwang, or Chaokochuang, in the literature, have been recently located in the palaeontological collections of the Royal Belgian Institute of Natural Sciences (Brussels). This historical material from one of the classic localities of the Kaiping Coalfield includes a large number of wings of stem-Dictyoptera, mainly from the Tangshan Formation and to a lesser extent from the Kaiping and Zhaogezhuang formations. The exceptional richness in insects of a particular horizon developed within the Moscovian part of the Tangshan Formation was already pointed out at the end of the 1920s by the French palaeoentomologist P. Pruvost, who provided the first account on the arthropods of Mathieu’s collection from the Kaiping Coalfield. This singular Dictyoptera material was later studied by D. Laurentiaux in his unpublished Ph.D. thesis. In order to promote the revision of Mathieu’s collection by specialists, we provide here a detailed scientific background and re-illustrate the arachnids (and formerly alleged ones: (Poliochera vel Curculioides) [sic] pustulatus Laurentiaux-Vieira & Laurentiaux), branchiopods (Lioestheria? mathieui (Pruvost)), and insects from the Zhaogezhuang colliery, notably using the Reflectance Transformation Imaging methodology.