A new dameselloid trilobite from the Fulu Biota, Longha Formation (Cambrian: Guzhangian), Yunnan, South China, and revised classification of dameselloids

Abstract

A new dameselloid trilobite, Leishuia leishuae n. gen. n. sp., from the Fulu Biota in the Longha Formation (Cambrian: Guzhangian) in southeastern Yunnan, South China, is described. At least six dameselloid trilobite genera are represented in the Fulu Biota. Leishuia n. gen., Karslanus, and Teinistion show a natant hypostomal condition, whereas Bergeronites, Damesops, and Palaeadotes show a conterminant hypostomal attachment condition. The discovery of two forms of hypostomal attachment in dameselloid trilobites warrants reinterpretation of the classification of the group. A revised classification of the superfamily Dameselloidea is proposed. It includes two families, Damesellidae and Dorypygellidae, and three subfamilies belonging to Damesellidae, Damesellinae, Drepanurinae, and Bergeronitinae n. subfam. The Dameselloidea embraces dameselloids characterized by having a hypostome in conterminant attachment and lacking a preglabellar field; and the Dorypygellidae, which have a hypostome in natant attachment and have a preglabellar field. The new subfamily, Bergeronitinae, is characterized by having macropleural segments in the thorax and pygidium, and a conterminant hypostomal condition.