ASAPHOID TRILOBITES FROM THE ARENIG–LLANVIRN OF THE SOUTH CHINA PLATE

Abstract:  Twenty-nine Arenig and Llanvirn trilobite species, representing 20 genera in the Asaphidae, Cyclopygidae, Dikelokephalinidae, Nileidae, Raphiophoridae, Remopleurididae, Taihungshaniidae and Trinucleidae, are treated in a taxonomic review of the South Chinese Asaphida. This review is based on large collections of trilobite material made from five formations at nine localities in western Hubei, northern Hunan and southern Shaanxi, representing a wide range of benthic marine environments across the Yangtze Platform and Jiangnan Transitional Belt regions of the South China Plate. Most South Chinese representatives of the Asaphidae are reassigned to the Nobiliasaphinae on the basis of cranidial and hypostomal characters, and taxonomic revisions are given for Liomegalaspides and Opsimasaphus pseudodawanicus . Taihungshania shui and T . tachengssuensis are revised and redescribed, and the establishment of lectotypes for these species and T . brevica clarifies the status of the type material of Taihungshania . Nileus walcotti is revised and restricted biogeographically to the South China Plate; material from Xinjiang previously assigned to this species is reassigned to N .  sericeus sp. nov. The new raphiophorid species Raphioampyx sinankylosus is described. Aocaspis , Incaia and Raphioampyx are recorded for the first time from South China, and the latter two genera are also recorded for the first time from the Arenig.