Transactions of the Royal Society of Edinburgh: Earth Sciences

Research Article

Agnostid trilobites from the Arenig–Llanvirn of South China

Samuel T. Turveya1 p1

a1 Department of Earth Sciences, University of Oxford, Parks Road, Oxford OX1 3PR, UK.

ABSTRACT

Agnostid trilobites are relatively abundant and taxonomically diverse in outer shelf facies of the Yangtze Platform and Jiangnan Transitional Belt regions of the South China Plate. Nine Arenig and Llanvirn species, representing at least five genera or subgenera in the Agnostidae, Diplagnostidae and Metagnostidae, are treated in a taxonomic review of the South Chinese Agnostida, based on new material from the Dawan and Kuniutan formations of W Hubei and the Zitai and Jiuxi formations of N Hunan. The new genus Han is established to incorporate the globally youngest known diplagnostid species. The new species Han solo, Geragnostus (Geragnostus) balanolobus and G. (G.) waldorfstatleri are established. G. carinatus is recognised as being based on inaccurately interpreted material, and is only tentatively retained within Geragnostus. Three further taxa represented by poorly preserved material are left in open nomenclature. The geographic distributions of different agnostid species across the South China Plate, and the endemicity to the palaeoplate displayed by all Arenig–Llanvirn South Chinese species, suggest that these agnostids at least were either benthic or epibenthic.

(Received May 05 2004)

(Accepted February 22 2005)

KEY WORDS

  • Geragnostella;
  • Geragnostus;
  • Han;
  • Hubei;
  • Hunan;
  • Micragnostus;
  • Ordovician;
  • Trinodus

Correspondence:

p1 Present address: Institute of Zoology, Zoological Society of London, Regent's Park, London NW1 4RY, UK.