ONTOGENY AND RELATIONSHIPS OF THE TRILOBITE PSEUDOPETIGURUS PRANTL AND PŘIBYL
The ontogeny of Pseudopetigurus deprati Turvey et al., 2006 from the Ordovician Dawan Formation (Arenigian), Anhui Province, South China, is described. The presence of an anterior cranidial border in Pseudopetigurus is recognized for the first time. On account of the short (tr.), spindle-shaped anterior border, and the distinct, steeply inclined, wall-like pygidial margin, Pseudopetigurus is assigned to the family Dimeropygidae, the first genus of this family endemic to Gondwana. It has previously been regarded as a member of family Isocolidae. Cladistic analysis of species assigned to Dimeropygidae supports the monophyly of a clade including Dimeropyge, Dimeropygiella, Ischyrotoma, Pseudohystricurus and Pseudopetigurus, which may represent a subfamily Dimeropyginae. The distribution of Dimeropyginae shows a predominantly palaeotropical distribution, while the Gondwana Pseudopetigurus must have diverged from the dimeropygine common ancestor in pre-Arenigian time.
Document Type: Research Article
Affiliations: 1: Department of Earth Sciences, Nanjing University, 22 Hankou Road, Nanjing 2100093, China;, Email: [email protected] 2: Department of Palaeontology, The Natural History Museum, London SW7 5BD, UK;, Email: [email protected] 3: Institute of Zoology, Zoological Society of London, London NW1 4RY, UK;, Email: [email protected]
Publication date: May 1, 2006