the extinction of the conulariidsconulariids的灭绝.pdfVIP

Geosciences 2012, 2, 1-10; doi:10.3390/geosciences2010001 OPEN ACCESS geosciences ISSN 2076-3263 /journal/geosciences Communication The Extinction of the Conulariids Spencer G. Lucas New Mexico Museum of Natural History, 1801 Mountain Road N.W., Albuquerque, NM 87104, USA; E-Mail: spencer.lucas@state.nm.us; Tel.: +1-505-841-2873; Fax: +1-505-841-2808 Received: 22 February 2012; in revised form: 12 March 2012 / Accepted: 15 March 2012 / Published: 22 March 2012 Abstract: Conulariids are unusual extinct metazoans most often considered to be a group of scyphozoan cnidarians or close relatives. Generally, the temporal range of conulariid fossils is perceived to be late Precambrian or Cambrian to Triassic, though a supposed Cretaceous conulariid from Peru was published 46 years ago. A re-evaluation of this fossil indicates it is not a conulariid, but instead a pinnacean bivalve (Pinna sp.), confirming that the geologically youngest conulariids are of Late Triassic age. However, a review of the Triassic conulariid fossil record indicates it is very sparse, with only eight published records. It does not provide a reliable basis for analyzing the structure of conulariid extinction. Nevertheless, conulariid extinction still appears to have taken place very close to the end of the Triassic. The cause of conulariid extinction may have been the onset of the Mesozoic marine revolution, in which durivorous predators developed new