Fabrosauridae, the basal family of ornithischian dinosaurs (Reptilia: Ornithopoda)

  • Peter M. Galton
Article

Abstract

In fabrosaurids the upper jaw is flat and the lower jaw is slender so the ’cheek’ teeth are marginal and not inset as is the case in all other ornithischian dinosaurs. The ’cheek’ teeth of fabrosaurids have anteroposteriorly expanded crowns but lack wear surfaces formed by tooth to tooth contact. Two genera are recognized from the Triassic-Jurassic boundary of Lesotho with good material previously referred toFabrosaurus as a new genus that represents the most conservative ornithopod described to date. The anatomy ofNanosaurus (Upper Jurassic, U.S.A.) andEchinodon (Jurassic-Cretaceous boundary, England) is redescribed; in both genera the tooth bearing bone of the lower jaw is deepened posteriorly and inEchinodon there is a true canine tooth in the upper jaw.

Zusammenfassung

Bei den Fabrosauridae ist der Oberkiefer flach und der Unterkiefer schlank gebaut, so daß die »Backenzähne« randlich stehen und nicht wie bei allen anderen Ornithischiern eingelassen sind. Die »Backenzähne« haben in der Längsrichtung gestreckte Kronen, aber keine durch Zahnkontakt gebildete Abkauflächen. Das von der Trias-Jura-Grenze in Lesotho (= Basutoland) bisher alsFabrosaurus beschriebene Material umfaßt eine weitere Gattung(Lesothosaurus n. gen.), welche den altertümlichsten bisher bekannten Ornithopoden darstellt. Die Anatomie vonNanosaurus (Oberjura U.S.A.) undEchinodon (Jura-Kreide-Grenze, England) wird neu beschrieben. Der zahntragende Unterkieferknochen beider Gattungen ist rückwärts eingetieft, während sich im Oberkiefer vonEchinodon außerdem ein richtiger Eckzahn findet.

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Copyright information

© E. Schweizerbart’sche Verlagsbuchhandlung 1978

Authors and Affiliations

  • Peter M. Galton
    • 1
  1. 1.Department of BiologyUniversity of BridgeportBridgeportUSA

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