R.B. Irmis Michael C. Hansen T.J. Olson D.K. Elliott 2004 <p>Teeth, spines, and dermal denticles of chondrichthyans are reported from the Middle Pennsylvanian (Desmoinesian) Naco Formation of central Arizona. The most common elements are crushing teeth of the cochliodont <i>Deltodus angularis</i>, less common are teeth of <i>D. sublaevis</i>, <i>Venustodus leidyi</i>, <i>Lagarodus angustus</i>, “<i>Cladodus</i>” <i>occidentalis</i>, <i>Petalodus ohioensis</i>, <i>Orodus</i> sp., and Hybodontoidea. Fin spines of <i>Acondylacanthus</i> sp., <i>Amelacanthus</i> sp., and <i>Physonemus</i> sp., and the dermal denticle <i>Petrodus patelliformis</i> are also present. The material of <i>Venustodus leidyi</i> shows for the first time that this animal was heterodont, having arched anterior teeth with a v-shaped profile grading posteriorly into lower crescentic, and finally flattened teeth. <i>Lagarodus angustus</i> is shown to have at least three tooth morphotypes, and a new tooth arrangement is proposed in which small anterior teeth are replaced posteriorly by large crushing teeth arranged in whorls.</p><p class="last">This fauna is similar to others in New Mexico, Colorado, and Ohio and constitutes a western extension of such faunas in North America. In addition, the presence of <i>Deltodus sublaevis</i> and <i>Lagarodus angustus</i> documents a range extension from a known European distribution, reinforcing the cosmopolitan nature of chondrichthyan faunas at this time.</p> application/pdf 10.1671/1978 en The Society of Vertebrate Paleontology Chondrichthyans from the Pennsylvanian (Desmoinesian) Naco Formation of central Arizona article