The first report of a macroloxoceratine cephalopod from the North American Mississippian

Abstract

The pseudorthoceratid subfamily Macroloxoceratinae Flower, 1957, comprises a rare group of nautiloid cephalopods homeomorphic with the Actinoceratida in the development of a siphonal canal system. With the exception of Macroloxoceras Flower, 1957, from the Upper Devonian of Colorado and New Mexico, this subfamily has previously been reported only from the Mississippian of Europe. A specimen described herein from the late Viséan–?early Namurian Kennetcook Limestone of the Windsor Group of Nova Scotia, assigned to Campyloceras cf. C. unguis (Phillips, 1836), extends the range of the Macroloxoceratinae into the North American Mississippian. This discovery further provides new data on the complex siphonal morphology of this poorly known group of nautiloids, and supplements the recent documentation of the pseudorthoceratids in the Windsor Group cephalopod fauna (Edgecombe, 1987).