New material of the Virgilian (Upper Carboniferous) nautiloid cephalopod Brachycycloceras? spectrum Hansman, 1965, from the Necessity Shale and the Finis Shale (the type stratum of this species) members of the Graham Formation in Texas, has prompted a reevaluation of this insufficiently described species. On the basis of morphologic differences between the present material and Brachycycloceras normale Miller, Dunbar and Condra, 1933, the type species of the genus, the species is transferred from its previous placement with reservation to the orthoceratid genus Cryptocycloceras Shimansky, 1968 as C. spectrum (Hansman, 1965). Specimens of Cryptocycloceras have been recovered from Russia, and an older, related genus Hidamichelinoceras Niko, 2000 has been recovered in Japan.
How to translate text using browser tools
1 December 2010
Reevaluation of the Late Carboniferous Cephalopod, Brachycycloceras? Spectrum Hansman, 1965 from Texas, USA
Shuji Niko,
ROYAL H. MAPES
ACCESS THE FULL ARTICLE
Brachycycloceras
Cryptocycloceras
Graham Formation
orthoceratid cephalopod
Texas
Virgilian (Upper Carboniferous)