Sanmartinoceras aff. walshense (ETHERIDGE, 1892) from the Early Cretaceous of California - the first evidence of the ammonite subfamily Aconeceratinae SPATH, 1923 in North America

Abstract

Sanmartinoceras aff. walshense (ETHERIDGE, 1892), a single large representative of the Aconeceratinae SPATH, 1923 from California is believed to be a macroconch. It shows close relations to Sanmartinoceras africanum KENNEDY & KLINGER, 1979 and Sanmartinoceras walshense, however the described combination of features is unique. Until the variability of this ammonite is established we assign this specimen to Sanmartinoceras aff. walshense. It is probably Late Aptian in age and represents the first evidence of the Aconeceratinae in North Americ