Aspidoceras, Zittel, 1868

Cecca, Fabrizio & Savary, Bérengère, 2007, Palaeontological study of Middle Oxfordian- Early Kimmeridgian (Late Jurassic) ammonites from the Rosso Ammonitico of Monte Inici (north-western Sicily, Italy), Geodiversitas 29 (4), pp. 507-548 : 536-537

? Aspidoceras gr. binodum (Oppel, 1863) ( Fig. 7A)

MATERIAL EXAMINED. — MI4N 6F/2.

STRATIGRAPHIC DISTRIBUTION. — The specimen has been collected in bed 6f of section Monte Inici, which is assigned to the upper part of the Transversarium Zone, Schilli Subzone, because of the occurrence of G. devauxi in beds 6c and 8a. This specimen could therefore represent the oldest record of the genus Aspidoceras . Olóriz et al. (1999: 91) stress the FAD of Aspidoceras gr. binodum at the bottom of the Bimammatum Zone or even in the Hypselum Subzone. In the Subbetic Zone the genus Aspidoceras appears in the upper part of the Bifurcatus Zone with A. sesquinodosum (Fontannes, 1876) whilst A. binodum appears at the base of the Bimammatum Zone ( Olóriz et al. 1998). New findings of better-preserved specimens are needed to confirm this early occurrence of Aspidoceras .

DESCRIPTION

Fragment of the internal mold of an individual that reached a diameter of at least 100 mm. The whorl section is depressed, with rounded venter and flanks. A row of tubercles is developed right below the lower half of the flank. A periumbilical row of tubercles is also developed but poorly visible due to insufficient preservation of the umbilical edge. No sutures are visible.

DISCUSSION

The aspect of the whorl section associated to the rows of tubercles strongly recall A. binodum . Nevertheless, the identification of our specimen is purely tentative because of its incomplete preservation.