Euaspidoceras cf. radisense (d’Orbigny, 1850)

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

Euaspidoceras cf. radisense (d’Orbigny, 1850) ( Fig. 12C )

MATERIAL EXAMINED. — MI4N 8 “top”/8.

STRATIGRAPHIC DISTRIBUTION. — The specimen has been collected at the top of bed 8 of section Monte Inici East, assigned with doubt to the Hauffianum Subzone of

the late Oxfordian Bimammatum Zone. The holotype of E. radisense comes from of the Bimammatum Zone, probably the lower part ( Hantzpergue 1994).

DESCRIPTION

Evolute shell of about 92 mm of diameter. The whorl section is subrectangular, with flat flanks, rounded ventrolateral margins and a large, rounded venter. The umbilical area is badly preserved, but the umbilical margin appears to be rounded and the umbilical wall is seemingly vertical. Small, rounded tubercles are developed on the umbilical margin of the last whorl. Shallow ribs are visible in the last portion of the last whorl. Due to the lack of any traces of suture line the diameter of the beginning of the body chamber cannot be observed. Measurements: see Table 20.

DISCUSSION

Despite its insufficient preservation this specimen shows the characteristics of d’Orbigny’s species. Clambites clambus (Oppel, 1863) shows morphological similarities, namely the shape of the whorl section and the presence of shallow ribs. However, it differs because umbilical tubercles are almost absent.

Figures

FIG. 12. — A, Physodoceras cf. wolfi (Neumayr, 1873), specimen MI4N 8c/3 from bed 8c of section Monte Inici East; B, Benetticeras cf. benettii Checa, 1985, specimen MI4W 8c top/1 from bed 8d of section Monte Inici East; C, Euaspidoceras cf. radisense (d’Orbigny, 1850), specimen MI4N 8 “top”/8, from bed 8top of section Monte Inici East. All figures natural size. Arrows indicate the beginning of the body chamber.