Palaeontological study of Middle Oxfordian- Early Kimmeridgian (Late Jurassic) ammonites from the Rosso Ammonitico of Monte Inici (north-western Sicily, Italy)
Author
Cecca, Fabrizio
Université Pierre et Marie Curie-Paris 6, CNRS-UMR 5143 “ Paléobiodiversité et Paléoenvironnements ”, case 104, 4 place Jussieu, F- 75252 Paris cedex 05 (France) cecca @ ccr. jussieu. fr
Author
Savary, Bérengère
Schlumberger Stavanger Research, Risabergveien 3, Tananger, P. O. Box 8013, N- 4068 Stavanger (Norway) BSavary @ stavanger. oilfield. slb. com
text
Geodiversitas
2007
29
4
507
548
journal article
10.5281/zenodo.4651042
1638-9395
4651042
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.