Nebrodites passendorferiiforme Caracuel, Olóriz & Rodriguez-Tovar, 1999

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 : 526-528

Nebrodites passendorferiiforme Caracuel, Olóriz & Rodriguez-Tovar, 1999 ( Fig. 8C )

Nebrodites (Nebrodites) macerrimus (Quenstedt, 1888) – Geyssant 1966: 108, pl. 1, fig. 6.

Non Ammonites macerrimus Quenstedt, 1888 .

Nebrodites passendorferiiforme Caracuel, Olóriz & Rodriguez-Tovar, 1999: 114 , figs 5-14.

MATERIAL EXAMINED. — MI4W 10top/2.

STRATIGRAPHIC DISTRIBUTION. — Top of bed 10 of section Monte Inici East, which has been assigned to the Early Kimmeridgian Platynota Zone, associated with Orthosphinctes (Ardescia) beticus Caracuel, Olóriz & Rodriguez-Tovar , which has been reported from the middle part of the Platynota Zone whereas the type specimens of N. passendorferiiforme have been reported from the upper part of the Platynota Zone ( Caracuel et al. 1999: fig. 2).

DESCRIPTION

Small, evolute shell with subcircular whorls. The ornamentation mostly consists of an alternation of simple and biplicate ribs. These are radial in the inner whorls, becoming slightly prorsiradiate in the last third of the last whorl. Bifurcate ribs branch at the upper third of the flank and are slightly projected forward. Ribs form an adoral convex trend on the venter. Two deep, oblique, constrictions and a weaker one occur on the last whorl. Due to the incomplete preservation, it is impossible to know whether other constrictions occurred or not. Measurements: see Table 13.

DISCUSSION

The described specimen bears a clear macerrimus -like aspect. It is almost identical to the specimen figured by Geyssant (1966: pl. 1, fig. 6). The latter has been implicitely considered different from N. macerrimus because Caracuel et al. (1999) acknowledged that it is possibly conspecific with N. passendorferiiforme , although they did not include it in the synonymy of the latter species. Due to Schweigert & Callomon’s (1997) data about the Late Oxfordian age of the type level of N. macerrimus , a new appraisal of the Early Kimmeridgian specimens ascribed to this species is needed ( Caracuel et al. 1999). The specimen from Monte Inici differs from the type specimens of N. passendorferiiforme for the less numerous constrictions (but note that the shell of our specimen is incompletely preserved).

Figures

FIG. 8. — Nebrodites aff. contortus (Neumayr, 1871), specimen MI4N 8d/2 of bed 8d top of section Monte Inici East; A, lateral view; B, ventral view; C, Nebrodites passendorferiiforme Caracuel, Olóriz & Rodriguez-Tovar, 1999, specimen MI4W 10top/2 from bed 10 of section Monte Inici East; D, Nebrodites cf. hospes (Neumayr, 1873), specimen MI4W 10top/3 from bed 10 of section Monte Inici East; E,?“Passendorferia” aff. teresiformis Brochwicz-Lewinski, 1973, specimen MI4N 8 “top”/5 from bed 8d of section Monte Inici East. All figures natural size. Arrows indicate the beginning of the body chamber.