Orthosphinctes (Ardescia) beticus 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 : 540

Orthosphinctes (Ardescia) beticus Caracuel, Olóriz & Rodriguez-Tovar, 1999 ( Fig. 13C )

Orthosphinctes (Ardescia) betica Caracuel, Olóriz & Rodriguez-Tovar, 1999: 112 , figs 3, 4.

MATERIAL EXAMINED. — MI4N top10/1.

STRATIGRAPHIC DISTRIBUTION. — Top of bed 10 of section Monte Inici East, Platynota Zone. It has been reported from the middle part of the Platynota Zone ( Caracuel et al. 1999: fig. 2).

DESCRIPTION

Evolute, planulate shell. Subelliptical whorl section with slightly rounded flanks that converge towards a rounded venter. The umbilical wall is well developed and the umbilical margin is rounded. The ornamentation is characterized by prorsiradiate ribs, which branch at the outer third of the flank. An intercalatory rib is observed between two bifurcates. At least three constrictions are visible on the last whorl; the deepest one, which is located close to the end of the last whorl, shows a slight adoral convexity. No traces of peristome and sutures are preserved. Measurements: see Table 25.

DISCUSSION

The poor preservation of this specimen does not allow the detailed study of the ornamental characters. It shows strong morphological similarities in both the ornamentation and the shell structure with the specimen studied by Caracuel et al. (1999: figs 3, 4), named O. (Ardescia) beticus . Species of the subgenus Ardescia described by Atrops (1982) from South- East France show different rib characters.

Figures

FIG. 13. — A, Orthosphinctes (Orthosphinctes) tiziani (Oppel, 1863), specimen MI4N 8 “top”/11 from bed 8d of section Monte Inici East; B, Orthosphinctes (Orthosphinctes) aff. fontannesi (Choffat, 1893), specimen MI4N 8 “top”/3, from bed 8d of section Monte Inici East; C, Orthosphinctes (Ardescia) betica Caracuel, Olóriz & Rodriguez-Tovar, 1999, specimen MI4N top10/1 from bed 10 of section Monte Inici East. All figures natural size. Arrows indicate the beginning of the body chamber.