Mortoniceras (Mortoniceras) pricei  (Spath, 1933)

Measurements	D mm	H/D	T/D	O/D	H/T
Holotype	90	0.40	--	0.32	--
RJ-248	187 (166)	0.45	0.22	0.30	2.08

Age	Origin
Limestone bank Top of Argiles tégulines pricei zone, Upper Albian	L'Étape Mathaux, Aube France

Description. A large, slightly worn, discoid ammonite in a block of gray limestone preserved as a base. The shell is replaced by a dark brown patina that hints at the sutures. The last suture shows that the body chamber occupies approximately the last half-whorl. At the beginning of last whorl, the section is globally tall and trapezoidal, with slightly convex flanks converging towards a fastigiate venter. The latter bears a strong siphonal keel with a triangular section. The umbilicus, with its low wall sloping at 70°, is broadly rounded towards the flank. The ribs, already visible in the umbilicus, originate on the umbilical shoulder. They are simple, proverse, slightly concave, and bear a distinct umbilical elevation and a slightly less prominent ventrolateral bulla. On the body chamber, the ventral region rises and rounds, consequently the ventrolateral shoulders become less pronounced. The umbilicus widens and its wall is less steep, at 45°. The overlap of the whorls decreases to 40%. The ribs swell and become more spaced out but are now only visible on the inner half of the flanks. The umbilical tubercles remain, but the ventrolateral ones become indistinct. There are a total of 24 ribs on the last whorl.

Remarks. This is an early Mortoniceras with two tubercles per rib (on each flank). It is the index species of the second zone of the Upper Albian of the Anglo-Paris Basin, after the Dipoloceras cristatum zone. The specimen was found during the excavation of the outflow channel of Temple Lake (also called Aube Reservoir).