Hoplites (Hoplites) dentatiformis  Spath, 1925

Measurements	D mm	H/D	T/D	O/D	H/T
Jaffré 2007 p.83	51	0.38	0.40	0.36	0.97
Holotype	60	0.37	0.37	0.30	1.00
CP-629	70 estimated	0.39	0.39	0.30	1.03

Age	Origin
Graviers à Opis, top of dentatus zone and bottom of intermedius zone, Middle Albian	Yonne France

Var.	vectensis	persulcatus	dentatiformis	rudis	maritimus
H/T	1.54	1.28-1.29	0.97-1.03	0.78-0.91	0.69-0.81
T/D	0.28	0.35-0.36	0.39-0.40	0.44-0.54	0.52-0.59

Description. A septate quarter of whorl in whitish phosphate, typical of the "Graviers à Opis" formation of Yonne. The section is trapezoidal, as tall as wide, with slightly convex flanks. The umbilicus slopes at 60° with a rounded edge. Four pinched, slightly proverse tubercles arise on the wall of umbilicus and point on its edge. Each of these tubercles gives a pairs of ribs, irregularly folded forward in the outer half of the flank, giving nine ribs in total. The rib terminations form a 35° angle with the siphonal line and alternate on either side of it. They are very tall, rounded and flattened, spatulate in shape (photo on the right). They define a deep and wide U-shaped groove. We can note that the two ribs before the last one originate from two successive tubercles but meet on the same spatula.

Remarks. Personal finding. Table 3 lists, in increasing thickness, the Hoplites with spatulate and irregularly folded ribs from the top of dentatus zone. They are considered today as variants of H. rudis, which has anteriority (Amédro, 1992; Amédro et al., 2014). Our ammonite is the medium variant of H. rudis. It still exists at the base of the intermedius zone. In thicker variants, the tubercles can move to 50% of whorl height: the ribs then lack space to fold and are instead very inclined from the tubercles, the latter remaining almost radial. Most rudis sold online are actually thick H. benettianus: their short ribs are also very prominent, but they are wider, less elevated, and lack spatulae.