Pictetia depressa  (Pictet & Campiche, 1861)

Measurements	D mm	H/D	T/D	O/D*	H/T
CP-429	46.2	0.44	0.68	0.34	0.64

* O denotes here the internal diameter of last whorl

Age	Origin
Lower Albian O. sinzowi zone P. (H.) puzosianus subzone	North Aktau Range Mangystau peninsula Kazakhstan

Description. A fully septate ammonite, well preserved in a fine, hard glauconitic sandstone, with an intact aperture and a preserved brown shell, except for the last eighth of last whorl. The coiling is criocone, meaning it forms a spiral wound in the plane but with disjoint whorls. Here, the successive whorls are barely separated, with a gap of at most 1 mm, and they increase very rapidly in height and width. Overall, whorl section is kidney-shaped, with a broad, rounded, slightly flattened venter, lacking distinct ventrolateral shoulders, and a slightly convex dorsum, not marked by an impressed area, transitioning to the flanks with a fairly distinct shoulder initially, which then fades with growth. The ornamentation consists only of very fine growth lines, more or less radial on the flanks but forming a convex, spreading sinus on venter. The internal mold, visible near the aperture, is smooth. Sutures are invisible.

Remarks. In the Anglo-Paris Basin, this very rare species is known from fragments in the basal Albian (tardefurcata zone). It is also found in the puzosianus zone in Mangystau (Saveliev, 1992) and in the upper Aptian of Madagascar (Collignon, 1962). Its full vertical range is unknown. It is distinguished from the later P. asteriana (benettianus zone) by its depressed, kidney-shaped cross-section instead of its nearly circular one. The inner whorls are generally in contact up to about 12 mm in diameter (Hoffmann et al., 2009). There may be a slight dorsal concavity, even when the whorls are disjoint. Fine, closely spaced ribs may be present. Specimens are illustrated in Pictet & Campiche (1861), Spath (1923), Casey (1960), Colleté (2010) and Hoffmann et al. (2009, 2013).