Szabó János szerk.: Fragmenta Mineralogica Et Palaentologica 19. 2001. (Budapest, 2001)

whorls, but the existence of straight, radial ribs can be confirmed. Straight, or slighdy prorsiradiate intercalatories may appear. Ribs seem to cross the venter. In later stages, and especially on the adult (or subadult) body chamber, primary ribs are distant, rising from minute, later from more developed umbilical bullae. At the end of the adult body chamber the ornamentation seems tend to be smoother. The changing of the style of ribbing, the appearance of the umbilical nodules can be seen very well on the type of DE GROSSOUVRE, too. This way of changing of the ornamentation appeared on the specimen M.63.1345/1 also, however at much smaller size (Plate III: 1). Therefore this mould is regarded as a possible microconch, while the rest of the ammonites are probably macroconchs of considerably bigger size. The suture line is very complex, however due to the strong subsolution, details can not be studied. Remarks — The species is close to the similarly built Pachydiscus perfidus GROSSOUVRE. Latter has a stronger ribbing, especially near to the ventro-lateral border (for illustrations, see BLASZKIEWICZ, A. (1980)). Comparison with some poorly known ammonites, including Pachydiscus brandti var. pégoti DE GROSSOUVRE, is given in the original description of DE GROSSOUVRE. Distribution — According to BLASZKIEWICZ, A. (1980) P. levyi occurs in the Lower Campanian Gonioteuthis quadrata Zone of the Vistula river valley (Poland) and also in the Lower Campanian of France and Russia. P. perfidus, a taxon close to the discussed species, is an Upper Campanian faunal element. Pachydiscus cf. precolHgatus COLLIGNON, 1955 (Plate 1:3-4, Plate III: 2-4) 1955 Pachydiscus precolHgatus nov. sp. — COLLIGNON, p. 64, pi. 21, fig. 1, pi. 25, figs. 2,3 1955 Pachydiscus Gignouxi nov. sp. — COLLIGNON, pi. 25, fig. 1, 1997 Pachydiscus precolHgatus COLLIGNON — YAZYKOVA in BODROGI et al., p. 693. 1998 Pachydiscus precolHgatus COLLIGNON — YAZYKOVA in BODROGI et al., p. 191. Material — Eight specimens (M 63 1345/2-6, M 63 1360/1-2, M 63 1361/2). Measurements: D WH WW U M.63.1345/3 127 58 ?28 30 ti 105 53 ?26 23 M.63.1360/1 84 42 18 17 it 64 32 14 14 Description — Moderately evolute, medium-sized internal moulds. Most of the ammonites are presumably immature macroconchs or fragments of them, except one specimen (M.63.1360/1, Plate I: 3.), which is probably an adult, nearly entire microconch. The umbilicus is rather shallow, the umbilical wall is deformed, but seems to be arched. The walls are slighdy convex, or nearly flat, the ventral region is rounded. The cross section is high oval. The ornamentation of the inner whorls can not be studied. At about 9 centimetre of diameter, the ribbing is built up by simple, prorsiradiate ribs originating from minute umbilical nodules. One or two intercalaries between each primaries, born in the lower third part of the wall, nearly as strong as the primaries, exist. At later stages, the ribs are straight, radial, or slighdy prorsiradiate, and less expressed. The umbilical bullae diminish also. The ventrolateral region seems to be epecially smoother (M.63.1345/3, Plate III: 4.). The supposed microconch shows a similar style of ribbing as the inner part of the macroconch of similar size (e.g. M.63.1

345/4, Plate III: 3.), but the ribbing tends to disappear on the end of the fragment, on the second part of the probably adult body chamber. Suture is complex, typical for the genus, but due to the poor state of preservation, cannot be studied in details. Explanation to Plate III 1 Pachydiscus cf. levyi DE GROSSOUVRE (M.63.1345/1), X 1. — Probably adult microconch, with the part of the fragmentary body chamber (bar indicates its beginning); lateral view. 2 Pachydiscus cf. precolHgatus COLLIGNON, 1955 (M.63.

1345/5), X 1. — Fully septate, strongly deformed specimen; lateral view. 3 Pachydiscus cf. precolHgatus COLLIGNON, 1955 (M.63.1345/4), X 1. — Fully septate, fragmentary specimen; lateral view. 4 Pachydiscus cf. precolHgatus COLLIGNON, 1955 (M.63.1345/3), X 1. — Fully septate, fragmentary specimen; lateral view; bar indicates beginning of body chamber.