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

The type is Pachydiscus neubergicus after the subsequent designation of DE GROSSOUVRE (1894). The species is the index of the widely accepted Lower Maastrichtian Neubergicus Zone. According to HENDERSON & KENNEDY (1986) P. neubergicus is a junior objective synonym of the practically forgotten ammonite, Ammonites chrishna FORBES, 1846. ICZN opinion, 1519 (1989) gives precedence over the name of FORBES. Five ammonites, found earlier in the Rendek Member of the Polány Marl Formation in Sümeg, stored in the Hungarian Geological Institute, were originally determined as P. neubergicus (HAAS et al. 1984). These fossils were recendy re-evaluated as Pachydiscus precolHgatus COLLIGNON, 1955 and Eupachydiscus levyi DE GROSSOUVRE, 1894 by YAZYKOVA (in: BODROGI et al. 1997), characteristic for the Early Campanian. Pachydiscus levyi was also determined by SUMMESBERGER (in: SlEGL-FARKAS 1997). (The very same specimen of P. leyyi was illustrated three times. For references see the synonym list.) It is not known, whether the five ammonites mentioned above and the fauna described in this paper came from the same ammonitiferous level, or only from the same formation. Determination of Pachydiscus species is complicated due to the appearance of the commonly demonstrated microconchs (bearing no lappets) and the existence of the too many names in the literature, without indication of precise stratigraphie occurrence. The Sümeg material, stored in the Hungarian Natural History Museum, was ranged into two taxa: P. cf. levyi DE GROSSOUVRE and P. cf. precolHgatus COLLIGNON. They differ in size of the conch, the relative size of the umbilicus and also in ornamentation. The possible existence of macro-, and microconchs were recognised. Pachydiscus cf. levyi DE GROSSOUVRE, 1894 (Plate II, Plate III: 1) 1894 Pachydiscus Levyi nov. sp. — DE GROSSOUVRE, p. 178, pi. 21, pi. 30, figs. 1, 2. 1932 Pachydiscus aff. Leiyi DE GROSSOUVRE — COLLIGNON, p. 23, text-fig. 2, pi. 6, figs 3, 3a. 1938 Eupachydiscus Levyi DE GROSSOUVRE — COLLIGNON, p. 14, pi. 3. figs. 3, 3a. 1955 Pachydiscus Levyi DE GROSSOUVRE — COLLIGNON, p. 34, text-fig. 5. ? 1980 Eupachydiscus levyi (DE GROSSOUVRE) — BLASZKIEWICZ, p. 41, pi. 34, figs. 1, 2. ? 1986 Eupachydiscus cf. levyi (DE GROSSOUVRE) — KENNEDY, p. 163, pi. 5, figs. 1, 2. 1997 Eupachydiscus levyi DE GROSSOUVRE — YAZYKOVA (in BODROGI et al.) p. 693. 1997 Pachydiscus levyi DE GROSSOUVRE — SUMxMESBERGER (in SIEGL-FARKAS), p. 85, pi. 8, figs. 1-3. 1998 Eupachydiscus levyi (DE GROSSOUVRE) — SUMMESBERGER (in SIEGEL-FARKAS & SUMMESBERGER), p. 266, pl. 1, figs. 1, 2. 1998 Eupachydiscus levyi (DE GROSSOUVRE) — YAZYKOVA (in BODROGI et al.) p. 1191. pl. figs. 1 a-d. Material — Six specimens (M.63.1344, M.63.1345/1, M.63.1358, M.53.1359/1, M.63.1359/2, M.63.1361/1). Measurements: D WH WW U M.63.1344 ?235 ?99 ?52 73 192 82 ?50 55 M.63.1345/1 128 59 ?24 35 107 45 ?20 26 M.63.1358 256 104 ?61 77 225 96 57 98 M.63.1369/2 176 76 ?32 45 144 65 ?30 39 M.63.1361 231 85 ?36 70 194 77 ?34 52 Description — Medium to big-sized internal moulds. The largest specimen (M.63.1358) is probably adult, however not complete. All are slighdy to strongly deformed and the innermost whorls cannot be studied. Coiling is relatively evolute, compared to other representatives of the genus. The umbilicus is moderately shallow, the umbilical wall is steep, the umbilical edge is rounded. The flanks are flat, the venter is rounded, the cross section is high oval. The ornamentation is not well visible on the inner and middle Explanation to Plate II 1 Pachydiscus cf. levyi De GROSSOUVRE, 1894 (M.63.1344), x 1. — A probably adult phragmocone, with a part of the body chamber (arrow indicates its beginning); lateral view. On the surface of the body chamber trace fossils can be seen. The inner side of the empty shell was probably inhabited, and later the attached organism was eaten by a bottom dweller animal. Subsequently, the shell was filled by limy mud. The results are well preserved, round-shaped, densely packed, slighdy convex domes.