Szabó János szerk.: Fragmenta Mineralogica Et Palaentologica 26. 2008. (Budapest, 2008)
distinguish the juvenile specimens of Pentagonodiscus reussii and Pentagonodiscus initiopentagonatus SZABÓ, 1979. Probably the measurements could help but the latter species has yet been known only in two specimens of rather poor preservation. The specimen, figured by CONTI & MONARI (1994) using open nomenclature, belongs certainly to Pentagonodiscus réussi because the cross section shows the characteristic inner shell morphology of the species (see also WENDT 1968, text-figs. 2G, 3P, 5). The diameter fairly exceeds that of the similarly shaped juvenile part of Pentagonodiscus initiopentagonatus that ma} 7 have also similar inner varices (in the latter species the cross-section, perpendicular to the coiling axis, has yet been unknown). Distribution — Hall statt, Hierlatz Alpe, Upper Sinemurian (Oxynotum Zone); Galati (Eastern Sicily, Italy), Upper Pliensbachian; Central Apennines (Italy), Pliensbachian; Bakony Alts (Hungary), Upper(?) Sinemurian to Lower Pliensbachian (Ibex Zone); Western Pontids (Turkey), Pliensbachian. => __ Figure 15 — Pentagonodiscus reussii (HÖRNES, 1853) (A-J and probably also L), and Discohelix aff. ornata (HÖRNES, 1853) (M-O that are the photos of the specimen, figured in STOLICZKA's Tafel III, 14 d); apart from "K", all figured specimens are probably syntypes of Euomphalus reusii HÖRNES, 1853 species, saved in STOLICZKA (1861) "originals collection" as Discohelix réussi HÖRNES, 1853. — 13, 14 a-d: copy of STOLICZKA's (1861) original figures from Tafel III; A-D: lectotype, selected by Wl.XDT (1968), with marked spiral ornament; spiral (A, C) and apertural (B, D) views, A-B = xl, C-D = x3; E-J: a paralectotype (GBa 2008/69/35/2) with obscure spiral ornament in spiral (E, I), umbilical (F, J), apertural (G) and dorsal (H) views, E-H = xl, I-J = x3; K: one of the Sümeg (Bakony Mts) Pentagonodiscus reussii specimens (HGM) with feebly concave, almost plane spire ( x 3); L: probably an aberrant shell of Pentagonodiscus reussii having "tetragonal" outline; M-O: a whorl fragment that is not Pentagonodiscus reussii, see above Discohelix aff. ornata; M-N = Xl.O = X3. M Shape — Dextral, discoidal form with slighdy less concave spiral than umbilical side. Coiling of protoconch follows normal logarithmic spiral, with nucleus, slighdy elevated on spiral side, juvenile whorls pentagonal in outline, but normal logarithmical coiling renewed on last two whorls. However, arrangement of sculpture on last two whorls retains pentagonal symmetry 7 . Angulations distinct and carinate on teleoconch. Whorls flat on spiral and umbilical sides, convex on outer side. Peristome and inner morphology of shell unknown. Sculpture — Because of strong re-crystallisation, sculpture of protoconch cannot be studied, only some uncertain portions of spiral lines are visible. From third whorl, more distinct spiral lines visible on whorl-surface. From penultimate whorl onwards, these lines arranged into pairs. Pairs 3 to 4 times more widely spaced than distance between them. On spiral and umbilical sides 6 of these paired lines appear. Outer side covered by dense, evenly spaced lineation. Simultaneous!}" with spiral lines, tiny transverse ribs appear that slighdy strengthen towards keels. On penPentagonodiscus initiopentagonatus SZABÓ, 1979 (Figure 16) 1979: Pentagonodiscus initiopentagonatus sp. n. — SZABÓ, p. 27, pi. 2, figs. 6—7; (text)fig. 6h. 1994: Pentagonodiscus initiopentagonatus SZABÓ — CONTI & MONARI, p. 201, pl. 1, fig. 3. a t e r i a 1 — Single specimen with preserved juvenile and damaged adult whorls (HGM J 9594). Measurements H HI HPW D W AS AU holotype (HGM J 9594) *9.8 - *20 *6.8 218°
