Szabó János szerk.: Fragmenta Mineralogica Et Palaentologica 26. 2008. (Budapest, 2008)

Sculpture — Smooth shell with fine growth lines (visible by magnification). Their shape indicates almost tangential peristome, consisting of strongly opisthoclineprosocyrt spiral and umbilical, and strongly opisthocyrt outer side components. Remarks — The holotype shows a peculiar phenomenon: on the inferable spire side (dextral case), the outer angulation is somewhat sharper than that of the opposite side of the whorl. This is uncommon, because these morphological elements usually develop equally in the other almost bilaterally symmetrical species. These shell parts are not comparable in the other available specimens. In the studied material, one of the similar species is Discohelix sima n. sp. (see above), having also growth-lines as the only ornament. However its shape is considerably different because all teleoconch whorls are weakly carinate and sharp along the outer angulations while uncarinate and blunt in Discohelix stolic^kai n. sp. Discohelix stolic^kai n. sp. is comparable also to the Late(?) Sinemurian Discohelix inornata SZABO, 1979 (see below) that may have also only growth-lines as ornament. However, the adult diameter in the latter species is much larger; the shell is more flattened (spiral angle smaller, umbilical angle wider), number of whorls is similar (9-10 in D. inornata) but their width is larger; the outer side of the whorls are less convex in all growth stages than in Discohelix stolic^kai n. sp. The sutures in D. inornata just overlap angulations of previous whorl (« flush) but do not coincide with angulations (= impressed) in Discohelix stolic^kai n. sp. An adult D. inornata specimen has trumpet like peristome while the available Discohelix stolic^kai n. sp. specimens do not show any trace of this character. Distribution — Hallstatt, Hierlatz Alpe, Upper Sinemurian (Oxynotum Zone). Figure 7 — Discohelix stoliczkai n. sp. — A-B: umbilical side of holotype, xl and xl.7; C: spiral side of holotype, xl.7; D-G: paratype, umbilical and outer side views; xl (D- E) and xl.7 (F-G). Discohelix lobitzeri n. sp. (Figure 8) Holotype — NhM 2007/0101/0006, paratype: NhM 2007/0101/0005 Type locality — Hallstatt, Hierlatz Alpe. Type strata — Upper Sinemurian (Oxynotum Zone) Hierlatz Limestone. Name — Dedicated to Harald LOBITZER, geologist of the Geologische Bundesanstalt. Diagnosis — Depressed, biconcave shell of rather narrow whorls. Angulations distinct along all teleoconch whorls but carinae present only on early juvenile shell. Periodically repeating, flat, ribbon-like, posteriorly sloping, suture to suture/outer angulation belts follow each-other "telescopically" on spire and umbilical side, and then rapidly fade away on outer side along angulations. Anterior edge of belts riblet-like; these riblets regularly corrugate outer angulations on spire whorls but become wide, sparse and irregularly repeating ribbons on last whorl. Material — Two fragmentary

7 specimens with shell pieces; the better preserved sides of theirs are visible in Figure 8. Measurements H HI HPW D W AS holotype *6.5 *19 *4.4 +*210° paratype - - - *20 - +

*215° AS values valid if Discohelix lobit^eri n. sp. was dextral; ++ or the complementary angles of AS must be regarded as AU in sinistral case. AU ++ ++ Shape — Nearly bilaterally symmetrical, medium size species in Discohelix. Visible post-protoconch whorls of available specimens have less steeply sloping walls then subsequent ones, this way indicating probable elevated side of protoconch, and spiral side at the same time. This way dextral coiling seems more feasible but identification of spiral and umbilical sides remains still somewhat uncertain because earliest shell parts covered by not removable matrix pieces in both specimens. Poorly preserved protoconch of paratype visible in rather deeply sunken position that suggests possibility of sinistral nature, but leaving also question of coiling direction uncertain. Whorls narrow, their number relatively large (9-10); spiral and umbilical side of whorls flat, excepting last whorl where feebly concave. Outer angulations distinct on full length of teleoconch; carinae present on angulations of early spire whorls, lacking from last ~3 whorls; outer side rather convex. Last whorl expanding, cross-section of holotype on damaged terminal shell part shows thickening at outer side, (inferably) near outer lip of last peristome. Suture weakly impressed (asymmetrically). Sculpture — Spiral and umbilical side ornamented by regularly repeating, narrow, collabral belts, following each-other as roof tiles. These appear on juvenile shell as weak corrugation of keels on outer angulations and gradually extend to adaxial sutures but remain