Szabó János szerk.: Fragmenta Mineralogica Et Palaentologica 26. 2008. (Budapest, 2008)
angulations with carinae appear on second whorl, collabral ornament visible from third whorl, and consisting of narrow, posteriorly clipping, suture to suture collabral riblets, following each other like roof-tiles. Abaxial end of single riblet strengthens into small knob on keel, men dying out rapidly outward. Riblets divided by extremely fine growth-lines. These collabral elements of ornament regularly repeating up to last whorl, where substituted by marked growth-lines, and carinae of angulations become less distinct. Strong growthlines appear firsdy in bundles that strengthen into low ridges subsequently. In last growth phase, gradually increasing nodes of angulations accompany ridges. Outer side shows only fine growth-lines, with few faded spiral lines. Remarks — The available stratigraphically oldest (Late Sinemurian) and youngest (Davoei Zone) specimens show significant differences that mean refinement and weakening of the sculpture. Arriving in Davoei times, the collabral riblets become narrower and attain 2 or 3 times bigger number per whorls. The ridges and the nodes of the last whorl are less marked and appear rather as weak undulations. There are also differences between the contemporaneous (Late Sinemurian) North Alpine and Bakony Mts specimens: the earlier ones have weaker collabral riblets than those from the latter area. From the further published D. excavata occurrences, the East Atlas one, described by DARESTE DE LA ClIAVANNE (1920), significantly differs from the others. In the North African forms the strong nodes on the angulations appear much (1 or 2 whorls) earlier that may result also in a taxonomical conclusion. The identification of the adult specimens does not present difficulties. This species, having a characteristic, strongly nodosed sculpture on the last whorl, is easily distinguishable from the similarly sized other species. A B Figure 5 — Discohelix excavata (REUSS, 1852). — 12 a-c: STOLICZKA's (1861) figures from Tafel III; A-C: xl dorsal (A), spire (B) and umbilical (C) view of the neotype; D-F: spire (D), "aperture" (E) and dorsal (F) view of GBa 2008/69/34/1/2 (paraneotype) specimen; G: magnified (x3) spire view of the neotype to show details of the ornament. C )n the last two whorls of Discohelix miocarinata SZABÓ, 1979 the angulations become rounded, and no nodes are present. On the other hand, juvenile specimens are rather hard to distinguish. The measurements provide the most reliable tool to do it; ratio of height to the diameter is significantly smaller in D. miocarinata. The adult specimens differ from the similarly shaped, Aalenian D. levis WENDT, 1968, because this latter has angulations without nodes on its last whorls and a peristome, which is reinforced outward by a varix. In this comparison, the distinction of the stratigraphically younger, juvenile D. excavata specimens, having almost as delicate bars as growth lines of D. levis, is problematic. Distinction from Discohelix sima n. sp.: see below. The small adult specimens of D. acarinata SZABÓ, 1979 with their rounded angulations without carinae can be easily distinguished from juvenile D. excavata. Distribution — Northern Calcareous Alps, Upper Sinemurian; \ r edana (Southern Alps), Pliensbachian; East Sicily (Galati), Upper Pliensbachian; East Atlas, Pliensbachian; Bakony Mts, Upper(?) Sinemurian to Lower Pliensbachian (Davoei Zone). Discohelix sima n. sp. (Figure 6) Holotype — GBa 2008/69/34/2/1. Type locality — Hallstadt, Hierlatz Alpe. Type strata — Sinemurian (Oxynotum Zone) Hierlatz Limestone. Name — Sima (Hung.) = smooth.
