Kaszab Zoltán (szerk.): A Magyar Természettudományi Múzeum évkönyve 72. (Budapest 1980)

Szabó, J.: Lower and Middle Jurassic Gastropods from the Bakony Mountains (Hungary). Part II.: Pleurotomariacea and Fissurellacea (Archaeogastropoda)

the middle of the whorls. However, this latter form, having higher whorls and narrower umbilicus, is easily distinguished from L. somhegyensis sp. n. Distribution — Bakony Mts., Somhegy: Humphriesianum to Garantiana Zones. Leptomaria cf. tardita (SIEBERER, 1907) (Plate III: fig. 4) cf. 1907: Pleurotomaria amalthei var. tardita SIEB. — SIEBERER, p. 19, pi. 2, fig. 2. Measurements: H HL HA W D A Plate III: fig. 4 — 15 11.5 25 Material — A single, poorly preserved specimen. Shape — Dextral form with convex outline of the shell. The surface of the whorls is convex. The broad, flat selenizone runs nearly medianly. Ornament — The whorl-surface is ornamented with spiral threads and growth-lines, and parallelly to these latter, periodical threads of strength similar to that of the spiral threads, are also visible. Remarks — P. tardita (SIEB., 1907) shows characteristic ridges in the shell of the juvenile whorls, but this parts are missing in the here studied specimen, thus no precise identification is possible. However, the dimensions and the last whorl's ornament are similar. Distribution — Bakony Mts., Somhegy: Subfurcatum and Garantiana Zones. Leptomaria sp. (Plate III: fig. 5) Measurements: H HL HA W D A Plate III: fig. 5 22 11 6.5 17 51° Material — Three, more or less fragmentary specimens with shell, and six additional juvenile specimens from Sümeg, which can also be regarded as representatives of this form. Shape — Dextral, conical form with average spire-height. The whorl-section is roundedtetragonal. The whorl-surface and the base are slightly convex. The selenizone is wide, situating in the middle of the whorls. The umbilicus is wide, open, the peristome is unknown. Ornament — The whole whorl-surface, as well as the base, is covered by spiral threads and very fine growth-lines transversely, and transverse lines, which are weaker than the spiral threads. Small tubercles also appear on the intersections of the ornamental elements below the suture and within the band between the selenizone and the umbilicus. Remarks — The specimens are poorly preserved, thus no precise determination is possible. However, these are distinguished from the other studied forms. On the other hand, this form differs from all published figures, therefore represents probably a new species. Distribution — Bakony Mts., Sümeg: Upper Sinemurian (?), Eplény: Domerian. Genus BATHROTOMARIA Cox, 1956 Bathrotomaria aff. subreticulata (D'ORBIGNY, 1850) (Plate II: fig. 1) aff. 1850: Pleurotomaria subreticulata D'ORB. — D'ORBIGNY, p. pi. 392, figs. 1-5. Measurements: H HL HA W D A Plate II: fig. 1 10 6 6.5 14 64° Material — Two damaged specimens with ferromanganese coating. Shape — Dextral form of small size, with gradate shell. A broad, steep ramp runs below the suture, which is, together with the bordering abaxial angulation, less distinct in the young growthstages. The selenizone courses upon the angulation, and below that a flattened band appears subparallelly to the axis and down to the rounded periphery. The base is flat, with a pseudoumbilicus in its centre. The columellar part of the inner lip is somewhat thickened; the outer lip is unknown. Ornament — The whorl-surface and the base are ornamented with spiral threads, interspaces and strength of which are nearly even. These threads are intersecred by riblets and growth-lines.