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)

Family Pleurotomariidae SWAINSON, 1840 Genus PLEUROTOMARIA DEFRANCE, 1826 Subgenus PLEUROTOMARIA DEFRANCE, 1826 Pleurotomaria cf. platyspira DESLONGCHAMPS, 1849 (Plate IP. fig. 10.) cf.1849: Plerotomaria debuchi var. platyspira DESL. — DESLONGCHAMPS, p. 94, pi. 16, figs, la-b.: cf. 1853: Pleurotomaria platyspira D'ORB. — D'ORBIGNY, p. 423, pi. 355, figs. 1-4. cf. 1861 : Pleurotomaria Buchi DESL. — STOLICZKA, p. 188, pi. 4, figs. 4-5. Measurements: H HL HA W D A Plate I: fig. 10 7.5 5.5 4.5 11 120° Material — Three poorly preserved, juvenile specimens. Shape — Dextral form with depressed spire. The surface of the whorls is convex, the whorlsection is rounded-pentagonal. The suture runs in a deep groove, and the selenizone is situated in the middle of the whorls. The umbilicus is wide, open. Ornament — The whorl-surface is ornamented with spiral cords, which are intersected by riblets running from the suture to the selenizone. The growth-lines are orthocline on the whorlsurface, opisthocline on the base, and prosocyrt on the umbilical margin, respectively. Remarks. — The poor state of preservation makes the certain determination impossible. On the basis of the previously published figures, broad, flattened ridges occur below the suture, down to the selenizone. The Bakony specimens show small ribs, however the juvenile shells of the tuberculate Pleurotomaria species initially bear ribs at the places of the adult ubercules. The shell of Cyclostomaria suessi differs from this form in having different dimensions and non-angular whorls. Distribution — Bakony Mts., Sümeg: ?Upper Sinemurian. Pleurotomaria anglica (SOWERBY, 1818) (Plate IT. fig. 5) 1818: Trochus anglicus Sow. — SOWERBY, p. 195, pi. 142. 1853: Pleurotomaria anglica DEFR. — D'ORBIGNY, p. 396, pi. 346. 1858: Pleurotomaria anglica Sow. — QUENSTEDT, p. 82, pi. 10, fig. 9. 1861: Pleurotomaria anglica Sow. — STOLICZKA, p. 191, pi. 4, fig. 10. 1894: Pleurotomaria anglica Sow. — PARONA, p. 162, pi. 6, figs. 1-2. 1907: Pleurotomaria anglica Sow. — SIEBERER, p. 14, pi. 1, fig. 3. 1937: Pleurotomaria anglica Sow. — PCELINCEV, p. 19, pl. 1, fig. 1. 1964: Pleurotomaria anglica (Sow.) — SACCHI VIALLI, p. 4. pl. 1, figs. 2a-c. Measurememts: H HL HA W D A Plate II: fig. 5 30 22 47 88° Material — Two (+ one?) fragmentary specimens with shell. Shape — Dextral form with gradate spire. Below the suture runs a narrow ramp of very low slope, which is bordered by a distinctly rounded angulation. The band between this angulation and the periphery is slightly convex, with the broad selenizone coursing on its middle part. The base is somewhat convex, the umbilicus is narrow, open. The outer lip is conspicuously prosocline above the selenizone, and the inner lip, as a rather big callus, overlaps a part of the base and the umbilicus. Ornament — The surface of the whorls, as well as the base, is covered by strong spiral cords. The transverse ornament consists of the growth-lines and distinct, elongate nodes. The growthlines are prosocline above the selenizone, prosocyrt between the selenizone and the periphery, and opisthocyrt on the base, respectively. The ramp of the juvenile whorls shows characteristic "opisthocline-opisthocryt' ' ridges intersecting the course of the growth-lines. These become shorter on the later whorls, tend to restrict to the lower rim of the ramp, and become parallel to the growth-lines in their arrangement. The elements of the row of nodes on the periphery are somewhat weaker and denser. These are slightly elongate transversally, and fade out rapidly toward the selenizone and the base. Remarks — The here described forms — as compared to the type — show slightly bigger spire angle, diameter and whorl-height. Similarly thicker are the PI. anglica of STOLICZKA, PARONA