Kaszab Zoltán (szerk.): A Magyar Természettudományi Múzeum évkönyve 73. (Budapest 1981)

Szabó, J.: Lower and Middle Jurassic Gastropods from the Bakony Mountains (Hungary). Part III.: Patellacea and Trochacea (Archaeogastropoda)

Genus PROCONULUS COSSMANN, 1918 Proconulus epuloides sp. n. (Plate I: figs. 2-3) Holotypus : Plate I : fig. 2-3 — Locus typicus : Eplény, Manganese Mine — Stratum typicum: vertical fissure-filling limestone. — Derivatio nominis: similar to the species Epulotrochus epulus (D'ORBIGNY) — Diagnosis : high conical or somewhat cyrtoconoid spire with somewhat acute juvenile whorls; the last one or two of the whorls are slightly concave, the others are flat; inner lip with callus Measurements: H HL HA D WA Plate I: fig. 2-3: 36.5 11.5 6.5 19.5 9.5 35° Material — One of the 22 specimens is an inner mould, the others are shelly specimens, of which some are excellently preserved. Shape — Dextral, high conical or slightly cyrtoconoid spire with somewhat acute juvenile shell. The surface of the whorls are flat, except the last whorls of the adult specimens, which are slightly concave. The periphery is sharply angulate, like a carina on the adult specimens. The basis is flattened, anomphalous, the aperture with strongly opisthocyrt outer (basal) lip. At the foot of the columella, there is a distinct callus. Ornament — It consists of fine growth lines being prosocline on the whorls and opisthocyrt on the basis. The adult whorls and mainly the basis show obscure spiral lines too. Remarks — The shape of the shell is similar to Epulotrochus epulus (D'ORB.) species. Beside the not too considerable difference between the measurements of the two species, Proconulus epuloides sp. n. has a callus and accordingly the species belongs to the genus Proconulus. Existence or non-existence of a callus is the least subjective basis for the distinction of the genera Proconulus and Epulotrochus. Both genera have one species each which are very similar to each other and differ by the mentioned feature only. Owing to this fact it seems to be unjustified to separate the two genera. Distribution — Bakony Mts.: Kericser, beds with mixed Upper Sinemurian to Ibex Zone fauna — Ibex Zone; Eplény, Domerian Proconulus scherinus (GEMMELLARO, 1874) (Plate I: figs. 4-5) 1874: Trochus Scherinus GEMMELLARO, G.G., p. 99, pl. XII, figs. lO.a, b. Measurements: H HL HA D W A Plate I: figs. 4-5 13 4.5 3 7.5 4 35° Material •— Four adult and one juvenile specimens with more or less damaged shells. Shape — Dextral, conical with slightly acute apex. The surface of the whorls are flat or somewhat convex. The periphery is rounded-angular; the base is convex, anomphalous; peristome quadrangular, prosocline, its columellar part has a callus. Ornament — The shell is ornamented by growth lines being prosocline on the whorls and opisthocyrt on the base. Obscure spiral lines appear under magnification also on the whorls along 0.5-1 whorl length. Remarks — The base of a juvenile specimen is striated concentrically, corresponding mostly to GEMMELLARO'S description. The adult specimens are without distinct spiral lines and their form is also slightly different : the surface of the last 1-2 whorls is somewhat more convex and the periphery is more rounded than on GEMMELLARO'S figures. From the species occurring in the Bakony Mts., the juvenile specimens of P. epuloides sp. n. cause difficulty in the separation. Above the measurements, P. epuloides sp. n. has always sharp periphery. Distribution — Sicily: Chiusa Sclafani, "Terebratula aspasia Zone"; Bakony Mts.: Sümeg? Upper Sinemurian; Kericser, Ibex Zone Proconulus epuliformis sp. n. (Plate I: figs. 6-8) Holotypus : Plate I: fig. 6. — Locus typicus: Bakonybél, Somhegy — Stratum typicum : horizontal fissure-filling limestone — Derivatio nominis: similarly shaped as "Epulotrochus epulus" D'ORB. — Diagnosis : numerous depressed whorls; flattened base; callus on columellar lip; ornament more or less distinct as spiral threads on the whorls