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)
Remarks — The juvenile shell is similar to P. marga (HUDL.), but its whorls are higher, its spiral angle is less than that of P. rimosus sp. n. and the embryonal (or juvenile) shell is without ornament. Proconulus rimosus sp. n. is closest to P. avernus (STOL.), which differs in its measurements and in having a carina on the adult last whorl, too, moreover in the absence of the basal ridge. Distribution — Bakony Mts. : Somhegy, Humphriesianum to Parkinsoni Zone. Genus MURICOTROCHUS COSSMANN, 1918 Muricotrochus aff. subluciensis (HUDLESTON, 1894) (Plate II: figs. 1-2) aff. 1894: Trochus subluciensis HUDLESTON, p. 381, pl. XXXII, figs. 6-7. Material — Five, only partially visible specimens. Shape — Dextral, conical shell with flattened surface over the whorls. Inner space of the volutions is axially depressed elliptic in cross-section. The periphery is angular, the base is slightly •convex, having a shallow depression medially with an umbilicus. The peristome is quadrangular, bearing a callus on its columellar part. Ornament — The whorls are covered by longitudinal, nodose cords. Their number on the last whorl may be five or six. The base is ornamented with fine spiral lines. The growth lines are prosocyrt between the sutures and strongly opisthocyrt on the base. Embryonal shape and ornament — A single fragmentary protoconch is avialable only, lacking the nucleus and roughly the first whorl. The remaining part is conical with flat volutions, its extent is about three whorls. The existing first coil bears a cord with tiny nodes above the suture. The next whorl is covered by fine spiral lines and the first distinct growth lines are visible. Parallel with the latest, small ridges appear periodically on the third whorl, dissecting the cord below the suture. This cord is strengthened from an earlier spiral line together the appearance of the ridges. From the existing fifth whorl, there are not any cord-free bands on the surface of the whorls. Remarks — Owing to the strong ornamentation, the specimens could not be freed from the limestone matrix. The available fragments are indicative of Muricotrochus subluciensis. Distribution — Bakony Mts. : Somhegy, condensed Subfurcatum to Garantiana Zone. Genus DIMORPHOTECTUS COSSMANN, 1918 Dimorphotectus sp. (Plate I: figs. 14-15) Material — A single, fragmentary specimen. Shape — Dextral, slightly cyrtoconoid; the surface of the low volutions is fiat, the periphery is carinated and the base is slightly convex. On the columellar lip, there is a large swelling. Ornament —• It consists of fine growth lines, which are prosocline on the whorls and opisthocyrt on the base. Remarks — Owing to bad preservation, the specimen is not identifiable to species. Its shape is similar to Epulotrochus acteon (D'ORB.) but its columellar swelling suggests another genus. Distribution — Bakony Mts. : Sümeg, ? Upper Sinemurian . Dimorphotectus unicarinatus sp. n. (Plate I: figs. 16-18) Holotype : Plate I : figs. 16-18. —• Locus typicus : Bakonybél, Somhegy—Stratum typicum : horizontal fissure —filling limestone — Derivatio nominis: unicarinatus = having one carina (on the periphery) — Diagnosis : high spire; carinate periphery; riblet-Iike nodes above the suture of every whorl; collabral ribs on the last whorl. Measurements: H HL HA D W A Plate I: figs. 161-18 5.3 3.3 9 5 27° Material — Six, mainly badly preserved specimens. Shape —• Dextral, high trochiform. The shell consists of numerous flat or slightly convex whorls, their inner shape is rounded quadrate in cross-section. The periphery is carinate, sharp, a flattened base is present below it, having a shallow medial depression. The aperture is quadrangular, its columellar margin thickened and bears a tooth-like swelling rather inside from the level of the peristome.
