Vörös A. szerk.: Fragmenta Mineralogica Et Palaentologica 18. 1996. (Budapest, 1996)

Description: Left valve (Pl. I: 9): higher than long, subaequilateral, moderately inflated. Dorsal margin straight. Umbones placed at about the three fifth of the length. Outline relatively regular. Anterior wing large, indistinctly demarcated. Some specimens bearing coarse comarginal plicae confined to the umbonal region. Valves ornamented with numerous fine radial costae, whose number is increasing toward the disc margin by intercalation of new costae gaining rapidly the size of original ones. - Right valve: Only an incomplete specimen is available (Pl. I: 10), which is almost flat and bears fine radial costae. Remarks: The remarkable variability observable within Eopecten has resulted in a plethora of specific names available for European Jurassic representatives of this genus. JOHNSON (1984) found, however, that they can be assigned to three species. Among them only left valves of E. spondyloides (Roemer, 1836) are ornamented with original costae of equal size and with intercalatory costae rapidly gaining the height of originals. The standardized numbers of costae of E. spondyloides (at H: 10 between 22 and 32, and at H: 20 between 30 and 48) (JOHNSON 1984) are, however, much smaller than those of E. johnsoni (at H: 10 about 70 and at H: 20 about 100). Assignement of the Bakony specimens to a new species seems to be therefore well justified. Range and occurrence: Eopecten johnsoni sp. n. is known from the Pliensbachian (Jamesoni to Margaritatus zones) of the Bakony Mts., Hungary. REFERENCES BERNARD, F. R. (1979): Bivalve mollusks of the Western Beaufort Sea. - Contrib. Sei., Nat. Hist. Mus. Los Angeles County, 313: 1-80. CONTI, M. A. & MONARI, S. (1991): Bivalve and gastropod fauna from the Liassic Ammonitico Rosso facies in the Bilecik area (Western Pontides, Turkey). - Geologica Romana, 27: 245-301. DOMMERGUES, J. L., FERRETTI, A., GÉCZY, B. & MOUTERDE, R. (1983): Éléments de corrélation entre faunes d'ammonites mésogéennes (Hongrie, Italie) et subboréales (France, Portugal) au carixien et au domérien inférieur. Précisions sur la limite carixien/domérien en Mesogée. - Geobios, 16 (4): 471-499. DULAI, A. (1995): Preliminary notes on Early and Middle Jurassic corals of the Bakony Mountains (Hungary). - Hantkeniana, 1: 49-58. FUCINI, A. (1895): Fauna dei calcari bianchi ceroidi con Phylloceras cylindricum Sow. sp. del Monte Pisano. -AttiSoc. Tosc. Sc. Nat., 14: 1-229. GALÁCZ, A. & VÖRÖS, A. (1972): Jurassic history of the Bakony Mountains and interpretation of principal lithological phenomena. - Földtani Közlöny, 102 (2): 122135 (in Hungarian). GÉCZY B. (1971a): The Pliensbachian of Kericser Hill, Bakony Mountains, Hungary. Ann. Univ. Sei. Budapest., Sect. Geol., 14: 29-52. GÉCZY B. (1971b): The Pliensbachian of the Bakony Mountains. - Acta Geol. Hung., 15: 117-125. GÉCZY B. (1972): Ammonite faunae from the Lower Jurassic standard profile at Lókút, Bakony Mountains, Hungary. - Ann. Univ. Sei. Budapest, Sect. Geol., 15: 47-76. GÉCZY B. (1974): The Lower Jurassic ammonite faunas of the Southern Bakony. (Transdanubia, Hungary). -Ann. Univ. Sei. Budapest, Sect. Geol., 17: 181-190.