Vörös A. szerk.: Fragmenta Mineralogica Et Palaentologica 16. 1993. (Budapest, 1993)

FRAGMENTA MINERALOGICA ET PALAEONTOLOGICA 16. BUDAPEST L993. p. 27-50 Hettangian (Early Jurassic) brachiopod fauna of the Bakony Mts. (Hungary) by A. DULAI Abstract: Up to now onlv sporadic Hettangian brachioDods were Known írom ihe Bakonv Nits. During a new collection, a surprisingly rich brachiopod fauna was lound at 13 localises ot the Bakony Mts. Fifteen Hettansian oracniopoo taxa are described, belonging to 5 genera. Some ot them are not determinable exactly owing to the bad preservation. INTRODUCTION The Hettangian Kardosret Limestone Formation is widespread in ihe Bakony Mts. but it contains scarce and badly preserved megafauna. The crisis at the Triassic/Jurassic boundary resulted in extremely poor faunas in Hettangian formauons (Michalik et al. 1991) and there are very few data about Hettangian fossils in ihe literature. Therefore the Hettangian brachiopods of the Bakonv Mts. were poorly known. Bockh (1874) described the characteristic Hettangian Terebramla ovatissimaeformis and Terebramla (Waldheimia) Bakonica n. sp. from Som-hegy and Tűzküves-hegy. Koch (1875) mentioned the former species from Kőris-hegy, Szépalmapuszta and Szesztra-hegy. Kovács (1931) listed some Late Triassic and Hettangian forms from Hamuházi-hegy (Zeilleria elliptica. Terebramla grezana. Terebramla ovatissimaeformis

). Noszky (1972) mentioned a great number of Hettangian brachiopod species from the Bakony but some of those were originated from Sinemurian rocks. Haas et al.

(1984) listed a rich brachiopod fauna from the Városierdő near Sümeg but their material is predominantly Sinemurian in my opinion. There are also very few data about Hettangian brachiopods in the other areas of the Mediterranean region. Gaetani (1970) described a rich silicified Hettangian material from Bergamo, in which there were four brachiopod species (Calcirhynchia rectemarginata, Cuneirhynchia latesinuosa, Lobothyris ovatissimaeformis, Zeilleria perforata). Michalik et al. (1991) examined the brachiopods of the Triassic/Jurassic boundary in the Tethys region. They mentioned Gaetani's four species and Lobothyris ovatissimaeformis, Zeilleria perforata from Bakony. They also referred to Hettangian brachiopods from the Western Carpathians, Outer Dinarides and Sicily but without mentioning names. Besides there are only sporadic references in some Sinemurian or Pliensbachian works. Hettangian brachiopods were collected recently at 13 localities of the Bakony Mts. (Text-fig. 1). About 90% of the collected fauna consists of brachiopods (562 specimens) but two-thirds of the collected brachiopods are undeterminable. Among the determined brachiopods terebratulids are prevailing (96.3%), rhynchonellids are rare (3.1%) and spiriferids are insignificant (0.5%). The determined brachiopod fauna is dominated by Lobothyris ovatissimaeformis (67%).