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

FRAGMENTA MINERALOGICA ET PALAEONTOLOGICA 16. BUDAPEST 1993. p. 51-59 Lessiniella benettii gen. et sp. n., a giant Middle Jurassic rhynchonellid brachiopod from the Southern Alps (Italy) by Attila VÖRÖS Abstract: Lessiniella benettii gen. et sp. n. (Rhynchonellida, Brachiopoda) is described on the basis of specimens found in the Callovian of the Lessini Mts. (Southern Alps, Italy). This very large, smooth, gibbose rhynchonellid shows strong external resemblance to certain Early Paleozoic Pentamerida. The internal features (strong dorsal median septum, long, radulifer crura) seem to connect Lessiniella to the family Septirhynchiidae. An apparent episode of gigantism among the rhynchonellids in the late Middle Jurassic is pointed out; each Tethyan faunal province had its own giant rhynchonellid (NW-European - "R." decorata, Ethiopian - Septirhynchia, Mediterranean - Lessiniella). INTRODUCTION In 1988, during the field-trip of the "Meeting on Bajocian Stratigraphy" the participants were taken to the nice village of Camposilvano (Lessini Mts., Southern Alps, Italy) to a local museum, the "Museo dei Fossili della Lessinia". The curator and owner of the Museum, Cavalière Attilio BENETTI had even a private cave behind his small house built at the foot of a cliff of Jurassic limestones. The knight, after offering some drinks, kindly showed us his rich fossil material collected by himself from the cave (Covolo) and from the wider surroundings. The collection was focused on Jurassic ammonites for the pleasure of the scientific community; the neatly arranged windows of the exhibition showed only one piece of brachiopod, but a bizarre piece, resembling a gryphon's or a giant parrot's beak rather than a true brachiopod. This huge, smooth, pentameroid-like rhynchonellid brachiopod was collected by Mr. BENETTI from the Callovian beds exposed in the cave (Covolo di Camposilvano) together with further four, but smaller specimens of the same species. It was quite obvious that the form was completely different from any other Jurassic brachiopods. The cave exposes a very condensed, Upper Bajocian to Middle Oxfordian red limestone sequence in less than 8 m thickness (see Clari et al. 1984). The approximately 1 m thick Callovian oncoidal-nodular limestone is bordered from below and above by hard-grounds, involving stratigraphie gaps. A condensed and mixed Lower Callovian ammonoid fauna from these beds is listed in Clari et al. (1984). Besides the curious, new rhynchonellid, there were a few dozens of other brachiopods, collected by Mr. BENETTI from the same horizon from the same locality. The majority of them seemed to be determinable with some certainty: Septocrurella ? defluxoides (Uhlig, 1881) Calvirhynchia cf. contraversa (Oppel, 1861) Striirhynchia sp., aff. subechinata (Oppel, 1863)