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

ribbed and so similar to Septirhynchia that they are regarded as members of the same subfamily (M. Mancenido, pers. comm.) but does not possess ventral median septum; a feature shared with Lessiniella. The phylogenetic relationships (ancestry) of Lessiniella are not clear (just as those of Septirhynchia) but the external resemblance to some Early Paleozoic pentameroid genera is astonishingly strong. As a matter of special interest, it may be mentioned that the Silurian genera Harpidium and Lissocoelina show so close external similarity to the new genus as if their photographs shown in the Treatise (Amsden & Biernat 1965, figs. 416/5a, 6) were made of the type specimens of Lessiniella. Distribution: So far, Lessiniella is known only from the Callovian of the Southern Alps (Italy). Holotype: Museo dei Fossili della Lessinia (Velo Veronese, Verona, Italy), Inventory number: CC 100 Cv-B (Plate I., Fig. la-e). - Locus typicus: Covolo di Camposilvano (Lessini Mts., Southern Alps, Italy). - Stratum typicum: Callovian, red, nodular linestone. Derivatio nominis: after the name of Cavalière Attilio Benetti, who collected the type specimens. Diagnosis: Large sized Lessiniella with no ribbing, poorly developed dorsal fold and ventral sulcus, anterior commissure parasulcate. Material: 5 specimens, partly incomplete. Dimensions (mm): length width thickness *-Approximate Description - External characters: This is a large Lessiniella and tends to be giant sized in late adult or gerontic stage. The general constitution is robust, gibbose, with massive, incurved beak. The outline is drop-shaped; the lateral margins are slightly divergent, almost straight, the anterior margin forms a half-circle. Both valves are strongly convex but the maximum convexity is nearer to the anterior margin in the brachial valve, whereas it is at the posterior one-third in the pedicle valve. The degree of convexity seems to be constant or slightly decreasing during the ontogeny. The umbo is very massive, the beaks are strongly incurved (even the concealed beak of the brachial valve, as revealed by the serial sections). The character of the pedicle opening and the delthyrium can not be seen externally but the cross-sectioned paratype showed a circular, hypothyridid foramen of about 2 mm in diameter, facing posteriorly. The blunt beak ridges are long and run to the antero-lateral extremities. The poorly delimited planareas are rather deep. The lateral commissures are sinuous; they run on the deepest line of the planareas; at mid-length they bend dorsally, then become straight. At the anterolateral extremities the lateral commissures deflect ventrally and immediately afterwards they pass into the dorsal uniplication of the anterior commissure. In spite Lessiniella benettii sp. n. (Plate I., Figs. 1-3) holotype sectioned paratype juvenile paratype 48* 34* 24 38* 27 18 36 25 19