Szabó János szerk.: Fragmenta Mineralogica Et Palaentologica 23. 2005. (Budapest, 2005)

Figure 1 — Sketch map, showing the location of Bánd and Devecser localities. Material — Bánd: 14 head, 3 intermediate and 80 tail valves. Description — The head valve is semicircular in outline (Plate I: 4), sometimes with a wide V-shaped posterior margin (Plate I: 1). The surface is ornamented by 6-9 prominent concentric ridges, which are unequally spaced with variable thickness. The secondary ornamental elements are about 70-80 radially arranged and closely spaced granulated striae (see mainly on Plate I: 1; the other two head valves are slightly eroded). The intermediate valves are wide and rounded rectangular in outline (Plate I: 5, 8, 10). 6-9 slightly arched and longitudinally arranged ridges ornament the lateral area. Weaker, radially arranged and granulated striae system can be observed on the surface of the ridges (3—5 granules/ridges; Plate I: 9). Numerous longitudinally arranged, granulated ribs ornament the pleural area. All of the available intermediate valves are strongly fragmented and about 16—20 ribs can be seen on the left or right half of the valve. So, the concluded number of longitudinal ribs may be approximately 32-40. The longitudinal ribs run more or less parallel to each other, but sometimes two ribs fuse together or intercalating ribs appear between them. Slightly weaker concentrical growth lines intersect the longitudinal ribs (24—28). The points of intersections of the two rib systems show strong granules (Plate I: 6—7). Each granule possesses several pores, both on lateral and pleural area. The central pore is the larger macroaesthete and 6—8 smaller microaesthetes can be observed around it. Apophyses (or suturai plates) are triangular but slightly broken. Three—four concentric ridges ornament the postmucronal area of the tail valves (Plate II: 1, 3—4). 28—32 radially arranged granulated ribs ornament the antemucronal area. These ribs are stronger on the tail valve than on the head valve. The radial ribs (Plate II: 6) are slightly diverging, sometimes two ribs fuse together or shorter, intercalating ribs appear between them. Sharp-pointed, backward directed mucro can be seen in the posterior third (Plate II: 2). The apophyses are wide, low and trapezoid-shaped. Remarks — SULC (1934) included very large-sized specimens into this species, which later were classified into L. subcajetanus (D'ORBIGNY, 1852) by LAG HI (1977). However, apart from the smaller size, these two species are very similar. Recent representatives of 7.. cajetanus can also attain large sizes: MALATESTA (1962) mentioned specimens with a total length of 30 mm. LAGH1 (1977) synonymized L. decoratus with L. cajetanus and later several authors followed this opinion (BALUK 1984; STUDENCKA & STUDENCKI 1988; DELL'ANGELO et al. 1999; KRÜH 2003). In some earlier papers SULC (1934), MALATESTA (1962) and BALUK (1971) supposed that L. decoratus (REUSS) is the Miocene ancestor of the Recent L. cajetanus (POLI). The Oligocène L, virgifer (SANDBERGER) has very similar intermediate valves but the tail valve is clearly different: it is longer, lower, and possesses a centrally situated mucro (MALATESTA 1962; STUDENCKA & STUDENCKI 1988). Lepidopleurus sulci was described by BALUK (1971) but this species later was synonymized with L. cancellatus (SOWERBY, 1839) by LAGHI (1977). LAGHI (1977) and DELLANGELO et al. (1998) recognized some morphological differences between juvenile and adult specimens. LAGHI (1977) showed the ontogenetic changes on the tail valve: e.g. the mucro is situated more posteriorly and the outline is more triangular at adult specimens. These features are also variable at the Hungarian valves (e.g. compare Plate II: 3 and 4). MACIOSZCZYK (1988) also mentioned that „apex displaced towards the tail" at larger specimens. The outline of the intermediate valves is just as strongly variable at MACIOSZCZYK's (1988) material, as in the case of the Bánd specimens. KROH'S (2003) specimens correspond to the studied ones; however, two of his specimens are much more eroded. His well-preserved tail valve (KROH 2003; Plate 2: 3) is slightly different, because the granules are separated at the postmucronal area and not arranged into granulated ribs (compare with my Plate II: 1). DELL'ANGELO et al. (1999) mentioned rather large specimens: the maximum size is 8.5 mm at both head and intermediate valves but tail valve is also larger (6.0 mm) than the Bánd specimens. The Bakony Mts intermediate valves are slightly different from the other specimens illustrated in the literature, because of the presence of strong granules at the intersections of longitudinal and concentric ribs. According to BALUK (1971) description the longimdinal ribs are granulated but these granules are not so conspicuous on the Polish specimens. However, the head valves correspond very well