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

Material — Bánd: 1 tail valve. Description — The outline of the tail valve is semicircular (Plate III: 6). The backward directed mucro is not very prominent between the central part and the posterior third. 8-8 slightly diverging, longitudinally arranged ribs ornament the antemucronal area. The ribs have similar appearance than in the case of C. corallinus, but the smooth ribs are narrower and the porous grooves are much wider here (Plate III: 7). The central part of the antemucronal area seems to be eroded showing large-sized pores. The postmucronal area is ornamented by 18 shallow radial grooves starting from the mucro. Some concentric growth lines also ornament this part. The whole surface of the postmucronal area shows numerous pores and the larger ones seem to be arranged along radial rows (Plate III: 8). The two apophyses are large, very wide, slightly trapezoidal but rounded. A shallow jugal plate connects the apophyses. Remarks — The similar Chiton saeniensis was described by LAGHI (1984) from the Pliocene yellow sands of Siena (Italy). According to LAGHI (1984), his new species is strictly related to C olivaceus SPENGLER and differs mainly in its larger size and lacking longitudinal overturned folds in lateropleural areas. The single Hungarian specimen clearly shows these longitudinal folds (Plate III: 6-7). LAGHI (1977) and MACIOSZCZYK (1988) synonymized Chiton bohemicus with C. olivaceus, while BALUK (1971) supposed that C. bohemicus (ROCHEBRUNE) was the Miocene ancestor of the Recent C. olivaceus SPENGLER. DELLANGELO et al. (1999) synonymized this species and C. miocenicus MlCHELOTTl but distinguished form olivaceus SPENGLER and form miocenicus MlCHELOTTl. Recendy CHIRLI (2004) considered C miocenicus as a separate species but at the same time he did not mentioned C. olivaceus from the Pliocene fauna of Toscana. Form miocenicus has more ribs both on intermediate and tail valves (see CHIRLI 2004; Plate 5: 14-15). The number of ribs at MARINESCU's (1964) C. miocenicus specimen is closer to form olivaceus. Some of LAGHl's (1977) specimens (e. g. Plate 2: 13) belong to form miocenicus because of the large number of longitudinal ribs. The shell structure and architecture of the valves of fossil and Recent C. olivaceus were studied in detail by LAGHI & RUSSO (1978). This is a common and very variable species, therefore several synonymous names can be found in the older literature (POPPE & GOTO 1991) According to STUDENCKA & STUDENCKI (1988) C. olivaceus belongs to the most frequent chiton remains both in the Early and Late Badenian of the Central Paratethys. Their paper mentioned this species from the Upper Badenian deposits of Western Ukraine. KROH (2002) have found C. olivaceus at Gainfarn in Austria. DELL'ANGELO et al. (2005) identified C. olivaceus in the Badenian deposits of Läpugiu (Romania). It was described from the Miocene (Colli Torinesi, Paullo, Montegibbio) and Pliocene (Tagliata) of Italy by LAGHI (1977). C. olivaceus was the most frequent element of the rich Pleistocene Polyplacophora fauna of Parma (Italy) (SABELLI & TAVIANI 1979). BELLOMO &c SABELLI (1995) mentioned several specimens from the Pleistocene of Calabria. According to MALATESTA (1962) this is the most common Mediterranean chiton. LELOUP (1980) mentioned its Recent representatives from the Red Sea. Distribution — Miocene: Central Paratethys (Austria, Czech Republic, Poland, Ukraine, Romania, Hungary), Mediterranean area (Italy); Pliocene and Pleistocene: Italy; Recent: Mediterranean Sea, Red Sea; in the Atlantic Ocean it is known from Tangiers and southern Portugal. Paleoecology — According to SABELLI & TAVIANI (1979) this species is a typical element of the infralittoral zone. The infralittoral zone was also mentioned by BELLOMO & SABELLI (1995). The representatives of this species live from below the low tide line down to depths of 25 m (POPPE & GOTO 1991). C olivaceus was the predominant Polyplacophora species in the algal-vermetid limestones exposed at Lychów (Roztocze Hills, Poland) (MACIOSZCZYK 1988). Suborder Acanthochitonina BERGENHAYN, 1930 Family Acanthochitonidae PlLSBRY, 1893 Subfamily Acanthochitoninae PlLSBRY, 1893 Genus Acanthochitona GRAY, 1821 Acanthochitona faluniensis (ROCHEBRUNE, 1883) (Plate IV: 5-10; Plate V: 1-4) 1977: Acanthochitona faluniensis (ROCHEBRUNE, 1883) —JAKUBOWSKI & MUSIAL, p. 78, pi. 3, fig. 3. 1977: Acanthochitona communis (RlSSO) — LAGHI, pp. 110-111, pi. 3, figs 13-19. 1979: Acanthochitona communis (RlSSO) —JAKUBOWSKI & MUSIAL, p. 51, pi. 2, fig. 3. 1998: Acanthochitonafasdcularis (LINNAEUS, 1766) —TOMASOVYCH, p. 362, pl. 1, figs 1-6. 2001: Acanthochitona faluniensis (ROCHEBRUNE, 1883) — DULAI, p. 43, pi. 2, figs 1-3. (cum. syn.) 2003: Acanthochitona faluniensis (ROCHEBRUNE, 1883) — KROH, pp. 134-135, pl. 1, figs 6-7. Material — Bánd: 2 head valves and 9 intermediate valves. Description — The head valve is semicircular and closely spaced granules ornament its surface (Plate IV

: 5, 7). The low granules are rounded in outline and they dorsally rather flattened. Generally 1—3 pores can be seen on the granules and their arrangement is irregular: they are sometimes in triangle but sometimes all of them are in one row (Plate IV: 6). The apical region is smooth due to erosion. The insertion plate of the head valve is cut by 4— 5 shallow and rounded slits. The moderately convex intermediate valves are wide and slightly subtriangular (Plate V: 1). The jugal area is ornamented by 8-10, not very prominent longitudinal