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

1979: Ischnochiton rissoi (PAYR.) — SABELLI & TAVIANI, p. 160, pl. 1, figs 17-19. 1984: ischnochiton rissoi (PAYRADEAU, 1826) — BALUK, pp. 287-288, pi. 6, figs 2a-b. 1991: Ischnochiton rissoi (PAYRAUDEAU, 1826) — POPPE & GOTO, p. 57, pl. 1, fig. 14. 1998: Ischnochiton {Ischnochiton) rissoi (PAYRAUDEAU, 1826) — DELL'ANGELO et al., p. 246, pi. 3, fig. 2. 1999: Ischnochiton {Simplischnochiton) rissoi (PAYRAUDEAU, 1826) — DELL'ANGELO et al., pp. 265-266, pi. 3, figs 3, 5. 2003: Ischnochiton rissoi (PAYRADEAU, 1826) — KRÜH, pp. 132-133, pl. 1, fig. 5. 2004: Ischnochiton rissoi (PAYRAUDEAU, 1826) — CH1RLI, pp. 6-7, pi. 2, figs 3-9. Material — Devecser: 1 tail valve. Description — The outline of the tail valve is semicircular but the anterior part slightly broken (Plate III: 1). The mucro is slightly elevated and backward directed at the central part of the tail valve (Plate III: 2). The postmucronal area of the valve is ornamented by 12 weak, concentric, wavy wrinkles. These wrinkles are wide but not high; the width of wrinkles is 5-6 times larger than width of the shallow grooves between them (Plate III: 5). The whole surface of the shell bears pores arranged to radial rows running from the mucro to the margins of the valve (Plate III: 2). The number of rows is about 90 at the antemucronal area and approximately 150 at the postmucronal area. Some of the pores are larger in diameter (macroaesthetes) but their arrangement is irregular between the smaller microaesthetes (Plate 111: 3-5). Both apophyses are broken; therefore their shape is unknown. Remarks — Already SULC (1934) mentioned the similarity between /. mdolticensis and 1. rissoi and later LAGHI (1977) placed SULC's species into the synonymy of I. rissoi. In some earlier papers MALATESTA (1962) and BALUK (1971) supposed that 7. mdolticensis SULC is the Miocene ancestor of the Recent I. rissoi (PAYRADEAU). I. korytnicensis described by BALUK (1971) is different from I. rissoi by the type of ornamentation. Radial ribs ornament the postmucronal area of the tail valve at BALUK's species, while I. rissoi shows concentric wrinkles (Plate III: 1, 5). BALUK's (1965) 1. mdolticensis specimen seems to be more similar to I. korytnicensis (DELLANGELO et al. 1999, KRÜH 2003) and the same is true for one of LAGHl's (1977) specimens (see his Plate 1: 9) (DELLANGELO et al. 1999). According to PoPPH & GOTO (1991) /. rissoi is a variable species and 4 different forms can be distinguish: form carinata (ISSEL, 1870), form fragilis (MONTEROSATO, 1878), form daut^enbergi (ANCEY, 1898) and form meneghinii (CAPELLINI, 1859). The outline of the single Hungarian tail valve is slightly different from DELL'ANGELO et al. (1998) material: the posterior part is more rounded at the latter specimen. CHIRLI'S (2004, Plate 2: 8-9) material has stronger ornamentation but it is probably due to the slighdy eroded preservation of the Devecser specimen. They also differ in the outline because the Italian valves are not so wide. BALUK (1971, Plate 3: 8) showed a very similar tail valve with the same outline but stronger ornamentation. This species is common in the Miocene of the Central Paratethys, as well as in the Miocene—Pleistocene deposits of the Mediterranean area but generally it belongs to the rare faunal elements. The most numerous record is known from Poland (BALUK 1971, 1984). KRÜH (2002) mentioned this species from Gainfarn, while KRÜH (2003) published a rather eroded tail valve from Grund, which is otherwise very similar to the Hungarian specimen. DELL'ANGELO et al. (2005) reported 1. rissoi from the Badenian of Romania for the first time (Lápugiu de Sus). STUDENCKA & STUDENCKI (1988) mentioned some I. rissoi specimens from the Late Badenian of Ukraine. LAGHI (1977) described several valves from Montegibbio (Miocene), as well as from Tagliata and Reggiano (Pliocene). DELL'ANGELO et al. (1999) described it from the Messinian deposits of Borelli. LAGHI (1984) mentioned this species from the Pliocene yellow sands of Siena (Italy). BELLOMO & SABELLI (1995) have found I. rissoi in the Pleistocene deposits of Calabria, while SABELLI & TAVIANI (1979) in the Pleistocene of the Stirone river section. CHIRU (2004) gave a detailed synonym list for the occurrences in the Mediterranean area. DELL'ANGELO et al. (1998) have found an abundant Recent I. rissoi material in the Strait of Sicily. Distribution — Middle Miocene (Badenian) of the Central Paratethys (Czech Republic, Poland, Ukraine, Romania, Austria, Hungary). Middle Miocene (Italy), Pliocene (Italy), Pleistocene (Italy). The recent representatives of this species can be found in the whole Mediterranean Sea. Explanation to Plate II 1-6 Lepidopleurus (Lepidopleurus) cajetanus (POLl, 1791). 1 Tail valve — (L: 2.75 mm; W: 4.9 mm), Band, 15x. 2 Details of image 1 — mucro of the tail valve, 60x. 3 Tail valve — (L: 3.25 mm; W: 5.75 mm), Bánd, 13x. 4 Tail valve — (L: 3.0 mm; W: 4.8 mm), Bánd, 15x. 5 Details of image 4 — granulöse concentric ribs of the postmucronal area, lOOx. 6 Details of image 4 — granulöse longitudinal ribs of the antemucronal area, 120x. 7—9 Lepidochitona sp. 7 Intermediate valve — (L: 1.2 mm; W: 2.25 mm), Bánd, 33x. 8 Details of image 7 — eroded surface and elongated pores of the jugal area, 240x. 9 Intermediate valve — (L: 1.25 mm; W: 2.25 mm), Bánd, 33x.