Parvamussium miopliocenicum (Ruggieri, 1949)
RUGGIERI, G. 1949. Contribuzione alla conoscenza della malacofauna e dell stratigrafia del Pliocene e del Quaternario. Giornale di Geologia. Annali del Museo Geologico di Bologna [Serie Seconda], 21: 65-89, pl 2.
1949 Amussium [sic] (Propeamussium) miopliocenicum Ruggieri, 1949
«Parvamussium miopliocenicum is a new name in troduced by Ruggieri for the Middle Pliocene (Piazenzian) specimens attributed by Sacco (1897) and by Deperet and Roman (1928) to P. felsineum. Un doubtedly, lack of illustrations of the felsineum type specimens caused Sacco (1897, p. 49, pl. 14, figs. 7–22) to assume incorrectly that Parvamussium specimens from Bordighera were identical to Foresti’s species felsineum. According to Ruggieri (1950, p. 79), the original description of felsineum by Foresti (1893, p. 381, 382) leaves no doubt that Sacco’s figures of felsineum from Bordighera as well as material illustrated by Deperet and Roman (1928, p. 182, 183, pl. 27, figs. 7–11) from Sant’Agata and Bordighera under the name Amussium felsineum have nothing in common with Foresti’s species felsineum. They clearly represent different species as recognized by the presence of reticulate sculpture on the left valve and prominent but irregularly spaced radial lirea on the right valve. For this species Ruggieri proposed the name Amussium (Propeamussium) miopliocenicum, and designated as a holotype the specimen figured by Deperet and Roman (1928, pl. 27, figs. 9, 9a). Ruggieri stated Bordighera in Piedmont as the type locality of this species. This statement was confirmed by Robba (1968, p. 489, 490), but unfortunately it has been ignored by other authors.
The separation of miopliocenicum from felsineum is based on the external sculpture of the right valve which in the latter species bears only very closely spaced concentric lamellae whereas in the former species distinctly finer and weaker, more spaced concentric lamellae overrun irregularly spaced, delicate (8 to 12) very narrow radial lirae, projecting scales at the intersection with lamellae (Deperet and Roman, 1928, pl. 27, figs. 9a, 10a; Robba, 1968, pl 37, figs. 6a, 7a). In several right valves from Bordighera a set of commarginal lamellae closer to the ventral margin have a ragged appearance due to projections at their intersections with numerous, fine radial lines (Deperet and Roman, 1929, pl. 27, fig. 7a). These specimens were reproduced by Hertlein as left valves [sic!] of P. felsineum (1969, N350, fig. C73. 2c). So far, this Parvamussium species, highly variable in sculpture, has been recorded from Upper Miocene (Tortonian) deposits in Piedmont (Deperet and Roman, 1928; Robba, 1968), and from the Middle Pliocene of both Northern Italy (Sacco, 1897; Deperet and Roman, 1928; Ceregato et al., 2007) and Calabria (Ruggieri, 1950). In contrast, there are no data about its presence in the Paratethys. But in respect to the taxonomic concept of Ruggieri (1950) it is question able whether all specimens de posited in various museums, originally referred to felsineum, represent this species. It seems likely that some of the Bulgarian specimens sculptured with faint but distinct radial, 8 to 10 very narrow irregularly spaced ribs on the right valve (Kojumdgieva, 1969, p. 86) are actually closer to P. miopliocenicum.» STUDENCKA, B., V. A. PRYSYAZHNYUK & S.A. LJUL’EVA. 2012. First record of the bivalve species Parvamussium fenestratum (Forbes, 1844) from the Middel Miocene of the Paratethys. Geological Quarterly, 56 (3): 513-528, figs. 1-5. [p. 524]
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Variamussium felsineum (For.); F. Sacco, 1897, I Mulluschi del terreni Terziarii del Piemonte e della Liguria, Parte XXIV (Pectinidae), plate 14, figures 7-22.
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