Hippuritella lapeirousei Goldfuss, 1840

Săsăran, Liana, Săsăran, Emanoil & Bucur, Ioan I., 2018, Upper Cretaceous Rudist-Bearing Mixed Siliciclastic-Carbonate And - Volcanoclastic Deposits From Strâmturii Valley, Borod Basin, Northern Apuseni Mountains: Description, Microfacies And Depositional Environments, Acta Palaeontologica Romaniae 14 (1), pp. 3-20 : 14

Hippuritella lapeirousei Goldfuss, 1840

Fig. 8 a-g

1895 Hippurites (Orbignya) lapeirousei Goldfuss- Douvillé, p. 164, pl.24, figs.7-10.

1903 Orbignya lapeirousei Goldfuss- Toucas, p. 53, pl.6, figs.10-11.

1976 Hippurites lapeirousei Goldfuss- Lupu, p. 122, pl.12, fig.5.

1995 Hippuritella lapeirousei (Goldfuss) - Caffau and Pleničar, p. 135, pl. 1, figs. 1-14.

1999 Hippuritella lapeirousei (Goldfuss) - Steuber, p. 116, text-fig.46h, J-M.

2000 Hippuritella lapeirousei (Goldfuss) - Steuber and Löser, p. 96.

2001 Hippuritella lapeirousei (Goldfuss) - Götz, p. 64, pl.1, fig.4, pl.3, fig.2, pl.4, fig.6, pl.7, fig.16

2005 Hippuritella lapeirousei (Goldfuss) - Pleničar, p. 172, pl. 74, fig. 1.

2010 Hippuritella lapeirousei (Goldfuss) - Moro et al., p. 626, 630, figs. 6, 9.

2014 Hippuritella lapeirousei (Goldfuss) - Pons et al., p. 64, fig. 16.1-6.

Material: 1 specimen with both valves (24085 BBU-MPS) and 3 fragments of lower valves (24086, 24087, 24088 - BBU-MPS) .

Description: The specimen with both valves shows a very thin, flat left valve (LV) with a sub-central apex. The almost all surface of the LV is eroded and only on the edge the radial canals are visible ( Fig. 8c ). All specimens have small, elongated-conical right valves (RV), without prominent longitudinal ribs, the surface of the shell is very eroded ( Fig. 8b,d ). The length of right valves (RV) varies between 20 to 42 mm and diameter measures 18 mm to 25 mm maximal. The position of the pillars (P1 and P2) is indicated externally on the outer shell layer by two shallow longitudinal furrow ( Fig. 8b,d ). The internal characters observed in the transversal sections of right valves shows lack of ligament ridge and small pillars ( Figs. 8a, e,f,g ). The pillars P1 and P2 are short and rounded and have same size ( Figs. 8a,e,f ). Only in one specimen (BBU-MPS-24088) the first pillar P1 is slightly smaller than the second pillar (P2) and both pillars are broad and less prominent ( Fig. 8-g ). The myocardinal apparatus is not visible in none of specimens. The outer shell layer shows variably thickness and seems to present radial ribbing ( Fig. 8a, c , e-g).

Discussion: Long time some authors placed Hipuritella nabresinensis in synonymies with Hipuritella lapeirousei ( Douville, 1895; Parona, 1900; 1926; Toucas, 1903 - 1904). Others rudistologists (Sladić - Trifunović, 1972, 1978; Lupu, 1976; Accordi et al., 1982; Laviano, 1985;

Caffau and Pleničar, 1995) considered that the two species have distinctive characteristics as follows: in H. nabresinensis the right valve is cylindrical (Sladić - Trifunović, 1978; Laviano, 1985), have more pronounced rounded costae ( Futterer, 1893; Lupu, 1976; Accordi et al., 1982) and their pillars are not of the same size ( Laviano, 1985; Caffau and Pleničar, 1995). In H. lapeirousei the right valve is small conical (Sladić - Trifunović, 1978) without prominent longitudinal ribs ( Steuber, 1999) and the pillars P1 and P2 are similar in size (Sladić - Trifunović, 1972; Lupu, 1976; Caffau and Pleničar, 1995; Moro et al., 2010) or P1 slightly smaller than P2 ( Douville, 1895; Moro et al., 2010). The ligamental ridge (L) is absent or reduced to a small inflexion in outer layer ( Douville, 1895; Vicens, 1992) in both species. Steuber (1999) considered as the thin outer shell layer and faintly projecting pillars as safe elements to recognition of H. lapeirousei . Our specimens resembles more with those described from Serbia (Sladić- Trifunović, 1972), Italy ( Laviano, 1985) and Spain ( Vicens et al., 2004) which have thick-shelled valves and same size pillars.

Age and distribution: late Santonian-early Campanian in Croatia ( Polšak and Mamuzic, 1969); middle Campanian in Spain ( Floquet, 1991); middle Campanian –early Maastrichtian in Croatia ( Polšak and Mamuzic, 1969), Italy ( Swinburne and Noacco, 1993), Spain ( Vicens, 1992); Maastrichtian in Greece ( Steuber, 1999), France ( Toucas, 1903; Bilotte, 1985), Italy ( Pons and Sirna, 1994), Spain ( Astre, 1962), Turkey ( Özer, 1994; Fenerci, 1999).

Figures

Fig. 8 a-g Hippuritella lapeirousei (Goldfuss)(nos. 24085, 24086, 24087, 24088-BBU-MPS). a Transverse section made close to the beak of right valve (RV), the outer shell layer is thick, reaching 3 mm. b RV showing the position of the pillars (P1 and P2) as shallow longitudinal furrows (24085 BBU-MPS). c thin and nearly flat LV very eroded showing remains of radial canals (24085 BBU-MPS). d ventral area of conical, slightly curved RV (24086 BBU- MPS) showing the position of the pillars as two shallow longitudinal furrows; e transverse section of RV showing short and rounded pillars (P1 and P2) with the same size (24086 BBU-MPS). f, g transverse sections through specimens (nos. 24087, 24088 BBU-MPS) that have the first pillar (P1) slightly smaller than the second pillar (P2). Note the erosion of the outer shell layer in f) (24087 BBU-MPS). h-i Vaccinites gosaviensis (Douvillé)- transverse section made on two RVs (nos. 23503, 24089 BBU-MPS) showing truncated ligamental ridge (L) and characteristic shape of the pillars. j Vaccinites archiaci (Douvillé), transverse section on RV (no. 24090 BBU-MPS) showing triangular in base and lamelliform ligamental ridge (L), first pillar (P1) thick and shorter and slightly pinched P2. k Vaccinites sulcatus (Defrance) – transverse section on lower valve (no. 23504 BBU-MPS) in which ligamental ridge (L) is wide and short having the same length with first pillar (P1) and second pillar is slightly pinched at its base and curved anteriorly.