Pleuroceras spinatum (Bruguière, 1789)

Geist, Jan, Weis, Robert, Schlögl, Ján, Košťák, Martin & Mazuch, Martin, 2025, Olistoliths as overlooked sources of information: an example from Pliensbachian belemnites and ammonites of Lukoveček (Czechia, Western Carpathians), Swiss Journal of Palaeontology (24) 144 (1), pp. 1-31 : 11-13

Pleuroceras spinatum (Bruguière, 1789)

( Fig. 4C–E )

* 1789 Ammonites spinatus Bruguière, p. 40

cf. 1841 Ammonites Buckmanii Moxon, pl. 24. fig. 5

1958 Pleuroceras spinatum (Bruguière) ; Howarth, pl. 7, figs 2 (neotype), 3–5, text-fig. 14 with synonymy

cf. 1958 Pleuroceras spinatum (Bruguière) var. buckmani (Moxon) ; Howarth, pl. 7, fig. 6 with synonymy

1964 Pleuroceras spinatum (Bruguière) var. buckmani (Moxon) ; Bourdenet, pl. 1, fig. 10

1964 Pleuroceras spinatum (Bruguière) ; Bourdenet, pl. 1, fig. 11

1988 Pleuroceras solare form spinatum (Bruguière) ; Meister, pl. 8, fig. 5; pl. 9 figs. 1, 2

1994 Pleuroceras spinatum (Bruguière) ; Fischer, pl. 27, figs. 5a–b, 6a–b

1996 Pleuroceras spinatum (Bruguière) ; Popa & Patrulius, pl. 3, figs. 11, 11a, 12, 12a

1998 Pleuroceras solare forme spinatum (Bruguière) ; Géczy & Meister, pl. 6, fig. 7

2004 Pleuroceras spinatum (Bruguière) ; Morard, pl. 3, fig. 9

2005 Pleuroceras cf. spinatum (Bruguière) ; Callomon & Gradinaru, pl. 4, fig. 3a–b

Non 2006 Pleuroceras spinatum (Bruguière) ; Topchishvili et al., pl. 12, figs. 4–7

2006 Pleuroceras spinatum (Bruguière) ; Fauré, p. 43, fig. 8.20.

2007 Pleuroceras spinatum (Bruguière) ; Rulleau et al., pl. 35, figs. 7a–b, 8a–b; pl. 36, fig. 3

2007 Pleuroceras spinatum (Bruguière) ; Mouterde et al., pl. 2, figs. 4, 9

2013 Pleuroceras spinatum (Bruguière) ; Bardin et al., p. 327, figs. 7A, cf. H, I; p. 329, figs. 8A–E

2014 Pleuroceras spinatum (Bruguière) ; Schubert, fig. 9

2021 Pleuroceras spinatum (Bruguière) ; Arp et al., fig. 10.3–4

2023 Pleuroceras spinatum (Bruguière) ; Bohain et al., pl. 15, fig. 3, pl. 16, figs. 1b-c, 2

2023 Pleuroceras spinatum (Bruguière) ; Meyer, pl. 3, fig. E

2025 (accepted) Pleuroceras solare form spinatum (Bruguière) ; Meister et al., pl. 86, figs. 5,9,11, pl. 87, fig. 1

Material: One complete specimen (Ge 2223), five fragments.

Description: Evolute forms with massive quadrilateral whorls which can reach 25–30 cm in adult diameter (Howarth, 1958, p. 37, however not figured by the author). Smaller but still very large forms (up to 20 cm in D) are known also from Vendée (Bohain et al., 2023) or Jura Massif (Meister et al. accepted) in France. Whorl section is almost square. Ribs are strong, radiate on the flank, raised already near the umbilical edge and sharptopped and projected forward on the ventral area. Rib density is weak. A tubercle develops on each rib slightly below the latero-ventral edge. Keel is strong and crenulated, bordered by smooth sulcate bands.

Remarks: P. spinatum differs from P. solare by its large size, massive whorls with approximately quadrate whorl section, strong and tuberculed ribs. P. paucicostatum (Howarth, 1955) differs only in its more evolute coiling and is considered as a subjective junior synonym by Meister (1988).

Occurrence: It is the index species of the Spinatum Zone , where it occurs from the Apyrenum Subzone to Hawskerense Subzone (Meister, 1988). A typical Euroboreal taxon, common also in Western Tethys in Southern Alps in Lombardy ( Italy), Bakony in Hungary, Betics in Spain, Lusitanian Basin in Portugal and Caucasus in Georgia.

Figures

Fig. 4 Ammonites from the Upper Pliensbachian of LukoveČek: A–B Pleuroceras sp. nov. aff. spinatum; C–E Pleuroceras spinatum (Ge 2223 and Ge 33512). Scale 10 mm