Bredyia alleoni (Dumortier, 1874)

Seyed-Emami, Kazem, Fürsich, Franz T., Wilmsen, Markus, Majidifard, Mahmoud R. & Shekarifard, Ali, 2008, Lower and Middle Jurassic ammonoids of the Shemshak Group in Alborz, Iran and their palaeobiogeographical and biostratigraphical importance, Acta Palaeontologica Polonica 53 (2), pp. 237-260 : 255

Bredyia alleoni (Dumortier, 1874)

Fig. 6M.

1874 Ammonites alleoni ; Dumortier 1874: 259, pl. 52: 3, 4.

1963 Parammatoceras alleoni (Dumortier, 1874) ; Elmi 1963: 55, pl. 8: 1–3; text−fig. 22.

2001 Bredyia alleoni (Dumortier, 1874) ; Rulleau et al. 2001: pl. 25: 10a, b.

2002 Bredyia alleoni (Dumortier, 1874) ; Cresta and Martinez in Pavia and Cresta 2002: 192, figs. 125–126.

Material.— Two specimens from Kuhe Bashm (050511−7/2, 050511−8).

Dimensions (in mm)

Specimen D U H W

050511−8 73 ~27 ~45 ~34

Description.—The figured specimen is slightly crushed. It is relatively involute with a high−ovate to triangular whorl cross−section and a narrow and fairly high keel. The flanks converge towards the relatively broad venter. The ribbing is coarse and sinuous with strong and nearly radiate primaries, which often trifurcate within the lower third of the flank. On the venter the ribs bend forward and nearly reach the keel.

Discussion.—The differences to the closely related B. subinsigne (Oppel, 1836) and B. iranica Seyed−Emami have been discussed by Senior (1977) and Seyed−Emami (1987).

Stratigraphic and geographic range.— Kuhe Bashm, level VII. Late Aalenian, Leioceras opalinum Zone. Bredyia alleoni was found in the beds with Leioceras opalinum .