Catacoeloceras Buckman, 1923

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 : 247-248

Genus Catacoeloceras Buckman, 1923 Catacoeloceras aff. raquinianum (d'Orbigny, 1845) Fig. 5O.

1845 aff. Ammonites Raquinianum ; d'Orbigny 1845: 332, pl. 106: 4, 5 (only).

1972 aff. Catacoeloceras raquinianum (d'Orb.) ; Guex 1972: 640, pl. 11: 6.

1994 aff. Catacoeloceras raquinianum (d'Orbigny, 1845) ; Atrops in Fischer 1994: 94, pl. 33: 2a–c.

Material.—One fragmentary impression and a small fragment from Sharif−Abad (050512−8/2, 0505128/4).

Description.—The figured specimen (050512−8/2) is a plaster cast of an external mould. It is a depressed and rather evolute member of the Dactylioceratidae with broad venter. The ribbing consists of relatively strong, prorsiradiate primary ribs, beginning at the umbilical seam. These end ventrolaterally in small and sharp tubercles, from where they usually trifurcate into fine secondary ribs. One or two intercalatory ribs, beginning at the seam or higher up, are present.

Discussion.—Except for the finer ribbing and the more numerous secondaries, our specimens compare well with the smaller specimen of d'Orbigny (1845: figs. 4, 5), which has been designated as lectotype by Guex (1972: 640).

At the same time Schmidt−Effing (1972: 63) designated the larger specimen of d'Orbigny (1845: figs. 1, 2) as lectotype. Also Atrops ( Fischer 1994: 94) considered the larger of d'Orbigny's specimens (d'Orbigny 1845: fig. 1a, b) as the lectotype of the species.

Stratigraphic and geographic range.—Sharif−Abad, level D. C. raquinianum has been recorded from the Middle Toarcian Hildoceras bifrons / Haugia variabilis Zone.