Asteroceras stellare.
 
Asteroceras stellare. J. Sowerby, 1815
Black ven, Charmouth, Dorset Coast
 
Family ARIETITIDAE Hyatt, 1874 Subfamily ASTEROCERATINAE Spath, 1946
 
A Subzone ammonite from the zone of Asteroceras obtusum, in the Upper Sinemurian Substage.
 
Large, Ribs strong and smooth, curved forward. Whorls high, enlarging rapidly, sides converging above the middle, keel large, prominent, flanked by 2 deep sulci which are lost on outer whorl. Size 40cm across.
 
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