Baculina
Baculina is an extinct   ammonoid cephalopod genus belonging to the ancylocerid family Bochianitidae. Baculina is known from the Valanginian of the Lower Cretaceous. References
Arkell et al., 1957, Mesozoic Ammonoidea; Treatise on Invertebrate Paleontology,  Part L, Ammonoidea. Geological Society of America & University of Kansas Press; R. C. Moore (ed) 
 Classification of J. Klein et al. 2007
J. Klein, et al. . 2007. Lower Cretaceous Ammonites III. Bochianitoidea, Protancyloceratoidea, Ancyloceratoidea, Ptychoceratoidea. Fossilium Catalogus I: Animalia 144:

Cretaceous ammonites
Ammonitida
Valanginian life