Hornung Th. (2009) Ein großwüchsiges Rasenia sp. aus dem "Alten Steinbruch" Ludwag (hypselocyclum-Zone, Kimmeridgium 1b) // Geologische Blätter für Nordost-Bayern, Bd.59. S.249-258. Pdf: http://rogov.zwz.ru/hornung,2009_rasenia.pdf
From the »old quarry« of Ludwag (Northern Franconian Alb), a large Rasenia from the Kimmeridgian 1b (hypselocyclum ammonite zone) is described. The fact that the diameter of 381 mm is chambered without parts of the living chamber, suggests not only a whole measure of somewhat 600 mm, but rather led fit this specimen to no classification scheme actually known for the ammonite faunas of Northern Bavaria. With respect to the genus Rasenia, that large dimension is completely unusual as most specimens are sized dwarfish to small. Thus, no literature could be found that dealt with very large-sized rasenoid ammonites. As for the differential diagnosis, a possible affiliation to the subgenera Rasenia, Prorasenia, Semirasenia, Involuticeras and to the genera of Aulacostephanus und Ringsteadia can be excluded, but it seems likely that the described specimen could be assigned to the subgenus Eurasenia and the associated species Rasenia (E.) pendula.
