286 A. Scherzinger et al. N. Jb. Geol. Palaont. Abh. 241 (2) 269-286 Stuttgart, Oktober 2006 ZIEGLER,M. A. (1960): Gravesienfunde aus dem ,,unteren Portland" der Gegend von Morteau (Doubs). - Eclogae geol. Helvet., 53: 670-677. ZIETEN,C. H. V. (1830-1833): Die Versteinerungen Wiirttembergs. - 102 pp.; Stutt- gart (Schweizerbart). New considerations on dimorphism and Manuscript received: January 24th, 2006. aptychus in Gravesia SALFELD(Ammonoidea; Revised version accepted: June 26th, 2006. Late Jurassic) Addresses of the authors: Armin Scherzinger, Immendingen-Hattingen, Gunter Schweigert, Dip1.-Ing. (FH) ARMIN SCHERZINGER,HewenstraBe 9, 78194 Irnmendingen-Hat- Stuttgart, and Horacio Parent, Rosario tingen, Germany; e-mail:
[email protected] With 6 figures Dr. GUNTERSCHWEIGERT, Staatliches Museum fiir Naturkunde Stuttgart, Rosen- stein 1, 70191 Stuttgart, Germany; e-mail:
[email protected] Dr. HORACIOPARENT, Laboratorio de Paleontologia, Universidad Nacional de Ro- SCHERZINGER,A., SCHWEIGERT,G. & PARENT,H. (2006): New considerations on sario, Pellegrini 250, 2000 Rosario, Argentina; dimorphism and aptychus in Gravesia SALFELD(Ammonoidea; Late Jurassic). - e-mail: parent @ fceia.unr.edu.ar N. Jb. Geol. Palaont. Abh., 241: 269-286; Stuttgart. Abstract: Recent findings of Gravesia gravesiana (D'ORBIGNY)from the Lower Tithonian (Hybonotum Zone, laisackerensis Horizon) of Liptingen (SW Germany) indicate the presence of dimorphism in the genus Gravesia SALFELDin which the dimorphic partners differ significantly in their mouth borders. A new type of aptychus occurring in the same beds most likely corresponds to Gravesia. The systematic position of ~ravesiais briefly discussed. Zusammenfassung: Neufunde von Gravesia gravesiana (D'ORBIGNY)aus dem Unter-Tithonium (Hybonotum-Zone, laisackerensis-Horizont) von Liptingen (Sud- westdeutschland) belegen die Existenz eines Dimorphismus bei der Gattung Gra- vesia SALFELD,wobei sich die beiden dimorphen Partner insbesondere hinsichtlich ihrer Mundung deutlich voneinander unterscheiden.