477_Fuchs.qxd-gültig 31.07.2007 6:50 Uhr Seite 239 (Schwarz Bogen) N. Jb. Geol. Paläont. Abh. 2007, vol. 245/2, p. 239 –252, Stuttgart, August 2007, published online 2007 Taxonomy, morphology and phylogeny of plesioteuthidid coleoids from the Upper Jurassic (Tithonian) Plattenkalks of Solnhofen Dirk Fuchs, Andreas Klinghammer and Helmut Keupp, Berlin With 5 figures and 1 table FUCHS, D., KLINGHAMMER, A. & KEUPP, H. (2007): Taxonomy, morphology and phylogeny of plesioteuthidid coleoids from the Upper Jurassic (Tithonian) Plattenkalks of Solnhofen. – N. Jb. Geol. Paläont. Abh., 245: 239 – 252; Stuttgart. Abstract: Plesioteuthis prisca (RÜPPELL, 1829) and “Senefelderiteuthis kraussi ENGESER & KEUPP, 1999” were previously the only two species of plesioteuthidid coleoids known from the Solnhofen Plattenkalks. Based on morphological comparisons of 154 specimens from the Solnhofen area, a third taxon must be considered as valid: Plesioteuthis subovata (MÜNSTER, 1846). Additionally, it turned out that “Senefelderiteuthis kraussi” is identical with Dorateuthis tricarinata (MÜNSTER, 1846). The stratigraphical range of the genus Dorateuthis can now be extended from the Late Cretaceous to the Late Jurassic. Despite a remarkable similarity between prototeuthid and teuthid gladii, Proto- teuthidids are attributed to the Vampyropoda. Unambiguous characters of teuthid Decabrachia such as a ventrolateral pair of elongated tentacles are unknown from the fossil record. Instead, characters such as interbrachial web, radial suckers and cirri rather indicate a closer relationship with the Vampyropoda. Key words: fossil Coleoidea, Vampyropoda, Plesioteuthis, Dorateuthis, taxonomy, gladius morpho- logy, Lower Tithonian, Solnhofen. 1. Introduction Plesioteuthis prisca is by far the commonest coleoid in the Upper Jurassic Solnhofen Plattenkalks. Plesioteuthidids are characterised by a more or less Thanks to excellent soft-part preservation, external slender body and a squid-like gladius. They probably and even internal details of the soft tissues have been evolved during the Early Jurassic (Toarcian) and documented by NAEF (1922: 118), BANDEL & LEICH disappeared at the K/T-boundary. Owing to the (1986: 134), MEHL (1990: 78) and KLUG et al. (2005: remarkable similarity of their gladius to a modern 183). So far Plesioteuthis prisca was widely believed ommastrephid gladius, plesioteuthidids play a pivotal to represent the sole plesioteuthid species in the Soln- role in the discussion on the origin of modern teuthid hofen Plattenkalks. However, even since the pioneer coleoids. Their systematic position – ancestors either days of fossil coleoid research, e. g. RÜPPELL (1829), of the ten-armed Teuthida or the eight-armed Vampy- MÜNSTER (1837, 1846), D´ORBIGNY (1845) and ropoda – is crucial for phylogenetic reconstructions. QUENSTEDT (1849), who recognised several species The controversy is well seen in discussions by from these strata, structural variations of the gladii BANDEL & LEICH (1986: 142), DONOVAN & TOLL have not been reconsidered. Because of its phylo- (1988: 93), YOUNG et al. (1998: 409), VECCHIONE et genetic significance, DONOVAN & TOLL (1988: 95) al. (1999: 116), HAAS (2002: 343), DOGUZHAEVA requested more structural studies on the gladius of (2005: 47), and FUCHS (2006b: 74-75). Plesioteuthis. The aim of the present paper is to show DOI: 10.1127/0077-7749/2007/0245-0239 0077-7749/07/0245-0239 $ 3.50 © 2007 E. Schweizerbart’sche Verlagsbuchhandlung, D-70176 Stuttgart.