Acta Palaeontologica Polonica

Gladius shape variation in coleoid cephalopod Trachyteuthis from the Upper Jurassic Nusplingen and Solnhofen Plattenkalks

Dirk Fuchs, Theo Engeser, and Helmut Keupp

Acta Palaeontologica Polonica 52 (3), 2007: 575-589

Although the fossil record of coleoid cephalopods is generally poor, the Upper Jurassic Nusplingen and Solnhofen Plattenkalks have provided numerous well-preserved coleoids. Trachyteuthis hastiformis, a comparatively large vampyropod coleoid, was previously known to represent the sole species of its genus in Nusplingen and Solnhofen. However, morphological comparisons based on 50 specimens from different museum collections revealed two additional species: T. nusplingensis sp. nov. and T. teudopsiformis sp. nov. Both species lack the distinct spindle-shaped elevation on the gladius median field typical for T. hastiformis. T. nusplingensis sp. nov. is clearly characterised by a smooth median field and a more or less regular granulation on the dorsal gladius surface, whereas T. teudopsiformis sp. nov. can be easily distinguished by the presence of a Teudopsis-like median keel and an extremely narrow granulation. Morphometric analyses have shown that length-width indices are ambiguous characters to differentiate between the three species. Phylogenetically, the keeled and anteriorly pointed T. teudopsiformis sp. nov. can be linked with the Early Jurassic genus Teudopsis and the Late Cretaceous genus Glyphiteuthis.

Key words: Cephalopoda, Coleoidea, Vampyropoda, Trachyteuthis, gladius, Kimmeridgian, Tithonian.

Dirk Fuchs drig@zedat.fu-berlin.de, Theo Engeser engeser@zedat.fu-berlin.de, and Helmut Keupp keupp@zedat.fu-berlin.de, Freie Universität Berlin, Institut für Geologische Wissenschaften, Fachrichtung Paläontologie, Malteserstr. 74-100, D-12249 Berlin, Germany.


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