Pachycormus Agassiz, 1833

Weis, Robert, Delsate, Dominique, Klug, Christian, Argyriou, Thodoris & Fuchs, Dirk, 2024, Pachycormid fish fed on octobrachian cephalopods: new evidence from the ‘ Schistes bitumineux’ (early Toarcian) of southern Luxembourg, Swiss Journal of Palaeontology (5) 143 (1), pp. 1-16 : 5-6

Pachycormus Agassiz, 1833

Specimen MNHNL TU899: Pachycormus macropterus

(Blainville,1818) Teudopsis sp. indet and ( Fig. 1 ).

Locality Foetz, industrial zone, collected by Jo Simon; ‘Schistes bitumineux’ formation, Serpentinum Chronozone.

Dimensions Preserved length of the fish 320 mm. Mandible length 70–75 mm. Total length estimation: mandible length × 6.3 = 441–472 mm. Preserved length of the gladius: 79 mm.

Exposed anatomic features Te skull is dorsoventrally crushed and seen in ventral view with the jaws split away but keeping symphyseal connection.

Identification of the fish Te fins, the smaller scales and teeth, the plates (smaller gular) and bones have the aspect of Pachycormus (more slender dentaries, ceratohyals), not the robustness of Saurostomus . Unfortunately, the absence of the orbit, the suborbital and the opercular apparatus do not allow a cranial biometric assessment of the species.

Identification and position of the gladius Te gladius is identified as Teudopsis sp. ( Teudopsidae , Teudopseina, Octobrachia, Coleoidea) due to its well-developed median keel (Fuchs & Weis, 2010). It lies 180 mm away from the mandibular symphysis, for a dentary length about 70 mm axial, the gladius has a proximodistal (= craniocaudal) direction. It is situated far behind the buccopharynx and gills, far behind the pectoral fin implantation, certainly in the stomach (gastrolite sensu Hunt & Lucas, 2012, consumulite in a broader sense).

Figures

Fig. 1 Specimen MNHNL n° TU899: Pachycormus macropterus (Blainville,1818) and Teudopsis sp. indet.; Serpentinum Chronozone, Foetz