Acta Palaeontologica Polonica

Triassic coleoid beaks and other structures from the Calcareous Alps revisited

Larisa A. Doguzhaeva, Herbert Summesberger, Franz Brandstaetter, Daniela Gruber, and Andrea Tintori

Acta Palaeontologica Polonica in press
available online 22 Jun 2022 doi:https://doi.org/10.4202/app.00953.2021

We performed comprehensive study of seven Carnian, Late Triassic specimens of a coleoid cephalopod Phragmoteuthis bisinuata, on which Suess based his hypothesis on “beaks of P. bisinuata”. Using SEM/EDS, we found that “beaks of P. bisinuata” consist of a micro-granular carbonized matrix containing ~4–30 μm diameter and ~50–200 μm visible length, dense calcified bone-like micro-structures. This strongly suggests that these objects are vertebrate bone-inducing cartilages in which the matrix was post-mortem reworked by carbon-accumulating bacteria and substituted by nano-particles of carbon accumulated in micro-granules. Hence, the presumed “beaks of P. bisinuata” are cartilaginous remains of a prey, presumably juvenile fish. This data dismissed the entire hypothesis of Seuss. A small spatula-shape plate with a rachis-like process in an association with 10 or so imprints around (arm crown), found in front of a proostracum of P. bisinuata evidences an unknown Late Triassic juvenile teuthid which possessed a gladius resembling that of the early Permian Glochinomorpha stifeli. It inhabited the open sea area of the northwestern Tethys Ocean, and was, along with juvenile fishes, in the diet of P. bisinuata. The first identified Anisian (Middle Triassic) coleoid beak is represented by an isolated specimen from the Gardena Valley, NE Italy. It has a typical composition and morphology of coleoid upper beak: chitinous, wide-oval lateral walls, short wings, and pointed hook-like rostrum. This suggests similar upper beak structure in the Carnian P. bisinuata in which the lower beaks were apparently similar to that of the co-occurring Lunzoteuthis schindelbergensis and had a widely open outer lamella with posteriorly elongated paired wings joined into a pointed rostrum in the anterior portion.

Key words: Cephalopoda, Coleoidea, Phragmoteuthis , beaks, vertebrate and invertebrate prey, Triassic, Alps.

Larisa A. Doguzhaeva [larisa.doguzhaeva@gmail.com], Department of Palaeobiology, Swedish Museum of Natural History, P.O. Box 50007, Stockholm SE-104 05, Sweden. Herbert Summesberger [herbert.summesberger@nhm-wien.ac.at], Department of Geology and Palaeontology, Museum of Natural History, Vienna, Burgring 7, Austria. Franz Brandstaetter [franz.brandstaetter@nhm-wien.ac.at], Mineralogical Department, Museum of Natural History, Vienna, Austria; Vienna, Burgring 7, Austria. Daniela Gruber [daniela.gruber@univie.ac.at], Core Facility of Cell Imaging and Ultrastructure Research, Life Sciences Faculty, University of Vienna, 1090 Wien Althanstraße 14, Austria. Andrea Tintori [paleo.tintori@outlook.it], Triassica, Institute for Triassic Lagerstätte, 23828 Periedo (LC), Via al Verder 6, Italy.


This is an open-access article distributed under the terms of the Creative Commons Attribution License (for details please see creativecommons.org), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.