Jaws of a large belemnite and an ammonite from the Aalenian (Middle Jurassic) of Switzerland (original) (raw)
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The buccal apparatus with radula of a ceratitic ammonoid from the German Middle Triassic
Complete ammonoid mouth parts including both mandibles and the radula are rare. A newly prepared specimen of Ceratites penndorfi of the late Anisian from the Franconian Muschelkalk reveals one such anaptychus-type jaw apparatus including several more or less clearly recognisable structures such as the shapes and proportions of the inner and outer lamellae of both mandibles. The lower mandible has a short inner and a long outer lamella with an ovoid outline, while the upper mandible has a slightly arched rostrum and the inner lamella carries two wings. The radula, as far as it is preserved, appears to be homodont with oblique, simply conical, monocuspidate teeth. Some other structures are here illustrated, described and interpreted as both mandibles and oesophageal remains. Additional structures of organic origin are preserved such as the radula, but others are difficult to interpret. Some, if not all, of these structures also were body parts of the ceratite, such as perhaps the radular support and/or the oesophagus. All mouthparts, which are preserved in the specimen described herein, are carbonised except for the radula remains, which are phosphatic. The taphonomy of ceratite mouth parts in the Muschelkalk is shortly discussed.
2021
Ammonoid soft parts have been rarely described. Here, we document the soft parts of a perisphinctid ammonite from the early Tithonian of Wintershof near Eichstätt (Germany). This exceptional preservation was enabled by the special depositional conditions in the marine basins of the Solnhofen Archipelago. Here, we document this find and attempt to homologize its parts with various organs such as the digestive tract, reproductive organs, the mantle cavity with gills, and the hyponome, with differing degrees of reservation. Alternative interpretations are also taken into account. We suggest that the soft parts were separated from the conch either taphonomically (following necrolytical processes affecting the attachment structures) or during a failed predation, where a predator (fish or coleoid) removed the soft parts from the conch but then dropped them. This find is interesting because it adds to the knowledge of ammonite anatomy, which is normally hidden in the conch. The reproductiv...
1 Benzstrasse 9, 73469 Riesbürg 2 Staatliches Museum für Naturkunde, Rosenstein 1, 70191 Stuttgart 3 Schillerstrasse 15, 68804 Altlussheim 4 Ahornweg 1, 73111 Nenningen 5 Lehenhof 2, 88693 Deggenhäusertal 6 Landhausstrasse 20, 72411 Bodelshausen 7 8 rue haute, F-67390 Mackenheim 8 Untere Ringstrasse 23, 79859 Schluchsee 9 Bezgenrieterstrasse 33, 73092 Heiningen 10 Hauptstrasse 48, 78589 Dürbheim Manuscript received December 8, 2009; revised manuscript accepted February 24, 2010 Zitteliana 71 -88 4 Pls, 4 Textfigs München, 30.06.2010 Abstract We present insufficiently or previously unknown am-monites of the families Erycitidae Spath, 1928, Otoitidae MaScke, 1907 and Stephanoceratidae NeuMayr, 1875 from the Upper Aalenian and early Lower Bajocian (Middle Ju-rassic) of southern Germany. The newly recorded taxa of the Erycitidae are: Abbasites gardincola (de GreGorio), Abbasites aff. abbas BuckMaN and Spinammatoceras aff. sagax (Vacek); of the Otoitidae: Docidoceras zemistephanoides Géc...
The first record of jaws of Boreal Valanginian ammonites (Cephalopoda, Polyptychitidae
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Jaws of ammonites which inhabited the Panboreal Superrealm during the Jurassic and Cretaceous are poorly known in comparison to those of Tethyan ammonoid faunas. This paucity may be explained by limited thickness, or even absence of an outer calcitic layer, in lower jaw elements (aptychi) of Boreal ammonites. Here we describe, for the first time, the jaws (both lower and upper) of ammonites of the Boreal family Polyptychitidae, of Early Cretaceous (Valanginian) age. Polyptychitid lower jaws are of the aptychus type, but have an unusual pointed and convex shape. However, lower jaws of Late Jurassic ancestors of polyptychitids (Craspeditidae) as well as Middle Jurassic cardioceratids (Pseudocadoceras) have a near-identical shape, as do previously described aptychi of the Late Cretaceous genera Neogastroplites and Placenticeras (Hoplitoidea). The close resemblance of lower jaws of evolutionarily distant ammonites may be linked to a similar lifestyle, but more data are needed to substantiate this. Upper jaws of polyptychitid are closely similar to previously described upper jaws of Jurassic ammonites, which indicates the conservatism of this part of the jaw apparatus. Together with shells and jaws of the Valanginian ammonites described herein, jaws of coleoids (likely belemnites) as well as arm hooks (onychites) have been found.
Neues Jahrbuch fiir Geologie und …, 2005
Aulacostephanus cf. subundorae (PAVLOW) is recorded for the first time from the Upper Jurassic Brenztaltrümmerkalk Member in Eastern Swabia (SW Germany). Together with Gravesia irius (D’ORBIGNY), this ammonite species of Subboreal origin is indicative of the youngest Late Kimmeridgian Autissiodorensis Zone. The co-occurring ammonites from this formation have a Submediterranean origin. Hence, a good correlation is possible between the Subboreal and the Submediterranean zonation around the Kimmeridgian/Tithonian boundary.