The jaw apparatus of the genus Kachpurites (Ammonoidea, Craspeditidae), consisting of a pair of aptychi and a beakshaped upper jaw is described and figured for the first time. A new aptychus species Praes triaptychus fulgens sp. nov. is established. Aptychi of this species are elongated triangular, weakly ribbed, with a well developed inner organic layer and a considerably thinner, often poorly preserved external calcite layer. Specimens of the type series were found in the body chamber of ammonites Kachpurites fulgens (Trautschold), from the Upper Jurassic (Upper Volgian) Kachpurites fulgens Zone of Moscow and the Moscow Region.
The article is devoted to the first finding of the jaw apparatus (aptychi and an upper jaw) in the body chambers of Upper Jurassic (Upper Volgian) ammonites Kachpurites fulgens (family Craspeditidae). The aptychi, described in this paper, are the first finding of ammonite jaws in the Moscow region and the first Craspeditid aptychi found in situ in ammonite body chambers. Photos of the aptychi and upper jaw are shown in the article, a new formal species Praestriaptychus fulgens is described.
In 2014 authors could submit manuscripts to the Russian Paleontological Journal only in Russian. Unfortunately, in the English translation, not by fault of the author, semantic errors appeared: the translator confused the inner and outer plates of the upper jaw of ammonites. On page 583 the external (outer) lamella of the upper jaw is named twice as an inner lamella. As printed in the article: "It should be said that quite often the upper jaws of Jurassic and Cretaceous ammonites (belonging to Aptychophora) are found without the INNER lamella". However, "without the OUTER lamella" should have been written. Further along in the same paragraph, the error persists: "suggest that the records of jaws lacking the INNER lamella are the product of separation of two loosely connected elements in the jaw, rather than the reduction of the outer lamella", whereas it should have stated that: "suggest that the records of jaws lacking the OUTER lamella are the product of separation of two loosely connected elements in the jaw, rather than the reduction of the outer lamella”.
Ammonoidea, Craspeditidae, aptychi, jaw apparatus, Upper Volgian, Russia