Klug Christian, Schweigert Günter, Tischlinger Helmut, Pochmann Helmut
Paläontologisches Institut Und Museum, Universität Zürich, Karl-Schmid-Strasse 4, 8006 Zurich, Switzerland.
Staatliches Museum Für Naturkunde, Rosenstein 1, 70191 Stuttgart, Germany.
Swiss J Palaeontol. 2021;140(1):3. doi: 10.1186/s13358-020-00215-7. Epub 2021 Jan 18.
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 reproductive organs show traces of what might have been spermatophores, thus supporting the hypothesis that the microconchs represented the males.
菊石的软体部分鲜有描述。在此，我们记录了来自德国艾希施泰特附近温特施霍夫提通阶早期的一种球旋菊石的软体部分。索尔nhofen群岛海盆的特殊沉积条件促成了这种特殊的保存状态。在此，我们记录这一发现，并尝试将其各部分与诸如消化道、生殖器官、带鳃的外套腔以及水管等各种器官进行不同程度的保留性同源对比。我们也考虑了其他解释。我们认为，软体部分要么是通过埋藏学方式（在影响附着结构的尸解过程之后）与壳体分离，要么是在一次失败的捕食过程中分离，即捕食者（鱼类或头足类动物）从壳体上移除了软体部分，但随后又将其丢弃。这一发现很有趣，因为它增加了通常隐藏在壳体内的菊石解剖学知识。生殖器官显示出可能是精荚的痕迹，从而支持了微壳代表雄性的假说。
