Corona, the Swabian Alb, and Africa
Ever since my childhood, so since I was about seven years old, I have been familiar with the mountains of the Swabian Alb. The fossils I found while hiking inspired my decision to become a palaeontologist.
I am most familiar with the area of the Zollernalb. In autumn of the very hot year 2003 I checked a freshly ploughed field in the vicinity of the Kornbühl hill, between the villages of Salmendingen and Ringingen, for fossils and discovered a piece of rock with a fossil nautilus inside.
I had already been checking this field for fossils for decades and found many rare ammonites. Nautilids, however, are more than 100 times rarer than ammonites in these Jurassic strata. Moreover, the specimen strikingly differed in its broad, angular whorl section from all specimens in the large collection of Late Jurassic nautilids in the museum (there are four drawers filled with these fossils). At that time, I was occupied with numerous other scientific projects; hence, I consigned my still indeterminate specimen to the collection.
This year, 2020, the Corona pandemic upended numerous plans. To reduce the number of personal contacts, working from home became a preferred option at the Natural History Museum, as almost everywhere else. I was wondering which projects could be easily done at home – and I remembered my small nautilus, which then became one of my “Corona projects”.
After intensive internet research using freely available scientific literature, I was able to identify my specimen as “Somalinautilus antiquus”. The sole specimen of this species known to date was described in 1905 by palaeontologists from Munich; it was discovered in the area of present-day Ethiopia. The specimen had been collected together with numerous other Jurassic fossils during a scientific expedition. I asked a friend and colleague in Munich about the nautilid from Ethiopia, and indeed the specimen was still present in the collection of the Bavarian State Palaeontological collection in Munich. In the original publication there had been no information given as to where the material was housed; therefore, other researchers had believed the specimen to be lost.
Thanks to numerous and well-known ammonites collected from the same limestone bed, my specimen from the Zollernalb is much easier to date than the specimen from Ethiopia –hunting for fossils on this field for decades finally paid off! The Somalinautilus specimen proves a faunal exchange occurred between widely separated marine areas during the Late Jurassic, 150 million years ago. The only plausible explanation is that geographic barriers normally hampering such a wide species distribution lost their function during times of high sea-level. In addition, my literature research showed that nautilids of the genus Somalinautilus migrated into the seas of present-day Central Europe during several short intervals in the Middle Jurassic. Unexpectedly, when looking for such material in our own collection, I found another specimen of this genus from the Middle Jurassic of eastern Swabia. That specimen became part of the collection in 1949 and nobody since then had been able to identify it.
The results of my “Corona project” are now published in the international journal “Neues Jahrbuch für Geologie und Paläontologie”. Encouragingly, the reviewers of the journal were pleased that somebody has started to become interested in fossil nautilids. I am curious as to whether my publication will encourage more research on this topic. Perhaps more specimens of this small nautilid will be discovered – either in the field or in other scientific collections.
References
Schweigert, G. 2020: First records of Somalinautilus (Cephalopoda: Nautiloidea) from the Jurassic of Southern Germany – inferences for trans-provincial migrations. – Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen, 298(2): 137-146.
