Arminisaurus

Arminisaurus (meaning "lizard of Arminius") is a genus of pliosaurid plesiosaur[1][2] that lived during the Lower Jurassic in present-day Germany. With Westphaliasaurus and Cryonectes, Arminisaurus is only the third plesiosaurian taxon that was described from the Pliensbachian stage.[1] The holotype and only known specimen is a fragmentary skeleton (about 40 percent complete), comprising an incomplete lower jaw, teeth, vertebrae and elements from the pectoral girdle and the paddles. The animal had an estimated body length of 3–4 metres (9.8–13.1 ft).[3]

Fragmentary lower jaw of Arminisaurus schuberti

Arminisaurus Temporal range: Early Jurassic, 190–182 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Arminisaurus schuberti skeleton, Naturkunde-Museum, Bielefeld
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Superorder:	†Sauropterygia
Order:	†Plesiosauria
Family:	†Pliosauridae
Genus:	†Arminisaurus Sachs & Kear, 2017
Type species
†Arminisaurus schuberti Sachs & Kear, 2017

Discovery and naming

The holotype was discovered in the early 1980s by the Hannover-based fossil collector Lothar Schulz in the now abandoned clay pit Beukenhorst II, located in the Bielefeld district of Jöllenbeck. The specimen was later given to amateur palaeontologist Siegfried Schubert who transferred it to the Naturkunde-Museum Bielefeld in 2015 (accession number: NAMU ES/jl 36052).[1]

Right scapula of Arminisaurus schuberti

Arminisaurus schuberti was described in 2018 by Sven Sachs and Benjamin Kear. The generic name Arminisaurus refers to Arminius, chieftain of the Cherusci tribe who defeated three Roman legions in the Battle of the Teutoburg Forest in 9 AD and is a homage to the region where the specimen was found. The species name schuberti honours Siegfried Schubert for his contributions (including numerous scientific publications[4][5]), enhancing the knowledge of the geology of the Bielefeld region.

Classification

Arminisaurus in its natural environment

A cladistic analysis found Arminisaurus schuberti to be a member of the family Pliosauridae,[1] a globally distributed plesiosaurian clade that is known from the Early Jurassic to the early Late Cretaceous.[6] Arminisaurus was a basal pliosaurid and differs from other members of the clade by a combination of characters found in the mandible, the neck vertebrae and the scapula.[1] These characters are shared with the plesiosaurian group Leptocleidia that occurred about 50 million years later in time.

The following cladogram by Sachs and Kear in 2017[1] shows the presumed relationships with related pliosaurids:

	Thalassiodracon           OUMNH J.28585       Hauffiosaurus longirostris       Hauffiosaurus tomistomimus     Hauffiosaurus zanoni               Attenborosaurus         Arminisaurus     Gallardosaurus       derived Pliosauridae

References

1. Sachs, S.; Kear, B. (2017). "A rare new Pliensbachian plesiosaurian from the Amaltheenton Formation of Bielefeld in northwestern Germany". Alcheringa: 1–14. doi:10.1080/03115518.2017.1367419.
2. "†Arminisaurus Sachs and Kear 2017". Paleobiology Database. Fossilworks. Retrieved 1 October 2018.
3. "Ancestor of sea reptile super predators found in Germany". University of Uppsala. Retrieved 27 October 2017.
4. Schubert, S. (2004). "Das Pliensbachium im Grenzbereich Unter- / Ober-Pliensbachium (Carixium / Domerium) von Pödinghausen in der Herforder Liasmulde". Berichte des Naturwissenschaftlichen Vereins für Bielefeld und Umgebung. 44: 7–39.
5. Schubert, S. (2007). "Das Ober-Pliensbachium (Domerium) der Herforder Liasmulde—Teil 1—Die Aufschlüsse". Geologie und Paläontologie in Westfalen. 68: 1–90.
6. Ketchum, H.F.; Benson, R.B.J. (2010). "Global interrelationships of Plesiosauria (Reptilia, Sauropterygia) and the pivotal role of taxon sampling in determining the outcome of phylogenetic analyses". Biological Reviews of the Cambridge Philosophical Society. 85 (2): 361–392. doi:10.1111/j.1469-185X.2009.00107.x. PMID 20002391.