Saturday, September 16, 2017

[Paleontology • 2017] Arminisaurus schuberti • A Rare New Pliensbachian Plesiosaurian from the Amaltheenton Formation of Bielefeld in northwestern Germany


Arminisaurus schuberti  Sachs & Kear, 2017


 Artwork by Joschua Knüppe  hyrotrioskjan.deviantart.com 

Abstract

We describe a new plesiosaurian from the upper Pliensbachian Amaltheenton Formation of Bielefeld in northwestern Germany. The taxon is based upon an incomplete associated skeleton comprising part of the right mandibular ramus, several teeth, a series of cervical, pectoral, dorsal and caudal vertebrae, as well as ribs, limb girdle elements including a nearly complete right scapula, and various distal limb bones. A unique character state combination serves to distinguish the Amaltheenton Formation remains from other previously documented Early Jurassic plesiosaurians. The most important features are the presence of a longitudinal notch incising the posterior rim of the glenoid fossa and retroarticular process, and a pronounced ventrolateral shelf on the scapula, both of which constitute derived states otherwise shared with Early Cretaceous leptocleidians. However, phylogenetic analysis using a ‘total group’ Plesiosauria data-set that specifically accommodates for Pliensbachian taxa unanimously placed the Amaltheenton Formation plesiosaurian among Early–Middle Jurassic pliosaurids. This discovery is significant because it reveals unexpected homoplasy, but also because it establishes what is only the third formally named plesiosaurian taxon thus far documented from Pliensbachian strata worldwide.

Key words: Plesiosauria, Early Jurassic, pliosaurid, ‘Pliensbachian gap’. 


Systematic palaeontology
SAUROPTERYGIA Owen, 1860
PLESIOSAURIA de Blainville, 1835
PLIOSAURIDAE Seeley, 1874

Arminisaurus gen. nov. 

Etymology. Armini-, referring to Arminius (Armin), chieftain of the Germanic Cherusci tribe who defeated a Roman army in the Battle of the Teutoburg Forest; and -saurus Latinized Greek for ‘lizard’. 

Arminisaurus schuberti sp. nov.

Etymology: The species name honours Mr. Siegfried Schubert, who recovered the holotype NAMU ES/jl 36052 for science and has contributed to palaeontological research in the Bielefeld region for the last decade.

Type locality and unit. Beukenhorst-II claypit in the Jöllenbeck district of Bielefeld, North Rhine-Westphalia, northwestern Germany. Type stratum is the upper Pliensbachian (Lower Jurassic) middle Amaltheus subnodosus Subzone (Amaltheus margaritatus Zone) of the Amaltheenton Formation.



Sven Sachs and Benjamin P. Kear. 2017. A Rare New Pliensbachian Plesiosaurian from the Amaltheenton Formation of Bielefeld in northwestern Germany. Alcheringa.  DOI: 10.1080/03115518.2017.1367419

 Ancestor of sea reptile super-predators found in Germany http://phy.so/424681896  via @physorg_com

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