Table 1. Overview and supplementary information about the analyzed eosauropterygian specimens.

Species	Higher taxon	Specimen number	Bone	Plane of section	Previous studies	Geological time	Reference to geological time
Anarosaurus heterodontus	Pachypleurosauridae	Wijk. 06-38fe	Femur	Transverse	Klein (2012)	Middle Triassic	Klein (2012)
Neusticosaurus edwardsii	Pachypleurosauridae	PIMUZ T3455	Humerus	Transverse	Sander (1989, 1990)	Middle Triassic	Carroll & Gaskill (1985)
Nothosaurus sp.	Nothosauroidea	IGWH 21	Femur	Transverse	Klein (2010)	Middle Triassic	Rieppel (2000) and Rieppel & Wild (1996)
Pistosaurus longaevus	Pistosauroidea	SMNS 84825	Humerus	Transverse	Krahl, Klein & Sander (2013)	Middle Triassic	Geissler (1895) and Sues (1987)
Plesiosaurus dolichodirus	Plesiosauria	STIPB R90	Femur	Transverse	Wintrich et al. (2017)	Early Jurassic	Conybeare (1824)
Rhaeticosaurus mertensi	Plesiosauria	LWL-MfN P 64047 section PM 3	Femur	Transverse	Wintrich et al. (2017)	Late Triassic	Wintrich et al. (2017)
Cryptoclidus eurymerus	Plesiosauria	STIPB R 324	Femur	Transverse	Wintrich et al. (2017)	Middle Jurassic	Brown & Cruickshank (1994)
Elasmosauridae indet.	Plesiosauria	OMNH MV 85	Humerus	Transverse	Wintrich et al. (2017)	Late Cretaceous	Williston (1906)

Note:

Abbreviations of collection numbers: Wijk, National Museum of Natural History Naturalis, Leiden, The Netherlands; PIMUZ, Paleontological Institute and Museum of the University of Zurich, Switzerland; IGWH, Institute of Geosciences of the Martin-Luther-University Halle-Wittenberg, Germany; SMNS, Stuttgart State Museum of Natural History, Germany; STIPB, Steinmann-Institute, Division of Paleontology, University of Bonn, Germany; LWL-MfN, Landschaftsverband Westfalen-Lippe, Museum für Naturkunde, Münster, Germany; OMNH, Osaka Museum of Natural History, Osaka, Japan. Histological thin sections are housed in the histology slide collections of the Steinmann Institute, University of Bonn, Germany.