A new specimen of Solnhofia parsonsi from the Upper Jurassic (Kimmeridgian) Plattenkalk deposits of Painten (Bavaria, Germany) and comments on the relationship between limb taphonomy and habitat ecology in fossil turtles

PLOS ONE RESEARCH ARTICLE A new specimen of Solnhofia parsonsi from the Upper Jurassic (Kimmeridgian) Plattenkalk deposits of Painten (Bavaria, Germany) and comments on the relationship between limb taphonomy and habitat ecology in fossil turtles a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 Felix J. Augustin ID1*, Márton Rabi1,2, Frederik Spindler ID3, Panagiotis Kampouridis1, Josephina Hartung1, Raimund Albersdörfer3, Andreas T. Matzke3 1 Department of Geosciences, University of Tübingen, Tübingen, Germany, 2 Natural Sciences Collections, Martin Luther University Halle-Wittenberg, Halle, Germany, 3 Dinosaurier Museum Altmühltal, Denkendorf, Germany * OPEN ACCESS Citation: Augustin FJ, Rabi M, Spindler F, Kampouridis P, Hartung J, Albersdörfer R, et al. (2023) A new specimen of Solnhofia parsonsi from the Upper Jurassic (Kimmeridgian) Plattenkalk deposits of Painten (Bavaria, Germany) and comments on the relationship between limb taphonomy and habitat ecology in fossil turtles. PLoS ONE 18(7): e0287936. https://doi.org/ 10.1371/journal.pone.0287936 Editor: Dawid Surmik, University of Silesia, POLAND Received: March 18, 2023 Accepted: June 15, 2023 Published: July 26, 2023 Copyright: © 2023 Augustin et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Abstract The limestones of the Solnhofen area in southern Germany are one of the most important fossil Lagerstätten from the entire Mesozoic era, especially famous for the exquisitely preserved vertebrates. The turtles from the Solnhofen Limestone have been always of special interest because they include some of the best-preserved specimens from the Mesozoic. Here, we describe a new turtle specimen from the Torleite Formation (Kimmeridgian) of Painten and refer it to the thalassochelydian turtle Solnhofia parsonsi based on the presence of a unique combination of characters. The far majority of morphological differences from previously published specimens can be explained by ontogeny as the new specimen represents a larger, more ossified, and presumably older individual. Additionally, the specimen from Painten is the first described specimen of S. parsonsi preserving the largely complete and articulated limbs, the preservation of which indicates that the taxon did not possess stiffened paddles present in more pelagic marine turtles and is consistent with a previously inferred nearshore marine lifestyle. Contrary to previous inferences, we argue that taphonomic preservation of digits in articulated fossil turtles from laminated deposits cannot be used alone to infer marine or freshwater habitat. Finally, the new specimen from Painten is only the second, for which detailed information on its stratigraphic position and locality of origin are known. Data Availability Statement: All relevant data are within the paper. Funding: The author(s) received no specific funding for this work. Introduction Competing interests: The authors have declared that no competing interests exist. The Upper Jurassic laminated limestone (German Plattenkalk) of the Franconian Alb in southern Germany represents one of the most important fossil Lagerstätten of the entire Mesozoic PLOS ONE | https://doi.org/10.1371/journal.pone.0287936 July 26, 2023 1 / 17 PLOS ONE Solnhofia parsonsi from the Upper Jurassic of Painten era. Especially the exquisitely preserved vertebrates, many with preserved soft tissues, made these deposits world famous, which are also known as the Solnhofen limestone, named after one of the most important localities on the Franconian Alb. Aside from abundant and diverse fishes–certainly the most common vertebrate group–the Plattenkalk of southern Germany yielded the remains of many different tetrapod clades, including ichthyosaurs, plesiosaurs, squamates, crocodyliforms, turtles, pterosaurs, non-avian theropod dinosaurs, and basal avialans. Among these groups, the turtles of the Solnhofen limestone and similar deposits in southwestern Germany, Switzerland and France have become the focus of detailed studies recently, concerning both their taxonomy and their palaeoecology (e.g., [1–6]). Despite this growing interest, many important turtle specimens that have been unearthed in recent years still await detailed study. This material, including some of the best-preserved turtle specimens recovered thus far, is, however, crucial for a better understanding of the diversity and ecology of the turtles from the Plattenkalk deposits of Europe. Such important new turtle specimens, currently lacking detailed study, are known primarily from the Plattenkalk deposits of the Rygol Quarry near Painten, located on the southeastern Franconian Alb. Although this quarry has been operated since the 1950s, systematic excavations have only relatively recently been conducted, first by Wolfgang Haeckel and later by the private Albersdörfer institute [7]. These excavations have yielded a diverse vertebrate fauna [7–11], including several exquisitely preserved, and yet to be described turtle specimens [10]. A recent examination of the fossil vertebrate collection from the Plattenkalk of Painten, housed in the Dinosaurier Museum Altmühltal (DMA), also led to the examination of DMA-JP-2004/ 005, an exquisitely preserved turtle specimen that has provisionally been referred to as Solnhofia sp. (Fig 1). In this paper, a detailed description of this specimen is provided and, based on a thorough comparison with the two previously recognized species assigned to the genus Solnhofia, it is assigned to Solnhofia parsonsi. The genus Solnhofia, with the type species S. parsonsi, was erected by Gaffney (1975) [12] based on two nearly complete skulls from the Upper Jurassic of Bavaria and Solothurn (Switzerland). A third specimen of S. parsonsi comprising the skull and an associated postcranium from Schamhaupten (Bavaria) has subsequently been referred to this species [13]. Additional cranial and postcranial material from the Upper Jurassic of France was later referred to Solnhofia sp. and Solnhofia cf. parsonsi [14–16], although the taxonomic affinities of this material are not entirely clear [2, 15]. A second species, S. brachyrhyncha, was erected recently and was based on a largely complete skull and associated postcrania from Solothurn, Switzerland [4]. Recent phylogenetic analyses have consistently placed Solnhofia in the Thalassochelydia [6, 17, 18], a group of predominantly coastal marine turtles from the Upper Jurassic and Lower Cretaceous of Europe and South America [2]. Moreover, based on morphological comparisons, Solnhofia has also been suggested to belong to the Sandownidae [19], a group that is likely part of Thalassochelydia [4, 6, 17, 19]. Institutional abbreviations BMM, Bürgermeister-Müller-Museum, Solnhofen, Germany; DMA, Dinosaur (...truncated)