Knoetschkesuchus langenbergensis gen. nov. sp. nov., a new atoposaurid crocodyliform from the Upper Jurassic Langenberg Quarry (Lower Saxony, northwestern Germany), and its relationships to Theriosuchus

Abstract

We report a new, small-sized atoposaurid crocodyliform from the Upper Jurassic of Langenberg, Northeastern Germany. Atoposaurids are small-sized Mesozoic crocodyliforms of mainly European distribution, which are considered to be phylogenetically close to the origin of Eusuchia. Knoetschkesuchus langenbergensis gen. nov. sp. nov. is represented by two well-preserved skulls and additional cranial and postcranial remains representing different ontogenetic stages. 3D reconstructions of a juvenile skull based on micro-computed tomography allow the most detailed description of cranial remains of any atoposaurid hitherto presented. Our new analysis contradicts previous preliminary assignment of the Langenberg atoposaurids to Theriosuchus. Knoetschkesuchus gen. nov. is characterized in particular by the presence of two dental morphotypes in the maxilla and dentary, slit-like secondary choanae within a narrow groove on the surface of the pterygoid, absence of lacrimonasal contact, presence of an antorbital foramen and an external mandibular fenestra, and proportional characters of the interorbital and intertemporal region. A similar combination of characters allows attribution of Theriosuchus guimarotae to Knoetschkesuchus, forming the new combination Knoetschkesuchus guimarotae. Our analysis provides an osteological basis for the separation of Theriosuchus and Knoetschkesuchus and helps further delineate generic differences in other closely related crocodylomorphs. Our phylogenetic analysis corroborates inclusion of Knoetschkesuchus into Atoposauridae and supports a position of Atoposauridae within Eusuchia.

Peer Review #1 of "Late Jurassic theropod dinosaur bones from the Langenberg Quarry (Lower Saxony, Germany) provide evidence for several theropod lineages in the central European archipelago (v0.1)"

“…We tentatively identify DfMMh/FV1/19 as belonging to a theropod dinosaur. Unfortunately, unguals of alternative taxa, such as crocodiles, lizards, and testudinids, all groups for which fossils have been found and described from the Langenberg Quarry (Thies, Windorf & Mudroch, 1997;Karl et al, 2006;Karl et al, 2008;Jansen & Klein, 2013;Richter et al, 2013;Schwarz et al, 2017), are even less described in the literature than theropod unguals, so that the following comments are largely based on personal observations. Testudinid taxa that appear in the Lower Saxony Basin, including the Langenberg Quarry (e.g.…”

“…Among them are the only known Jurassic mammals from Germany, the pinheirodontid multituberculate Teutonodon langenbergensis (Martin et al, 2016), the paulchoffatiid multituberculate Cimbriodon multituberculatus (Martin et al, 2019), and the large morganucodontan mammaliaform Storchodon cingulatus (Martin et al, in press). Additionally, a threedimensionally preserved articulated skeleton of a small pterosaur (Fastnacht 2005), teeth and skeletons of the small non-marine atoposaurid crocodilian Knoetschkesuchus langenbergensis (Schwarz et al 2017), various remains of marine crocodylians (Karl et al, 2006;2008) and the partial skeleton of a paramacellodid lizard (Richter et al 2013) have been reported. Diverse marine turtle material (including several skulls) comprises cf.…”

Late Jurassic theropod dinosaur bones from the Langenberg Quarry (Lower Saxony, Germany) provide evidence for several theropod lineages in the central European archipelago

“…Among them are the only known Jurassic mammals from Germany, the pinheirodontid multituberculate Teutonodon langenbergensis (Martin et al, 2016), the paulchoffatiid multituberculate Cimbriodon multituberculatus (Martin et al, 2019a), and the large morganucodontan mammaliaform Storchodon cingulatus (Martin et al, 2019b). Additionally, a three-dimensionally preserved articulated skeleton of a small pterosaur (Fastnacht, 2005), teeth and skeletons of the small non-marine atoposaurid crocodilian Knoetschkesuchus langenbergensis (Schwarz, Raddatz & Wings, 2017), various remains of marine crocodylians (Karl et al, 2006;Karl et al, 2008) and the partial skeleton of a paramacellodid lizard (Richter et al, 2013) have been reported. Diverse marine turtle material (including several skulls) comprises cf.…”

An unusual small-bodied crocodyliform from the Middle Jurassic of Scotland, UK, and potential evidence for an early diversification of advanced neosuchians

“…However, the various phylogenetic analyses appear to converge on a divergence between the large-bodied and primarily aquatic neosuchian clades (Pholidosauridae þ Dyrosauridae) and the relatively smaller-bodied, terrestrial or semi-aquatic clades (although the position of Goniopholididae is variable; Adams 2014; Turner 2015; Young et al 2016b;Schwarz et al 2017). Yet little is known about neosuchians before the Late Jurassic due to a patchy non-marine fossil record (Mannion et al 2015;Tennant et al 2016b).…”