Novel track morphotypes from new tracksites indicate increased Middle Jurassic dinosaur diversity on the Isle of Skye, Scotland

Abstract

Dinosaur fossils from the Middle Jurassic are rare globally, but the Isle of Skye (Scotland, UK) preserves a varied dinosaur record of abundant trace fossils and rare body fossils from this time. Here we describe two new tracksites from Rubha nam Brathairean (Brothers' Point) near where the first dinosaur footprint in Scotland was found in the 1980s. These sites were formed in subaerially exposed mudstones of the Lealt Shale Formation of the Great Estuarine Group and record a dynamic, subtropical, coastal margin. These tracksites preserve a wide variety of dinosaur track types, including a novel morphotype for Skye: Deltapodus which has a probable stegosaur trackmaker. Additionally, a wide variety of tridactyl tracks shows evidence of multiple theropods of different sizes and possibly hints at the presence of large-bodied ornithopods. Overall, the new tracksites show the dinosaur fauna of Skye is more diverse than previously recognized and give insight into the early evolution of major dinosaur groups whose Middle Jurassic body fossil records are currently sparse.

First and most northern occurrence of a thalattosuchian crocodylomorph from the Jurassic of the Isle of Skye, Scotland

“…The Inner Hebrides boasts one of the most complete fossiliferous Middle Jurassic sequences in the world, and the Isle of Skye, in particular, has become a globally important site for Jurassic research (Clark, 1993(Clark, , 2001(Clark, , 2018Morton and Hudson, 1995;Anquetin, 2010;Wills et al, 2014;Brusatte et al, 2015;Young et al, 2016;Yi et al, 2017;dePolo et al, 2018dePolo et al, , 2020Panciroli et al, 2017Panciroli et al, , 2018Panciroli et al, , 2019. The specimen described here was found in 2018 by Gert Greitens as a loose cobble at Prince Charlie's Cave, north of Portree (Fig.…”

“…Here we report new crocodylomorph material (NMS G.2020.11.1) from the Jurassic of the Isle of Skye, Scotland. This new specimen is the sixth crocodylomorph taxon (Table 1) (Evans and Waldman, 1996;Wills et al, 2014;Young et al, 2016;Yi et al, 2017) from the increasingly diverse tetrapod assemblage of the Jurassic lagoonal/coastal deposits of Skye (Clark, 1993;Anquetin, 2010;Brusatte et al, 2015;Young et al, 2016;dePolo et al, 2018dePolo et al, , 2020Panciroli et al, 2017Panciroli et al, , 2018Panciroli et al, , 2019. Extensive comparisons with contemporaneous terrestrial and marine tetrapods demonstrate that this specimen shares affinities with thalattosuchian teleosauroids.…”

“…The Inner Hebrides were home to diverse terrestrial and marine faunas during the Jurassic. Since the earliest discoveries by Hugh Miller (1858), an ever increasing variety of amphibians (Evans and Waldman, 1996), lepidosauromorphs (Waldman and Evans, 1994), turtles (Anquetin, 2010), dinosaurs (Clark, 2018;dePolo et al, 2018dePolo et al, , 2020, ichthyosaurs (Brusatte et al, 2015), plesiosaurs (Clark, 1993), crocodylomorphs (Evans and Waldman, 1996;Wills et al, 2014;Young et al, 2016;Yi et al, 2017), and mammaliamorphs (Waldman and Savage, 1972;Panciroli et al, 2017Panciroli et al, , 2018Panciroli et al, , 2019 Pérez-García, 2012). However, as in Eileanchelys waldmani from Skye, the vertebrae of turtles differ from those of crocodylomorphs and NMS G.2020.11.1 in being platycoelous (Joyce et al, 2009;Anquetin, 2010;Pérez-García, 2012).…”

A skeleton from the Middle Jurassic of Scotland illuminates an earlier origin of large pterosaurs

“…The skeleton was embedded in a well-sorted lagoonal bioclastic limestone (rich in Neomiodon, ostracods, and conchostracans), which overlies and infills dinosaur trackways impressed in subaerially exposed mudstones. 11 These units formed in a marginal marine/nearshore environment that fluctuated between submerged and exposed. (G-H) Reconstruction of skull in dorsal (G) and ventral (I) views and skeleton in lateral view (H).…”

First dinosaur from the Isle of Eigg (Valtos Sandstone Formation, Middle Jurassic), Scotland

“…Finds from other formations within the Great Estuarine Group and underlying units include a theropod limb bone , an isolated theropod tooth (Young et al 2019), isolated sauropod teeth (Barrett 2006), and a thyreophoran proximal ulna and radius (Clark 2001). Dinosaur ichnofossil tracks range from isolated tracks on loose boulders (from the Valtos Sandstone Formation, Clark & Gavin 2016, from other formations in the Great Estuarine Group, Andrews & Hudson 1984;Clark et al 2005), to extensive in situ trackway sites (from the Valtos Sandstone Formation, Marshall 2005, and from other formations in the Great Estuarine Group, Clark et al 2004;Marshall 2005;Brusatte et al 2016;dePolo et al 2018dePolo et al , 2020.…”