Archosaur footprints (cf. Brachychirotherium ) with unusual morphology from the Upper Triassic Fleming Fjord Formation (Norian–Rhaetian) of East Greenland

Abstract

The Ørsted Dal Member of the Upper Triassic Fleming Fjord Formation in East Greenland is well known for its rich vertebrate fauna, represented by numerous specimens of both body and ichnofossils. In particular, the footprints of theropod dinosaurs have been described. Recently, an international expedition discovered several slabs with 100 small chirotheriid pes and manus imprints (pes length 4–4.5 cm) in siliciclastic deposits of this unit. They show strong similarities with Brachychirotherium, a characteristic Upper Triassic ichnogenus with a global distribution. A peculiar feature in the Fleming Fjord specimens is the lack of a fifth digit, even in more deeply impressed imprints. Therefore, the specimens are assigned here tentatively to cf. Brachychirotherium. Possibly, this characteristic is related to the extremely small size and early ontogenetic stage of the trackmaker. The record from Greenland is the first evidence of this morphotype from the Fleming Fjord Formation. Candidate trackmakers are crocodylian stem group archosaurs; however, a distinct correlation with known osteological taxa from this unit is not currently possible. While the occurrence of sauropodomorph plateosaurs in the bone record links the Greenland assemblage more closer to that from the Germanic Basin of central Europe, here the described footprints suggest a Pangaea-wide exchange.Supplementary material:Three-dimensional model of cf. Brachychirotherium pes–manus set (from MGUH 31233b) from the Upper Triassic Fleming Fjord Formation (Norian–Rhaetian) of East Greenland as pdf, ply and jpg files (3D model created by Oliver Wings; photographs taken by Jesper Milàn) is available at https://doi.org/10.6084/m9.figshare.c.2133546

Cyclotosaurus naraserluki,sp. nov., a new Late Triassic cyclotosaurid (Amphibia, Temnospondyli) from the Fleming Fjord Formation of the Jameson Land Basin (East Greenland)

“…Numerous Grallator and cf. Brachychirotherium tracks are seen on upper bedding planes of the wave-rippled siltstones, the former attributed to theropod dinosaurs and the latter to stem crocodylians (Clemmensen et al, 2016;Klein et al, 2016).…”

An introduction to the Mesozoic biotas of Scandinavia and its Arctic territories

“…Here, body fossils and footprints evidence various dinosaurian taxa, especially sauropodomorphs, together with plagiosaurid and capitosaurian temnospondyl amphibians, rare rhamphorhynchoid pterosaurians, and early mammaliforms (e.g. Bendix-Almgreen 1976;Jenkins et al 1994;Milàn et al 2012a;Sulej et al 2014;Clemmensen et al 2015;Hansen et al 2015;Klein et al 2015). Fragmentary Late Triassic (CarnianRhaetian) temnospondyls are likewise known from both Svalbard and southern Sweden and references therein), and coincide with lush vegetation comprising ginkgoes, cycads and bennettites, lycophytes, sphenophytes, and ferns (Vajda et al 2013).…”

“…The coeval chronicle of Triassic terrestrial faunas is not well represented until the NorianRhaetian of the Fleming Fjord Formation in Jameson Land, East Greenland (Klein et al 2015;. Here, body fossils and footprints evidence various dinosaurian taxa, especially sauropodomorphs, together with plagiosaurid and capitosaurian temnospondyl amphibians, rare rhamphorhynchoid pterosaurians, and early mammaliforms (e.g.…”

“…In the Scandinavian territories, this is evidenced by successions from East Greenland (Klein et al 2015). These reveal an abrupt replacement of the Rhaetian 'Lepidopteris flora' (typified by seed ferns, Taxodiaceae and the enigmatic Ricciisporites-producing plants) by the Hettangian 'Thaumatopteris flora' (Harris 1931), which was dominated by ferns, Cheirolepidaceae, Pinaceae and new groups of cycadophytes (Vajda et al 2013).…”

Digital Photogrammetry Applied to Footprints of Medium and Large Mammalfrom Two Forest Fragments in the Area Influence of the Ilha Solteira Hydroelectric Complex, Brazil / Fotogrametria Digital Aplicada a Pegadas De Mamíferos Médios E Grandes De Dois Fragmentos De Floresta Na Área De Influência Do Complexo Hidroeléctrico Da Ilha Solteira, Brasil

“…Digital photogrammetry is a technique that enables the development of threedimensional digital models based on photographs. The use of this technique is already established in other areas of biology, as in the study of fossil footprints (KLEIN et al, 2015;LALLENSACK et al, 2015). To date, however, this tool has not been extensively applied to studies of footprints of living mammals.…”