Browsing by Autor "Marko Yurac"

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Diverse dinosaur tracks from the Upper Jurassic – Lower Cretaceous Chacarilla Formation of Quebrada de Arcas, northeast Chile: Evidence of high ichnodiversity in an arid palaeoenviroment
(Elsevier BV, 2025) Vincenzo Gesualdi; Matteo Belvedere; Marko Yurac; Dorothee Hippler; Nejla Hurem; Christian Salazar; Jose Nicanor Mendez; Christian A. Meyer
We report diverse dinosaur tracks from siltstone to fine-grained sandstone facies of the Chacarilla Formation, Quebrada de Arcas of northeast Chile. Track-bearing surfaces were studied using 3D modelling and false-colour depth maps, derived from UAV photographs. Five morphotypes are identified based on morphology and morphometric criteria. Morphotype I comprises rounded tracks with a consistent narrow-gauge and resembles the sauropod ichnogenus, Parabrontopodus ; diplodocids or titanosaurids are probable trackmakers. Morphotype II is assigned to the theropod ichnotaxon Abelichnus astigerrae and comprises some of the largest theropod tracks ever recorded from South America with a maximum footprint length of 51 cm; the trackmaker was most likely a large carcharodontosaurid, such as Giganotosaurus carolinii . Morphotype III is an indeterminate theropod track, which shows a distinctive and prominent metatarsal impression, but does not closely match any ichnotaxon although it bears some morphometrical affinity to Changpeipus carbonicus . The Morphotypes IV and V both belong to small-sized theropod trackmakers, and resemble Grallatoridae and Kayentapus -like forms, respectively. Additional theropod material cannot be assigned to specific morphotypes or trackmakers, due to poor preservation. Our findings show the existence of three distinct size classes (small, medium and large) of theropod morphotypes and point to a high ichnodiversity at the Jurassic-Cretaceous transition in the subtropical arid environments of Gondwana. • New track-bearing surfaces are found in the Chacarilla Fm. in Quebrada des Arca. • Five morphotypes: one of sauropod and four for different size theropod tracks are defined. • Huge theropod tracks have been found and identified.
The first gravid ichthyosaur from the Hauterivian (Early Cretaceous): a complete <i>Myobradypterygius hauthali</i> von Huene, 1927 excavated from the border of the Tyndall Glacier, Torres del Paine National Park, southernmost Chile
(Taylor & Francis, 2024) Judith Pardo-Pérez; Matthew A. Malkowski; Patricio Zambrano; Dean R. Lomax; Cristina Gascó Martín; Jonatan Kaluza; Héctor Ortíz; Alan Marín; Rodrigo Villa-Martínez; Marko Yurac
Upper Jurassic dinosaur tracks from the Majala Formation in the Huatacondo area (Tarapacá Basin, Chile): reappraisal of known localities and new tracksite discoveries
(Springer Nature, 2025) Marko Yurac; Matteo Belvedere; Christian Salazar; Jose Nicanor Mendez; Christian A. Meyer
Abstract The bone record of non-avian dinosaurs from Chile consists of sauropods, theropods, ornithopods, and rare thyreophorans. However, the ichnological record is potentially even more abundant and plays a significant role in supplementing and enlarging the Chilean dinosaur record. Rich track-bearing levels, dated from the Upper Jurassic to the Lower Cretaceous, are known mainly from northern Chile. This study describes for the first time a stratigraphic section of the Majala Formation (late Oxfordian) in the Quebrada Huatacondo. In this section, five track-bearing levels were recorded confirming the presence of ichnites of giant (lengths between 51 and 52.8 cm), large (lengths between 43.5 and 46.5 cm) and medium (lengths between 25 and 27 cm) theropods. One surface (Maj5) has more than 25 footprints of minute to small theropods (footprints lengths ranging from 8 to 13 cm). Morphological parameters from the small footprints are similar to Carmelopodus , Grallator , and Therangospodus . Meanwhile, some similarities were observed with Kayentapus and Megalosauripus for the range of medium to giant footprints. When comparing track sizes from Quebrada Huatacondo with other theropod tracks from the Tarapacá Basin (Quebrada Chacarilla and Río San Salvador localities), their dimensions and morphology are similar, but the small tracks are substantially smaller than those from the other localities and constitute to the smallest footprints found on the western margin of Gondwana for this time. These tracks and trackways represent the oldest dinosaur footprints reported for Chile and the western margin of Gondwana.