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| Shri devi Turner, Montanari & Norell, 2021 DOI: 10.1206/3965.1 |
Abstract
A new dromaeosaurid dinosaur, Shri devi, from the Late Cretaceous deposit of the Barun Goyot Formation at Khulsan, Mongolia, is described here. The Barun Goyot Formation (herein referred to as the Barun Goyot) is stratigraphically intermediate between the overlying Nemegt Formation and the underlying Djadokhta Formation, where much of the dromaeosaurid diversity has been reported to date. Sediments of the Barun Goyot are typically considered Upper Campanian in age. Although dromaeosaurid remains have been noted to occur in the Barun Goyot for decades, descriptive and taxonomic work has never been completed for the material. The holotype specimen (IGM 100/980) consists of a partially articulated individual preserving the right hind limb; left tibiotarsus; pelvis; and adjacent cervical, dorsal, and caudal vertebrae. IGM 100/980 is referable to a clade with Velociraptor based on the presence of a distinct ambiens tubercle located proximally on the anterior face of the pubis, a well-developed anterior tuberosity proximally located on the ischium, and a rounded longitudinal ischial ridge. It is distinguishable from Velociraptor mongoliensis based on a weak fourth trochanter (shared with all other dromaeosaurids) and deep anterior pedicular fossae in the cervical vertebrae; epipophyses in the last four cervicals are not raised but are instead represented by rugose circular scars. A suite of axial and appendicular characters are diagnostic for the new species. New discoveries including Shri devi allow for an improved understanding of dromaeosaurid anatomy, as well as the temporal and regional variation of the dromaeosaurid fauna of Mongolia and Inner Mongolia (Nei Mongol Autonomous Region, China), during the Late Cretaceous.
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| Pelvis and right hind limb of IGM 100/980 after initial stage of preparation. Top image is a left lateral view; bottom image is a ventral view of pelvis and medial view of hind limb. |
SYSTEMATIC PALEONTOLOGY
THEROPODA MARSH, 1884
COELUROSAURIA VON HUENE, 1914
MANIRAPTORA GAUTHIER, 1986
DROMAEOSAURIDAE MATTHEW AND BROWN, 1922
Shri devi, new genus, new species
Etymology: “Shri Devi,” Sanskrit for a female protector deity in Tibetan/Mongolian Buddhism. Part of the Gelug tradition and particularly venerated in Mongolia, Shri Devi (Palden Lhamo) rides a horse or donkey across an ocean of blood. Her accoutrements include a saddle of a flayed human skin, the book of the law, and the dice of fortune.
Formation and Locality: Bayun Goyot Formation, Khulsan, Ömnögov, Mongolia. No complete section for the Barun Goyot Formation at Khulsan has been constructed. What can be said is that IGM 100/980 is composed of the type of sediments present at other Djadoktha (Ukhaa Tolgod, Udan Sayr, and Bayn Dzak) and Djadoktha-like (Red Beds of Kheerman Tsav, Bayan Mandahu and Khulsan) localities. These are considered to be a mélange of aeolian, debris flow, fluvial, and lacustrine sediments. The environment of these sediments at time of deposition is considered to be an arid to semiarid region, with an equable climate (Dingus et al., 2008, Montanari et al., 2013).
Diagnosis: Referable to a clade including Velociraptor based on the presence of a distinct ambiens tubercle located proximally on the anterior face of the pubis, a well-developed anterior tuberosity proximally located on the ischium, and a rounded longitudinal ischial ridge. Distinguishable from Velociraptor mongoliensis based on a weak fourth trochanter (shared with all other dromaeosaurids), deep anterior pedicular fossae in the cervical vertebrae, epipophyses in the last four are not raised but instead represented by rugose circular scars. Shri devi is furthered diagnosed by the following combination of characters (asterisks denote autapomorphies): epipophysis on the first dorsal vertebra (d1) large and overhanging the posterior margin of the postzygapophysis*; two dorsoventrally aligned pleurocoels on d1 and d2*; posteriorly inclined scar on the lateral surface of the neural arch*; proportionally longer metatarsus (44% femur length compared to 35% femur length in IGM 100/986), and proportionally larger ungual phalanx on pedal digit 2 (1.01% MT II length compared to 90% MT II length in IGM 100/982 and IGM 100/985).
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| Pedal unguals of right pes after final preparation: A, digit I; B, digit II; C, digit III; D, digit IV |
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| Map depicting the geographic and temporal distribution of the Late Cretaceous dromaeosaurid fauna of Mongolia and Inner Mongolia (Nei Mongol Autonomous Region, China). |
Alan H. Turner, Shaena Montanari and Mark A. Norell. 2021. A New Dromaeosaurid from the Late Cretaceous Khulsan Locality of Mongolia. American Museum Novitates. 2020; 1-48. DOI: 10.1206/3965.1
