The Dromaeosaurs were a group of small-to-medium sized Theropod Dinosaurs, closely related to the earliest Birds. They are noted for the presence of an enlarged and highly curved claw on their second toe, a long, straight tail formed from tightly interlocked caudal vertebrae, and the presence of feathers. The group were widespread, with numerous fossils from the Cretaceous of Asia, North and South America, and Europe, although their Bird-like, often delicate skeletons did not usually preserve well, so most species are known only from fragmentary remains. One area where more complete Dromaeosaur skeletons are more frequently found is the Djadokhta strata of the Gobi Desert, Mongolia, an area which has produced several fairly complete skeletons of the Late Cretaceous Dromaeosaur, Velociraptor mongoliensis.
These Upper Cretaceous deposits of the Gobi desert have produced a range of other Velociraptorine Dromaeosaurs, including Adasaurus mongoliensis, Tsaagan mangas, 'Velociraptor' osmolskae, Linheraptor exquisitus, Shri devi, and Kuru kulla, although most of these are known only from a single specimen.
In a paper published in the journal Acta Paleontologica Polonica on 21 June 2023, Łukasz Czepiński of the Institute of Palaeobiology of the Polish Academy of Sciences, describes a new Dromaeosaur specimen from the Late Cretaceous Baruungoyot strata of the Gobi Desert, which he assigns to the species Shri devi.
The new specimen, ZPAL MgD-I/97, was collected in 1970 by a Polish-Mongolian Palaeontological Expedition, and initially described and illustrated as Velociraptor sp., then later redescribed as a specimen of Velociraptor mongoliensis. However, upon re-examination of the specimen, Czepiński disagrees with this diagnosis, noting that the skull is much less elongated than in that species.
Specimen ZPAL MgD-I/97 comprises a partial skull, including the left jugal, left lacrimal, left maxilla, fragment of the right maxilla, palatine elements, both dentaries lacking the anteriormost portions, both splenials, surangulars, and angulars, in close association with a distal portion of the left hindlimb, containing the distal parts of the left fibula and tibia, astragalus and complete pes, with four metatarsals and all phalanges. The holotype specimen of Shri devi, MPC-D 100/980, is a partial articulated skeleton including cervical, dorsal, and proximal caudal vertebrae, the right femur, the right and left tibiotarsa, and the right pes but lacking a skull, There is almost no overlap in the bones of the two specimens, with ZPAL MgD-I/97 being about 20% smaller than MPC-D 100/980, but both specimens preserve a single hind foot (left in ZPAL MgD-I/97 and right in MPC-D 100/980), and Czepiński is confident that these are similar enough to assign the two specimens to the same species.
The skull of Shri devi is apparently much shorter than in other Mongolian Dromaeosaurids, based upon the shape of the antorbital fenestra (opening in the skull in front of the eye), which is almost round in Shri devi, but elongated in most Mongolian Dromaeosaurids, despite Shri devi otherwise being very similar, and presumably closely related to, Velociraptor mongoliensis. A similar short-snouted condition is seen in many North American Dromaeosaurids, though these are not thought to be closely related to Shri devi, suggesting that this is an ecological adaptation, rather than an indicator of relatedness.
Dromaeosaurid Dinosaur Shri devi (ZPAL MgD-I/97) from the Upper Cretaceous, Khulsan, Ömnögovi, Gobi
Desert, Mongolia. Photographs (A₁), (A₂), (A₄), and (A₅) and 3D model (A₃), (A₆), and (A₇) obtained from the CT scan of the left side of the skull in dorsal (A₁), medial
(A₂, A₃), anterior (A₆), and lateral (A₇) views. Elements of the left palate in dorsal (A₄) and ventral (A₅) views. Right maxilla in the lateral (A₈, A₉) and
anterior (A₁₀) views, with the margin of the antorbital fenestra indicated by dashed lines, and the close up of the fifth (A₁₁) and the second (A₁₂) preserved
tooth in labial views showing very weakly developed denticles on the mesial carina. Right mandible in the lateral (A₁₃) and (A₁₄) and medial (A₁₅) and (A₁₆) views. (B) Explanatory drawings of the skull in left (B₁) and right (B₂) lateral views with the preserved bones (in grey). Czepiński (2023).Most of the Dromaeosaurid Dinosaurs from Mongolia, particularly those with very long snouts, are found in palaeodesert environments, covered by aeolian sands. Both specimens of Shri devi, on the other hand, comes from a more mixed environment, with a mixture of aeolian and fluvial deposits, suggesting a wetter (though still fairly arid) environment. The available prey to a small predatory Dinosaur would appear to have been similar in both environments, including Lizards, Mammals, Protoceratopsids, Oviraptorosaurs, and Birds (larger Ankylosaurids were also present, but unlikely to have been hunted by small Dromaeosaurs), suggesting that the variation in snout length is unlikely to be related to feeding. Instead, Czepiński suggests that an elongated snout may have been related to an elongated sinus, something which would have improved thermoregulation in Dromaeosaurs living in exposed, arid environments.
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