[Paleontology • 2024] Eoneophron infernalis • A New oviraptorosaur (Theropoda: Oviraptorosauria: Caenagnathidae) from the end-Maastrichtian Hell Creek Formation of North America

Eoneophron infernalis

Atkins-Weltman, Simon, Woodward, Funston & Snively, 2024

DOI: 10.1371/journal.pone.0294901

Illustration by Zubin Erik Dutta  facebook.com/ZDuttaArt

Abstract

Caenagnathidae is a clade of derived, Late Cretaceous oviraptorosaurian theropods from Asia and North America. Because their remains are rare and often fragmentary, caenagnathid diversity is poorly understood. Anzu wyliei is the only caenagnathid species currently described from the late Maastrichtian Hell Creek Formation of the USA and is also among the largest and most completely preserved North American caenagnathids. Smaller, less complete caenagnathid material has long been known from the Hell Creek Formation, but it is unclear whether these are juvenile representatives of Anzu or if they represent distinct, unnamed taxa. Here, we describe a relatively small caenagnathid hindlimb from the Hell Creek Formation, and conduct osteohistological analysis to assess its maturity. Histological data and morphological differences from Anzu wyliei and other caenagnathids allow us to conclude that this specimen represents a new species of caenagnathid from the Hell Creek Formation, with a smaller adult body size than Anzu. This new taxon is also distinct from other small caenagnathid material previously described from the area, potentially indicating the coexistence of three distinct caenagnathid species in the Hell Creek Formation. These results show that caenagnathid diversity in the Hell Creek ecosystem has been underestimated.

Systematic paleontology

Theropoda Marsh 1878 

Oviraptorosauria Barsbold 1976 

Caenagnathidae Sternberg 1940 

Eoneophron gen. nov. 

Eoneophron infernalis sp. nov.

 

Holotype: CM 96523, partial hindlimb including right femur, right tibia and astragalocalcaneum, a right metatarsal III, and a right metatarsal IV.

Diagnosis: Caenagnathid oviraptorosaur diagnosed by the following combination of traits (autapomorphies are denoted with an asterisk): femoral head directed dorsomedially, rather than perpendicular to the shaft; astragalocalcaneum fused to tibia*, metatarsal III with well-developed posterior cruciate ridges continuous with the distal condyle; distal condyle of metatarsal III transversely wider than anteroposteriorly deep, with medial portion of condyle larger than lateral portion; proximal end of metatarsals III and IV project posteriorly to form proximal protuberance; distal tarsal IV coossified with the proximal end of metatarsal IV at maturity; shaft of metatarsal IV with well-developed oblique longitudinal ridge on anterior surface extending along the distal three-quarters of the shaft*.

Etymology: Genus name derived from the Ancient Greek “eo”–meaning “dawn,” and from the genus name of the Egyptian vulture, Neophron, sometimes referred to as the “pharaoh’s chicken.” The species name derives from Latin for Hell, in reference to the Hell Creek Formation. Together the taxon name equates to “Pharaoh’s dawn chicken from Hell.”

Locality and horizon: Collected from exposures of the upper Maastrichtian Hell Creek Formation, Meade County, South Dakota, United States of America. The specimen was prepared prior to acquisition, but matrix remains adhered to some areas, such as the proximal portion of the tibia and anterodistal region of the femur. These sediments resemble those of typical floodplain deposits such as siltstones with organic material as seen elsewhere in the Hell Creek Formation (KLAW, pers. obs.).

Artist’s depiction of Eoneophron infernalis (top left), MOR 752 (bottom left), and Anzu wyliei (right) in the Hell Creek Formation.

Illustration by Zubin Erik Dutta.

 Kyle L. Atkins-Weltman, D. Jade Simon, Holly N. Woodward, Gregory F. Funston and Eric Snively. 2024. A New oviraptorosaur (Dinosauria: Theropoda) from the end-Maastrichtian Hell Creek Formation of North America. PLoS ONE. 19(1): e0294901. DOI: 10.1371/journal.pone.0294901

 facebook.com/ZDuttaArt/posts/822554889885490

[Paleontology • 2023] Jaculinykus yaruui • A New alvarezsaurid Dinosaur (Theropoda: Alvarezsauria) from the Upper Cretaceous Baruungoyot Formation of Mongolia provides insights for Bird-like Sleeping behavior in Non-avian Dinosaurs

Jaculinykus yaruui

Kubo, Kobayashi, Chinzorig & Tsogtbaatar, 2023

 

DOI: 10.1371/journal.pone.0293801

Artwork courtesy of Seiji Yamamoto

 

Abstract

Alvarezsauria is a group of early-branching maniraptoran theropods that are distributed globally from the Late Jurassic to the latest Cretaceous. Despite recent increases in the fossil record of this group, the scarcity of complete specimens still restricts interpreting their detailed anatomy, ecology, and evolution. Here, we report a new taxon of derived alvarezsaur, Jaculinykus yaruui gen. et sp. nov., from the Late Cretaceous of Mongolia, which represents a nearly complete and articulated skeleton. Our phylogenetic analysis reveals that Jaculinykus belongs to the sub-clade of Alvarezsauridae, Parvicursorinae, and forms a mononphyletic group with Mononykus and Shuvuuia. Its well-preserved manus has only two fingers, composed of a hypertrophied digit I and greatly reduced digit II, which implies an intermediate condition between the tridactyl manus of Shuvuuia and monodactyl manus of Linhenykus. This highlights a previously unrecognized variation in specialization of alvarezsaurid manus. Notably, the preserved posture of the specimen exhibits a stereotypical avian-like sleeping position seen in the troodontids Mei and Sinornithoides. Evidence of this behavior in the alvarezsaur Jaculinykus suggests that stereotypically avian sleeping postures are a maniraptoran synapomorphy, providing more evidence of bird-like traits being distributed broadly among avian ancestors.

Geographic and stratigraphic occurrence of the Mongolian alvarezsaurids.
(C) The stratigraphic horizon of  Jaculinykus yaruui gen. et sp. nov. and other alvarezsaurids in the Nemegt, Baruungoyot, and Djadokhta formations. The composite stratigraphy was modified from Eberth [2018] and Jerzykiewicz and Russell [1991].

Geographic and stratigraphic occurrence of the Mongolian alvarezsaurids.
(A) Plan view of Mongolia. (B) Location of Jaculinykus yaruui gen. et sp. nov. (MPC-D 100/209) and alvarezsaurid occurrences in the Nemegt Basin. The map was generated using Simplemappr (www.simplemappr.net) before modification and modified from Jerzykiewicz et al. [2021]. 

Holotype of Jaculinykus yaruui gen. et sp. nov. (MPC-D 100/209).
(A) Photograph of the specimen. (B) Explanatory drawing of (A). Highlighted areas refer to the indication of the skeletal elements; skull in green, tail in grey, pectoral girdle and forelimbs in red, pelvis and hind limbs in purple.
(C) Reconstruction of Jaculinykus yaruui gen. et sp. nov. Grey areas are missing parts.

Life restoration of sleeping posture of Jaculinykus yaruui

 (Artwork courtesy of Seiji Yamamoto)

Systematic paleontology

Dinosauria Owen, 1842  

Theropoda Marsh, 1882 

Maniraptora sensu Gauthier, 1986  

Alvarezsauria Bonaparte, 1991  

Alvarezsauridae Bonaparte, 1991  

Parvicursorinae Karhu and Rautian, 1996  

Jaculinykus yaruui gen. et sp. nov.

 

Etymology: Jaculinykus is from “Jaculus,” a tiny dragon from the Greek myth, and “onykus,” claw; yaruui, derived from Mongolian word, yaruu (яаруу): speedy (= hasty).

Holotype: The type specimen (MPC-D 100/209) is a nearly complete skeleton with a skull, missing some cranial elements (vomers, nasals, postorbitals, and supraoccipitals), eighth or ninth cervical vertebra, posterior dorsal vertebrae, seven anterior caudal vertebrae, sternum, furcula, right manual phalanx (II-2), right manual ungual and left fibula (Fig 2). It is housed in the Institute of Paleontology of Mongolian Academy of Sciences (IP-MAS), Ulaanbaatar, Mongolia.

Type locality and horizon: Nemegt locality, Ömnögovi Province, Mongolia (Fig 1). The specimen was collected from the upper section of the Baruungoyot (or Barun Goyot) Formation, suggested as the Campanian in age, (Fig 1). The stratigraphic horizon of Jaculinykus belongs to a part of “Big Red” in the transitional stratigraphic interval (Zone 4).

Diagnosis: Jaculinykus differs from all other alvarezsaurs in having a dorsoventrally high narial opening of the premaxilla, medially curved parasagittal crest on the parietal, slender and nearly straight dentaries, triangular-shaped deltopectoral crest being separated from the humeral head by a notch, strong medial tab of metacarpal I, weakly developed proximodorsal process of phalanx I-1, robust medial condyle of the tibia relative to the fibular condyle, and sharply indented base of the ascending process of astragalus. Jaculinykus is also distinguished from other alvarezsaurs by the unique combination of the following characters: slender ischial shaft relative to the pubic shaft, an open popliteal fossa of the femur, and prominent external projection of the ectocondylar tuber of the femur. It differs from the hypothesized sister taxon Shuvuuia deserti in possessing the following additional features: the deltopectoral crest being separated from the humeral head by a notch; the absence of the third manual digit. It also differs from stratigraphically same or older (the Baruungoyot Formation) alvarezsaurid, Ondogurvel alifanovi, from the same locality (the Nemegt locality) in possessing the following features ....

Evolution of avian-like sleeping posture in theropod dinosaurs. Skeletal disposition of Jaculinykus yaruui gen. et sp. nov. (MPC-D 100/209) in dorsal (photograph courtesy of Tomonori Tanaka) (A) and ventral (reversed) (B) views. (C), Interpretive line drawing of skeletal disposition.
 (D), Life restoration of sleeping posture of Jaculinykus yaruui (Artwork courtesy of Seiji Yamamoto).
(E), Simplified coelurosaurian phylogeny represents presence for evidence of avian ‘tuck-in’ posture.

 Kohta Kubo, Yoshitsugu Kobayashi, Tsogtbaatar Chinzorig and Khishigjav Tsogtbaatar. 2023. A New alvarezsaurid Dinosaur (Theropoda, Alvarezsauria) from the Upper Cretaceous Baruungoyot Formation of Mongolia provides insights for Bird-like Sleeping behavior in Non-avian Dinosaurs. PLoS ONE. 18(11): e0293801. DOI: 10.1371/journal.pone.0293801

[Paleontology • 2023] Skull of A dromaeosaurid Dinosaur Shri devi from the Upper Cretaceous of the Gobi Desert suggests Convergence to the North American forms

Shri devi Turner, Montanari & Norell, 2021

 pan.pl/article/item/app010652023.html

 twitter.com/LCzepinski  

Artwork by Jakub Zalewski

 

Numerous dromaeosaurid taxa recovered from the Upper Cretaceous strata of the Gobi Desert raise questions over niche partitioning among closely related species. Here, I describe a dromaeosaurid specimen from the Baruungoyot strata of the Khulsan locality, containing a partial skull in close association with the left hind limb. The material can be referred to the velociraptorine Shri devi, until now known only from a single specimen lacking a skull, collected from the same site. The referral is based on the apomorphic morphology of the pes, including the highly hypertrophic ungual of the second digit and details of the metatarsus. The skull of S. devi confirms its close affinities with Velociraptor mongoliensis, but shows distinctive features among Velociraptorinae, including a short antorbital fenestra, a Z-shaped maxillo-jugular suture, a distinct labial ridge above the supralabial foramina row of the maxilla, and the posterior position of the last maxillary tooth. The skull of S. devi is slender, but relatively short when compared to other velociraptorines, suggesting convergence to the North American eudromaeosaurians. The Baruungoyot strata with S. devi represent less arid conditions than the aeolian Djadokhta strata yielding V. mongoliensis, supporting earlier observations linking the elongation of the dromaeosaurid snout with the environment.

Key words: Dinosauria, Theropoda, Dromaeosauridae, convergence, Cretaceous, Mongolia, Gobi Desert.

Dromaeosaurid dinosaur Shri devi Turner, Montanari, and Norell, 2021 (ZPAL MgD-I/97) from the Upper Cretaceous, Khulsan, Ömnögovi, Gobi Desert, Mongolia. Specimen prior to the preparation work (A1), and the 3D model of the skeleton, based on the CT and surface scanner data, with elements arranged as originally found (A2).

Reconstruction of the dromaeosaurid dinosaur Shri devi Turner, Montanari, and Norell, 2021, based on ZPAL MgD-I/97 and MPC-D 100/980.

A. Skull; missing elements reconstructed on the base of Velociraptor mongoliensis Osborn, 1924 (MPC-D 100/25 and MPC-D 100/54).

B. Whole body silhouette with known remains of the holotype and referred material. Silhouette based on V. mongoliensis drawn by J.A. Headden (Wikimedia Commons CC-BY-3.0).

Artistic post-mortem reconstruction of the Shri devi Turner, Montanari, and Norell, 2021,
individual represented by a specimen ZPAL MgD-I/97 before its final burial.

Artwork by Jakub Zalewski.

    

Łukasz Czepiński. 2023. Skull of A dromaeosaurid Dinosaur Shri devi from the Upper Cretaceous of the Gobi Desert suggests Convergence to the North American forms. Acta Palaeontologica Polonica. in press. DOI: 10.4202/app.01065.2023

 app.pan.pl/article/item/app010652023.html

 twitter.com/LCzepinski/status/1671475053165268993

    

[Paleontology • 2023] Wulong bohaiensis • Iridescent Plumage in A juvenile dromaeosaurid Theropod Dinosaur

Wulong bohaiensis  Poust, Gao, Varricchio, Wu & Zhang, 2020

in Croudace, Shen, Lü, Brusatte et Vinther, 2023. 

   pan.pl/article/item/app010042022.html

Artwork by Robert Nicholls (Bob Nicholls Art).

Colour reconstructions have provided new insights into the lives of dinosaurs and other extinct animals, by predicting colouration patterns from fossilised pigment-bearing organelles called melanosomes. Although these methods have become increasingly popular, only a small number of dinosaurs have been studied using these techniques, which require exceptional preservation of fossil feathers, leaving open key questions such as whether dinosaurs changed their plumage patterns during ontogeny. Here we reconstruct the feather colouration of an approximately one-year-old individual of the Early Cretaceous dromaeosaurid theropod Wulong bohaiensis, which to our knowledge is the first unequivocal juvenile paravian for which aspects of the original colour has been predicted. Using quadratic discriminant analysis (QDA) and multinomial logistic regression (MLR) on the most comprehensive available datasets, we find strong evidence for iridescent plumage of the forelimb and hindlimb remiges and grey plumage on other portions of the body. This suggests that some juvenile paravians used shiny iridescent feathers for signalling purposes, possibly even before reaching somatic or sexual maturity, and thus we can conclude that this paravian used iridescent signalling for intraspecific communication other than sexual signalling. Finally, our results show that when analysing fossil datasets that are entirely comprised of solid and cylindrical melanosomes QDA consistently outperforms MLR, providing more accurate and higher classification probability colour predictions.

Key words: Dinosauria, Dromaeosauridae, Paraves, Wulong bohaiensis , iridescence, melanosome, palaeocolour, juvenile, colour reconstruction, Cretaceous, China.

Reconstruction of the dromaeosaurid dinosaur Wulong bohaiensis Poust, Gao, Varricchio, Wu, and Zhang, 2020 (DNHM D2933),
from Shangheshou, Chaoyang, Liaoning, China, Early Cretaceous Jiufotang Formation with a minimum age of 120.3Ma.
This illustration broadly depicts iridescent plumage on the limbs and grey feathers on the body. It should be noted that the full extent of the iridescence has been extrapolated in the creation of this illustration, based on the evidence provided by a small but significant distribution of iridescent samples across several limbs of the fossil.

Artwork by Robert Nicholls (Bob Nicholls Art).

 

Angus D. Croudace, Caizhi Shen, Junchang Lü, Stephen L. Brusatte and Jakob Vinther. 2023. Iridescent Plumage in A juvenile dromaeosaurid Theropod Dinosaur. Acta Palaeontologica Polonica.  in press. https://app.pan.pl/article/item/app010042022.html

DOI: 10.4202/app.01004.2022

[Paleontology • 2023] Evidence for Heterothermic Endothermy and Reptile-like Eggshell Mineralization in Troodon, A Non-avian Maniraptoran Theropod

Troodon

in Tagliavento, Davies, Bernecker, Staudigel, Dawson, ... et  Fiebig, 2023. 

  DOI: 10.1073/pnas.2213987120

artwork: Alex Boersma

Abstract

The dinosaur–bird transition involved several anatomical, biomechanical, and physiological modifications of the theropod bauplan. Non-avian maniraptoran theropods, such as Troodon, are key to better understand changes in thermophysiology and reproduction occurring during this transition. Here, we applied dual clumped isotope (Δ47 and Δ48) thermometry, a technique that resolves mineralization temperature and other nonthermal information recorded in carbonates, to eggshells from Troodon, modern reptiles, and modern birds. Troodon eggshells show variable temperatures, namely 42 and 29 ± 2 °C, supporting the hypothesis of an endothermic thermophysiology with a heterothermic strategy for this extinct taxon. Dual clumped isotope data also reveal physiological differences in the reproductive systems between Troodon, reptiles, and birds. Troodon and modern reptiles mineralize their eggshells indistinguishable from dual clumped isotope equilibrium, while birds precipitate eggshells characterized by a positive disequilibrium offset in Δ48. Analyses of inorganic calcites suggest that the observed disequilibrium pattern in birds is linked to an amorphous calcium carbonate (ACC) precursor, a carbonate phase known to accelerate eggshell formation in birds. Lack of disequilibrium patterns in reptile and Troodon eggshells implies these vertebrates had not acquired the fast, ACC-based eggshell calcification process characteristic of birds. Observation that Troodon retained a slow reptile-like calcification suggests that it possessed two functional ovaries and was limited in the number of eggs it could produce; thus its large clutches would have been laid by several females. Dual clumped isotope analysis of eggshells of extinct vertebrates sheds light on physiological information otherwise inaccessible in the fossil record.

Several Troodon females laid their eggs in communal nests.

artwork: Alex Boersma/PNAS

 

Significance: The dinosaur–bird transition is among the most fascinating events in evolutionary history, but several biological aspects such as changes in reproductive system, nesting strategy, and body temperature are still poorly understood. Dual clumped isotope thermometry (Δ47 and Δ48) can shed light on these biological aspects in fossils. Our results show that eggshells of modern reptiles and birds differ in their isotopic compositions. Interestingly, analyses of eggshells of Troodon, a non-avian theropod, reveal that it retained a slower, reptile-like mineralization to produce its eggs, despite having already evolved the capacity of changing its body temperature (heterothermic endothermy) like modern birds. Our findings also suggest that Troodon possessed two functional ovaries and that their nests were shared by multiple females.

 

Mattia Tagliavento, Amelia J. Davies, Miguel Bernecker, Philip T. Staudigel, Robin R. Dawson, Martin Dietzel, Katja Götschl, Weifu Guo, Anne S. Schulp, François Therrien, Darla K. Zelenitsky, Axel Gerdes, Wolfgang Müller and Jens Fiebig. 2023. Evidence for Heterothermic Endothermy and Reptile-like Eggshell Mineralization in Troodon, A Non-avian Maniraptoran Theropod. Proceedings of the National Academy of Sciences. 120 (15) e2213987120. DOI: 10.1073/pnas.2213987120

phys.org/news/2023-04-analysis-dinosaur-eggshells-bird-like-troodon.html

[Paleontology • 2022] Natovenator polydontus • A Non-avian Dinosaur (Theropoda: Dromaeosauridae) with A Streamlined Body exhibits Potential Adaptations for Swimming

 

 Natovenator polydontus 

Lee, Lee, Currie, Sissons, Park, Kim, Barsbold & Tsogtbaatar, 2022

DOI: 10.1038/s42003-022-04119-9

(Artwork by Yusik Choi).

Abstract

Streamlining a body is a major adaptation for aquatic animals to move efficiently in the water. Whereas diving birds are well known to have streamlined bodies, such body shapes have not been documented in non-avian dinosaurs. It is primarily because most known non-avian theropods are terrestrial, barring a few exceptions. However, clear evidence of streamlined bodies is absent even in the purported semiaquatic groups. Here we report a new theropod, Natovenator polydontus gen. et sp. nov., from the Upper Cretaceous of Mongolia. The new specimen includes a well-preserved skeleton with several articulated dorsal ribs that are posterolaterally oriented to streamline the body as in diving birds. Additionally, the widely arched proximal rib shafts reflect a dorsoventrally compressed ribcage like aquatic reptiles. Its body shape suggests that Natovenator was a potentially capable swimming predator, and the streamlined body evolved independently in separate lineages of theropod dinosaurs.

Skull of Natovenator polydontus (MPC-D 102/114, holotype).

Body plan of Natovenator polydontus (MPC-D 102/114, holotype) and dorsal rib morphology of various diving birds and terrestrial taxa.

Dinosauria Owen, 1842

Theropoda Marsh, 1881

Dromaeosauridae Matthew and Brown, 1922

Halszkaraptorinae Cau et al., 2017

Natovenator polydontus gen. et sp. nov.

Holotype: MPC-D 102/114 (Institute of Paleontology, Mongolian Academy of Sciences, Ulaanbaatar, Mongolia) is a mostly articulated skeleton with a nearly complete skull (See Supplementary Table 1 for measurements).

Locality and horizon: Baruungoyot Formation (Upper Cretaceous), Hermiin Tsav, Omnogovi Province, Mongolia. 

Diagnosis: A small halszkaraptorine dromaeosaurid with the following autapomorphies: wide groove delimited by a pair of ridges on the anterodorsal surface of the premaxilla, premaxilla with an elongated internarial process that overlies nasal and extends posterior to the external naris, 13 premaxillary teeth with large and incisiviform crowns, first three anteriormost maxillary teeth are greatly reduced and are clustered together with the following tooth without any separations by interdental septa, anteroposteriorly long external naris (about 30% of the preorbital skull length), paroccipital process with a anteroposteriorly broad dorsal surface, elongate maxillary process of the palatine that extends anteriorly beyond the middle of the antorbital fenestra, pterygoid with a deep fossa on the medial surface of the quadrate ramus, distinct posterolaterally oriented projection on the lateral surface of atlas, absence of pleurocoels in cervical vertebrae (not confirmed in the missing fifth cervical centrum), posterolaterally oriented and nearly horizontal proximal shafts in the dorsal ribs, hourglass-shaped metacarpal II with distinctly concave medial and lateral surfaces.

Etymology: Natovenator, from the Latin nato (swim) and venator (hunter), in reference to the hypothesized swimming behaviour and piscivorous diet of the new taxon; polydontus, from the Greek polys (many) and odous (tooth) in reference to the unusually many teeth.

Life reconstruction of Natovenator polydontus (Artwork by Yusik Choi).

Sungjin Lee, Yuong-Nam Lee, Philip J. Currie, Robin Sissons, Jin-Young Park, Su-Hwan Kim, Rinchen Barsbold and Khishigjav Tsogtbaatar. 2022. A Non-avian Dinosaur with A Streamlined Body exhibits Potential Adaptations for Swimming. Communications Biology.  5, 1185. DOI: 10.1038/s42003-022-04119-9

 smithsonianmag.com/science-nature/worlds-first-swimming-dinosaur-discovered-in-mongolia-180981217

[Paleontology • 2022] Daurlong wangi • Intestinal Preservation in A Birdlike Dinosaur (Theropoda: Dromaeosauridae) supports Conservatism in Digestive Canal Evolution Among Theropods

 Daurlong wangi 

Wang, Cau, Guo, Ma, Qing & Liu, 2022

 DOI: 10.1038/s41598-022-24602-x

Abstract

Dromaeosaurids were bird-like dinosaurs with a predatory ecology known to forage on fish, mammals and other dinosaurs. We describe Daurlong wangi gen. et sp. nov., a dromaeosaurid from the Lower Cretaceous Jehol Biota of Inner Mongolia, China. Exceptional preservation in this specimen includes a large bluish layer in the abdomen which represents one of the few occurrences of intestinal remnants among non-avian dinosaurs. Phylogenetically, Daurlong nests among a lineage of short-armed Jehol Biota species closer to eudromaeosaurs than microraptorines. The topographic correspondence between the exceptionally preserved intestine in the more stem-ward Scipionyx and the remnants in the more birdlike Daurlong provides a phylogenetic framework for inferring intestine tract extent in other theropods lacking fossilized visceral tissues. Gastrointestinal organization results conservative among faunivorous dinosaurs, with the evolution of a bird-like alimentary canal restricted to avialan theropods.

 Daurlong wangi holotype.
(a), whole specimen. (b), skull. (c), detail of orbit region. (d), feather remains associated to the thoracic vertebrae. (e), anuran skeleton.

Scale bars: 20 mm (b), 10 mm (c).

Diagnosis of Daurlong wangi. Specimen IMMNH-PV00731. Skull (a, b), left scapula (c), sternum and left hand (d, e), right forelimb (f). Reconstruction in (g) by M. Auditore (CC-BY 4.0).

Combination of features diagnostic for D. wangi: 1, slender subnarial ramus of premaxilla extended caudally well beyond the external naris; 2, large, trapezoid promaxillary recess placed at the rostroventral corner of antorbital fossa; 3, maxillary fossa large, shallow and caudodorsally located, so that the pila promaxillaris is wider than the pila interfenestralis; 4, stepped subcutaneous surface of the ventral ramus of maxilla; 5, absence of pitted ventral ramus of the antorbital fossa; 6, robust fang-like maxillary teeth with straight to slightly convex distal crown margins; 7, distal end of first sternal rib fan-shaped. 8, bowed scapula; 9. radius and ulna more robust than any manual element; 10. wide overlap of the semilunate carpal over metacarpal II. In D, gray area indicates sternum, black areas indicate left hand elements. Abbreviations: af, antorbital fossa; de, dentary; ju, jugal; la, lacrimal; ma, maxilla; na, nasal; pm, premaxilla; su, surangular. Scale bar in G = 10 cm.

 

Systematic palaeontology

Dinosauria

Theropoda

Dromaeosauridae

 Daurlong wangi gen. et sp. nov.

Holotype IMMNH-PV00731, an almost complete dromaeosaurid (Figs. 1, 2, Supplementary information).

Locality and Horizon: Pigeon Hill, Morin Dawa Daur Autonomous Banner, Inner Mongolia Autonomous Region (N 48°39′40.76″/E 123°52′ 41.15″); Longjiang Formation, Lower Cretaceous.

Etymology: The genus name is derived from the Daur Nation, and the Chinese 龙 ("lóng") for "dragon". The species name honors Mr. Wang Junyou, director of the IMMNH.

Diagnosis: Mid-sized dromaeosaurid with (autapomorphies marked by asterisk): slender subnarial ramus of premaxilla extended caudally well beyond the external naris; large, trapezoid promaxillary recess placed at the rostroventral corner of antorbital fossa*; maxillary fossa large, shallow and caudodorsally located, so that the pila promaxillaris is wider than the pila interfenestralis*; stepped transition from the subcutaneous surface of maxillary ventral ramus to the antorbital fossa; fan-shaped distal end of first sternal rib*. Differential diagnosis: Daurlong further differs from Tianyuraptor because it bears longer and more robust maxillary teeth and a more robust ulna. Daurlong further differs from Zhenyuanlong because it lacks a pitted ventral ramus of the antorbital fossa, lacks markedly concave distal margins in maxillary tooth crowns, bears a bowed scapula, a more robust radius, and a wider overlap of the semilunate carpal over metacarpal II (Fig. 3).

Xuri Wang, Andrea Cau, Bin Guo, Feimin Ma, Gele Qing and Yichuan Liu. 2022. Intestinal Preservation in A Birdlike Dinosaur supports Conservatism in Digestive Canal Evolution Among Theropods. Scientific Reports. 12, 19965  DOI: 10.1038/s41598-022-24602-x

  

[Paleontology • 2021] Vectiraptor greeni • A New Dromaeosaurid Dinosaur from the Wessex Formation (Lower Cretaceous, Barremian) of the Isle of Wight, and Implications for European Palaeobiogeography

 

Vectiraptor greeni

 Longrich, Martill & Jacobs, 2021

DOI: 10.1016/j.cretres.2021.105123  

 Researchgate.net/publication/357133076 

  facebook.com/NickLongrich

A B S T R A C T

The Lower Cretaceous of England has produced a diverse assemblage of dinosaurs, including ornithischians, sauropods, and theropods. The origins of this assemblage are poorly understood. Here, we describe a new dromaeosaurid, Vectiraptor greeni gen. et sp. nov., from the Barremian Wessex Formation of the Isle of Wight. The animal is represented by associated dorsal vertebrae and a partial sacrum. Dorsal vertebrae are short, with pleurocoels, camellate pneumatization, stalked parapophyses and enlarged neural canals. Neural spines are tall, with large ligament scars. Sacral centra lack pleurocoels but have large neural canals and foramina suggesting pneumatization. These characters suggest affinities with Dromaeosauridae and specifically the derived, large-bodied Eudromaeosauria. Vectiraptor resembles Early Cretaceous eudromaeosaurs from North America, suggesting a faunal exchange between Europe and North America. The diverse Early Cretaceous dinosaur assemblage found in England and Europe resulted from dispersal from North America, Asia, and West Gondwana, likely involving both land bridges and oceanic dispersal. Europe served as a biotic crossroads in the Early Cretaceous, allowing faunal interchange between landmasses.

Keywords: Dinosauria, Theropoda, Dromaeosauridae, Biogeography, Barremian, United Kingdom

Vectiraptor greeni gen. et sp. nov.

   

Nicholas R. Longrich, David M. Martill and Megan L. Jacobs. 2021. A New Dromaeosaurid Dinosaur from the Wessex Formation (Lower Cretaceous, Barremian) of the Isle of Wight, and Implications for European Palaeobiogeography. Cretaceous Research. In Press, 105123. DOI: 10.1016/j.cretres.2021.105123 

  Researchgate.net/publication/357133076_A_new_dromaeosaurid_dinosaur_from_the_Wessex_Formation_of_the_Isle_of_Wight 

  facebook.com/NickLongrich/posts/10158872223129125

[Paleontology • 2021] The Phylogenetic Affinities and Morphological Peculiarities of the Bird-like Dinosaur Borogovia gracilicrus (Maniraptora: Troodontidae) from the Upper Cretaceous of Mongolia

Borogovia gracilicrus  Osmólska, 1987

in Cau​ & Madzia, 2021.

DOI: 10.7717/peerj.12640 

Artwork by Edyta Felcyn-Kowalska

 twitter.com/DanielMadzia 

 theropoda.blogspot.com 

Abstract 

Borogovia gracilicrus is a small-bodied theropod dinosaur from the Maastrichtian (Upper Cretaceous) Nemegt Formation of southern Mongolia. The taxon is based on a single fragmentary specimen preserving only the distal part of the hindlimbs. The morphology of Borogovia shows a peculiar combination of features, some of which are traditionally considered troodontid synapomorphies and others which are unusual for Troodontidae but are shared with other maniraptoran clades. In particular, the second toe of B. gracilicrus differs from other troodontids in lacking some of the features which contribute to the specialized ‘sickle-clawed’ second toe, here termed the ‘falciphoran condition’, shared with dromaeosaurids and some other paravians, such as the strongly compressed and falciform ungual. Phylogeny reconstructions intended to explore the affinities of Borogovia consistently support its referral within a subclade of troodontids including all Late Cretaceous taxa. The placement of Borogovia is not significantly affected by its unusual combinations of hindlimb features or by the homoplasy of the elements forming the falciphoran condition. Borogovia is supported as a valid taxon and is distinct from the other Nemegt troodontids, Tochisaurus and Zanabazar. The lack of a falciform ungual, and the distinctive morphology of the second toe in B. gracilicrus are interpreted as a derived specialization among Troodontidae and not as retention of the plesiomorphic condition of non-paravian theropods.

Theropoda Marsh, 1881 [Naish et al., 2020]

Paraves Sereno, 1997

Troodontidae Gilmore, 1924

Borogovia gracilicrus Osmólska, 1987

 

Conclusions: 

Borogovia gracilicrus is a troodontid dinosaur from the Nemegt Formation of Mongolia. Although overlapping material with the other Nemegt trooodontids (Tochisaurus nemegtensis and Zanabazar junior) is limited, Borogovia can be differentiated from these taxa based on the unique combination of features in its tibiotarsus and metatarsus.

The phylogenetic position of B. gracilicrus among Maniraptora is investigated in detail for the first time. This taxon is robustly supported as a member of Troodontidae, and reconstructed among non-troodontine troodontids. These results are not biased by a priori assumptions on character weighting.

The foot of Borogovia is autapomorphic and combines troodontid synapomorphies (e.g., the arctometatarsus) and the secondary loss of some elements of the falciphoran condition widespread among paravians. In particular, the morphology of the second toe of Borogovia might indicate an ecological niche distinct from those of other ‘deinonychosaur-grade’ paravians. Such a scenario could account for the co-occurrence of several troodontids in the paleofauna of the Nemegt Formation.

Andrea Cau​ and Daniel Madzia. 2021. The Phylogenetic Affinities and Morphological Peculiarities of the Bird-like Dinosaur Borogovia gracilicrus from the Upper Cretaceous of Mongolia. PeerJ.  9: e12640. DOI: 10.7717/peerj.12640.  

 twitter.com/DanielMadzia/status/1467829316146929678

 theropoda.blogspot.com/2021/12/borogovia-reloaded.html

[Paleontology • 2021] Kuru kulla • A New Dromaeosaurid (Coelurosauria: Maniraptora) from Khulsan, Central Mongolia

Kuru kulla

Napoli, Ruebenstahl, Bhullar, Turner & Norell, 2021

 DOI: 10.1206/3982.1

 digitallibrary.AMNH.org

 twitter.com/JGN_Paleo

Abstract

Dromaeosaurid theropods represent a rare but important clade of nonavialan dinosaurs. Their close evolutionary relationship to modern birds has placed them at the center of paleontological research for the last several decades. Herein we describe a new species of dromaeosaurid—Kuru kulla, gen. et sp. nov.—based on a partial skeleton from the Late Cretaceous Khulsan locality (Barun Goyot Formation) of Mongolia. This species is diagnosed by several autapomorphies within Dromaeosauridae, including a sharp groove anterior and ventral to the narial fossa on the premaxilla, a posterolaterally directed hornlet on the posterodorsal process of the lacrimal, a deep surangular bearing two surangular foramina, and anteriorly displaced pleurocoels on the dorsal centra. The taxon is further characterized by a unique combination of characters, including a mediolaterally narrow metatarsal II, serrations on both carinae of the dentary teeth, hyposphenes that are widely separated but joined by a web of bone, and a lacrimal with a poorly developed boss on its lateral surface. Phylogenetic analysis finds Kuru kulla to be the sister taxon of Adasaurus mongoliensis, from the slightly later Nemegt Formation, with which it is united by three synapomorphies: a posterior surangular foramen that is ∼30% the depth of the surangular, absence of a fourth trochanter of the femur, and thoracic centra that are markedly longer than their midpoint widths. The recognition of this taxon has important implications for common assumptions of Mesozoic terrestrial ecosystem structure and adds new data to a recently recognized pattern in dromaeosaurid faunal composition among Late Cretaceous localities in Mongolia and Inner Mongolia (Nei Mongol Autonomous Region, China).

Kuru kulla
Right dentary of IGM 100/981, showing all fragments in life position, in lateral view.

Tangka depicting Kurukullā
from the Hall of Asian Peoples,

American Museum of Natural History.

Dinosauria Owen, 1843 

Theropoda Marsh, 1881 

Coelurosauria Huene, 1920 

Maniraptora Gauthier, 1986 

Dromaeosauridae Matthew and Brown, 1922 

Kuru kulla, gen. et sp. nov 

Etymology: Kurukullā (fig. 1) is a deity venerated in Tibetan Buddhism. Considered peaceful to semiwrathful, she is usually depicted with four arms, holding in one pair of hands a bow and arrow, and in the other pair a hook and noose, all of which are made of flowers. Kurukullā is particularly associated with major life transitions. We emphasize here that the generic name Kuru is not in reference to the cannibalism-borne prion disease of the same name. 

SUMMARY:

Kuru kulla is a new species of velociraptorine dromaeosaurid from the Barun Goyot Formation at Khulsan. It is the first velociraptorine to be recognized from a locality and stratum that has previously yielded a different velociraptorine species, in this case, the recently described Shri devi (Turner et al., 2021). As such, it provides important insight into the structure of Late Cretaceous nonavian dinosaur-bearing faunas. Kuru kulla demonstrates that similar, closely related dinosaur species could and did coexist, contrary to general expectations that such species would not tolerate each other due to competitive exclusion (Molnar, 1990). This has ramifications for the taxonomic referral of new fossil material and argues strongly for an apomorphy-based (rather than similarity- and provenance-based) approach to referral. 

 

James G. Napoli, Alexander A. Ruebenstahl, Bhart-Anjan S. Bhullar, Alan H. Turner and Mark A. Norell. 2021. A New Dromaeosaurid (Dinosauria: Coelurosauria) from Khulsan, Central Mongolia. American Museum Novitates. (3982); 1-47. DOI: 10.1206/3982.1

 digitallibrary.AMNH.org/handle/2246/7286

 twitter.com/JGN_Paleo/status/1457782742972723200