[Paleontology • 2024] Lishulong wangi • The largest sauropodomorph skull from the Lower Jurassic Lufeng Formation of China

 Lishulong wangi  

 

Q.-N. Zhang​, Jia, Wang, Y.-G. Zhang & You,. 2024 

DOI: doi.org/10.7717/peerj.18629 

 

The Lower Jurassic Lufeng Formation of China has long been recognized for its diverse early-diverging sauropodomorph dinosaurs, with eight genera and ten species, representing more than half the Laurasian records. In this paper, we describe a new genus and species of non-sauropodan sauropodomorph, Lishulong wangi gen. et sp. nov., from Yunnan Province in southwestern China. This new taxon is represented by a partial skeleton including the skull and nine articulated cervical vertebrae, which differs from other Lufeng forms in both cranial and cervical characteristics. It bears several autapomorphies of the nasal process, the maxillary neurovascular foramen, and the cervical neural spine. Phylogenetic analysis reveals that Lishulong is an early-diverging member of the Sauropodiformes, and the sister-taxon of Yunnanosaurus. Elucidating the novel osteology of Lishulong, it possessed the largest sauropodomorph cranial material currently identified from the Lufeng Formation, not only enriches the diversity of the Lufeng dinosaur assemblage, but also enhances our understanding of the character evolution in early-diverging sauropodiforms. Furthermore, information about paleobiogeographic distributions indicates that Early Jurassic sauropodomorphs, especially Chinese taxa, have maintained multiple dispersions and exchanges within Pangaea.

the cranium of Lishulong wangi gen. et sp. nov. 
 Photograph (A) and interpretative line drawing (B), 
in right lateral view and left lateral view.

Systematic Paleontology

Dinosauria Owen, 1842

Saurischia Seeley, 1888

Sauropodomorpha von Huene, 1932 (sensu Sereno, 2007)

Massopoda Yates, 2007

Sauropodiformes Sereno, 2007 (sensu McPhee et al., 2014)

Lishulong wangi gen. et sp. nov.

Holotype: LFGT-ZLJ0011. An associated partial skeleton that includes the cranium and mandible, and nine cervical vertebrae (axis and C3–C10)

Differential diagnosis: A large non-sauropodan sauropodiform dinosaur with the following unique combination of character states (autapomorphies are indicated by an asterisk): width of the anteroventral process of nasal at its base less than that of its anterodorsal process*; size of the neurovascular foramen at the posterior end of the lateral maxillary row not larger than the others*; shape of the supraoccipital is semilunate and wider than high in posterior view; height to length ratio of the dentary greater than 0.2; lingual concavities of the teeth present; lateral expansion at the anterior region of the dorsal surface of the cervical neural spines*.

Type locality and horizon: The specimen was discovered near the Jiudu Village in Konglongshan Town (formerly named Chuanjie Township), Lufeng County, Yunnan Province, China; and the upper-middle part of the Shawan Member of the Lufeng Formation (Fang et al., 2000), Lower Jurassic. Magnetostratigraphic analyses (Cheng et al., 2004; Huang et al., 2005) revealed the age to be Early Jurassic (late Sinemurian–Toarcian).

Etymology: The generic name is from ‘Lishu’ (chestnut tree in Chinese spelling), the name of the locality where the specimen was found, and ‘long’ refers to a dragon (in Chinese spelling); this specific epithet is in honor of Mr. Zheng-Ju Wang, for his great contributions to the early discoveries of vertebrate fossils from Lufeng.

Qian-Nan Zhang​, Lei Jia, Tao Wang, Yu-Guang Zhang and Hai-Lu You​. 2024. The largest sauropodomorph skull from the Lower Jurassic Lufeng Formation of China. PeerJ. 12:e18629 DOI: doi.org/10.7717/peerj.18629 

[Paleontology • 2024] Ardetosaurus viator • A New diplodocine Sauropod from the Morrison Formation, Wyoming, USA

 Ardetosaurus viator

van der Linden, Tschopp, Sookias, Wallaard, Holwerda & Schulp, 2024

 DOI: 10.26879/1380 

  Life reconstruction by Ole Zant. x.com/TheBioBob

ABSTRACT

The Morrison Formation of the western United States is well-known for its high diversity of sauropod dinosaurs. The Howe-Stephens Quarry in northern Wyoming is one of several quarries which has yielded several associated to completely articulated dinosaur specimens, among which a semi-articulated diplodocid specimen, MAB011899, which was excavated in 1993. This diplodocid specimen is represented by posterior cervical, dorsal, sacral, and anterior caudal vertebrae, multiple thoracic ribs, two chevrons, a left coracoid, a left ilium, both pubes and ischia, a left femur, a left tibia, and a left fibula. Through comparative anatomy, we interpret this specimen as a new species of diplodocine sauropod, Ardetosaurus viator gen. et sp. nov. Unambiguous autapomorphies include paired accessory laminae in the spinoprezygapophyseal fossae of posterior cervical and anterior dorsal vertebrae, bifurcating anterior centrodiapophyseal laminae in the anterior dorsal vertebrae, fossae present in the centropostzygapophyseal laminae of the second dorsal vertebra, a low vertebral height/centrum length ratio of the posterior dorsal vertebrae and reduced to absent centroprezygapophyseal laminae in the anterior caudal vertebrae. Local autapomorphic features include single centroprezygapophyseal laminae in the posterior cervical vertebrae and a highly elliptical cross-section of the femoral midshaft. Ardetosaurus viator is the first skeletally mature sauropod specimen described from the Howe-Stephens Quarry. This specimen provides insight into serial variation of vertebral laminae and laminar transitions. Finally, the peculiar morphology of the—often not preserved—first chevron is described in detail, and its possible use in studying sexual dimorphism in sauropods is discussed.

Keywords: sauropod; new genus; new species; Morrison Formation; Diplodocinae; Wyoming

  Skeletal reconstruction of  Ardetosaurus viator MAB011899. Skeletal reconstruction indicating preserved bones (white), excavated bones but subsequently lost (light gray) and not preserved (dark gray). Unknown elements are based on other diplodocines.

Scale bar equals 1 m. Reconstruction by Ole Zant.

SYSTEMATIC PALEONTOLOGY

DINOSAURIA Owen, 1842

SAUROPODA Marsh, 1878

EUSAUROPODA Upchurch, 1995

NEOSAUROPODA Bonaparte, 1986

DIPLODOCOIDEA Marsh, 1884

FLAGELLICAUDATA Harris and Dodson, 2004

DIPLODOCIDAE Marsh, 1884

DIPLODOCINAE Marsh, 1884

ARDETOSAURUS gen. nov.

 

Ardetosaurus viator gen. et sp. nov.

 

Holotype. MAB011899: two cervical vertebrae, 10 dorsal vertebrae, sacrum, five caudal vertebrae, eight dorsal ribs, two chevrons, a left coracoid, a left ilium, both pubes, both ischia, a left femur, a left tibia, and a partial left fibula.

Diagnosis. Ardetosaurus viator is diagnosed by the combination of the following autapomorphies: 1) the presence of distinct, paired accessory laminae in the spinoprezygapophyseal fossae (SPRF) in the posterior cervical and anterior dorsal vertebrae, 2) anteroventrally bifurcating anterior centrodiapophyseal laminae (ACDLs) in the anterior dorsal vertebrae, 3) the presence of centropostzygapophyseal lamina fossae (CPOL-f) in the second dorsal vertebra, 4) a vertebral height/centrum length ratio of <2.5 of the posterior dorsal vertebrae, and 5) reduced or absent centroprezygapophyseal laminae (CPRLs) in the anterior-most caudal vertebrae. Ardetosaurus viator differs from all other diplodocines by having unbifurcated CPRLs in the posterior cervical vertebrae and a highly elliptical femoral cross-section. Ardetosaurus viator differs from Amphicoelias Cope, 1878, in lacking the rounded, lateral projections of the neural spine tip and the thin neural spine base in the dorsal vertebrae; from Barosaurus Marsh, 1890, by having tall cervical neural spines, single midline keels, narrower prezygapophyseal rami in the cervical vertebrae, ten dorsal vertebrae, the presence of ...

Etymology. ‘Ardeto’ is an inflection of Latin ārdēre, meaning ‘to burn.’ It refers to the history of some of the elements, which were either fully destroyed in a fire, or still show burn scars from the fire. ‘saurus, ’ Latinized form of the Greek σαῦρος (saúros), meaning lizard or reptile. ‘viator’ is Latin for traveler, referring to the journey of the specimen from the USA, via Switzerland and Germany, to the Netherlands.

Locality and horizon. Ardetosaurus viator comes from the Howe-Stephens Quarry of northern Wyoming, USA. The quarry is dated, based on magnetostratigraphy and correlation with other sections in the Morrison basin (Maidment and Muxworthy, 2019; Maidment, personal communication, 2022) at 150.44 to 149.21 million years old, placing it in the Kimmeridgian Stage of the Upper Jurassic.

 Quarry map of Ardetosaurus viator MAB011899. Excavation map of the Howe-Stephens Quarry, indicating the major finds from 1992-2000. Individual dinosaurs are color coded, and MAB011899 is coded with dark blue, and named ‘Diplodocus Brösmeli’ herein. The red crosses indicate the missing/lost cervical vertebrae. Note the relatively similar color for ‘Brösmeli’ and ‘David’ (SMA 0086), but their significant separation in the quarry.

 Figure is courtesy of the SMA. Quarry sections equal 1 by 0.5 m.

  Life reconstruction of  Ardetosaurus viator MAB011899.

Illustration by Ole Zant.

The skeleton of Brösmeli is on display in the Oertijdmuseum.

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Tom T.P. van der Linden, Emanuel Tschopp, Roland B. Sookias, Jonathan J.W. Wallaard, Femke M. Holwerda, and Anne S. Schulp. 2024. A New diplodocine Sauropod from the Morrison Formation, Wyoming, USA. Palaeontologia Electronica. 27(3): a50. DOI: doi.org/10.26879/1380

palaeo-electronica.org/content/2024/5327-new-diplodocine-sauropod

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[PaleoOrnithology • 2024] Direct Evidence of Frugivory in the Mesozoic Bird Longipteryx contradicts Morphological Proxies for Diet

 Longipteryx, a fossil bird with unusually strong teeth right at the tip of its beak.

in O’Connor, Clark, Herrera, Yang, Wang, Zheng, Hu et Zhou. 2024. 

DOI: doi.org/10.1016/j.cub.2024.08.012

Illustration by Ville Sinkkonen.

Highlights: 

• Unusual enantiornithine Longipteryx with an elongate rostrum predicted to be a faunivore

• Direct evidence indicates Longipteryx was a frugivore, eating gymnosperm “fruits”

• Like crown birds, morphological proxies fail to predict diet in early birds

Summary: 

Diet is one of the most important aspects of an animal’s ecology, as it reflects direct interactions with other organisms and shapes morphology, behavior, and other life history traits. Modern birds (Neornithes) have a highly efficient and phenotypically plastic digestive system, allowing them to utilize diverse trophic resources, and digestive function has been put forth as a factor in the selectivity of the end-Cretaceous mass extinction, in which only neornithine dinosaurs survived. Although diet is directly documented in several early-diverging avian lineages, only a single specimen preserves evidence of diet in Enantiornithes, the dominant group of terrestrial Cretaceous birds. Morphology-based predictions suggest enantiornithines were faunivores, although the absence of evidence contrasts with the high preservation potential and relatively longer gut-retention times of these diets. Longipteryx is an unusual Early Cretaceous enantiornithine with an elongate rostrum; distally restricted dentition; large, recurved, and crenulated teeth; and tooth enamel much thicker than other paravians. Statistical analysis of rostral length, body size, and tooth morphology predicts Longipteryx was primarily insectivorous. Contrasting with these results, two new specimens of Longipteryx preserve gymnosperm seeds within the abdominal cavity interpreted as ingesta. Like Jeholornis, their unmacerated preservation and the absence of gastroliths indicate frugivory. As in Neornithes, complex diets driven by the elevated energetic demands imposed by flight, secondary rostral functions, and phylogenetic influence impede the use of morphological proxies to predict diet in early-diverging avian lineages.

Keywords: trophics, gymnospermous disseminules, consumulites, stomach contents, Cretaceous, Enantiornithes, Aves/Avialae

 

 Longipteryx, a fossil bird with unusually strong teeth right at the tip of its beak.

Illustration by Ville Sinkkonen.

 

Jingmai O’Connor, Alexander Clark, Fabiany Herrera, Xin Yang, Xiaoli Wang, Xiaoting Zheng, Han Hu and Zhonghe Zhou. 2024. Direct Evidence of Frugivory in the Mesozoic Bird Longipteryx contradicts Morphological Proxies for Diet.  Current Biology.  DOI: doi.org/10.1016/j.cub.2024.08.012

[Paleontology • 2024] Qunkasaura pintiquiniestra • A Spanish saltasauroid Titanosaur reveals Europe as a Melting Pot of Endemic and Immigrant Sauropods in the Late Cretaceous

Qunkasaura pintiquiniestra

Mocho, Escaso, Marcos-Fernández, Páramo, Sanz, Vidal & Ortega, 2024. 

DOI: 10.1038/s42003-024-06653-0

Abstract

A new lithostrotian titanosaur, Qunkasaura pintiquiniestra gen. et sp. nov., is described based on a single partial skeleton from the late Campanian-early Maastrichtian fossil-site of Lo Hueco (Cuenca, Spain). This new taxon is supported by an exclusive combination of characters that highlights strong convergences with members of the South American Aeolosaurini. Qunkasaura allows to reorganise the complex phylogenetic relationships of the increasingly diverse finicretaceous sauropods of Europe. Phylogenetic analyses places Qunkasaura within Saltasauridae and possibly Opisthocoelicaudiinae, together with Abditosaurus. A new clade is established, Lohuecosauria, including Saltasaurus, Lohuecotitan, their most recent common ancestor and all its descendants. Two distinct Ibero-Armorican Campanian-Maastrichtian saltasauroid lineages are recognised: (i) Lirainosaurinae that is exclusive from Europe, and (ii) a saltasaurid lineage with possible opisthocoelicaudiine affinities, with a Laurasian distribution. Lirainosaurinae was a relict lineage including possible dwarf forms that evolved in isolation after reaching Europe before the Late Cretaceous through the Apulian route. The occurrence of opisthocoelicaudiines in Europe may be the result of a Late Cretaceous interchange between Europe and Asia. No evidence of insular dwarfism is found in the Ibero-Armorican opisthocoelicaudiines suggesting that they may have been newcomers to the area that arrived before the ‘Maastrichtian Dinosaur Turnover’ in southwestern Europe.

Qunkasaura pintiquiniestra

Pedro Mocho, Fernando Escaso, Fátima Marcos-Fernández, Adrián Páramo, José Luis Sanz, Daniel Vidal and Francisco Ortega. 2024. A Spanish saltasauroid Titanosaur reveals Europe as a Melting Pot of Endemic and Immigrant Sauropods in the Late Cretaceous. Communications Biology. 7: 1016. DOI: doi.org/10.1038/s42003-024-06653-0

  

[Paleontology • 2024] Alpkarakush kyrgyzicus • A new theropod dinosaur (Theropoda: Metriacanthosauridae) from the Callovian Balabansai Formation of Kyrgyzstan

 

Alpkarakush kyrgyzicus 

 Rauhut, Bakirov, Wings, Fernandes & Hübner, 2024

  

DOI: 10.1093/zoolinnean/zlae090

Art by Joschua Knüppe 

Abstract

Recent fieldwork in the late Middle Jurassic Balabansai Formation of Kyrgyzstan has yielded a partial skeleton of a large theropod dinosaur. The material includes a few bones of the skull (postorbital, quadratojugal), dorsal and sacral vertebrae, fragments of the pectoral girdle and forelimbs, and an almost complete pelvic girdle and hindlimbs, and is here made the type of a new theropod taxon, Alpkarakush kyrgyzicus gen. et sp. nov. Alpkarakush can be diagnosed by an extremely developed orbital brow on the postorbital, a pneumatic opening leading into cavities in the neural arch from the centroprezygodiapophyseal fossa in the posterior dorsal vertebrae, an almost enclosed ventral sulcus in manual phalanx II-1, a narrow and deep intercondylar groove on the anterior side of the distal femur, and an epicondylar crest on the distal femur that is offset from the distal end. A second, fragmentary, and smaller specimen from the same site represents the same taxon. Based on long bone histology, the type of Alpkarakush represents a late subadult individual, whereas the smaller specimen is a juvenile, possibly indicating gregarious behaviour. Phylogenetic analysis places Alpkarakush in the Metriacanthosauridae, underlining the diversity and wide distribution of this clade in the Jurassic of Asia.

Central Asia, Middle Jurassic, Tetanurae, Metriacanthosauridae, bone histology

 Outline reconstruction of Alpkarakush kyrgyzicus, with recovered elements indicated. Scale bar is 1 m.

SYSTEMATIC PALAEONTOLOGY

Dinosauria Owen, 1842,

Saurischia Seeley, 1887,

Theropoda Marsh, 1881,

Tetanurae Gauthier, 1986,

Metriacanthosauridae Paul, 1988

Alpkarakush gen. nov.

 

Etymology: Named after Alpkarakush, a mythological large bird [Алпкаракуш] that often comes to the help of heroes in critical moments in the ‘Manas’ epos, one of the central mythological elements in Kyrgyz culture (Seiilbek et al. 2018).

Alpkarakush kyrgyzicus sp. nov.

Etymology: The species epithet refers to the Kyrgyz Republic, the provenance of the type specimen.

Diagnosis: Alpkarakush kyrgyzicus can be diagnosed by the following combination of characters (autapomorphies are indicated by *): extremely developed supraorbital brow on the postorbital, overhanging the orbit; posterior dorsal vertebrae with a channel leading from the centroprezygodiapophyseal fossa posteromedially into pneumatic chambers in the neural arch*; sacral vertebrae with fused neural spines that are approximately as high as the combined height of the vertebral centrum plus neural arch; manual phalanx II-1 with a ventral sulcus proximally that is almost completely enclosed by medial and lateral ventral flanges*; dorsal margin of the ilium slopes steeply posteroventrally*; brevis fossa on ilium reduced to a small medial shelf; shaft of pubis strongly bowed anteriorly; well-developed longitudinal depression on the posterolateral side of the pubic shaft adjacent to the pubic boot (based on paratype); unusually high pubis/tibia ratio (1.22 or higher); articulated ischia with pronounced ischial boots that are convex distally and fused anteriorly, but separated posteriorly; ischium with small obturator flange that is offset from the pubic peduncle; pubic peduncle of ischium very long; iliac articulation in proximal ischium cup-shaped; narrow and deep intercondylar groove on the anterior side of distal femur*; robust and well-developed medial epicondylar crest on distal femur, considerably offset proximally from distal end*; tibia with robust, bulbous fibular flange; astragalus and calcaneum fused.

Type locality and horizon: Locality FTU-1, just west of the town of Tashkumyr, Jalal-Abad Oblast, Kyrgyzstan (Figs 1, 2). The specimens were found in the higher part of the Balabansai Formation, Callovian.

Oliver W. M. Rauhut, Aizek A. Bakirov, Oliver Wings, Alexandra E. Fernandes and Tom R. Hübner. 2024. A new theropod dinosaur from the Callovian Balabansai Formation of Kyrgyzstan. Zoological Journal of the Linnean Society. 201(4); zlae090. DOI: doi.org/10.1093/zoolinnean/zlae090

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[Paleontology • 2024] Campananeyen fragilissimus • They all floated in the Cretaceous: New rebbachisaurid (Sauropoda: Diplodocoidea) with a highly pneumatized skeleton from the Upper Cretaceous (lower Cenomanian) of Patagonia, Argentina

 

 Campananeyen fragilissimus

 Lerzo, Fernández-Baldor, Canale, Whitlock, Otero & Gallina, 2024

DOI: 10.1080/08912963.2024.2383708  

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ABSTRACT

Rebbachisaurids are a group of basal diplodocoid sauropods that diversified primarily in Gondwana between the early Lower Cretaceous and the early Upper Cretaceous. Their phylogenetic relationships are still under debate given the fragmentary and incomplete nature of its remains. Here, we provide a detailed description of the postcranial remains of Campananeyen fragilissimus gen. et sp. nov. from the Candeleros Formation (lower Cenomanian) of Neuquén Province, Argentina. Campananeyen presents notable features that allow it to be recognised as a new species by the presence of an underdeveloped crista prootica, paraoccipital process internally hollow and a fuse dorsal alar arm of the ilium. The phylogenetic analysis recovered this taxon as a basal rebbachisaurid closely related to Zapalasaurus, Sidersaura and the specimen from La Amarga Formation MACN-Pv-N 35. The new rebbachisaurid is recovered as the sister taxon of Sidersaura due the presence of procoelous posterior caudal vertebrae and dorsoventrally flattened posterior caudal centra. C. fragilissimus presents an extreme pneumatization of the sacral region with an autapomorphic dorsal alar arm of the sacral transverse processes. Finally, the phylogenetic analysis supports a South American origin for Rebbachisauridae and an early diversification to Africa and Europe by the Barremian-Aptian as previously suggested.

KEYWORDS: Candeleros formation, Dinosauria, Pneumatization, Gondwana, Campananeyen, Rebbachisauridae

Campananeyen fragilissimus gen. et sp. nov. 

 

Lucas N. Lerzo, Fidel Torcida Fernández-Baldor, Juan I. Canale, John A. Whitlock, Alejandro Otero and Pablo A. Gallina. 2024. They all floated in the Cretaceous: New rebbachisaurid (Sauropoda, Diplodocoidea) with a highly pneumatized skeleton from the Upper Cretaceous (lower Cenomanian) of Patagonia, Argentina. Historical Biology: An International Journal of Paleobiology. DOI: doi.org/10.1080/08912963.2024.2383708  

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[Paleontology • 2024] The Axial Biomechanics of Trigonosaurus pricei (Neosauropoda: Titanosauria) and the importance of the cervical–dorsal region to Sauropod high-browser Feeding Strategy

Trigonosaurus pricei  

in Vidal, Bergqvist, Candeiro, Bandeira, ... et Pereira. 2024. 

DOI: 10.1093/zoolinnean/zlae087 

 x.com/PaleoVidal

Abstract

Trigonosaurus pricei is a small to medium-sized sauropod dinosaur (Sauropoda: Titanosauria) from the Late Cretaceous Bauru Group of Brazil that is known from a significant amount of recovered axial elements [four cervical vertebrae, 10 dorsal vertebrae, sacrum (MCT 1488-R), and 10 caudal vertebrae (MCT 1719-R)]. In this biomechanical work, we approach the hypothesis of the cartilaginous neutral pose and the range of motion of the axial series of Trigonosaurus. The results show that this sauropod could be capable of high elevation of the neck resulting from morphological adaptations of the cervicodorsal region on dorsal (D) vertebrae D2 and D3 (e.g. postzygapophyses of D2 positioned over the vertebral centrum and prezygapophyses of D3 over the anterior vertebral centrum). This implies that D2 articulates (cartilaginous neutral posture) with D3 only at a strong dorsally directed angle, resulting in a shift in the direction of the neck to a more elevated posture. Furthermore, the tail attributed to Trigonosaurus as a paratype could be oriented in the horizontal ‘direction’ and presented a sigmoidal ‘shape’. This work contributes generally to the understanding of variation in the body plan of sauropods and, more specifically, to the feeding strategy of small and medium-sized titanosaurs from semi-arid regions of Gondwana.

vertebrate palaeontology, Suropodomorpha, biomechanics, palaeoecology

Trigonosaurus pricei 

 Luciano S Vidal, Lílian P Bergqvist, Carlos R A Candeiro, Kamila L N Bandeira, Sandra Tavares, Stephen L Brusatte and Paulo V L G C Pereira. 2024. The Axial Biomechanics of Trigonosaurus pricei (Neosauropoda: Titanosauria) and the importance of the cervical–dorsal region to Sauropod high-browser Feeding Strategy. Zoological Journal of the Linnean Society. 201(3); zlae087. DOI: doi.org/10.1093/zoolinnean/zlae087

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[Paleontology • 2024] Asiatyrannus xui • The first deep-snouted tyrannosaur from Upper Cretaceous Ganzhou City of southeastern China

Asiatyrannus xui

 Zheng, Jin, Xie & Du, 2024

 

DOI:  10.1038/s41598-024-66278-5

Abstract

Tyrannosaurids were the most derived group of Tyrannosauroidea and are characterized by having two body plans: gracile, long-snouted and robust, deep-snouted skulls. Both groups lived sympatrically in central Asia. Here, we report a new deep-snouted tyrannosaurid, Asiatyrannus xui gen. et sp. nov., from the Upper Cretaceous of Ganzhou City, southeastern China, which has produced the large-bodied and long-snouted Qianzhousaurus. Based on histological analysis, the holotype of Asiatyrannus xui is not a somatically mature adult, but it already passed through the most rapid growth stages. Asiatyrannus is a small to medium-sized tyrannosaurine, with a skull length of 47.5 cm and an estimated total body length of 3.5–4 m; or around half the size of Qianzhousaurus and other large-bodied tyrannosaurines in similar growth stages. Asiatyrannus and Qianzhousaurus are sympatric tyrannosaurid genera in the Maastrichtian of southeastern China. Asiatyrannus differs from Qianzhousaurus in that it has a proportionally deeper snout, longer premaxilla, deeper maxilla, and deeper dentary, and the cornual process of the lacrimal is inflated without developing a discrete horn. The different skull proportions and body sizes suggest that Asiatyrannus and Qianzhousaurus likely had different feeding strategies and occupied different ecological niches.

 

Keywords: Asiatyrannus xui, Tyrannosauridae, Nanxiong Formation, Upper Cretaceous, China

 

Systematic paleontology

Theropoda Marsh, 1881

Tetanurae Gauthier, 1986

Coelurosauria Huene, 1914

Tyrannosauroidea Osborn, 1905

Tyrannosauridae Osborn, 1905

Tyrannosaurinae Osborn, 1905

Asiatyrannus xui gen. et sp. nov.

Diagnosis: Asiatyrannus xui is a small to medium-sized tyrannosaurine theropod that differs from other tyrannosauroids in possessing the following autapomorphies: two small, deep fossae located on the lateral surface of the premaxilla just lateral to the anteroventral border of the external naris, a large and sub-rectangular shaped maxillary fenestra, the posterior protuberances of the nasals connect to form two separated medium low ridges, a low ridge-like jugal accessory horn, the ventral margin of the anterior ramus of the jugal curving ventrally anterior to the accessory horn, the lateral surface of the descending process of the postorbital developed the anterodorsally trending fine lineations, the slender, straight, and banded-shaped postorbital bar, with almost straight and parallel anterior and posterior margins in lateral view, and the lateral surangular shelf extends to the posterior end of the surangular.

Type locality: Nanxiong Formation (Upper Cretaceous, Maastrichtian) of Shahe Town, Nankang District, Ganzhou City, Jiangxi Province, China.

The photograph (A) and line drawing (B) of the skull of Asiatyrannus xui (ZMNH M30360) in right lateral view. The inset box in (A) indicates the position of the detailed jugal accessory horn in (C).

 acf accessory fossa of maxilla; ang angular; aof antorbital fenestra; cor cornual process; d dentary; d.t dentary tooth; emf external mandibular fenestra; en external naris; f frontal; gr groove; itf infratemporal fenestra; j jugal; jah jugal accessory horn; L left; la lacrimal; mf maxillary fenestra; mnvf maxillary neurovascular foramina; mx maxilla; nas nasal; nr nasal ridge; orb orbit; par parietal; pal palatine; pmx premaxilla; po postorbital; q quadrate; qj quadratojugal; R right; sa surangular; sf surangular foramen; snf subnarial foramen; sq squamosal; t1–6 maxillary tooth 1–6.

Fossil remains of Asiatyrannus xui (ZMNH M30360).
(A) Skeletal outlines showing recovered elements in yellow color. The skeletal reconstruction is the proportional scaling of Lythronax argestes drawn by Scott Hartman from Loewen et al.23; (B) the skull in right lateral view; (C) the caudal vertebrae in left lateral view; (D) the right femur in posterior view; (E) the right tibia and fibula in posterior view; (F) The distal portion of the right metatarsal III in medial view and metatarsal IV in anterior view; (G) the middle shaft of the left tibia and fibula in anterior view; (H) The middle shaft of the left metatarsals in anterior view. ft the fourth trochanter; ift iliofibularis tubercle; mt metatarsal.

Etymology: The generic name is derived from Asia, and the suffix ‘tyrannus’ is derived from the Latin word for ‘king’ or ‘tyrant’, to emphasize that this is the new tyrannosaur collected in the continent of Asia. The specific name honors Dr. Xing Xu (Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences), a distinguished dinosaurologist who contributed greatly to the study of dinosaurs from China, including the research of several tyrannosaurs: Guanlong, Dilong, and Yutyrannus. Dr. Xing Xu has also been a great supporter of the paleontological research and science popularization work of the Zhejiang Museum of Natural History.

Wenjie Zheng, Xingsheng Jin, Junfang Xie and Tianming Du. 2024. The first deep-snouted tyrannosaur from Upper Cretaceous Ganzhou City of southeastern China. Scientific Reports. 14,  16276. DOI:  doi.org/10.1038/s41598-024-66278-5

[Paleontology • 2024] Harenadraco prima • The first troodontid (Theropoda: Troodontidae) from the Upper Cretaceous Baruungoyot Formation of Mongolia

  

Harenadraco prima

S. Lee, Y.-N. Lee, Park, Kim, Badamkhatan, Idersaikhan & Tsogtbaatar, 2024

 

 DOI: 10.1080/02724634.2024.2364746 

artwork by Yusik Choi

ABSTRACT

Among non-avian dinosaurs, troodontids are relatively rare but diverse. The Nemegt Basin in the Mongolian Gobi Desert, which incorporates three of the most fossiliferous beds in the world, is one such region with high troodontid diversity and has also produced eight troodontid taxa until now. The diversity of troodontids is biased towards the two formations, Nemegt and Djadochta. Despite its rich vertebrate fossil record, no troodontids have been described from the Baruungoyot Formation. This faunal absence is perplexing as the Baruungoyot Formation has often been considered intermediate between the other two units in stratigraphy and paleoenvironment, but there are no definite troodontid materials that could fill this ‘gap.’ Here, we report a new troodontid, Harenadraco prima gen. et sp. nov., from the Baruungoyot Formation in Hermiin Tsav, Mongolia. It is represented by an incomplete skeleton that mainly consists of partially articulated left hind limb elements. Harenadraco is small and lightly built like other troodontids, but its tarsometatarsus exhibits extreme slenderness comparable only to Philovenator among cursorial non-avian maniraptorans. It also implies high cursoriality that could be an adaptation of Harenadraco to its environment where potential prey animals like mammals and predators such as eudromaeosaurs were likely to be agile. The discovery of Harenadraco confirms the presence of troodontids in all three formations in the Nemegt Basin.

 Left pedal phalanges and the skeletal reconstruction of the preserved parts in Harenadraco prima (MPC-D 110/119, holotype). A, left pedal digits II–IV in lateral view. 
 M, skeletal reconstruction of Harenadraco prima (MPC-D 110/119, holotype) with missing parts in gray.

Abbreviations: II-3, pedal phalanx II-3; III-3, pedal phalanx III-3; IV-2, pedal phalanx IV-2.

 Life reconstruction of Harenadraco prima 

(artwork by Yusik Choi).

DINOSAURIA Owen, 1842

THEROPODA Marsh, 1881

TROODONTIDAE Gilmore, 1924

HARENADRACO PRIMA, gen. et sp. nov.

Diagnosis—A small-sized troodontid diagnosed by the following unique combination of characters (autapomorphies indicated with an asterisk): tall S-shaped medial margin of medial condyle of astragalocalcaneum in anterior view*, poorly developed flexor sulcus on the distal articular end of metatarsal II, which also lacks collateral ligament fossae*, metatarsal III excluded from the proximal end of the metatarsus in dorsal view (shared with Tochisaurus, Zanabazar, and Philovenator), metatarsal IV only slightly more robust than metatarsal II at the proximal end in ventral view (shared with Daliansaurus and Philovenator), pronounced ventral protrusion near the proximal end of metatarsal IV (shared with Liaoningvenator), extremely narrow proximal shaft of metatarsal IV*, greatly elongated flexor tubercle of pedal phalanx II-3 that reaches the shaft of the preceding phalanx when in articulation*, and the distal articular surface of pedal phalanx III-3 not ginglymoid*.

Etymology—The name of the genus is a composition of the Latin words harena (sand) and draco (dragon). The species name “prima” means first in Latin, referring to the taxon being the first troodontid from the Baruungoyot Formation.

 

Sungjin Lee, Yuong-Nam Lee, Jin-Young Park, Su-Hwan Kim, Zorigt Badamkhatan, Damdinsuren Idersaikhan and Khishigjav Tsogtbaatar. 2024. The first troodontid (Dinosauria: Theropoda) from the Upper Cretaceous Baruungoyot Formation of Mongolia. Journal of Vertebrate Paleontology. e2364746. DOI: doi.org/10.1080/02724634.2024.2364746  

[Paleontology • 2024] Diuqin lechiguanae • A New unenlagiine (Theropoda: Dromaeosauridae) from the Bajo de la Carpa Formation (Neuquén Group, Upper Cretaceous) of Neuquén Province, Patagonia, Argentina

 

Diuqin lechiguanae 

Porfiri, Baiano, dos Santos, Gianechini, Pittman & Lamanna. 2024

 

 DOI: 10.1186/s12862-024-02247-w 

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Abstract

Background: 

Unenlagiine paravians are among the most relevant Gondwanan theropod dinosaur clades for understanding the origin of birds, yet their fossil record remains incomplete, with most taxa being represented by fragmentary material and/or separated by lengthy temporal gaps, frustrating attempts to characterize unenlagiine evolution.

Results and conclusions: 

Here we describe Diuqin lechiguanae gen. et sp. nov., a new unenlagiine taxon from the Upper Cretaceous (Santonian) Bajo de la Carpa Formation of the Neuquén Basin of Neuquén Province in northern Patagonia, Argentina that fills a substantial stratigraphic gap in the fossil record of these theropods. Although known only from a very incomplete postcranial skeleton, the preserved bones of Diuqin differ from corresponding elements in other unenlagiines, justifying the erection of the new taxon. Moreover, in several morphological aspects, the humerus of Diuqin appears intermediate between those of geologically older unenlagiines from the Neuquén Basin (e.g., Unenlagia spp. from the Turonian–Coniacian Portezuelo Formation) and that of the stratigraphically younger, larger-bodied Austroraptor cabazai from the Campanian–Maastrichtian Allen Formation. Consequently, the morphology of the new taxon appears to indicate a transitional stage in unenlagiine evolution. Phylogenetic analysis recovers Diuqin as a paravian with multiple plausible systematic positions, but the strongest affinity is with Unenlagiinae. The humerus of the new form exhibits subcircular punctures near its distal end that are interpreted as feeding traces most likely left by a conical-toothed crocodyliform, mammal, or theropod, the latter potentially corresponding to a megaraptorid or another unenlagiine individual. Thus, in addition to filling important morphological and temporal gaps in unenlagiine evolutionary history, the new taxon also offers information relating to the paleoecology of these theropods.

Keywords: Unenlagiinae, Dromaeosauridae, Cretaceous, Bajo de la Carpa Formation, Patagonia, South America, Biostratigraphy, Phylogeny, Paleoecology, Megaraptoridae

Left humerus of Diuqin lechiguanae gen. et sp. nov. (MUCPv 1401/4) in lateral (A), medial (B), anterior (C), posterior (D), proximal (E), and distal (F) views.

Abbreviations: brf, brachial fossa; cr, crest; dldpr, distolateral deltopectoral ridge; dpc, deltopectoral crest; ect, ectepicondyle; ent, entepicondyle; ics, intercondylar sulcus; int, internal tuberosity; rac, radial condyle; sul, sulcus; tm, tooth marks; trab, trabecular tissue; tub, tuberosity; ulc, ulnar condyle. Asterisk indicates hypothesized autapomorphic feature (the distally arising distolateral deltopectoral ridge). Scale bar equals 5 centimeters

Systematic paleontology

Theropoda Marsh, 1881  

Tetanurae Gauthier, 1986 

Coelurosauria Huene, 1920 

Paraves Sereno, 1997 

Dromaeosauridae Matthew & Brown, 1922 

Unenlagiinae Bonaparte, 1999  

Diuqin lechiguanae gen. et sp. nov.

 

Holotype: MUCPv 1401, a fragmentary but associated postcranial skeleton consisting of the posteriormost sacral vertebral neural arch, an anterior caudal vertebral neural arch, the nearly complete left humerus, and four unidentified fragments (at least two of which may be small pieces of vertebrae). Accessioned in the Museo de Ciencias Naturales of the Universidad Nacional del Comahue in Neuquén, Neuquén Province, Argentina to ensure free access to qualified researchers in perpetuity.

Locality and horizon: The specimen was collected from the isthmus between the southeast coast of Lago Barreales and the northwest coast of Lago Mari Menuco, in Neuquén Province, northwestern Patagonia, Argentina (Fig. 1), from a stratum of the Bajo de la Carpa Formation of the Neuquén Group (Upper Cretaceous: Santonian).

Associated fauna: An isolated megaraptorid theropod tooth (MUCPv 1557; see below) and fragmentary bones of an indeterminate sauropod were also found near the site that yielded the D. lechiguanae holotype (MUCPv 1401). The megaraptorid tooth was found approximately 2–3 m from Diuqin, whereas the sauropod fragments were found some 10–12 m away.

Diagnosis: First unenlagiine theropod dinosaur to be discovered from the Bajo de la Carpa Formation (Neuquén Group, Upper Cretaceous), exhibiting the following autapomorphies and a unique combination of characters. Autapomorphies: (1) horizontal accessory lamina between spinopostzygapophyseal laminae on posteriormost sacral vertebra; (2) pair of elliptical, bilateral, dorsolaterally–ventromedially oriented foramina immediately anterolateral to base of neural spine in (at least) posteriormost sacral and anterior caudal vertebrae; (3) distolateral deltopectoral ridge of humerus arises on distal half of deltopectoral crest. Unique combination of characters: postzygapophyses of posteriormost sacral vertebra strongly posteriorly projected; humeral deltopectoral crest oriented anteriorly (also present in Austroraptor cabazai); absence of sulcus between deltopectoral crest and humeral shaft (also present in Austroraptor); sharp crest proximal to humeral ectepicondyle with proximally positioned tubercle (also present in Buitreraptor).

Etymology: Genus name: Diuqin (from Mapuzungun, the language of the Mapuce people indigenous to the region where the fossil was found), bird of prey. Species name: lechiguanae, after Lechiguana, the witch in the 1975 film Nazareno Cruz y el Lobo (directed by eminent Argentinian filmmaker Leonardo Favio) who foresaw that the film’s titular character would become a werewolf. Intended etymology: “Lechiguana’s bird of prey.”

 

Juan D. Porfiri, Mattia A. Baiano, Domenica D. dos Santos, Federico A. Gianechini, Michael Pittman and Matthew C. Lamanna. 2024. Diuqin lechiguanae gen. et sp. nov., A New unenlagiine (Theropoda: Paraves) from the Bajo de la Carpa Formation (Neuquén Group, Upper Cretaceous) of Neuquén Province, Patagonia, Argentina. BMC Ecology and Evolution. 24: 77. DOI: 10.1186/s12862-024-02247-w

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