[Paleontology • 2024] Huaxiazhoulong shouwen • A New ankylosaurid Dinosaur (Ankylosauria: Ankylosauridae) from the Upper Cretaceous of Jiangxi Province, southern China

Huaxiazhoulong shouwen 

Zhu, Wu, You, Jia, Chen, Yao, Zheng & Xu, 2024 

 

DOI: 10.1080/08912963.2024.2417208  

artwork by YE Jianhao

ABSTRACT

Huaxiazhoulong shouwen gen. et sp. nov. is a new ankylosaurid recovered from the Upper Cretaceous Tangbian Formation of Jiangxi Province, southern China. Huaxiazhoulong shouwen can be diagnosed on the basis of three autapomorphies (the middle shaft and distal end of the ischium are expanded; the ratio of width of distal end to minimum shaft width is greater than 3 in humerus, the maximum length of femur to humerus length ratio is about 1.45) and a unique combination of characters (the centra of anterior caudal vertebrae in anterior view is heart-shaped; the dorsal surface of scapula is straight; the scapulocoracoid has a large medial brace; the humeral head and deltopectoral crest are separated by a distinct notch anteriorly). The phylogenetic analysis shows that Huaxiazhoulong shouwen is an early member of Ankylosauridae.

KEYWORDS: Ankylosauria, Upper Cretaceous, Tangbian Formation, Jiangxi Province, Huaxiazhoulong shouwen

  

Huaxiazhoulong shouwen gen. et sp. nov.

Ziheng Zhu, Jie Wu, Yue You, Yingli Jia, Chujiao Chen, Xi Yao, Wenjie Zheng and Xing Xu. 2024. A New ankylosaurid Dinosaur from the Upper Cretaceous of Jiangxi Province, southern China. Historical Biology: An International Journal of Paleobiology. DOI: doi.org/10.1080/08912963.2024.2417208  

[Paleontology • 2024] Extremely rapid, yet noncatastrophic, Preservation of the Flattened-feathered and 3D Dinosaurs of the Early Cretaceous of China

  

 Extremely rapid preservation of the flattened-feathered and 3D Dinosaurs of the Early Cretaceous, Yixian Formation in China

in MacLennan, Sha, Olsen, Kinney, Chang, Fang, Liu, Slibeck, Chen et Schoene, 2024.

DOI: doi.org/10.1073/pnas.2322875121

Significance: 

Traditionally, the spectacular preservation of fossils of feathered dinosaurs and early birds and other animals found in sedimentary strata of the Yixian Formation in northeast China has been attributed to Pompeii-like volcanic catastrophes. We provide high-resolution geochronology and sedimentological analysis challenging this model and show that these strata instead record normal life and death processes preserved in a succession of depositional environments that span less than 100 thousand years.

Abstract

Northeast China’s Early Cretaceous Yixian Formation preserves spectacular fossils that have proved extraordinarily important in testing evolutionary hypotheses involving the origin of birds and the distribution of feathers among nonavian dinosaurs. These fossils occur either flattened with soft tissue preservation (including feathers and color) in laminated lacustrine strata or as three-dimensional (3D) skeletons in “life-like” postures in more massive deposits. The relationships of these deposits to each other, their absolute ages, and the origin of the extraordinary fossil preservation have been vigorously debated for nearly a half century, with the prevailing view being that preservation was linked to violent volcanic eruptions or lahars, similar to processes that preserved human remains at Pompeii. We present high-precision zircon U-Pb geochronology from cores and outcrops, demonstrating that Yixian Formation accumulation rates are more than an order of magnitude higher than usually estimated. Additionally, we provide zircon provenance and sedimentological data from 3D dinosaur fossils, which imply that their death and burial occurred in collapsed burrows, rather than via a catastrophic volcanogenic mechanism. In the studied area, the three principal fossil-rich intervals of the Yixian occur as a cyclic sequence that correspond to periods of high precipitation. Using Bayesian–Markov Chain Monte Carlo approaches, we constrain the total duration of the sequence to less than ~93,000 y and suggest that climatic precession paced the expression of these cyclic sediments. Rather than representing multiple, Pompeii-like catastrophes, the Yixian Formation is instead a brief snapshot of normal life and death in an Early Cretaceous continental community.

Two perfectly articulated skeletons of the sheep-size dinosaur Psittacosaurus, found in China's Yixian Formation. New research suggests they died in burrow collapses, not via volcanism, as previously thought.

by Jun Liu, IVPP, Chinese Academy of Sciences

Artist's rendition of a Psittacosaurus dinosaur with babies being hunted by Repenomamus, a mammal. One fossil assemblage from the Yixian Formation preserved the remains of these species in mortal combat, frozen in mid-action. The dinosaur here is shown with bristly proto-feathers on its tail.

artwork by Alex Boersma

 Scott A. MacLennan, Jingeng Sha, Paul E. Olsen, Sean T. Kinney, Clara Chang, Yanan Fang, Jun Liu, Bennett B. Slibeck, Elaine Chen, and Blair Schoene. 2024. Extremely rapid, yet noncatastrophic, Preservation of the Flattened-feathered and 3D Dinosaurs of the Early Cretaceous of China. PNAS. 121 (47) e2322875121. DOI: doi.org/10.1073/pnas.2322875121

[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

[PaleoOrnithology • 2024] Synthetic Analysis of Trophic Diversity and Evolution in Enantiornithes with New insights from Bohaiornithidae

Life reconstruction of enantiornithine birds feeding.
Longipteryx (left), Bohaiornis (centre), and Pengornis (right) are pictured in the Early Cretaceous forests of northeastern China, roughly 120 million years ago.

in Miller, Bright, Wang, Zheng & Pittman. 2024.

DOI: 10.7554/eLife.89871.3 

 facebook.com/PalaeoPittman

Abstract

Enantiornithines were the dominant birds of the Mesozoic, but understanding of their diet is still tenuous. We introduce new data on the enantiornithine family Bohaiornithidae, famous for their large size and powerfully built teeth and claws. In tandem with previously published data, we comment on the breadth of enantiornithine ecology and potential patterns in which it evolved. Body mass, jaw mechanical advantage, finite element analysis of the jaw, and traditional morphometrics of the claws and skull are compared between bohaiornithids and living birds. We find bohaiornithids to be more ecologically diverse than any other enantiornithine family: Bohaiornis and Parabohaiornis are similar to living plant-eating birds; Longusunguis resembles raptorial carnivores; Zhouornis is similar to both fruit-eating birds and generalist feeders; and Shenqiornis and Sulcavis plausibly ate fish, plants, or a mix of both. We predict the ancestral enantiornithine bird to have been a generalist which ate a wide variety of foods. However, more quantitative data from across the enantiornithine tree is needed to refine this prediction. By the Early Cretaceous, enantiornithine birds had diversified into a variety of ecological niches like crown birds after the K-Pg extinction, adding to the evidence that traits unique to crown birds cannot completely explain their ecological success.

Life reconstruction of enantiornithine birds feeding.
Longipteryx (left), Bohaiornis (centre), and Pengornis (right) are pictured in the Early Cretaceous forests of northeastern China, roughly 120 million years ago.
Bohaiornis is depicted feeding on cypress (Cupressaceae, Ding et al., 2016) leaves after the findings in this work. Longipteryx is depicted feeding on the mayfly Epicharmeropsis hexavenulosus (Huang et al., 2007) after (Miller et al., 2022). Pengornis is depicted feeding on the fish Lycoptera davidi (Chang and Miao, 2004) after Miller et al., 2023.

 

Case Vincent Miller, Jen A. Bright, Xiaoli Wang, Xiaoting Zheng and Michael Pittman. 2024. Synthetic Analysis of Trophic Diversity and Evolution in Enantiornithes with New insights from Bohaiornithidae. eLife. DOI: 10.7554/eLife.89871.3

  facebook.com/PalaeoPittman/posts/1828804674249023

[Paleontology • 2024] Datai yingliangis • A New Armored Dinosaur (Ankylosauria: Ankylosauridae) with double cheek horns from the early Late Cretaceous of southeastern China

  

Datai yingliangis

Xing, Niu, Mallon & Miyashita, 2024

 DOI: 10.18435/vamp29396

 twitter.com/Jordan_Mallon

Reconstruction by Kaitlin T. Lindblad twitter.com/Crocodontist

ABSTRACT

Ankylosaurines are the iconic armoured dinosaurs that characterize terrestrial vertebrate faunas in the Late Cretaceous of Asia and Laramidia (western North America). The earliest members of this clade are known from the early Late Cretaceous (Cenomanian–Santonian) times of Asia, but little consensus has emerged as to how they are related to the anatomically derived and chronologically younger forms. In southeastern China, the Cretaceous red sand beds crop out across basins from Zhejiang to Guandong provinces. However, the horizons corresponding to the early Late Cretaceous stages remain poorly sampled. Here, we report the first definitive vertebrate skeleton — let alone that of an armoured dinosaur — from the Coniacian/Turonian Ganzhou Formation, Datai yinliangis gen. et sp. nov. Despite the immature ontogenetic status of the type materials, D. yingliangis can be diagnosed with autapomorphic traits in the cranial caputegulae (such as double horns on the quadratojugal) and extensive gular osteoderms. Morphologically, it is intermediate between the chronologically older ankylosaurids from Asia (e.g., Crichtonpelta and Jinyunpelta) and derived post-Cenomanian ankylosaurines (e.g., Pinacosaurus). Phylogenetic analyses broadly corroborate this assessment. The new taxon either falls in the grade of Asian ankylosaurines proximal to the lineages of derived forms or forms a sister lineage to Pinacosaurus. Based on these insights, Datai makes a significant addition to the early Late Cretaceous vertebrate fauna from southeastern China and highlights the future potential in this region for improved understanding of the origin and early evolution of ankylosaurines.

Keywords: Ankylosauria, Ankylosaurinae, Zhoutian Formation, Guanzhou Group

The type specimens of Datai yingliangis gen. et ap. nov. (individual lying on top: YLSNHM 01003; individual on bottom: YLSNHM 01002, holotype) prepared and reconstructed in situ. The head, cervical, and thoracic regions of the specimens were discovered and extracted from a single block.

Dinosauria Owen, 1842

Ornithischia Seeley, 1887

Thyreophora Nopcsa, 1915

Ankylosauria Osborn, 1923

Ankylosauridae Brown, 1906

Datai gen. nov.

Etymology: 'Datai,' a composite of the last character (syllable) each from tongda (to understand/to be sensible) and antai (stable) in Chinese Pinyin.

Datai yingliangis sp. nov.

Diagnosis: An ankylosaurine with dual jugal/quadratojugal horns. This taxon is also distinguished from all other ankylosaurines with a unique combination of the following characters: protruded premaxilla such that prenarial portion is longer than infranarial portion (also present in Zhongyuansaurus luoyangensis), distinct 'postfrontal' caputegulum (also in Pinacosaurus mephistocephalus and Talarurus plicatospineus), well-developed supraorbitals forming no lacrimal incisure or postorbital peak (potentially controlled ontogenetically), parasagittaly projecting squamosal horn (also in Scolosaurus cutleri/Oohkotokia horneri), nuchal horn (also in Ankylosaurus magniventris, Euoplocephalus tutus, Nodocephaosaurus kirtlandensis, Zuul crurivastator), and polygonal, monotypic gular osteoderms covering the interman-dibular region and the entire throat (polymorphic gular osteoderms occur in Jinyunpelta sinensis).

Type locality and horizon: Zhoutian Formation, Ganzhou Group (Turonian–early Coniacian; Upper Cretaceous; 96–90 Ma).

Etymology: 'yingliangis', in recognition of the Yingliang Group. The Yingliang Stone Natural History Museum is operated as a public museum by the philanthropic program of the founder (Liang Liu) of the Yingliang Group, and the type specimens are curated in this museum in Shuitou, Fujiang, China.

Lida Xing, Kecheng Niu, Jordan Mallon and Tetsuto Miyashita. 2024. A New Armored Dinosaur with double cheek horns from the early Late Cretaceous of southeastern China. Vertebrate Anatomy Morphology Palaeontology. 11. DOI: 10.18435/vamp29396

 twitter.com/Jordan_Mallon/status/1759569971590414802

 twitter.com/Crocodontist/status/1759661617791336850

[Paleontology • 2023] Fujianvenator prodigiosus • A New Avialan Theropod from an emerging Jurassic Terrestrial Fauna

Fujianvenator prodigiosus 

Xu, Wang, Chen, Dong, Lin, Xu, Tang, You, Zhou, Wang, He, Li, Zhang & Zhou, 2023

DOI: 10.1038/s41586-023-06513-7

Abstract

Birds are descended from non-avialan theropod dinosaurs of the Late Jurassic period, but the earliest phase of this evolutionary process remains unclear owing to the exceedingly sparse and spatio-temporally restricted fossil record. Information about the early-diverging species along the avialan line is crucial to understand the evolution of the characteristic bird bauplan, and to reconcile phylogenetic controversies over the origin of birds. Here we describe one of the stratigraphically youngest and geographically southernmost Jurassic avialans, Fujianvenator prodigiosus gen. et sp. nov., from the Tithonian age of China. This specimen exhibits an unusual set of morphological features that are shared with other stem avialans, troodontids and dromaeosaurids, showing the effects of evolutionary mosaicism in deep avialan phylogeny. F. prodigiosus is distinct from all other Mesozoic avialan and non-avialan theropods in having a particularly elongated hindlimb, suggestive of a terrestrial or wading lifestyle—in contrast with other early avialans, which exhibit morphological adaptations to arboreal or aerial environments. During our fieldwork in Zhenghe where F. prodigiosus was found, we discovered a diverse assemblage of vertebrates dominated by aquatic and semi-aquatic species, including teleosts, testudines and choristoderes. Using in situ radioisotopic dating and stratigraphic surveys, we were able to date the fossil-containing horizons in this locality—which we name the Zhenghe Fauna—to 148–150 million years ago. The diversity of the Zhenghe Fauna and its precise chronological framework will provide key insights into terrestrial ecosystems of the Late Jurassic.

Fujianvenator prodigiosus gen. et sp. nov.

 

Liming Xu, Min Wang, Runsheng Chen, Liping Dong, Min Lin, Xing Xu, Jianrong Tang, Hailu You, Guowu Zhou, Linchang Wang, Wenxing He, Yujuan Li, Chi Zhang and Zhonghe Zhou. 2023. A New Avialan Theropod from an emerging Jurassic Terrestrial Fauna. Nature. DOI: 10.1038/s41586-023-06513-7

https://phys.org/news/2023-09-chinese-paleontologists-fossil-link-bird.html

[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 • 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 • 2022] Cranial Osteology and Palaeobiology of the Early Cretaceous Bird Jeholornis prima (Aves: Jeholornithiformes)

Jeholornis 

in Hu, Wang, Fabbri, O’Connor, ... et Benson, 2022. 

DOI: 10.1093/zoolinnean/zlac089

https://twitter.com/tetaneuron

Artistic reconstruction by Michael Rothman

Abstract

Jeholornis is a representative of the earliest-diverging bird lineages, providing important evidence of anatomical transitions involved in bird origins. Although ~100 specimens have been reported, its cranial morphology remains poorly documented owing to poor two-dimensional preservation, limiting our understanding of the morphology and ecology of the key avian lineage Jeholornithiformes, in addition to cranial evolution during the origin and early evolution of birds. Here, we provide a detailed description of the cranial osteology of Jeholornis prima, based primarily on high-quality, three-dimensional data of a recently reported specimen. New anatomical information confirms the overall plesiomorphic morphology of the skull, with the exception of the more specialized rostrum. Data from a large sample size of specimens reveal the dental formula of J. prima to be 0–2–3 (premaxillary–maxillary–dentary tooth counts), contrary to previous suggestions that the presence of maxillary teeth is diagnostic of a separate species, Jeholornis palmapenis. We also present evidence of sensory adaptation, including relatively large olfactory bulbs in comparison to other known stem birds, suggesting that olfaction was an important aspect of Jeholornis ecology. The digitally reconstructed scleral ring suggests a strongly diurnal habit, supporting the hypothesis that early-diverging birds were predominantly active during the day.

Keywords: dentition, diurnality, Jehol Biota, neurocranium

Han Hu, Yan Wang, Matteo Fabbri, Jingmai K O’Connor, Paul G Mcdonald, Stephen Wroe, Xuwei Yin, Xiaoting Zheng, Zhonghe Zhou and Roger B J Benson. 2022. Cranial Osteology and Palaeobiology of the Early Cretaceous bird Jeholornis prima (Aves: Jeholornithiformes). Zoological Journal of the Linnean Society. zlac089. DOI: 10.1093/zoolinnean/zlac089

 twitter.com/tetaneuron/status/1584544150405251074

https://phys.org/news/2022-10-fossil-bird-skull-reconstruction-reveals.html

[Paleontology • 2022] The Shishugou Fauna of the Middle-Late Jurassic Transition Period in the Junggar Basin of Western China

The Shishugou Fauna in the Junggar Basin of Western China

in Xu, Clark, Eberth & Currie, 2022. 

DOI: 10.1111/1755-6724.14996

illustrated by Chuang ZHAO 

  

 Abstract

The Middle–Late Jurassic transition period is a critical period for the evolution of terrestrial vertebrates, but the global fossil record from this time is relatively poor. The Shishugou Fauna of this period has recently produced significant fossil remains of dinosaurs and other vertebrate groups, some representing the earliest known members of several dinosaurian groups and other vertebrate groups and some representing the best-known specimens of their group. These discoveries are significant for our understanding of the origin and evolution of several vertebrate lineages. Radiometric dating indicates that the fauna is aged approximately 159–164 Ma. Comparisons with other similarly-aged terrestrial faunas such as Shaximiao and Yanliao show both taxonomic similarities and differences between these faunas and indicate that the Junggar deposits might have preserved the most complete vertebrate fossil record for a Middle–Late Jurassic Laurasian terrestrial fauna.

 Keywords: Middle–Late Jurassic, Shishugou Fauna, Shishugou Formation, terrestrial ecosystem, Shaximiao, Yanliao, Junggar Basin

 

Xing Xu, James M. Clark, David A. Eberth and Philip J. Currie. 2022. The Shishugou Fauna of the Middle-Late Jurassic Transition Period in the Junggar Basin of Western China. Acta Geologica Sinica - English Edition. Special Paper for 100th Anniversary. DOI: 10.1111/1755-6724.14996

 twitter.com/pnso_official/status/1572556252097392640

Shishugou Formation, China, 157 million years ago. 

Mamenchisaurus, Sinraptor, Guanlong, Limusaurus, Zuolong, ..

[Paleontology • 2022] Earliest Evidence for Fruit Consumption and Potential Seed Dispersal by Birds

  

in Hu, Wang, McDonald, et al., 2022. 

DOI: 10.7554/eLife.74751

Abstract

The Early Cretaceous diversification of birds was a major event in the history of terrestrial ecosystems, occurring during the earliest phase of the Cretaceous Terrestrial Revolution, long before the origin of the bird crown-group. Frugivorous birds play an important role in seed dispersal today. However, evidence of fruit consumption in early birds from outside the crown-group has been lacking. Jeholornis is one of the earliest-diverging birds, only slightly more crownward than Archaeopteryx, but its cranial anatomy has been poorly understood, limiting trophic information which may be gleaned from the skull. Originally hypothesised to be granivorous based on seeds preserved as gut contents, this interpretation has become controversial. We conducted high-resolution synchrotron tomography on an exquisitely preserved new skull of Jeholornis, revealing remarkable cranial plesiomorphies combined with a specialised rostrum. We use this to provide a near-complete cranial reconstruction of Jeholornis, and exclude the possibility that Jeholornis was granivorous, based on morphometric analyses of the mandible (3D) and cranium (2D), and comparisons with the 3D alimentary contents of extant birds. We show that Jeholornis provides the earliest evidence for fruit consumption in birds, and indicates that birds may have been recruited for seed dispersal during the earliest stages of the avian radiation. As mobile seed dispersers, early frugivorous birds could have expanded the scope for biotic dispersal in plants, and might therefore explain, at least in part, the subsequent evolutionary expansion of fruits, indicating a potential role of bird–plant interactions in the Cretaceous Terrestrial Revolution.

Seeds preserved in the abdominal area of selected Jeholornis prima specimens.
(A) IVPP V13274 (holotype). (B) STM 2–41.
(C) Close-up image of seeds in IVPP V13274 (A). (D) Gastrolith mass in J. prima STM 2–15.

 Photos in A–D followed figures in O’Connor et al., 2018. 

Scale bars equal 5 mm.

 Han Hu, Yan Wang, Paul G. McDonald, Stephen Wroe, Jingmai K. O'Connor, Alexander Bjarnason, Joseph J Bevitt, Xuwei Yin, Xiaoting Zheng, et al. 2022. Earliest Evidence for Fruit Consumption and Potential Seed Dispersal by Birds. eLife 11:e74751. DOI: 10.7554/eLife.74751

 phys.org/news/2022-08-early-bird-fruit-fossil-earliest.html

[Paleontology • 2022] Bashanosaurus primitivus • New Stegosaurs (Ornithischia, Stegosauria) from the Middle Jurassic Lower Member of the Shaximiao Formation of Chongqing, China

Bashanosaurus primitivus

Dai, Li, Maidment, Wei, Zhou, Hu, Ma, Wang, Hu & Peng, 2022

DOI: 10.1080/02724634.2021.1995737 

 

ABSTRACT

Stegosaurs are a major clade of ornithischian dinosaurs, yet because of their fragmentary fossil record, their interrelationships and early evolution are poorly understood. Here, we describe a new stegosaur, Bashanosaurus primitivus, gen. et sp. nov., and some other indeterminate stegosaur materials. We provide new U-Pb detrital zircon ages for horizons bounding the holotypic quarry in the Lower Member of the Shaximiao Formation, Yunyang, Chongqing Municipality, China, which indicate a Middle Jurassic (Bajocian) age. Bashanosaurus represents the earliest record of stegosaurs in Asia and one of the earliest records of this clade in the world. The dorsal vertebrae, scapula, coracoid, femur, and plates of Bashanosaurus primitivus possess several unique characters among Stegosauria, including the elevation of the parapophyses of dorsal vertebrae on stalks at the base of the transverse processes, a flared distal end of the scapula, and a small acromial process. Among armored dinosaurs (thyreophorans), these features are reminiscent of the basally branching taxon Scelidosaurus, indicating that Bashanosaurus possesses a unique mosaic of plesiomorphic thyreophoran and derived stegosaur features. Phylogenetic analysis shows that Bashanosaurus primitivus is the earliest-diverging stegosaur, along with Chungkingosaurus, from the Upper Member of the Shaximiao Formation, consistent with the early age of the taxon.

DINOSAURIA Owen, 1842

ORNITHISCHIA Seeley, 1887

STEGOSAURIA Marsh, 1877

BASHANOSAURUS PRIMITIVUS, gen. et sp. nov.

Diagnosis—Bashanosaurus primitivus differs from all other stegosaurs by possession of the following autapomorphies: (1) the parapophyses of dorsal vertebrae are elevated on stalks at the base of the transverse process and are clearly visible in anterior and posterior views; (2) the scapula blade is slender and flares distally; (3) the acromial process of the scapula is small, triangular and poorly developed; (4) the 4th trochanter of the femur is positioned below the middle of the shaft; (5) the bases of plates are strongly convex and transversely thickened, and are separated from the anterior/posterior margins of the plates by a distinct groove.

Etymology—The generic name “Bashan” refers to the ancient name of Chongqing, and the specific name “primitivus” indicates that this newly named species represents the earliest-diverging stegosaur.

...

 CONCLUSIONS: 

Bashanosaurus primitivus is the earliest record of Stegosauria in Asia and represents one of the earliest records of this clade from anywhere in the world. Geochronological data and analysis support a Middle Jurassic (Bajocian) age for the Shaximiao Formation in the vicinity of Pu’an Township, China. Phylogenetic analysis indicates that Bashanosaurus primitivus is the earliest-diverging stegosaur along with Chungkingosaurus supporting an Asian origin for Stegosauria based on currently available data.

 

Dai Hui, Li Ning, Susannah C. R. Maidment, Wei Guangbiao, Zhou Yuxuan, Hu Xufeng, Ma Qingyu, Wang Xunqian, Hu Haiqian and Peng Guangzhao. 2022. New Stegosaurs from the Middle Jurassic Lower Member of the Shaximiao Formation of Chongqing, China. Journal of Vertebrate Paleontology.   e1995737. DOI: 10.1080/02724634.2021.1995737 

 nhm.ac.uk/discover/news/2022/march/new-stegosaur-dinosaur-species-could-be-oldest-ever-discovered.html