[Paleontology • 2026] Invictibellatrix amberina • A new megaraptoran dinosaur (Coelurosauria: Megaraptora) from the Lower Cretaceous Wessex Formation, UK, and its implications for theropod evolution and biogeography

 

 Invictibellatrix amberina
with contemporary fauna in the lower part of the Wessex Formation. 

Morrison, Scherer, Mannion, Porro, Clark, Folkes & Barrett, 2026

DOI: doi.org/10.1098/rsos.260937 

Artwork by Sergey Krasovskiy and Pedro Salas

Abstract

Theropod dinosaur remains from the Barremian (Lower Cretaceous) Wessex Formation of the Isle of Wight, UK, are rare and often fragmentary. Here, we present a previously undescribed braincase from this formation that represents a new coelurosaurian, Invictibellatrix amberina gen. et sp. nov. Phylogenetic analysis and comparative anatomy indicate that Invictibellatrix is distantly related to all previously named theropods from this stratigraphic unit. Theropod braincases are often regarded as morphologically and phylogenetically conservative, but we demonstrate that neurocranial characters provide essential data that can help clarify the phylogenetic relationships of theropods. The sub-circular occipital condyle, sub-oval foramen magnum and presence of a sagittal nuchal crest indicate that Invictibellatrix is referable to Megaraptora, with phylogenetic analyses recovering it as an early-diverging member of this clade, within a paraphyletic array of Eurasian taxa. Incorporation of Invictibellatrix into a biogeographical analysis suggests that non-megaraptorid megaraptorans likely had a cosmopolitan distribution in the Early Cretaceous, and that the absence of megaraptorans in the Late Cretaceous of Laurasia is best explained by regional extinction. The recognition of this new genus increases our knowledge of Early Cretaceous European coelurosaurian diversity, which now includes tyrannosauroids, maniraptoriforms and megaraptorans.

Keywords: megaraptora, endocast, Early Cretaceous, theropod, dinosaur, biogeography, Wessex Formation 

Systematic palaeontology

Dinosauria Owen, 1842

Saurischia Seeley, 1888

Theropoda Marsh, 1881

Tetanurae Gauthier, 1986

Coelurosauria Huene, 1914

Megaraptora

Photographs of the holotype braincase (NHMUK PV R6775) of Invictibellatrix amberina gen. et sp. nov. in A: anterior, B: posterior; C: right lateral; D: left lateral; E: ventral; F: dorsal views.

Abbreviations: atr, anterior tympanic recess; boc, basioccipital crest; bpr, basipterygoid recess; bsr, basisphenoid recess; bt, basal tubera; btw, basituberal web; CN, cranial nerves V, VII; cp, cultriform process; cvl, crista ventrolateralis of basisphenoid; fm, foramen magnum; oc, occipital condyle; ova, fenestra ovalis; pcr, paracondylar recess; pit, depression of the pituitary gland within the pituitary fossa; pp, paraoccipital process; prp, preotic pendant; psncr, parasagittal nuchal crest recess; scr, sub-condylar recess; snc, parasagittal nuchal crest; sok, supraoccipital knob; sta, sella turcica. Scale bar equals 50 mm.

Invictibellatrix amberina gen. et sp. nov.

Etymology: the generic name Invictibellatrix is derived from the Latin ‘invictus’ (‘unconquered’) and ‘bellatrix’ (‘warrior’ in the feminine form) and honours the future role of Megaraptora as Gondwanan apex predators, while early on in their evolutionary history they were smaller, non-apex predators [55–57]. This name is to give hope and strength to all those who are bullied, discriminated, victimized and oppressed that tomorrow will be theirs and not to give up in the face of such odds. The species epithet amberina is derived from the amber present in the plant debris beds of the Wessex Formation [58].

Locality and horizon: Sudmoor Point, near Brook, southwestern coast of the Isle of Wight, UK; Wessex Formation, Barremian, Lower Cretaceous. Most likely from the lower plant debris beds (L1 to L5).

Holotype: NHMUK PV R6775, a partial braincase.

Diagnosis: Invictibellatrix amberina can be diagnosed by the following unique character combination (autapomorphies marked with an asterisk): (i) *presence of a small basipterygoid recess anterior to the anterior tympanic recess (ATR) on each side of the parabasisphenoid, (ii) *slightly transversely compressed, hourglass-shaped nuchal crest, (iii) the presence of two large, deep and dorsoventrally elongate paracondylar recesses on the ventrolateral sides of the basioccipital, and (iv) *parasagittal nuchal crest recesses that are slightly curved and pronounced.

An artist's illustration of the new theropod dinosaur, Invictibellatrix amberina (center of the image), in its ecosystem on the Isle of Wight, United Kingdom, in the Early Cretaceous (around 120 million years ago). It lived in what was likely a seasonally wet-to-dry floodplain environment and is surrounded by other dinosaurs including large long-necked rebbachisaurid sauropods (directly behind Invictibellatrix, center) and relatives of Iguanodon (right). A spinosaurid theropod, potentially the apex predator of the time, fishes (left). Invictibellatrix has just caught and is consuming two small mammals. Gymnosperms dominate the environment as flowering plants (angiosperms) were not common at this time. Other reptiles including relatives of modern lizards, crocodiles and turtles enjoy the warm Early Cretaceous weather of the U.K.

Artwork by Sergey Krasovskiy and Pedro Salas

Cassius Morrison; Charlie R. Scherer; Philip Mannion; Laura B. Porro; Brett Clark; Daniel D. Folkes; Paul M. Barrett. 2026. A new megaraptoran dinosaur from the Lower Cretaceous Wessex Formation, UK, and its implications for theropod evolution and biogeography. R. Soc. Open Sci. 13(10): 260937. DOI: doi.org/10.1098/rsos.260937 [14 Oct 2026]

[Paleontology • 2026] Yuezhuornis yangyuanensis • Jurassic flightless Bird reveals early Ecological Diversity of avialans

Yuezhuornis yangyuanensis

L. Xu, Wang, G. Lin, Dong, Deng, X. Xu, Du, M. Lin, Chen & Zhou, 2026

DOI: doi.org/10.1038/s41586-026-10972-z

Life reconstruction by Min Wang.

 Abstract

The origin and early diversification of birds remain highly debated in vertebrate evolution. Although estimates of the evolutionary timescales suggest a Jurassic period radiation, a profound scarcity of fossils from this period has hampered how the distinctive bird bauplan was assembled. Selection for powered flight has been viewed as the primary driver of early avialan skeletal modifications, attesting to the independent occurrences of aerodynamic features among paravian lineages. Here we report on the discovery of a Late Jurassic avialan, Yuezhuornis yangyuanensis, gen. et sp. nov., from the Zhenghe Fauna of southeastern China. As one of the earliest diverging avialans, Y. yangyuanensis exhibits a striking mosaic of features, combining a mixture of avialan- and troodontid-like cranial characters, paired with derived postcranial traits and a deinonychosaur-like hyperextensible second pedal digit. Phylogenetically informed analyses show that Y. yangyuanensis possesses markedly short forelimbs—a condition present widely among non-avialan theropods. These findings provide strong evidence for a terrestrial, flightless lifestyle of Y. yangyuanensis. Our study demonstrates that evolution works intensively as exemplified by the occurrence of several, divergent ecological pathways being exploited in the initial diversification of birds.

 

Yuezhuornis yangyuanensis, gen. et sp. nov.

Life reconstruction of the Late Jurassic bird Yuezhuornis yangyuanensis.

Artwork by Min Wang.

 

Liming Xu, Min Wang, Ganmin Lin, Liping Dong, Ke Deng, Xing Xu, Honggang Du, Min Lin, Runsheng Chen and Zhonghe Zhou. 2026. Jurassic flightless Bird reveals early Ecological Diversity of avialans. Nature. 658; 690–697. DOI: doi.org/10.1038/s41586-026-10972-z [14 October 2026]

Liming Xu  (徐立明), Min Wang  (王敏), Ganmin Lin  (林淦旻), Liping Dong  (董丽萍), Ke Deng  (邓克), Xing Xu  (徐星), Honggang Du  (杜红岗), Min Lin  (林敏), Runsheng Chen  (陈润生) & Zhonghe Zhou  (周忠和)

[Paleontology • 2026] Norellraptor barsboldi • Independent Assembly of the Flight Apparatus in A Non-avian Dinosaur Clade

  

 Norellraptor barsboldi 

Wang, Ji, Cau, Kundrát, Liu, Wang & Ji, 2026

 DOI: doi.org/10.1038/s41467-026-77804-6

Abstract

The discovery of feathered dinosaurs revolutionized the studies on the origin of birds and the evolution of their flight. Among paravians (birds and their closest relatives), the microraptorine dromaeosaurids are unique in bearing several flight-related adaptations with a controversial evolutionary interpretation, supporting, alternatively, flight as ancestral to Paraves or having evolved multiple times among the latter. Here, we introduce an exquisitely-preserved member of Microraptorinae, Norellraptor barsboldi gen. et sp. nov., and describe in detail forelimb osteohistological features for that clade. Norellraptor nests among late-diverging microraptorines and supports step-wise assembly of aerial adaptations in that clade. About 30% of the microraptorine synapomorphies are convergently acquired by the bird lineage (Avialae). Yet, the sequences of flight-related novelties reconstructed along the two lineages differ consistently; combined with histological evidence which might indicate a peculiar limb growth model in Microraptorinae, these results dismiss a shared developmental pattern driving the evolution of the flying dinosaurs and support multiple and independent selective regimes at the origin of the winged taxa in Paraves.

 Norellraptor barsboldi 130108-MHGU-F4281
a Whole specimen. b Skull in lateral view. c Close up of the rostrum. d Close up of the posterior part of skull. e Pectoral region. f Distal end of tail.

aof, antorbital fossa; arm, ascending ramus of maxilla; at, anterior tympanic recess; bt, basal tuber; bp, basypterygoid process; cf, coracoid fenestra; ct, caudal tympanic recess; cnV, 5th cranial nerve opening; cnVII, 7th cranial nerve opening; cv, cervical vertebra; d1, first dorsal vertebra; de, dentary; dt, dorsal tympanic recess; fo, foramen; fr, frontal; fu, furcula; gl, glenoid; h, humerus; la, lacrimal; lat, laterosphenoid; lcv, last caudal vertebra; lp, lateral pneumatic recess; mc, metacarpus; mxf, maxillary fenestra; na, nasal; oc, otosphenoid crest; or, otic region; pa, parietal; paw, postantral wall; pmx, premaxilla; pp, paroccipital process; ppd, posterior processes of dentary; pt, pterygoid; pxf, promaxillary fenestra; r, radius; rp, retroarticular process; sa, surangular; sc, scapula; so, supraoccipital; sp, sternal plate; sr, sclerotic ring; u, ulna; up, uncinate process; vor, ventral otic recess. 

Arrow indicates point of histological sampling. 

Scale bar = 50 mm (a); 10 mm (b–f).

 Norellraptor barsboldi 130108-MHGU-F4281, appendicular elements.
a Right hand. b Pubis. c Feet.

am, acetabular margin; ap, apron; cs, claw soft tissue; gi, gastral impression; mcI-III, metacarpals I to III; mtI-V, metatarsals I to V; p, phalanx; pf, pubic foot; r, radius; sc, semilunate carpal; t, tibiotarsus; u, ulna; uI-III, unguals 1 to 3. 

Scale bar = 10 mm.

Systematic palaeontology

Dinosauria Owen, 1842 

Theropoda Marsh, 1881 

Dromaeosauridae Matthew and Brown, 1922  

Microraptorinae Senter et al., 2004 

Microraptorini (Senter et al., 2004) 

Norellraptor barsboldi gen. et sp. nov.

Locality and horizon: Lamadong Town, Jianchang County, western Liaoning, China. Jiufotang Formation, Lower Cretaceous. China.

Diagnosis: Microraptorine dromaeosaurid with the unique combination of features (autapomorphies marked by asterisk; Supplementary Fig. 2): premaxilla with length of prenarial part half the depth of the subnarial body; large promaxillary fenestra occupying the whole rostral third of the antorbital fossa*, and with long axis inclined 35° caudodorsally; pila promaxillaris narrower than the pila interfenestralis and both less than half the diameter of the maxillary fenestra*; pubis gently curved caudoventrally with small foot having the posterior projection less than the diameter of the pubic shaft*. Differential diagnosis: Norellraptor differs from Changyuraptor in having basally-constricted dentary crowns and in the semilunate carpal barely

 

Etymology: The genus name refers to the American palaeontologist Mark Allen Norell (1957-2025), with Latin word “raptor” (“robber”), a frequently used suffix in dromaeosaurid taxonomy. The species name refers to the Mongolian palaeontologist Rinchen Barsbold (1935-2025). The new taxon name remarks and honours the exceptional contributions by R. Barsbold and M. A. Norell to the study of the bird-like dinosaurs.

 

Xuri Wang, Yannan Ji, Andrea Cau, Martin Kundrát, Yichuan Liu, Yang Wang and Qiang Ji. 2026. Independent Assembly of the Flight Apparatus in A Non-avian Dinosaur Clade. Nature Communications. 17: 10074. DOI: doi.org/10.1038/s41467-026-77804-6 [29 September 2026]

[Paleontology • 2026] Sauropod teeth from the Khorat Group of Thailand suggest the Faunal Replacement of Sauropod Dinosaurs across the Late Jurassic–Early Cretaceous

Sauropod diversity interpretation throughout the Jurassic–Cretaceous transition of Thailand based on dental evidence in

A, the Late Jurassic (Tithonian); B, the Early Cretaceous (late Valanginian to Barremian), C, the late Early Cretaceous (Aptian to Albian). 

in Chowchuvech, Manitkoon, Chanthasit et Ketwetsuriya. 2026. 

DOI: doi.org/10.1080/08912963.2026.2710631 

  x.com/JobSaurusRex

Illustrations by Pakorn Chotchaiyaporn x.com/Peak4651

ABSTRACT

Sauropod teeth are among the most abundant vertebrate fossils recovered from the Upper Jurassic to Lower Cretaceous Khorat Group of Thailand. However, their taxonomic and palaeoecological significance has not previously been examined in detail. This research presents the first comprehensive taxonomic identification of isolated sauropod teeth from several localities across the Khorat Plateau in Northeastern and Eastern Thailand. Based on morphological analyses, these teeth were assigned to four distinct morphotypes. Additionally, multi-quantitative analyses revealed affinities with four sauropod clades: Mamenchisauridae, Brachiosauridae, Somphospondyli, and Dicraeosauridae. The taxonomic framework recovered in this study is consistent with the broader sauropod fossil record of the Khorat Group and reveals a marked faunal shift across the Jurassic–Cretaceous of Thailand. Mamenchisaurids appeared during the Late Jurassic to the earliest Cretaceous, whereas neosauropods, such as titanosauriforms and diplodocoids, became more prevalent during the Early Cretaceous. These findings suggest new evidence for a major sauropod faunal replacement event, likely driven by ecological changes affecting herbivorous dinosaurs during this crucial timeframe of the Mesozoic.

KEYWORDS: Sauropoda, Mamenchisauridae, Brachiosauridae, Somphospondyli, Diplodocoidea

Sauropod diversity interpretation throughout the Jurassic–Cretaceous transition of Thailand based on dental evidence in A, the Late Jurassic (Tithonian); B, the Early Cretaceous (late Valanginian to Barremian), C, the late Early Cretaceous (Aptian to Albian).

 Illustrations by Pakorn Chotchaiyaporn.

 

Wongwech Chowchuvech, Sita Manitkoon, Phornphen Chanthasit and Chatchalerm Ketwetsuriya. 2026. Sauropod teeth from the Khorat Group of Thailand suggest the Faunal Replacement of Sauropod Dinosaurs across the Late Jurassic–Early Cretaceous. Historical Biology: An International Journal of Paleobiology. DOI: doi.org/10.1080/08912963.2026.2710631 [15 Sep 2026]

   x.com/JobSaurusRex/status/2100237729351221602

  x.com/Peak4651/status/2100259226346201579

[Paleontology • 2026] Uragasaurus kalasinensis • A New mamenchisaurid Sauropod (Sauropoda: Mamenchisauridae) from the Lower Phu Kradung Formation, Upper Jurassic of northeastern Thailand

Uragasaurus kalasinensis

Nilpanapan, Manitkoon, Suteethorn & Lauprasert, 2026

 

อุรคาซอรัส กาฬสินธุ์เอนซิส  ||  DOI: doi.org/10.1038/s41598-026-49822-3

 Artwork by Pakorn Chotchaiyaporn (Jæsica ẞababi: x.com/Peak4651).

Abstract

Mamenchisauridae is a group of long-necked non-neosauropodan eusauropod dinosaurs that were abundant in East Asia during the Middle to Late Jurassic, but their diversity and geographic distribution outside China remain poorly documented. Here we describe Uragasaurus kalasinensis gen. et sp. nov., a new sauropod dinosaur from the Phu Kradung Formation of northeastern Thailand. The new taxon is based on a well-preserved anterior dorsal vertebra exhibiting a distinctive combination of characters, including a unique Y-shaped configuration formed by the intraprezygapophyseal and single intraprezygapophyseal laminae and a camellate internal pneumatic structure within the centrum revealed by computed tomography (CT). Phylogenetic analyses recover the new taxon as an early-diverging member of Mamenchisauridae. This discovery represents the first formally named mamenchisaurid from Thailand and expands the known geographic distribution of the clade in Southeast Asia. The occurrence of this taxon in the Lower part of the Phu Kradung Formation also contributes to understanding faunal succession within the unit, supports an Upper Jurassic age for the lower part of the formation, and improves understanding of sauropod diversity in Southeast Asia during the Jurassic-Cretaceous transition.

Keywords: Sauropoda, Mamenchisauridae, Upper Jurassic, Phu Kradung Formation, Northeastern Thailand

Holotype of Uragasaurus kalasinensis (PRC 460) and associated materials in the quarry map. PRC 460 Anterior dorsal vertebra in anterior view (a), KS 34-581 anterior dorsal neural arch in anterior view (b), KS 34-602a middle cervical vertebra in ventral view (c), KS 34-586 anterior dorsal neural arch in anterior view, attached by KS 34-588 fibula (d), KS 34-587 coracoid in lateral view (e), KS 34-602b right cervical rib in lateral view (f).

Uragasaurus kalasinensis gen. et sp. nov.

อุรคาซอรัส กาฬสินธุ์เอนซิส

 

Holotype: The isolated anterior dorsal vertebra PRC 460 has been housed at the Palaeontological Research and Education Centre (PRC), Mahasarakham University, Thailand. Following standard paleontological protocols, the vertebrae were mechanically prepared using pneumatic tools and fine brushes to remove the surrounding sediment matrix.

 

Locality: Phu Noi Locality, Kalasin Province, northeastern Thailand (16.93298° N, 103.72327° E).

Horizon: Lower part of the Phu Kradung Formation, Khorat Group.

Age: Latest Jurassic, based on regional stratigraphic correlations and the composition of the vertebrate assemblage; precise chronostratigraphic constraints remain uncertain.

Diagnosis: Uragasaurus kalasinensis gen. et sp. nov. is a mamenchisaurid sauropod diagnosed by the following unique combination of characters (autapomorphy is marked by *): (1) anterior dorsal vertebra with prominent, elongated teardrop-shaped pneumatic fossae on the distal portion of the transverse processes*; (2) intraprezygapophyseal laminae (tprl) meeting ventromedially to form a Y-shaped configuration in anterior view, incorporating a single vertical intraprezygapophyseal lamina (stprl); and (3) shallow, subtriangular pleurocoel lacking an internal septum.

Etymology: The genus name “Uraga” originates from the Sanskrit word उरग, meaning “snake” or “serpent”, referring to the distinguished long neck of the family. The term “saurus” is derived from the Greek word saûros, meaning lizard. The specific epithet refers to Kalasin Province, where the specimens are from.

Holotype of Uragasaurus kalasinensis (PRC 460) and associated materials in the quarry map. PRC 460 Anterior dorsal vertebra in anterior view (a), KS 34-581 anterior dorsal neural arch in anterior view (b), KS 34-602a middle cervical vertebra in ventral view (c), KS 34-586 anterior dorsal neural arch in anterior view, attached by KS 34-588 fibula (d), KS 34-587 coracoid in lateral view (e), KS 34-602b right cervical rib in lateral view (f).
Quarry map showing the spatial distribution of the holotype and associated materials from the Phu Noi Locality (g). PRC 460, representing the new taxon Uragasaurus kalasinensis, is indicated in red. Associated sauropod elements include KS 34-586, KS 34-587, KS 34-588, and KS 34-602a–b, highlighted in yellow, green, blue, purple, and pink, respectively. The inset shows a close-up of the excavation grid highlighting the relative positions of the holotype and nearby associated materials. Each grid square represents 0.75 × 0.75 m.

Life reconstruction of a herd of five individuals of Uragasaurus kalasinensis inhabiting a Late Jurassic forest in Thailand, accompanied by a pair of rhamphorhynchoid pterosaurs and a metriacanthosaurid theropod.

 Artwork by Pakorn Chotchaiyaporn (Jæsica ẞababi).

Apirut Nilpanapan, Sita Manitkoon, Varavudh Suteethorn and Komsorn Lauprasert. 2026. A New mamenchisaurid Sauropod from the Lower Phu Kradung Formation, Upper Jurassic of northeastern Thailand. Scientific Reports. 16: 21205. DOI: doi.org/10.1038/s41598-026-49822-3 [08 July 2026]

 x.com/Peak4651/status/2074902585660919922

[Paleontology • 2026] Zhengheornis buyu • Jurassic Avialan reveals stepwise Evolution of Bony Tail in Birds

Zhengheornis buyu

Wang, Tang, Deng, Dong, L. Xu, X. Xu, M. Lin,  Du, G. Lin, Chen, Zhang & Zhou, 2026 

 

DOI: doi.org/10.1126/sciadv.aeb5202 

Abstract

The evolutionary assembly of the flight-adapted bird body plan encompasses some of the most profound morphological changes in terrestrial vertebrate history. Beyond feathered wings, the short pygostyle-bearing tail has been pivotal to the clade’s ecological success. However, transition from the long bony tail to the short pygostyle-bearing tail remains a mystery, hindered by the scarcity of early branching avialans with transitional morphologies. Here, we report on a new avialan, Zhengheornis buyu, gen. et sp. nov., from the Upper Jurassic of southeastern China, suggesting that the vertebral reduction and shortening preceded pygostyle fusion in early avialan evolution, providing critical evidence for the stepwise evolution of the bird tail. Z. buyu is smaller than all known non-pygostylian paravians, expanding the species and body size diversity of stemward taxa.

Systematics

Theropoda Marsh, 1881  

Maniraptora Gauthier, 1986  

Avialae Gauthier, 1986 

Zhengheornis buyu gen. et sp. nov. 

Etymology: “Zhenghe” (Mandarin), referring to Zhenghe Country, where the holotype specimen was found; “ornis,” bird (Greek); “buyu,” unexpected (Mandarin), from the ancient Chinese book Guoyu, referring to the unique tail and pelvic morphologies preserved in this species. 

Holotype: Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) V34168, an articulated and partially complete skeleton (most limb bones are preserved as molds) with feathers preserved on a slab and counter slab (Fig. 1, figs. S1 and S2, and table S1). 

Locality and horizon: Near Yangyuan Village, Zhenghe Country, Nanping City, Fujian Province; Upper Jurassic, Nanyuan Formation [Tithonian stage]. 

Diagnosis: IVPP V34168 is distinguishable from all other paravians in the following combination of characters (*denotes probable autapomorphy): short tail comprising 15 vertebrae that is shorter than the hindlimb (combined length of femur, tibia, and metatarsal III)*; middle and posterior caudal vertebrae less elongate (opposite to the condition in other long tailed avialans); final two caudal vertebrae box-like*; manual phalanx III-1 shorter than III-2, opposite to the condition in Archaeopteryx and Fujianvenator [the three manual digits of maniraptorans are here identified as I, II, and III, as in (Tamura, et al. 2011)]; manual phalanx III-3 50% longer than III-2 (the length ratio greater than 2 in Anchiornis and Archaeopteryx); slender ischium that has a knob-like, distally located obturator process and lacks the posterior process*; short fibula that terminates far proximal to the ankle; metatarsal I that articulates at the distal third of metatarsal II; metatarsal II that ends far proximal to metatarsal III trochlea; short hallux with an ungual that is smaller than that of other pedal digits; and robust digit II that has the longest non-ungual (II-2) and ungual pedal phalanges.

 

Min Wang, Jianrong Tang, Ke Deng, Liping Dong, Liming Xu, Xing Xu, Min Lin, Honggang Du, Ganmin Lin, Runsheng Chen, Chi Zhang and Zhonghe Zhou. 2026. Jurassic Avialan reveals stepwise Evolution of Bony Tail in Birds. Science Advances. 12(27); DOI: doi.org/10.1126/sciadv.aeb5202 [1 Jul 2026]

[Paleontology • 2026] Jian changmaensis • First non-Avian Theropod (Dromaeosauridae: Microraptorinae) from the Bird-bearing Lower Cretaceous Xiagou Formation of the Changma Basin, Gansu Province, Northwestern China

 

Jian changmaensis 

Zhou, Lamanna, Poust, Li, You & O’Connor, 2026

attacks the early bird Gansus yumenensis 

  

 facebook.com/CarnegieMNH 

 illustration by Lewis LaRosa  x.com/LewisLaRosa, colorized by Jão Canola.

ABSTRACT

Lacustrine sediments of the Lower Cretaceous (lower Aptian) Xiagou Formation exposed near the village of Changma in the Changma Basin of northwestern Gansu Province, China have yielded more than 100 avian partial skeletons, many of which also preserve remnants of soft tissues such as feathers and skin. Collectively, these fossils characterize a rich avifauna dominated by the crownward ornithuromorph Gansus yumenensis Hou and Liu, 1984. Despite this wealth of Early Cretaceous bird material, no skeletal remains of other dinosaurs have been described from Changma to date. Here we report the first non-avian dinosaur body fossil from the Xiagou Formation of the Changma Basin. Consisting of an articulated left pectoral girdle and forelimb lacking the carpus and manus, the specimen pertains to a new dromaeosaurid theropod taxon, Jian changmaensis, gen. et sp. nov. Phylogenetic analysis recovers Jian within Microraptorinae, expanding the definitive fossil record of this clade to include northwestern China. The new Changma microraptorine constitutes an additional similarity between the theropod faunas of the Xiagou Formation of the Changma Basin and penecontemporaneous strata of the Jehol Group of northeastern China. In particular, the Changma theropod assemblage closely resembles that of the Sihedang locality of the Jehol Group in that both include representatives of Microraptorinae and are overwhelmingly dominated by single ornithuromorph taxa that phylogenetic analyses have repeatedly resolved as close relatives. This raises the possibility that the two sites were deposited under comparable paleoenvironmental settings that are otherwise poorly represented at known Jehol localities. 

Key Words: Early Cretaceous, Gansus yumenensis, Jian changmaensis, microraptorine, paleobiogeography, paleoenvironment, phylogeny, Sihedang 

SYSTEMATIC PALEONTOLOGY 

Dinosauria Owen, 1842 

Saurischia Seeley, 1888 

Theropoda Marsh, 1881 

Maniraptora Gauthier, 1986 

Dromaeosauridae Matthew and Brown, 1922 

Microraptorinae Xu, 2002 

Holotype of Jian changmaensis, gen. et sp. nov. (GSGM-D050), an articulated partial left pectoral girdle (scapulocoracoid) and forelimb (humerus, radius, and ulna). A, silhouette of generalized microraptorine dromaeosaurid theropod (courtesy Scott Hartman) showing skeletal elements preserved; B, photograph of specimen as preserved, exposed primarily in dorsomedial (scapulocoracoid), caudodorsal (humerus), and dorsal (radius and ulna) views; C, interpretive line drawing of B; D, detail photograph of scapulocoracoid and proximal end of humerus in caudodorsal view, showing supracoracoid fenestra and other structures; E, interpretive line drawing of D.

Abbreviations: ac, acromion; bc, bicipital crest; C, coracoid; cr, caudal ridge; dep, dorsal epicondyle; dpc, deltopectoral crest; dr, dorsal ridge; ed, epicondylar depression; fs?, fossa for M. supinator?; H, humerus; hh, humeral head; lp, lateral process; ‘mb’, ‘medial bar’; op, olecranon process; R, radius; S, scapula; scb, scapular blade; scf, supracoracoid fenestra; sta, sternal articulation; U, ulna.

Jian changmaensis, gen. et sp. nov.

Diagnosis.—Medium-sized (intermediate in skeletal dimensions between adult specimens of Microraptor zhaoianus and Sinornithosaurus millenii Xu et al., 1999; see Table 2) microraptorine dromaeosaurid theropod characterized by the following three autapomorphies: (1) a coracoid that is proportionally longer relative to the humerus than in any other microraptorine (~36% humerus length; the next closest individuals are the immature Microraptor IVPP V31612, with a value of ~35%, and IVPP V12811, the holotype of Sinornithosaurus, with a value of 33%) (Table 2); (2) humeral distal condyles developed on the cranial surface of this bone (Figs. 2B–C, 3E; a local autapomorphy within Microraptorinae, shared with nonmicroraptorine theropods such as the therizinosaur Erlikosaurus andrewsi Barsbold and Perle, 1980, and Aves); and (3) a well-developed foramen on the ventral aspect of ...

Etymology.—The genus name is for the Jiān (鹣), a one winged bird in Chinese mythology, in reference to the bird-like, possibly volant nature of this microraptorine taxon and the skeletal composition of its holotype (an isolated partial pectoral girdle and forelimb). The specific name is for Changma (昌马), the locality where the holotype was discovered.

 The new microraptor dinosaur Jian changmaensis (left) attacks the early bird Gansus yumenensis (right) in what is now the Changma Basin of northwestern China approximately 120 million years ago. 

 illustration by Lewis LaRosa  x.com/LewisLaRosa,
colorized by Jão Canola.

Ling-Qi Zhou, Matthew C. Lamanna, Ashley W. Poust, Da-Qing Li, Hai-Lu You and Jingmai K. O’Connor. 2026. First non-Avian Theropod (Dromaeosauridae, Microraptorinae) from the Bird-bearing Lower Cretaceous Xiagou Formation of the Changma Basin, Gansu Province, Northwestern China. ANNALS OF CARNEGIE MUSEUM. 92(2); 89–110. [4 June 2026]

https://carnegiemnh.org/wp-content/uploads/2026/06/Jian-changmaensis-Annals-of-Carnegie-Museum.pdf

 facebook.com/CarnegieMNH/posts/1431015332396739

 x.com/LewisLaRosa/status/2062606679980556631

[Paleontology • 2026] Nagatitan chaiyaphumensis • The First Sauropod Dinosaur (Titanosauriformes: Euhelopodidae) from the Lower Cretaceous Khok Kruat Formation of Thailand enriches the Diversity of somphospondylan titanosauriforms in Southeast Asia

Nagatitan chaiyaphumensis 

Sethapanichsakul, Khansubha, Manitkoon, Hanta, Mannion & Upchurch, 2026

นาคาไททัน ชัยภูมิเอนซิส  ||  DOI: doi.org/10.1038/s41598-026-47482-x 

Artwork by facebook.com/DinoThaiThai

 facebook.com: Perth Thitiwoot

Abstract

Sauropod dinosaur remains comprise the majority of the Mesozoic vertebrate fossil record in Thailand. However, they are rare and fragmentary in the Aptian–Albian (Lower Cretaceous) Khok Kruat Formation, the stratigraphically youngest fossil-bearing Mesozoic Thai stratigraphic unit. Based on a partial postcranial skeleton, we present the first diagnostic sauropod specimen from this formation, which represents a new somphospondylan titanosauriform, Nagatitan chaiyaphumensis n. gen. n. sp. Nagatitan is diagnosed by two autapomorphies and a unique character combination, including the presence of two distinct hyposphene-hypantrum morphologies within the middle–posterior dorsal vertebrae. Phylogenetic analyses under maximum parsimony, using a data matrix containing 153 taxa and 570 characters, produce well-resolved topologies that place Nagatitan within the somphospondylan clade Euhelopodidae. Nagatitan does not form an endemic subclade with the approximately contemporaneous Southeast Asian euhelopodids Phuwiangosaurus and Tangvayosaurus, with a suite of anatomical features distinguishing these taxa. We estimate a body mass of 25–28 tonnes for Nagatitan, and suggest it was part of a broader middle Cretaceous body size increase in Asian titanosauriforms, facilitated by rising temperatures and expanded suitable habitat. The discovery of Nagatitan expands the known diversity of Southeast Asian sauropods and improves our understanding of titanosauriform biogeography within the region.

Schematic representation of the skeleton of Nagatitan chaiyaphumensis gen. et. sp. nov. Preserved bones are highlighted. Scale bar equals 1 m.

Systematic palaeontology

Dinosauria Owen, 1842

Saurischia Seeley, 1887

Sauropoda Marsh, 1878

Titanosauriformes Salgado, Coria & Calvo, 1997

Somphospondyli Wilson & Sereno, 1998

Euhelopodidae Romer, 1956 (sensu D’Emic, 2012)

Nagatitan chaiyaphumensis gen. et sp. nov.

นาคาไททัน ชัยภูมิเอนซิส

Holotype: SM2025-1-546 to SM2025-1-556—four dorsal vertebrae, five dorsal ribs, four sacral vertebrae, five sacral ribs, right humerus, right ilium, left and right pubis, mostly complete right femur.

Diagnosis: Nagatitan can be diagnosed by a unique combination of characters (autapomorphies denoted with an asterisk): (1) paired postzygapophyseal centrodiapophyseal fossa present on posterior dorsal neural arches; (2*) hyposphene of middle dorsal vertebrae exhibits a triangular morphology, becoming a vertical ridge in posterior dorsal vertebrae; (3) parapophysis positioned dorsal to the prezygapophysis on posterior dorsal neural arches; (4) spinopostzygapophyseal laminae of middle and posterior dorsal neural spines divided into lateral and medial branches throughout their length; (5) bifurcated middle dorsal neural spines; (6*) triangular anterior aliform processes present on posterior dorsal neural spines; (7) prominent bulge on posterolateral margin of humerus, approximately level with the deltopectoral crest, that interrupts the lateral humeral margin in anterior view; (8) rounded proximolateral corner of humerus; (9) humeral shaft exhibits a high eccentricity value (> 2.5); (10) distal end of the pubis transversely expanded along the lateral surface relative to the shaft; and (11) proximal third of femur with anteroposteriorly narrowed lateral margin forming a flange-like trochanteric shelf and a medially bounding vertical ridge along the posterior surface.

Locality and Horizon: Ban Pha Nang Sua, Nong Bua Rawe District, Chaiyaphum Province, Thailand; Khok Kruat Formation, Aptian–Albian, upper Lower Cretaceous. 

Etymology: The generic name is derived from Naga, referring to the mythological serpent-like creature found in various Asian cultures, especially in northeastern Thailand, often associated with water and Buddhism, and titan, a giant in Greek mythology. The specific epithet is derived from the province of Chaiyaphum, Thailand.

3D skeletal reconstruction by Matus Charoenjit

Stylized life reconstruction of Nagatitan chaiyaphumensis gen. et. sp. nov. within the arid floodplains of late Early Cretaceous Aptian–Albian Thailand  

Artistic reconstruction by Patchanop Boonsai (Draconos Takeji) 

Non-sauropod faunal remains discovered in the Ban Pha Nang Sua locality:
(a) Allosauroid tooth (SDM2025-1-562) in labial view, (b) spinosaurid tooth (SDM2025-1-561) in labial view, (c) crocodyliform tooth (specimen lost during the excavation) in lingual view, (d) Heteroptychodus steinmanni tooth (SDM2025-1-563) in apical view, and (e) mold of cf. Yunnanoconcha sp. (SDM2025-1-560) in external view. (f) Stylized illustration displaying the vertebrate fauna assemblage known from the Khok Kruat Formation modified from Manitkoon et al. 2023. Shaded black silhouette indicate tentative taxa. Nagatitan chaiyaphumensis gen. et sp. nov. shaded in blue. Scale bars equal 10 mm.

  

 

Thitiwoot Sethapanichsakul, Sasa-On Khansubha, Sita Manitkoon, Rattanaphorn Hanta, Philip D. Mannion and Paul Upchurch. 2026. The First Sauropod Dinosaur from the Lower Cretaceous Khok Kruat Formation of Thailand enriches the Diversity of somphospondylan titanosauriforms in Southeast Asia. Scientific Reports. 16; 12467. DOI: doi.org/10.1038/s41598-026-47482-x [14 May 2026]

 facebook.com/perth.thitiwoot/posts/3901053680026079

[Paleontology • 2026] Phosphatotitan khouribgaensis • A Titanosaurian Sauropod with South American Affinities (Lognkosauria: Argentinosauridae) from the Late Maastrichtian of Morocco and Evidence for Dinosaur Endemism in Africa

 

Phosphatotitan khouribgaensis

Longrich, Pérez-Moreno, Díez Díaz, Pereda-Suberbiola, Bardet & Jalil, 2026

DOI: doi.org/10.3390/d18050241

Artwork by Andrey Atuchin facebook.com/AndreyAtuchin

Abstract

The latest Cretaceous saw the final diversification of dinosaurs before the K/Pg extinction. Discussions of end-Cretaceous dinosaur diversity have focused on well-sampled faunas from Laurasia; far less is known about dinosaurian faunas of the Southern Hemisphere, especially Africa. The late Maastrichtian Phosphates of Morocco provide a rare window into African dinosaur diversity. Abelisaurids, lambeosaurines, and titanosaurian sauropods are known. However, no diagnostic titanosaur remains have been recovered, leaving the affinities of these sauropods unclear. We describe Phosphatotitan khouribgaensis gen. et sp. nov., a new titanosaur from the Maastrichtian of Sidi Chennane, Khouribga Province. Phosphatotitan is represented by dorsal, sacral, and caudal vertebrae, and the pelvis. The new species differs from titanosaurs described from the Cretaceous of Africa and Europe but resembles South American Lognkosauria, and especially Patagotitan, in having short dorsal and caudal centra, expanded dorsal and caudal neural spines, and a broad pubis. Its small size relative to other Lognkosauria (3.5–4 tonnes) suggests a lineage selected for small size. The close relationships of Morocco’s titanosaurs and abelisaurids to South American species may reflect a wide distribution of these clades prior to the opening of the South Atlantic and the separation of Africa and South America ~100 Ma, while a complex pattern of oceanic dispersal may explain the presence of distinct saltasauroid lineages worldwide. The latest Cretaceous Gondwanan dinosaur faunas were highly endemic due to a combination of continental fragmentation, extinction, and dispersal, creating high endemism in southern continents and within Africa, suggesting that Maastrichtian dinosaur diversity is underestimated.

Keywords: Dinosauria; Sauropoda; Titanosauria; Argentinosauria; Upper Cretaceous; biogeography; Gondwana

Phosphatotitan khouribgaensis gen. et sp. nov.

 Nicholas R. Longrich, Agustín Pérez-Moreno, Verónica Díez Díaz, Xabier Pereda-Suberbiola, Nathalie Bardet and Nour-Eddine Jalil. 2026. A Titanosaurian Sauropod with South American Affinities (Lognkosauria: Argentinosauridae) from the Late Maastrichtian of Morocco and Evidence for Dinosaur Endemism in Africa. Diversity. 18(5); 241. DOI: doi.org/10.3390/d18050241 [22 April 2026]

 facebook.com/AndreyAtuchin/posts/26756211193972997