Jinchuanloong niedu: A new species of Eusauropod Dinosaur from the Middle Jurassic of Gansu Province, China.

Sauropod Dinosaurs first appeared around the begining of the Jurassic, undergoing an extinction event at the end of the Early Jurassic, which has been linked to a period of intense global warming, which only a single lineage, the Eusauropods, survived. All subsequent Sauropod groups diversified from this single lineage. One group of Eusauropods, the Neosauropods, would eventually radiate and become the dominant Sauropods through the Late Jurassic and Cretaceous, but in the Middle Jurassic a variety of non-Neosauropod Eusauropods could still be found, particularly in East Asia.

In a paper published in the journal Scientific Reports on 23 May 2025, Ning Li of the School of Earth Sciences and Resources at the China University of Geosciences, Xiaoqin Zhang of Chuxiong Normal University, Xinxin Ren of the Key Laboratory of Stratigraphy and Paleontology of the Ministry of Natural Resources at the Institute of Geology of the Chinese Academy of Geological Sciences, Daqing Li of the Institute of Vertebrate Paleontology at the Gansu Agricultural University, and Hailu You of the Key Laboratory of Vertebrate Evolution and Human Origins at the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences, and the College of Earth and Planetary Sciences at the University of the Chinese Academy of Sciences, describe a new species of non-Neosauropod Eusauropod from the Middle Jurassic Xinhe Formation of Gansu Province, China.

The Xinhe Formation is a 120 m thick sequence exposed in the Jinchuan District of Jinchang City, which starts at its bottom with a succession of conglomerates, sandstones, and siltstones, becoming finer further up where it becomes a sequence of interbedded shales and mudstones. It is thought to have been laid down in an ancient lake environment, roughly 166-165 million years ago. the specimen from which the new species is described was found in the lower part of this formation.

The new species is named Jinchuanloong niedu, where 'Jinchuanloong' means 'Jinchuan-dragon', and 'niedu' means 'Nickel-city', in reference to the abundant nickel resources in Jinchang, where the metal is mined extensively. It is described from a single specimen, comprising an almost intact skull, lateromedially compressed on its left side, along with the five anteriormost cervical (neck) vertebrae, and, separately, a section of twenty nine articulated caudal (tail) vertebrae. These were confirmed to be from the same animal by impressions of the pelvic girdle and sacral vertebrae, which connect them to the cervical vertebrae. These caudal vertebrae have not been excavated, but remain in place with a protective fence around them.

Skull of Jinchuanloong niedu (JCMF0132) in left lateral view. Abbreviations: a, aperture; an, angular; aof, antorbital fenestra; d, dentary; en, external naris; f, frontal; fo, foramen; inf, infratemporal fenestra;j, jugal; l, lacrimal; m, maxilla; n,nasal; o, orbit; p, parietal; pf, prefrontal; pm, premaxilla; po, postorbital; pop, paraoccipital process; q, quadrate; qj, quadratojugal; sa, surangular; snf, subnarial foramen; sq, squamosal. Li et al. (2025).

A phylogenetic analysis recovered Jinchuanloong niedu as a non-Neosauropod Eusauropod outside the two major non-Neosauropod Eusauropod clades, the Mamenchisauridae and the Tauriasauria, forming a sister taxon to the Tauriasauria plus the Neosauropoda. Li et al. suggest that the status of Jinchuanloong niedu as an apparently separate lineage outside of any of the major clades lends support to the idea that East Asia was a significant centre for Sauropod diversification in the Middle Jurassic.

Phylogenetic relationships of Jinchuanloong niedu. Li et al. (2025).

Li et al. further note that the dentition of Middle Jurassic Sauropods from East Asia, and in particular taxa from western China, is extremely variable, which they take as a sign of niche partitioning (i.e. different species having different diets), which in turn could have driven a high rate of taxonomic diversification.

Caudal vertebrae of Jinchuanloong niedu (JCMF0132). Li et al. (2025).

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Igai semkhu: A new species of Titanosaur from the Latest Cretaceous of Kharga Oasis in the Western Desert of Egypt.

The last three decades have seen a great improvement in our understanding of the Dinosaurs, and other terrestrial Animals, inhabiting the Gondwana supercontinent during the Latest Cretaceous (Campanian–Maastrichtian). A large number of new Dinosaur species have been described from South America, India, Pakistan, Madagascar, and even Antarctica. However, two significant regions of Gondwana, Africa and Australia, still have very poor fossil records from this time, making it hard to understand the biogeographical connections between the faunas of these regions and that of other parts of the world. The Campanian–Maastrichtian Dinosaur record of mainland Africa is exceptionally poor, with a very limited amount of material known and most of that comprising of very fragmentary material and isolated skeletal elements, of limited use for morphological or phylogenetic studies.

The most complete Dinosaur fossil from the Latest Cretaceous of Africa is the Titanosaurian Sauropod Mansourasaurus shahinae, from the Campanian Quseir Formation of the Dakhla Oasis in the Western Desert of Egypt. This is a partial skeleton comprising the craniomandibular, postcranial axial, appendicular, and possible dermal elements, though many of the bones are significantly deformed, which makes interpreting these remains challenging. The partial hind limb of another Titanosauriform Sauropod has been reported from Maastrichtian phosphatic deposits in the Ouled Abdoun Basin of Morocco, and Sauropod fossils from the Latest Cretaceous of Kenya and Jordan (which lies on the Arabian Peninsula, still part of Africa in the Cretaceous). Furthermore, two species of Titanosaur, Rukwatitan bisepultus and Shingopana songwensis, have been described on the basis of partial skeletons from the Upper Cretaceous Namba Member of the Galula Formation of southwestern Tanzania, which may be Campanian or a little older. Numerous isolated Sauropod bones have also been reported from the Namba Member. 

Most of these fossils were discovered in the first two decades of the twenty first century, however, another, as yet undescribed, Titanosaur is known from a partial skeleton recovered from the Quseir  Formation  of  the Kharga Oasis in 1977, by a field team from the Technische Universität Berlin. Although briefly mentioned in several publications in the 1990s, no formal description of this skeleton or attempt to place it within a broader phylogenetic analysis has ever been published. Although this specimen is fragmentary, and many of the elements are distorted, it is the second-most complete Dinosaur skeleton from the Latest Cretaceous of Africa.

In a paper published in the Journal of Vertebrate Paleontology on 20 July 2023, Eric Gorscak of the Department of Anatomy at Midwestern University, Matthew Lamanna of the Section of Vertebrate Paleontology at the Carnegie Museum of Natural History, Daniela Swartz and Verónica Díez Díaz of the Museum für Naturkunde at the Leibniz-Institut für Evolutions-und Biodiversitätsforschung, Belal Salem of the Department of Geology at Benha University, the Mansoura University Vertebrate Paleontology Center, and the Department of Biological Sciences and Ohio Center for Ecological and Evolutionary Studies at Ohio University, Hesham Sallam, also of the Mansoura University Vertebrate Paleontology Center, and of the Institute of Global Health and Human Ecology at the American University in Cairo, and Marc Filip Weichmann of the Bundesanstalt für Geowissenschaften und Rohstoffe, present a formal description of the Kharga Oasis Titanosaur.

The skeleton was discovered by Werner Barthel and Ronald Böttcher of the Technische Universität Berlin in November 1977, collected in 27 plaster jackets, and returned to Berlin, where it remained overlooked for the next two decades. Barthel's records of the excavation show that the skeleton was damaged during the process, due to insufficient use of preservatives. In the 1990s the skeleton was transferred to the Institut für Paläontologie of the Freie Universität Berlin (where it was studied by Marc Filip Weichmann as the subject of his diploma thesis, as part of a wider transfer of palaeontological material collected in the Western Desert. In 2008, the Freie Universität Berlin abandoned its vertebrate palaeontology program, and the specimen was tranferred to the collection of the Museum für Naturkunde, along with a large number of other fossils from the Cretaceous of Egypt and Sudan. Gorscak et al. re-examined the specimen in 2017, finding that most of the material observed by Weichmann in the 1990s was still present, although some skeletal elements had received further damage, most of which has since been repaired, using photogrammetric records made by Weichmann during his study, and the left tibia had gone missing, although the records made of this bone by Weichmann during his study still exist.

Based upon the available material, Gorscak et al. describe the specimen as a new species, Igai semkhu, where 'Igai' was a deity worshipped in the region around the Dakhla and Kharga oases from at least the Old Kingdom to the Pharaonic Late Period, whose name is thought to mean something like 'Lord of the Oasis', and 'semkhu' means 'the forgotten', making 'Igai semkhu' 'the forgotten Lord of the Oasis', a reference both to its place of origin and the long period it sat overlooked in the collections of various institutions.

The skeleton comprises five fragmentary dorsal vertebrae, partial left coracoid, partial left ulna, three left metacarpals (I, IV, and V), the proximal part of the left pubis, both tibiae (a partial right and the complete and well-documented but currently missing left, Vb-634), the left fibula, and three metatarsals (left I, left and right II). Numerous other elements were apparently present when the skeleton was discovered, but are not missing and have not been observed by any members of the team.

Location of discovery and quarry map of Igai semkhu (Vb-621–640). (A) Map of Egypt showing the location of the town of Baris in the Kharga Oasis region, denoted by orange star; (B) satellite image from Google Earth Pro of the research areas south of Baris with approximate quarry location indicated by orange star; (C) quarry map showing disposition of skeletal elements in situ with currently missing and/or obliterated elements in grey; and (D) skeletal silhouette with elements described shown in orange. Abbreviations: cor, coracoid; dv, dorsal vertebra; fib, fibula; mtcI, metacarpal I; mtc IV, metacarpal IV; mtc V, metacarpal V; mtt I, metatarsal I; mtt II, metatarsal II; pub, pubis; tib, tibia; ul, ulna. Gorscak et al. (2023).

The dorsal vertebrae of Igai semkhu lack hyposphene-hypantrum articulations, and its ulna has a prominent olecranon process, both of which mark it out as a Titanosaur. The fragmentary nature of the material, combined with the fact that many of the elements are distorted, prevent a very detailed reconstruction of the specimen, but it is estimated to have been about 10-15 m in length in life, and either mature or very close to maturity. This makes it slightly larger than Mansourasaurus shahinae, which is estimated to have been 8-10 m in length.

A phylogenetic study recovered both Igai semkhu and Mansourasaurus shahinae as Saltosaurids. This is interesting, as Saltosaurids are otherwise absent from Africa, while in Europe almost all Titanosaurs from the Latest Cretaceous are Saltosaurids, and of similar size to Igai semkhu and Mansourasaurus shahinae, implying a link between the Sauropod fauna of Egypt and that of Europe in the Latest Cretaceous. In sub-Saharan Africa and Madagascar, in contrast, there appears to have been a wider range of Titanosaur groups, matching the more diverse faunas of the Americas, and many species appear to have grown far larger than their Egyptian and European relatives.

Maximum clade credibility tree for variable-rates tip-dated Bayesian phylogenetic analysis of Igai semkhu within Titanosauria. Numbersat nodes represent posterior probabilities (posterior probabilities at or above 50% are in bold), light gray bars at each node represent 95% highest posterior density of each node age. African terminal taxa are denoted in bold. Time scale is in units of millions of years. Abbreviations: Aeol, Aeolosaurini; Eutitan, Eutitanosauria; Lith, Lithostrotia; Rinc, Rinconsauria; Salt, Saltasauridae; Titan, Titanosauria. Gorscak et al. (2023).

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Tuebingosaurus maierfritzorum: A new species of Massopodan Sauropodomorph Dinosaur from the Palaeontological Collection of the University of Tübingen.

The Palaeontological Collection of the University of Tübingen contains one of the largest assemblages of Sauropodomorph Dinosaurs in Europe, but also one of the least studied. Much of this material was collected from sites around Tübingen, Aixheim and Löwenstein in the nineteenth and early twentieth centuries and classified under the genus Plateosaurus. 

The genus Plateosaurus was once used to classify almost all non-Sauropod Sauropodomorph Dinosaurs, and by the mid twentieth century contained over 20 species, of which only four are considered valid today. Unfortunately, while it is now recognised that the non-Sauropod Sauropodomorph Dinosaurs are a more diverse group than once understood, and that understanding this diversity is the key to understanding the emergence of the true Sauropods, one of the most remarkable groups of organisms ever to appear on Earth, several rival schemes for the classification of this group have appeared, hampering this understanding.

In a paper published in the journal Vertebrate Zoology on 8 September 2022, Omar Rafael Regalado Fernández of the Fachbereich Geowissenschaften an der Universität Tübingen, and Ingmar Werneburg, also of the Fachbereich Geowissenschaften an der Universität Tübingen, and of the Senckenberg Centre for Human Evolution and Palaeoenvironment an der Universität Tübingen, describe a new species of Sauropodomorph Dinosaur from the Palaeontological Collection of the University of Tübingen, based upon a specimen, GPIT-PV-30787, collected from Lower Dinosaur Bed at Obere Mühle in 1932.

The complex nature of Sauropodomorph Dinosaur taxonomy meant that Regalado Fernández and Werneburg were obliged to carry out multiple phylogenetic analyses in order to try to accommodate specimen GPIT-PV-30787 into the competing phylogenies for the group. Fortunately, these produced reasonably consistent results, with the specimen being found to be closely related to Schleitheimia schutzi, making it a Massopodan Sauropodomorph, close to the origin of the true Sauropods.

Based upon this information, Regalado Fernández and Werneburg describe specimen GPIT-PV-30787 as the holotype of a new species, giving it the name Tuebingosaurus maierfritzorum, where 'Tuebingosaurus' refers to Tübingen and 'maierfritzorum' honours Wolfgang Maier, professor of evolutionary zoology in Tübingen from 1987 to 2007, and Uwe Fritz, former editor-in-chief of the journal Vertebrate Zoology.

Specimen GPIT-PV-30787 comprises a complete pelvis (three sacral vertebrae, two ilia, two pubes, two ischia), five anterior caudal vertebrae, four chevrons, left femur, left tibia, left and right fibulae, left astragalus, left calcaneum, metatarsal I, and pedal fingers 3 and 4.

Reconstruction of Tuebingosaurus maierfritzorum, as a quadruped Dinosaur, using the outline of Riojasaurus as a base, next to the silhouette of Friedrich von Huene. The drawing of the bones is based on and modified from the original illustrations of specimen 'GPIT IV' (the name originally ascribed to GPIT-PV-30787) by von Huene. The right fibula is marked in grey as it was found nearby with similar measurements to the left fibula and has been assumed to be part of the same individual. Regalado Fernández & Werneburg (2022).

Regalado Fernández and Werneburg's phylogeny suggests that Tuebingosaurus maierfritzorum is a Massopodan, making it the earliest member of the group known from the Upper Triassic Trossingen Beds. Despite this taxonomic placement, Tuebingosaurus maierfritzorum still shares a number of features more generally associated with Plateosaurian Sauropodomorphs, most notably a heel-like projection in the posterior part of the ischiadic peduncle of the ilium and a straight lateral margin in metatarsal II, features which led to the assumption that this was a specimen of Plateosaurus. 

This presence of Plateosaurian-like features in early Massopodan Dinosaurs is unlikely to be unique to Tuebingosaurus maierfritzorum, and re-examination of other historic specimens at Tübingen and other palaeontological collections may provide more examples, helping to unravel the origins of the Sauropods.

Reconstruction of the last moments in the life of Tuebingosaurus maierfritzorum (collection number of the painting: GPIT-PV-41827). The cortical bone on the left side of the fossil is fractured into flakes, which can be explained if the carcass was exposed over a long time on the mud, two to four years, before being buried – in the reconstruction, the Animal will fall to its right body side. The reconstruction shows the animal sinking in a mud trap, attacked by a Rauisuchian, Teratosaurus, which has also been found in the Trossingen Formation in Baden-Württemberg. In the background, a herd of Plateosaurus trossingensis runs away from the scene. The flora in the swamp is reconstructed based on fossils from the Germanic basin, with shoots of Horsetails and Ferns covering the swamp and a forest comprising Cycads (Taeniopteris), Lycophytes (Lepacyclotes) and Coniferous Plants (Brachyphyllum). Regalado Fernández & Werneburg (2022).

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Perijasaurus lapaz: A Eusauropod Dinosaur from the Early Jurassic of Colombia.

The Sauropods are a highly distinctive group of Dinosaurs, with a long fossil record, covering the entirety of the Jurassic and Cretaceous periods. Although the Sauropods were a morphologically conservative group, the popular view of these Animals can be a bit limited, due to the high profile of the Sauropods of the Late Jurassic Morrison Formation of North America and Tendaguru Formation of Tanzania, both of which have produced Sauropods of enormous sizes, with columnar legs, long necks and tails, small heads, and deep bodies, leading to an under-appreciation of the actual diversity present within the group. 

The term Neosauropoda was coined by Argentinian palaeontologist José Bonaparte to cover these distinctive Late Jurassic forms and their Cretaceous descendants, with earlier branching Sauropods which did not fit this bodyplan being referred to as 'Eosauropods'. This term has now fallen from favour, as it is seen as polyphyletic, as the Neosauropoda are clearly descended from this group but excluded from it, and expanding the group to include the Neosauropoda would make it identical to the Sauropoda. Instead the Sauropods are seen as being made up of a series of nested clades, with all members belonging to the Saurapoda, within which the majority belong to a more derived group, the Eusauropoda, withing which the Neosauropoda arise. Sauropods which do not belong to the Eusaurapoda can therefore be referred to as 'basal Sauropods', and Eusauropods which do not belong to the Neosauropoda as 'basal Neosauropods'.

Since the Neosauropods were clearly an established group by the Late Jurassic, understanding their origin requires examination of the (rather limited) fossil record of Early and Middle Jurassic Sauropods. Of the 1094 Sauropod body fossils are known globally from the Jurassic, 139 of these (12.7%) from the Middle Jurassic, and only 65 (5.9%) from the Early Jurassic, these fossils extremely rare, and each one important to our understanding of the history of the group.

Of the 65 known Early Jurassic Sauropod body fossils, twenty are from Africa, nineteen from Asia, nine each from India and South America, seven from Europe, and one from Madagascar. These remains are almost all from a very low number of sites, for example all bar one of the South American Early Jurassic Sauropod fossils come from Chubut and Santa Cruz provinces in southern Argentina. The one exception to this is an isolated vertebra, currently housed in the University of Michigan Museum of Paleontology, where it has been given the specimen number UCMP 37689, recovered from the redbeds of the Early-Middle Jurassic La Quinta Formation in the Department of Cesar, Colombia, by an oil exploration team in 1943.

The La Quinta redbeds extend from Colombia into Venezuela, and have produced a number of other Dinosaur remains, but no further Sauropod material. This paucity of Sauropod material from northern South America extends throughout the remainder of the Mesozoic, with one other Sauropod known from Colombia, the Early Cretaceous Padillasaurus leivaensis, a single specimen from Ecuador, the Late Cretaceous Yamanasaurus lojaensis, as well as two poorly preserved and unidentified specimens from Cretaceous localities in northern Peru and northern Brazil.

This absence of Sauropod specimens from northern South America is puzzling. Southern South America is considered to have been somewhat of a biodiversity hotspot for Sauropods, driven by the extinction of other large herbivores in the region during the volcanic break-up of Pangea, and the global distribution of Sauropods suggests they were capable of inhabiting a wide variety of habitats, including those likely to have been found in northern South America. Many tropical environments are considered to have low potential for the preservation of fossils today, due to high erosion rates and acid soils, and this is likely to have been the case in the Mesozoic too, but the absence of Sauropods from formations such as the La Quinta redbeds, which have produced numerous other Dinosaur fossils, is harder to explain.

In a paper published in the Journal of Vertebrate Paleontology on 10 August 2022, Aldo Rincón and Daniel Raad Pájaro of the Departamento de Física y Geociencias at the Universidad del Norte, Harold Jiménez Velandia of the Departamento de Geología at Universidad EAFIT, and the Departamento de Ciencias Geológicas at the Universidad de Caldas, Martín Ezcurra of the Sección Paleontología de Vertebrados at the Museo Argentino de Ciencias Naturales 'Bernardino Rivadavia', and Jeffrey Wilson Mantilla of the Museum of Paleontology and Department of Earth & Environmental Sciences at the University of Michigan, redescribe specimen UCMP 37689, formally naming it and examining its importance for our understanding of the history of Sauropods as a group.

UCMP 37689 comprises two sections of a dorsal vertebra interpreted as that of a medium-sized Sauropod, reconstructed as having been roughly 55 cm high and 45 cm wide. The two sections do not fit, but it has been possible to reconstruct the original size by virtually reversing the upper neural arch. 

Although the material is extremely limited, Rincón et al. were able to carry out a phylogenetic analysis using a character matrix developed by Kevin Leonel Gomez, Jose Luis Carballido, and Diego Pol, and published in a paper on an Early Jurassic Sauropod in 2021. This suggested that the species closest to specimen UCMP 37689 were species for which the dorsal vertebrae were known; while there are several South American Sauropod species for which the dorsal vertebrae are not known, these can be shown on the basis of other parts of their anatomy to be closely related to other species with dorsal vertebrae quite different to UCMP 37689. On which basis Rincón et al. feel comfortable formally naming the specimen as a new species, and giving it the name Perijasaurus lapaz, where 'Perijasaurus' derives from Serranía del Perijá, a mountain range on the border between northeast Colombia and northwest Venezuela, where the specimen was found, and 'lapaz' refers both the the town of La Paz, close to where the specimen was found, and the 2016 Acuerdos de Paz peace agreement, which enabled Rincón et al. to carry out fieldwork in this area.

Original reconstruction of the dorsal vertebra of Perijasaurus lapaz (UCMP 37689) in left lateral view (A), posterior view (B), and in transverse section at tickmark (C). Note that the two pieces of the vertebra, which have no snap fit, have been partially reconstructed after reversing the upper neural arch component. Rincón et al (2022).

Sauropod vertebrae show a range of features which change across the cervico-dorsal transition and throughout the dorsal series, enabling fairly accurate estimation of the position of even a lone vertebra on the spine. These include the degree of opisthocoely, position of the parapophysis, development of spinodiapophyseal laminae, and presence of hyposphene-hypantrum articulations. Furthermore, in mature Sauropods the cervical vertebrae have fused cervical ribs, and a parapophysis on the ventrolateral edge of the centrum, whereas on dorsal vertebrae the ribs are unfused and the parapophysis positioned on the ventrolateral edge of the centrum over the course of the first few vertebrae. Based upon this, Rincón et al. believe that UCMP 37689 is probably a fifth dorsal vertebrae.

Specimen UCMP 37689 only includes 8.75% of the features used to classify Sauropods in Gomez et al.'s matrix, nevertheless this was enough to make some estimations about its relationships, with Perijasaurus lapaz either being the sister taxon to Cetiosaurus, from the Middle Jurassic of England, Patagosaurus and closely related forms from southern South America, Africa, and Asia, and the Eursaurapod line that leads to the Neosauropods, or Cetiosaurus and the Eursaurapod line that leads to the Neosauropods, or the Mamenchisaurids and the Eursaurapod line that leads to the Neosauropods. 

Time-calibrated strict reduced consensus tree showing the phylogenetic relationships of Perijasaurus lapaz among early Sauropods. Taxa diverging more basally than Aardonyx have been omitted, and Neosauropods and Turiasaurs have been collapsed for simplicity. The reduced consensus tree was generated from 500,000 MPTs of 2423 steps (consistency index 0.28683, retention index 0.70652) after the a posteriori pruning of Chinshakiangosaurus, Sanpasaurus, and NHMUK PV R36834. The temporal bars represent chronostratigraphic uncertainties rather than actual ranges. The paleolatitudinal occurrence of each taxon is shown in the plot on the top; colors code Sauropodomorph grades (Perijasaurus highlighted with a thicker bounding circle). Rincón et al. (2022).

Sauropods achieved a global distribution in the Early Jurassic, with numerous groups being found in the temperate zones of both hemispheres. Sauropods from tropical regions, however, remain rare, despite the Animals clearly having passed through these regions. Perijasaurus lapaz provides a rare example of such a tropical Sauropod, and demonstrates that basal Eusauropods had reached South America by the Early Jurassic, less than 10 million years after the End Triassic extinction of the earlier Prosauropods.

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Three-dimensionally preserved Dinosaur remains from a new Jehol Biota outcrop in Inner Mongolia.

The Jehol Biota produces a wide range of exquisitely preserved Early Cretaceous fossils from locations across Liaoning, Inner Mongolia, and Hebei provinces in northeastern China. However, in almost all cases these are two-dimensionally preserved (i.e. flattened), with only a single site, an outcrop of the the Lujiatun Unit of the Yixian Formation in western Liaoning, producing fossils in three dimensions. The fossils from this location are predominantly Dinosaurs, with some Lizards and Mammals, and show signs of representing an area with an area with a different faunal composition and ecology to the rest of the Jehol Biota, as well as having a different taphonomy (mode of preservation).

In a paper published in the journal Acta Palaeontologica Polonica on 20 June 2022, Honggang Zhang of the College of Earth Science and Engineering, and Paleontological Institute at Shandong University of Science & Technology, Dongxiang Yu, also of the College of Earth Science and Engineering at Shandong University of Science & Technology, Yuhui Feng, also of the Paleontological Institute at Shandong University of Science & Technology, Rui Pei of the Key Laboratory of Evolutionary Systematics of Vertebrates at the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences, and Chang-Fu Zhou, again of the College of Earth Science and Engineering at Shandong University of Science & Technology, describe a second outcrop producing three-dimensionally preserved fossils from the Jehol Biota, this time located in the Ningcheng Basin of Inner Mongolia.

The new outcrop, at a site called Xidayingzi in Ningcheng County, comprises an outcrop of interbedded volcanic and sedimentary rocks about 80 m thick. The volcanic rocks here are predominantly basaltic andesites, rhyolitic breccia lavas and andesitic tuffs, while the sedimentary units are gravel-rich siltstones, sandstones, and conglomerates, all containing volcanically derived material.

Map of the Inner Mongolia, Liaoning and Hebei (A) showing location of the Xidayingzi site and the outcrops of the Lujiatun Unit of the Yixian Formation of the Jehol Biota in Beipiao, western Liaoning Province. Stratigraphic column (B) and corresponding photographic image (C) of the Early Cretaceous Xidayingzi site. Zhang et al. (2022).

Initial investigations at this site uncovered the remains of Dinosaurs from four different groups, plus Lizard and Mammal remains, all preserved in three dimensions and many in a semi-articulated state, although most material is individual bones.

Fossils found in the Xidayingzi site from the Early Cretaceous Ningcheng Basin, Inner Mongolia. (A) Sinovenator-like Troodontid Dinosaur (SDUST-V1062), the left pes is exposed in medial view. (B) Ceratopsian Dinosaur Psittacosaurus sp. (PMOL-AD00163), the maxilary teeth are loosely arranged and exposed in lateral view. (C) Neornithischian Dinosaur Jeholosaurus sp. (SDUST-V1063), the scapulocoracoid, humerus, ulna, and radius in lateral view. (D) Euhelopus-like Sauropod (SDUST-V1064), digital image of the tooth crown in medial view. (E) Indeterminated Lizard (PMOLAR00268), digital image of the fragmentary mandible in lingual view. (F) Symmetrodont-like Mammal (PMOL-AM00036), digital image of the mandible in lingual view. Zhang et al. (2022).

The most notable specimen from the site (SDUST-V1062) is the articulated post-cranial skeleton of a Troodontid Dinosaur, possibly a specimen of Sinovenator; the specimen resembles Sinovenator changii in most regards, but differs in having having a round anterior margin of the preacetabular process of the ilium and a moderately developed ambiens process of the pubis, and may therefore represent a second species in the genus.

Three Sauropod teeth were found at the site, two of them well preserved and similar to those of Euhelopus, a Titanosauriform of similar age to the Jehol Biota, but not previously reported from there.

Eight Neornithischian Dinosaur fossils were found at the site, with four being semi-articulated partial postcranial skeletons. These all resemble  Jeholosaurus shangyuanensis, a small Neornithischian previously only known from the Lujiatun Unit of the Jehol Biota.

Six specimens of Ceratopsian Dinosaurs were found, although these were rather fragmentary in nature. All appear similar to the early-diverging Psittacosaurus, often used as an index fossil for the Lower Cretaceous in East Asia, and common in the Jehol Biota. Curiously, the maxillary teeth of the new specimens appear to be spaced apart rather than being imbricated as in all other known Psittacosaurs, which may again indicate they belong to a new species.

A single fragment of a Lizard mandible (PMOL-AR00268) was found. This has pleurodont, conical, single-cusped, and closely packed teeth, which, are features common in a range of Mesozoic Lizards, and not helpful diagnostically.

Mammals are also represented by a single mandible (PMOL-AM00036), which has one premolar, five molars, and eight empty alveoli; the molars have acutely-triangulated molar cusps, which allows the specimen to be referred to the Symetrodonts, although this is a polyphyletic assemblage of Mammals, made up of members of different groups which converged on a similar morphology, possibly as a response to some Mesozoic ecological condition.

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Pneumatisation in a nanoid Saltasaurid Titanosaur from the Upper Cretaceous of western São Paulo State, Brazil.

The Dinosaurs were (and are) and exceptionally diverse group of Animals, and developed a wide range of novel innovations over their long evolutionary history. One of these inovations was the pneumatisation of the post-cranial skeleton, a trait found in both Sauropods and Theropods (including the living Birds). In these Dinosaurs the axial skeleton is infiltrated by a system of diverticula (pouches) which derive from the lungs. Although the pneumatisation of  the post-cranial skeleton has been known about in non-Avian Dinosaurs for a long time, the phenomenon has not been widely studied, as traditionally the only way to do this was through the observation of macroscopic structures, which could not usually be observed without cutting into the bone, and which were not always preserved anyway. More recently, the advent of computed tomography has enabled the non-destructive study of a wider range of bones, and led to a better understanding of the distinctive bone histologies associated with pneumatisation.

In a paper published in the journal Scientific Reports on 17 December 2021, Tito Aureliano of the Laboratory of Paleontology and Paleohidrogeology at the University of Campinas, the Diversity, Ichnology and Osteohistology Laboratory at the University of Rio Grande do Norte, and the Laboratório de Paleoecologia e Paleoicnologia at the Federal University of São Carlos, Aline Ghilardi, also of the Diversity, Ichnology and Osteohistology Laboratory at the University of Rio Grande do Norte, Bruno Navarro, also of the Laboratório de Paleoecologia e Paleoicnologia at the Federal University of São Carlos, and of the Laboratório de Paleontologia and Museu de Zoologia at the University of Sao Paulo, Marcelo Fernandes, again of the Laboratório de Paleoecologia e Paleoicnologia at the Federal University of São Carlos, Fresia Ricardi‑Branco, also of the Laboratory of Paleontology and Paleohidrogeology at the University of Campinas, and Mathew Wedel of the College of Osteopathic Medicine of the Pacific and College of Podiatric Medicine at the Western University of Health Sciences, present the results of a study of a posterior dorsal vertebra from an adult Saltasaurid Titanosaur from the Upper Cretaceous São José do Rio Preto Formation of western São Paulo State, Brazil.

The specimen studied by Aureliano et al. (LPP-PV-0200) was collected by Marcelo and Luciana Fernandes at the 'Vaca morta' locality in Ibirá in western São Paulo State, and subsequently prepared by Aline Ghilardi. It is part of a skeleton which is currently in the process of being described as a new species of  'nanoid' Saltasaurid Titanosaur, with a total length of only 5.7 m, despite clearly being mature, and indeed apparently of advanced years. This specimen is one of the three members of the new species discovered, with one of the other specimens apparently suffering from pathologies associated with acute osteomyelitis and preserved phosphatized blood parasites inside the vascular canals.

 

Posterior dorsal vertebra of the Upper Cretaceous nanoid Saltasaurid LPP-PV-0200. Three-dimensional reconstruction from computed tomography scan in left lateral view (A). Circle and rectangle show sampling planes and the respective thin sections are in (B) and (C). Abbreviations: ce, centrum; ns, neural spine; pn, pneumatopore; poz, postzygaphophysis; prz, prezygapophysis. Scale bar in (A) 10 cm; in (B) and (C) 1 cm. Aureliano et al. (2021).

A three-dimensional vertebra was made using computed tomography. The internal structure of the bone proved to be well preserved, allowing assessment of most of the pneumatic structures. The centrum (disk) of the vertebra has an array of elongated parallel cavities extending dorsoventrally in anterior view and anteroposteriorly in lateral view. This creates a honeycomb of cavities within the bone, which is also present within the neural arch. The cavities within the centrum average 3.9 mm in width, those within the neural arch 4.8 mm.

 

Dorsal vertebra internal structures of LPP-PV-0200. Reconstructed tomography model in distal (A) and right lateral (B) views illustrating subvertical tangential computed tomography scan slices in false colour (1)–(9). Images show that only a few structures had survived diagenesis which restricted the assessment of the internal architecture to limited spaces. Lighter blue and green indicate lower densities (e.g., pneumatic cavities). Purple and darker blue demonstrate denser structures (e.g., camellate bone). Dashed lines indicate internal plates of bone that sustain radial camellae. Abbreviations: ce, centrum; cc, circumferential chambers; cml, camellae; hc-cml, ‘honeycomb’ camellae; ns, neural spine; pf, pneumatic foramen; pn, pneumatopore; pacdf, parapophyseal-centrodiapophyseal fossa; pocdf, postzygapophyseal-centrodiapophyseal fossa; rad, radial camellae. Aureliano et al. (2021).

The vertebra shows a complex arrangement of foramina, fossae, laminae, and camellate internal architecture, which in life would have housed a system of pulmonary diverticula, similar to the air sac system in extant Birds. These camellae are elongate within the central part of the centrum, but radially arranged close to the surface. As a similar arrangement has been seen in cervical vertebrae of the Titanosaurs Austroposeidon and Uberabatitan, Aureliano et al. assume that this pattern relates to the to the structural needs of the vertebral articulation surfaces, rather than the position of the vertebae within the spine or body. Plates of bony tisue separate the camellae from the concave surfaces of the centrum; this has also been seen in vertabrae of the Opisthocoelicaudiine Titanosaur Alamosaurus and the Saltasaurid Titanosaur Saltasaurus. Curiously, both LPP-PV-0200 and Alamosaurus have multiple bony plates, whereas Saltasaurus had one single plates, despite Saltasaurus and LPP-PV-0200 being more closely related to one-another than to Alamosaurus. 

Circumferential camellae are found around the margins of the centrum, and in particular close to the concave faces. This arrangement has previously been recorded in the Diplodocoid Sauropod Apatosaurus, but not in a specimen with as extensive a (preserved) camellae system as LPP-PV-0200. The basal Titanosaur Giraffatitan has a different structure, with the surface camellae becoming chaotically arranged closer to the concave surfaces, possibly suggesting that the situation seen in LPP-PV-0200 and Apatosaurus evolved convergently in Diplodocoids and Titanosaurs.

 

Dorsal vertebra centrum near the cotyle. Detail of internal structures of the Saltasaurid Titanosaur LPP-PV-0200 in (A)-(C) and comparison with Apatosaurus (OMNH 01094) in (E). Reconstructed tomography model in lateral view (D) illustrating computed tomography scan slices in false colour (A)–(C). Small circumferentially arranged chambers are present in LPP-PV-0200 near the cotyle. A similar condition has previously been documented in the camerate vertebra of Apatosaurus (E). Abbreviations: cc, circumferential chambers; cmr, radially arranged camerae. Scale bar 10 cm. Aureliano et al. (2021).

The high level of pneumatisation seen in LPP-PV-0200 has been reported in other Titanosaurs, and the suggestion has been made that this is related to the extreme size of some of these Animals. However, the presence of a similar level of pneumatisation in the dwarf LPP-PV-0200 suggests that whatever prompted the evolution of these chambers, they were not exclusively linked to large size.

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