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Hadrosaurs from the far east: Historical perspective and new amurosaurus material from blagoveschensk (amur region, Russia)
... OUSM-FV-001 also differs from the immature lambeosaurine Velafrons in having the gently curved squamosal process of the postorbital ( Figure 3G). Although the incompleteness of OUSM-FV-001 hinders comparisons with the diagnostic characters of the Asian Lambeosaurini, the dentary of OUSM-FV-001 differs from those of Amurosaurus (Bolotsky et al., 2014;Godefroit et al., 2004) and Sahaliyania (Godefroit et al., 2008) in the absence of the strong ventral deflection of the anterior half of the dentary (Figure 4g-i). OUSM-FV-001 also differs from another Asian lambeosaurine Olorotitan (Godefroit et al., 2012) in the relatively short edentulous region of the dentary. ...
Despite the long history of research in the late Campanian Judith River Formation in northern Montana, most of the vertebrate fossils are represented by fragmentary remains, making precise taxonomic identifications difficult. Contrary to this, the partially contemporaneous Dinosaur Park Formation, Alberta, Canada is known for its tremendous fossil preservation, permitting rigorous studies of dinosaur diversity, evolution, and biostratigraphy. Hadrosaurids comprise one of the most abundant dinosaur clades in the Dinosaur Park Formation, but taxonomic affinities of hadrosaurid specimens remain poorly understood in the Judith River Formation. Corythosaurus is the most common hadrosaurid in the Dinosaur Park Formation and, to date, has been restricted to this formation. This study reports the first definitive Corythosaurus specimens from the Judith River Formation, which were discovered on two private ranches in northern Montana. The attribution of the most complete skeleton to Corythosaurus is indicated by: wide crest-snout angle, presence of premaxilla-nasal fontanelle, dorsoventrally expanded nasal, laterally exposed ophthalmic canal of the laterosphenoid, and tall neural spines. A second specimen preserves a large ilium that can be positively identified as Corythosaurus based on its associated skull, which is now in private hands. The specimens were recovered from the Coal Ridge Member of the Judith River Formation, which is approximately time equivalent to the Dinosaur Park Formation. Thus, the discovery of Corythosaurus in the Judith River Formation extends the biogeographic range of this genus and establishes a framework for future interformational biostratigraphic studies of Late Cretaceous dinosaur faunas in North America.
... Some character states of Velafrons coahuilensis, Sabinas PASAC-1 taxon, are modified based on direct observations (see supplementary material). In addition, some scores of Tsintaosaurus spinorhinus Young, 1958, Pararhabdodon isonensis Casanovas-Cladellas, Santaf e-Llopis, and Isidro-Llorens, 1993, Amurosaurus riabinini are modified based on recent studies (Bolotsky et al., 2014;Zhang et al., 2019;Serrano et al., 2021), and for the case of Kritosaurus navajovious the skull material of IGM 6685 is removed from the remainder of the species hypodigm to form a separated OTU (see supplementary material). Four taxa were removed from the original data matrix: Ugrunaaluk Mori et al., 2016, Koutalisaurus Prieto-M arquez et al., 2006, and Kundurosaurus Godefroit et al., 2012, because the current evidence places them as invalid taxa Xing et al., 2014a;Takasaki et al., 2020), and Nipponosaurus Nagao, 1936 because it represents an immature specimen (Takasaki et al., 2017). ...
This work provides a review of the taxonomic diversity, phylogenetic relationships, and historical biogeography of the seven described hadrosauroids from Mexico. Their interrelationships were inferred via maximum parsimony analysis, which indicates that these taxa are part of five groups: unnamed clade of basal Hadrosauromorpha (Huehuecanauhtlus tiquichensis), Kritosaurini (Kritosaurus navajovious, IGM 6685), Edmontosaurini (Sabina’s taxon, PASAC-1), Parasaurolophini (Tlatolophus galorum), and Lambeosaurini (Magnapaulia laticaudus, Velafrons coahuilensis, and Latirhinus uitstlani). To trace back their biogeographical history, the ancestral range reconstruction was implemented using Statistical Dispersal Vicariance Analysis, which reveals that these hadrosauroids represent a southern Laramidia-Asia common ancestral range. It also shows that these dinosaurs evolved via three vicariance and two dispersals events during the Turonian, Coniacian, Santonian and Campanian age, representing a complex biogeographical history.
... Recent fieldwork in central Asia, particularly in Kazakhstan and the Amur region of far eastern Russia and China, have provided new information on hadrosaur diversity and yielded a number of important new taxa including Charonosaurus jiayinensis (Godefroit et al., 2000(Godefroit et al., , 2001, Olorotitan aharensis (Godefroit et al., 2003), Kerberosaurus manakini (Bolotsky and Godefroit, 2004), Sahaliyania elunchunorum , and Wulagasaurus dongi . Extensive monodominant bonebeds of Charonosaurus (Godefroit et al., 2000), Amurosaurus (Godefroit et al., 2004a;Lauters et al., 2008;Bolotsky et al., 2014), Sahaliyania , and Shantungosaurus (Hone et al., 2014;Xing et al., 2014a) are known from this region, and at least two other species (K. manakini, W. dongi) comprise minor components of some of these bonebeds. ...
The famous "Dragon's Tomb" Saurolophus bonebed at Altan Uul II preserves multiple complete skeletons with skin impressions, and is exceptional among Nemegt Formation dinosaur localities as the only mass accumulation of articulated individuals. Here, we present results from an on-going paleontological project focused on the Baruungoyot-Nemegt succession in order to document this unique locality. Sedimentological data allow us to confirm that the fossils and host sediments were deposited in the thalweg of a meandering paleochannel that experienced a variety of high and lower energy flow conditions. A variety of taphonomic data were collected from exposed fossils, including those displaced by poaching. Three-dimensional maps of the host sediments and fossils were generated, and 13m² of exposed, in-situ bones were mapped. Previously undocumented portions of at least 13 additional Saurolophus individuals and a partial subadult Tarbosaurus skeleton were identified. The Dragon's Tomb is a monodominant bonebed with at least three size classes (juvenile, subadult, and large adult) of Saurolophus preserved. The bonebed has a minimum size of ∼2000m², suggesting that over 100 Saurolophus carcasses may have contributed to the thanatocoenose. Although the data provide evidence for a catastrophic mass death of a social group of Saurolophus and provide the first evidence of gregariousness in this taxon, the cause of death cannot be determined.
... Uppermost Cretaceous hadrosaurid dinosaur remains are not so abundant in South America (see Coria, 2014) as they are in Laurassian continents: North America (see Gates and Scheetz, 2014), Europe (see Dalla Vecchia, 2014) and Asia (see Bolotsky et al., 2014). Uppermost Cretaceous large ornithopod tracks, also called "hadrosaur tracks", are abundant in North America and Asia as well (e.g., Lockley et al., 2003;Xing et al., 2009;Díaz-Martínez et al., 2015, and references therein), but in Europe and Gondwana this record is very scarce (Lockley et al., 2003;Vila et al., 2013). ...
Uppermost Cretaceous (Campanian-Maastrichtian) large ornithopod tracks are scarce in Gondwana. This record is limited to few citations in the northern Argentina, Peru and possibly Bolivia, although their ichnological affinities are still under discussion. Recently, a new vertebrate tracksite with large ornithopod tracks has been found in the Maimará locality, Jujuy province, Argentina, from the Yacoraite Formation (Maastrichtian-Danian). The best preserved track is characterized by having large and bilobed heel impressions and wide and short digit impression with blunt claw marks. This record represents the unambiguous record of large ornithopod tracks in Gondwana in the Uppermost Cretaceous, and its features allow classifying it as Hadrosauropodus. Previously, this ichnotaxon had exclusively Laurasian distribution. Therefore, this record is the first evidence of Hadrosauropodus from Gondwana expanding the geographic range of this ichnogenus. A member of Hadrosauridae is reinforced as possible trackmaker of the Hadrosauropodus tracks. Uppermost Cretaceous hadrosaurid dinosaurs are scarce in Gondwana, being the record limited to Patagonia, La Pampa province and Antarctica. Therefore, the Maimará tracks increase the knowledge of this kind of dinosaur from Gondwana.
The skull of the hadrosauroids is the most complex structure of its anatomy, with features of systematic and phylogenetic
importance. Recent discoveries have increased the anatomical diversity, causing confusion to recognize unique
characters or derivatives, by using different terms for the same structures. This situation is more complex when Spanish-
speaking researchers and students need to make a detailed description. This work represents the second part of the
anatomical guide of the hadrosauroids, which includes an updated and illustrated introductory compendium of their
cranial anatomy. The purpose is to facilitate the handling of new data of phylogenetic importance and the taxonomic
identification of isolated or associated remains, using morphotypes
The osteology and taxonomy of the lambeosaurine Sahaliyania elunchunorum from the upper Yuliangzi Formation (middle Maastrichtian) are reevaluated herein. Based on detailed morphological comparisons among hadrosauroids, we argue that Wulaga lambeosaurine specimens, most of which were previously ascribed to S. elunchunorum, display a combination of features that is typical of Amurosaurus riabinini from the upper Udurchukan Formation (middle Maastrichtian) at the Blagoveschensk locality. This combination includes several anterodorsally-posteroventrally oriented lateral foramina of the maxilla with a very large last one partially obscured by the ventral extremity of the jugal contact, a narrow infratemporal region of the jugal that is ~70% as wide as the orbit, a relatively low anterior third of the strongly dorsally concave sagittal crest of the parietal, mesiodistally wide maxillary tooth crowns (~1.2–1.3 teeth per cm), the sternal posterolateral process slightly shorter than the anteromedial plate, and a gently ventrally deflected preacetabular process of the ilium. Considering the osteological similarities and the fact that the Yuliangzi and Udurchukan formations were deposited synchronously in the same basin, S. elunchunorum is regarded here as a junior synonym of A. riabinini. ~70% of the complete Amurosaurus fibulae from the Wulaga bonebed exhibit a total length of more than 85 cm that probably corresponds to the adult stages. Histological sections from these fibulae are sufficiently remodeled by dense secondary osteons, with poorly developed vascularization of primary osteons along fibrolamellar bone in the outer cortex. The phylogenetic analysis of Lambeosaurinae recovers a sister-taxon relationship between Amurosaurus and Lambeosaurus.
In 2013, a joint team of INAH and UNAM paleontologists launched a project to recover a semi-articulated tail of a putative hadrosaur, that was discovered in 2005, on the superficial upper Campanian deposits of the Cerro del Pueblo Formation, near Presa de San Antonio, General Cepeda Municipality, Coahuila, northern Mexico. Currently, this specimen is the most complete lambeosaurine so far found in Mexico. Herein, Tlatolophus galorum gen. et sp. nov. is erected based on features shown in the head of this specimen. The distinctive characters of this new species are the skull high, with a length/height ratio equals to 1.79; the premaxilla wide, in which maximum/minimum width ratio is about 2.4; the maxillary ascending ramus has a low dorsal apex; the pterygoid dorsal crest is high and convex; the supracranial crest is high, spatula-shaped and similar to an inverse-comma; the occipital condyle is inclined 56° ventrally; the supraoccipital crest is laminar, wide and located inside a deep nuchal fossa; the squamosal shelf is moderately long, as long as the foramen magnum diameter; the dorsal margins of the infratemporal fenestra and orbit are located at the same level; and the nasal is elongated, caudally expanded, and bilobed. The phylogenetic analysis performed here recovers Tlatolophus within the Tribe Parasaurolophini; in this result, the supracranial crest spatula-shaped of this new parasaurolophini represent a plesiomorphic condition within the tribe.
The key to the expansion of Russia to the Far East and to America is to be found in the loss of the valley of the Amur to China by the Treaty of Nerchinsk in 1689 and its reacquisition in the period from 1854 to 1860. R. J. Kerner, “Russian Expansion to America, Its Bibliographical Foundations, Papers of the Bibliographicul Society of America.