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A tyrannosaurid pedal ungual from the Williams Fork Formation (Campanian) of Colorado and its implications for the biogeography of Laramidian dinosaurs

Yun Chan-Gyu

Acta Geologica Polonica

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2023

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Vol. 73, no. 1

63--72

EN

A right theropod pedal ungual phalanx II-3 from the Campanian Williams Fork Formation of northwestern Colorado is described, and a combination of features, including the large size, tapering distal tip, robust and stout overall form, triangular cross-section, and a relatively flat ventral surface allows a confident referral to Tyrannosauridae Osborn, 1906. Although this specimen was found in a relatively southern state, the proximal articular surface of this ungual is similar to that of Gorgosaurus libratus Lambe, 1914, a taxon found in the northern state, Alberta. Although based on limited evidence, this may suggest that the range of tyrannosaurids considered endemic to the north of Laramidia extended farther south than previously thought.

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An enigmatic theropod Cryolophosaurus: reviews and comments on its paleobiology

Yun Changyu

Volumina Jurassica

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2019

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Vol. 17, no. 1

103--110

EN

Cryolophosaurus is a genus of theropod dinosaur that is characterized by its distinctive crest formed by dorsally expanded lacrimals. Although its fossils are rare, currently recognized materials suggest this taxon was the largest predator in the Early Jurassic times in Antarctica, indicating it was the apex predator in its ecosystem. The skeleton of Cryolophosaurus bears both advanced and basal characteristics of theropods, making its position within theropod phylogenetic tree controversial. Its unusual anatomical features, size, and the habitat located close to the Jurassic polar circle all differ from other Early Jurassic theropods, indicating it was one of the most ecologically significant taxon of all theropods.

3

Osteology of a large allosauroid theropod from the Upper Jurassic (Tithonian) Morrison Formation of Colorado, USA

Dalman S.

Volumina Jurassica

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2014

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Vol. 12, no. 2

159--180

EN

Two partial skeletons of allosaurid theropods belonging to an adult and a juvenile from the Upper Jurassic (Tithonian) Morrison Formation of McElmo Canyon in Montezuma County, southwestern Colorado, were discovered in 1953 by the late Joseph T. Gregory and David Techter. The adult specimen consists of several isolated cranial and postcranial skeletal elements that are exceptionally well-preserved and include the left premaxilla, maxilla, dentary, teeth, quadratojugal, two caudal vertebrae, pubic peduncle, ischium, proximal tibia, a nearly complete left foot, and several isolated teeth, whereas the juvenile specimen is represented by the distal portion of the right dentary and a fragmentary splenial. The specimens represent a new species of Allosaurus, here named Allosaurus lucasi, which differs from Allosaurus fragilis by having a relatively short premaxilla and robust quadratojugal with short jugal process and a short quadrate process of the quadratojugal that is at the same level as the rostral quadratojugal ramus. The presence of a new species of Allosaurus in the Tithonian of North America provides further evidence of the taxonomic and morphological diversity of the Allosauridae clade and their continuous evolutionary success, which extended to the Cretaceous.

4

New data on small theropod dinosaurs from the Upper Jurassic Morrison Formation of Como Bluff, Wyoming, USA

Dalman S.

Volumina Jurassica

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2014

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Vol. 12, no. 2

181--196

EN

In 1879, Othniel C. Marsh and Arthur Lakes collected in the Upper Jurassic Morrison Formation Quarry 12 at Como Bluff, Wyoming, USA, several isolated axial and appendicular skeletal elements of small theropod dinosaurs. Since the discovery the specimens remained unnoticed for over a century. The skeletal remains of small theropods are rare at Como Bluff and throughout the Morrison Formation. Their bones are delicately constructed, so they are not as well-preserved as the bones of large-bodied theropods. The bones of small theropods described here were found mixed with isolated crocodile teeth and turtle shells. Comparison of the skeletal materials with other known theropods from the Morrison Formation reveals that some of the bones belong to a very small juvenile Allosaurus fragilis and Torvosaurus tanneri and also to a new ceratosaur taxon, here named Fosterovenator churei, whereas the other bones represent previously unidentified juvenile taxa of basal tetanuran and coelurid theropods. The discovery and description of these fossil materials is significant because they provide important information about the Upper Jurassic terrestrial fauna of Quarry 12, Como Bluff, Wyoming. The presence of previously unidentified theropod taxa in the Morrison Formation indicates that the diversity of basal tetanuran and coelurid theropods may have been much greater than previously expected. Although the fossil material here described is largely fragmentary, it is tenable that theropods of different clades co-existed in the same ecosystems at the same time and most likely competed for the same food sources.

5

Tropy wielkich teropodów z osadów górnego pliensbachu Gór Świętokrzyskich

Niedźwiedzki G., Remin Z.

Przegląd Geologiczny

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2008

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Vol. 56, nr 9

823-823

EN

New gigantic theropod dinosaur footprints were discovered in the upper Pliensbachian deposits of the Holy Cross Mountains (Poland). This discovery provides new ichnological evidence for the global occurrence of gigantic predatory dinosaurs in the earliest Jurassic time. Interestingly, this is the third find of gigantic theropod ichnites in the Lower Jurassic of Poland. The first record of gigantic tracks from this area came from the well-known lower Hettangian tracksite in Sołtyków. New finds from the Szydłówek quarry were discovered in siliciclastic strata, which are interpreted as nearshore, shoreface and marginal marine. Hitherto, five isolated specimens of gigantic theropod footprints (40–60 cm long) were found in this tracksite. Another large theropod footprints (30–40 cm) identified at Szydłówek, resemble classic theropod ichnotaxa of the Newark Supergroup (i.e., Eubrontes). Intriguing gigantic theropod ichnites from the Holy Cross Mountains are more similar to large prints left byMiddle and Late Jurassic theropods than to those from the Early Jurassic. These footprints seem even larger because of their large metatarsophalangeal area. Relatively large metatarsophalangeal area is often observed in the large theropod footprints from the post-Liassic strata. New paleoichnological finds from Poland suggest rapid increase of predatory dinosaur body size in Early Jurassic time.

6

Ślady dinozaurów drapieżnych z osadów retyku w Seebergen (Turyngia, Niemcy)

Niedźwiedzki G.

Przegląd Geologiczny

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2008

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Vol. 56, nr 7

539-539

EN

Four ichnotypes of theropod dinosaur tracks (described in this paper as cf. Grallator isp., Anchisauripus isp., cf. Eubrontes isp., and Theropoda indet.) were identified in the middle-upper Rhaetian deposits exposed in the Seebergen quarry located near Kammerbruch in the Thuringia Basin, Central Germany. This new paleoichnological find is very important for understanding of diversity and composition of the latest Triassic (Rhaetian) vertebrate assemblages (especially dinosaur assemblages), what is essential for studies on the Late Triassic and Early Jurassic faunal change.

7

Ślady wielkich teropodów z wczesnojurajskich osadów Gór Świętokrzyskich

Niedźwiedzki G.

Przegląd Geologiczny

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2006

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Vol. 54, nr 7

615-621

EN

Numerous gigantic and large theropod dinosaur footprints were recently discovered in the Lower Jurassic deposits of the Holy Cross Mountains (central Poland). These finds provide paleoichnological evidence for the occurrence of gigantic predatory dinosaurs in the earliest Jurassic (Hettangian) times. The gigantic and large theropod tracks came from two well-known lower Hettangian tracksites at Sołtykow and Gromadzice. The Sołtyków outcrop represents a siliciclastic coal-bearing lithofacies association of a fairly well-watered alluvial plain. The sequence from the Gromadzice site is dominated by typical meandering river deposits with lenticular, incised channels and overbank mudstones, rich in drifted flora and plant roots. Hitherto, twenty four specimens of gigantic theropod Eubrontes-like footprints (50–65 cm long) were found at Sołtyków tracksite. Another large theropod footprints (30–45 cm) identified at Sołtyków, resemble Kayentapus-like ichnites and classic ichnotaxa of the Newark Supergroup (i.e., Eubrontes giganteus Hitchcock, 1845 sensu Olsen et al., 1998). In the Gromadzice site, large Eubrontes giganteus, Eubrontes sp., and cf. Eubrontes sp. footprints were identified. The intriguing gigantic ichnites from Sołtyków are more similar to the large prints left by Middle–Late Jurassic theropods than to other finds from the Early Jurassic.

8

Isolated theropod teeth from the Cretaceous strata of Khouribga, Morocco

Niedźwiedzki G., Gierliński G.

Geological Quarterly

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2002

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Vol. 46, No 1

97-100

EN

Predatory dinosaur (Theropoda) teeth are described from Khouribga near Casablanca (Ad-Dar al-Bajda) in northern Morocco. A morphological study of specimens shows that two teeth represent the family Spinosauridae. A third tooth shows features characteristic of the genus Carcharodontosaurus. These are the first finds of dinosaurs from Khouribga.

9

Dinosaur footprints from the Upper Jurassic of Błaziny, Poland

Gierliński G., Niedźwiedzki G.

Geological Quarterly

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2002

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Vol. 46, No 4

463-466

EN

New dinosaur tracks are reported from the Late Jurassic platform carbonates of Poland. Footprints discovered in a new tracksite of Błaziny resemble large theropod ichnite of Megalosauripus sensu Lockley et al., 1998 and sauropod tracks of Brontopodus Farlow et al., 1989.