scholarly journals Dinosaur eggshells from the lower Maastrichtian St. Mary River Formation of southern Alberta, Canada

2018 ◽  
Vol 55 (3) ◽  
pp. 272-282 ◽  
Author(s):  
Jared T. Voris ◽  
Darla K. Zelenitsky ◽  
François Therrien ◽  
Kohei Tanaka
Keyword(s):  
Body Size ◽  
North America ◽  
Upper Cretaceous ◽  
General Trend ◽  
Geographic Range ◽  
Taxonomic Composition ◽  
Skeletal Remains ◽  
Eggshell Thickness ◽  
Southern Alberta ◽  
Lower Maastrichtian

North America is known for its rich uppermost Cretaceous record of dinosaur egg remains, although a notable fossil gap exists during the lower Maastrichtian. Here we describe a diverse dinosaur eggshell assemblage from the St. Mary River Formation of southern Alberta that, in conjunction with recently described eggs from the same formation in Montana, helps fill this gap and sheds light on the dinosaur diversity in this poorly fossiliferous formation. Three theropod eggshell types (Continuoolithus cf. C. canadensis, Montanoolithus cf. M. strongorum, and Prismatoolithus cf. P. levis) and one ornithopod (Spheroolithus cf. S. albertensis), are reported from Albertan exposures of the St. Mary River Formation, increasing the ootaxonomic diversity of the formation from two to five ootaxa. The taxonomic composition of the eggshell assemblage is consistent with the dinosaurian fauna known from the St. Mary River Formation based on skeletal remains. Spheroolithus eggshells constitute the majority of identifiable eggshells in our assemblage, a trend also observed in several other Upper Cretaceous formations from North America. Continuoolithus is shown to be synonymous with Spongioolithus, thus expanding the Maastrichtian geographic range of the ootaxon to include Utah. The St. Mary River eggshell assemblage supports a general trend of increase in eggshell thickness among theropod ootaxa from the uppermost Santonian through the Maastrichtian, which is inferred to reflect an increase in body size among some clades of small theropods through the Upper Cretaceous. Eggshell preservation in the St. Mary River Formation may be related to the semiarid climatic and environmental conditions that prevailed.

The first record of spiral coprolites from the Dinosaur Park Formation (Judith River Group, Upper Cretaceous) southern Alberta, Canada

1995 ◽  
Vol 69 (6) ◽  
pp. 1191-1194 ◽  
Author(s):  
Clive E. Coy
Keyword(s):  
North America ◽  
Upper Cretaceous ◽  
First Record ◽  
Niobrara Formation ◽  
Southern Alberta ◽  
Dinosaur Park Formation

Spiral coprolites from the Upper Cretaceous of North America are poorly known. Enterospirae (fossilized intestines) reported from the Upper Cretaceous Niobrara Formation of western Kansas (Stewart, 1978) were disputed by McAllister (1985), who felt they represented spiral coprolites similar to those described from the Permian by Neumayer (1904). Previously described coprolites from the Upper Cretaceous of Alberta are small, unstructured, ellipsoidal forms thought to derive from a crocodilian or terrestrial, carnivorous reptile of necrophagic or piscivorous habits (Waldman, 1970; Waldman and Hopkins, 1970).

New caenagnathid (Dinosauria: Theropoda) specimens from the Upper Cretaceous of North America and Asia

1993 ◽  
Vol 30 (10) ◽  
pp. 2255-2272 ◽  
Author(s):  
Philip J. Currie ◽  
Stephen J. Godfrey ◽  
Lev Nessov
Keyword(s):  
North America ◽  
South Dakota ◽  
Upper Cretaceous ◽  
New Genus ◽  
Food Type ◽  
New Genus And Species ◽  
Hell Creek Formation ◽  
Central Asian ◽  
Southern Alberta ◽  
Judith River Formation

New specimens of caenagnathid theropods are described from the Judith River Formation (Campanian) of southern Alberta, the Hell Creek Formation (Maastrichtian) of South Dakota, and the Bissekty Formation (Turonian) of Uzbekistan. With the exception of the Hell Creek specimen, and a vertebra from Alberta, all are from the symphysial regions of the lower jaws. Caenagnathids are rare and poorly known animals, and the described fossils preserve heretofore unknown features, including vascular grooves and foramina in the symphysial region, and the pattern of overlapping sutures between jaw elements. Most of the new specimens are different from the holotype of Caenagnathus collinsi Sternberg and may represent the second described species, Caenagnathus sternbergi. The two jaws from the Bissekty Formation are the first oviraptorosaurian jaws described from Uzbekistan and represent a new genus and species anatomically closer to Caenagnathus than to central Asian forms like Oviraptor, Conchoraptor and Ingenia. There are at least five characters that distinguish caenagnathid and oviraptorid jaws, but it is concluded that the length of the symphysial region must be used with caution. Jaw anatomy supports the idea that oviraptorids were well adapted for eating eggs, although their diet was probably not restricted to one food type.

A 100 million year old gecko with sophisticated adhesive toe pads, preserved in amber from Myanmar

Zootaxa ◽  
2008 ◽  
Vol 1847 (1) ◽  
pp. 62 ◽  
Author(s):  
E. NICHOLAS ARNOLD ◽  
GEORGE POINAR
Keyword(s):  
Body Size ◽  
Lower Limb ◽  
Upper Cretaceous ◽  
New Genus ◽  
Skeletal Remains ◽  
New Genus And Species ◽  
Lower Eocene ◽  
Adult Body ◽  
Firm Evidence ◽  
Large Adult

A new genus and species of gecko is described from a posterior lower limb and foot, and a partial tail, preserved in Lower Cretaceous amber from Myanmar that is 97–110My old. It appears to be the oldest unequivocal fossil gecko, predating fragmentary skeletal remains from the Upper Cretaceous and being 43–56 My older than Yanatarogecko from the Lower Eocene, previously the oldest known gecko preserved in amber. It also provides firm evidence that gekkotans and possibly gekkonids were in Asia at this time. The Myanmar specimen shows, that the distinctive foot proportions and sophisticated adhesive mechanism, involving pads on the toes with transverse lamellae probably bearing numerous hairlike setae found in many modern geckos, had already evolved around 100My ago. The specimen is very small, even compared with juveniles of the smallest living geckos. However, the high numbers of lamellae on its toe pads suggest it is from a juvenile of a species with relatively large adult body size.

scholarly journals Taphonomy and taxonomy of a juvenile lambeosaurine (Ornithischia: Hadrosauridae) bonebed from the late Campanian Wapiti Formation of northwestern Alberta, Canada

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11290
Author(s):  
Brayden Holland ◽  
Phil R. Bell ◽  
Federico Fanti ◽  
Samantha M. Hamilton ◽  
Derek W. Larson ◽  
...  
Keyword(s):  
Life History ◽  
North America ◽  
Upper Cretaceous ◽  
Size Range ◽  
Life History Strategy ◽  
Breeding Population ◽  
Southern Alberta ◽  
Northern Regions ◽  
Age Segregation ◽  
Untapped Resource

Hadrosaurid (duck-billed) dinosaur bonebeds are exceedingly prevalent in upper Cretaceous (Campanian–Maastrichtian) strata from the Midwest of North America (especially Alberta, Canada, and Montana, U.S.A) but are less frequently documented from more northern regions. The Wapiti Formation (Campanian–Maastrichtian) of northwestern Alberta is a largely untapped resource of terrestrial palaeontological information missing from southern Alberta due to the deposition of the marine Bearpaw Formation. In 2018, the Boreal Alberta Dinosaur Project rediscovered the Spring Creek Bonebed, which had been lost since 2002, along the northern bank of the Wapiti River, southwest of Grande Prairie. Earlier excavations and observations of the Spring Creek Bonebed suggested that the site yielded young hadrosaurines. Continued work in 2018 and 2019 recovered ~300 specimens that included a minimum of eight individuals, based on the number of right humeri. The morphology of several recovered cranial elements unequivocally supports lambeosaurine affinities, making the Spring Creek sample the first documented occurrence of lambeosaurines in the Wapiti Formation. The overall size range and histology of the bones found at the site indicate that these animals were uniformly late juveniles, suggesting that age segregation was a life history strategy among hadrosaurids. Given the considerable size attained by the Spring Creek lambeosaurines, they were probably segregated from the breeding population during nesting or caring for young, rather than due to different diet and locomotory requirements. Dynamic aspects of life history, such as age segregation, may well have contributed to the highly diverse and cosmopolitan nature of Late Cretaceous hadrosaurids.

A new skeletal remain of the durophagous shark, Ptychodus mortoni, from the Upper Cretaceous of North America: an indication of gigantic body size

2010 ◽  
Vol 31 (2) ◽  
pp. 249-254 ◽  
Author(s):  
Kenshu Shimada ◽  
Michael J. Everhart ◽  
Ramo Decker ◽  
Pamela D. Decker
Keyword(s):  
Body Size ◽  
North America ◽  
Upper Cretaceous

scholarly journals Saldenioichthys remotus gen. et sp. nov. (Teleostei, Perciformes) and other acanthomorph remains from the Maastrichtian Saldeño Formation (Mendoza, Argentina)

Fossil Record ◽  
2003 ◽  
Vol 6 (1) ◽  
pp. 161-168
Author(s):  
A. López-Arbarello ◽  
G. Arratia ◽  
M. A. Tunik
Keyword(s):  
Upper Cretaceous ◽  
Character Evolution ◽  
Skeletal Remains ◽  
Neural Spine ◽  
New Taxon ◽  
Postcranial Skeleton ◽  
Caudal Skeleton ◽  
Lower Maastrichtian ◽  
Upper Campanian

Some isolated acanthomorph remains and a new taxon of perciform fishes, <i>Saldenioichthys remotus</i> gen. et sp. nov., from the Maastrichtian Saldeño Formation of Mendoza province, Argentina, are described and their systematic affinities are discussed. The new taxon is represented by a single incomplete, but well preserved postcranial skeleton. With the exception of a fully developed neural spine on the second preural centrum, it agrees with the generalized skeletal features of basal percoids, in particular the generalized perciform caudal skeleton. The only other Mesozoic perciform skeletal remains known so far are <i>Nardoichthys</i>, from the upper Campanian-lower Maastrichtian of Nardo (Italy) and <i>Eoserranus</i> from the Upper Cretaceous Lameta Formation (India). Therefore, the new perciform taxon from the Saldeño Formation represents one of the oldest members of this group, and due to its peculiar combination of primitive and derived characters, it raises several questions regarding character evolution on this lineage. <br><br> Es werden einige isolierte Reste acanthomorpher Fische sowie ein neues Taxon der Perciformes, <i>Saldenioichthys</i> remotus gen. et sp. nov., aus dem Maastricht der Saldeño Formation in der Provinz Mendoza, Argentinien, werden beschrieben und ihre systematische Stellung wird diskutiert. Das neue Taxon ist durch ein einziges, unvollständiges, aber gut erhaltenes postkraniales Skelett repräsentiert. Mit Ausnahme eines vollstandig ausgebildeten Dornfortsatzes auf dem ersten präuralen Zentrum stimmt es mit der generalisierten Skelettmorphologie basaler Percoiden überein, insbesondere mit dem generalisierten perciformen Caudal-Skelett. Die einzigen anderen Skelettreste von Perciformen aus dem Mesozoikum sind <i>Nardoichthys</i> aus dem Ober-Campan/Unter-Maastricht von Nardo, Italien, und <i>Eoserranus</i> aus der Oberkreide der Lameta Formation, Indien, und die Gruppe ist ansonsten praktisch nur aus känozoischen Sedimenten bekannt. Somit stellt das neue Taxon aus der Saldeño Formation einen der ältesten Nachweise dieser Gruppe dar, und wirft aufgrund seiner ungewöhnlichen Kombination primitiver und fortschrittlicher Merkmale einige Fragen zur Merkmalsevolution in dieser Linie auf. <br><br> doi:<a href="http://dx.doi.org/10.1002/mmng.20030060109" target="_blank">10.1002/mmng.20030060109</a>

scholarly journals Biological and extrinsic correlates of extinction risk in Chinese lizards

2021 ◽  
Author(s):  
Yuxi Zhong ◽  
Chuanwu Chen ◽  
Yanping Wang
Keyword(s):  
Body Size ◽  
Extinction Risk ◽  
Species Traits ◽  
Geographic Range ◽  
Range Size ◽  
Habitat Specialization ◽  
Mean Annual Precipitation ◽  
Mean Annual Temperature ◽  
Small Range ◽  
Extrinsic Factors

Abstract China is a country with one of the most species rich reptile faunas in the world. However, nearly a quarter of Chinese lizard species assessed by the China Biodiversity Red List are threatened. Nevertheless, to date, no study has explicitly examined the pattern and processes of extinction and threat in Chinese lizards. In this study, we conducted the first comparative phylogenetic analysis of extinction risk in Chinese lizards. We addressed the following three questions: 1) What is the pattern of extinction and threat in Chinese lizards? 2) Which species traits and extrinsic factors are related to their extinction risk? 3) How can we protect Chinese lizards based on our results? We collected data on ten species traits (body size, clutch size, geographic range size, activity time, reproductive mode, habitat specialization, habitat use, leg development, maximum elevation, and elevation range) and seven extrinsic factors (mean annual precipitation, mean annual temperature, mean annual solar insolation, normalized difference vegetation index (NDVI), human footprint, human population density, and human exploitation). After phylogenetic correction, these variables were used separately and in combination to assess their associations with extinction risk. We found that Chinese lizards with small geographic range, large body size, high habitat specialization, and living in high precipitation areas were vulnerable to extinction. Conservation priority should thus be given to species with the above extinction-prone traits so as to effectively protect Chinese lizards. Preventing future habitat destruction should also be a primary focus of management efforts because species with small range size and high habitat specialization are particularly vulnerable to habitat loss.

Sign in / Sign up

Export Citation Format

Share Document