scholarly journals Deep-time biodiversity patterns and the dinosaurian fossil record of the Late Cretaceous Western Interior, North America

2021 ◽  
Vol 288 (1953) ◽  
pp. 20210692
Author(s):  
Susannah C. R. Maidment ◽  
Christopher D. Dean ◽  
Robert I. Mansergh ◽  
Richard J. Butler
Keyword(s):  
North America ◽  
Late Cretaceous ◽  
Model Fitting ◽  
Terrestrial Ecosystem ◽  
Generalized Least Squares ◽  
Sampling Bias ◽  
Least Squares Regression ◽  
Deep Time ◽  
Biodiversity Patterns ◽  
Future Work

In order for palaeontological data to be informative to ecologists seeking to understand the causes of today's diversity patterns, palaeontologists must demonstrate that actual biodiversity patterns are preserved in our reconstructions of past ecosystems. During the Late Cretaceous, North America was divided into two landmasses, Laramidia and Appalachia. Previous work has suggested strong faunal provinciality on Laramidia at this time, but these arguments are almost entirely qualitative. We quantitatively investigated faunal provinciality in ceratopsid and hadrosaurid dinosaurs using a biogeographic network approach and investigated sampling biases by examining correlations between dinosaur occurrences and collections. We carried out a model-fitting approach using generalized least-squares regression to investigate the sources of sampling bias we identified. We find that while the raw data strongly support faunal provinciality, this result is driven by sampling bias. The data quality of ceratopsids and hadrosaurids is currently too poor to enable fair tests of provincialism, even in this intensively sampled region, which probably represents the best-known Late Cretaceous terrestrial ecosystem on Earth. To accurately reconstruct biodiversity patterns in deep time, future work should focus on smaller scale, higher resolution case studies in which the effects of sampling bias can be better controlled.

scholarly journals Lepidosaurian diversity in the Mesozoic–Palaeogene: the potential roles of sampling biases and environmental drivers

2018 ◽  
Vol 5 (3) ◽  
pp. 171830 ◽  
Author(s):  
Terri J. Cleary ◽  
Roger B. J. Benson ◽  
Susan E. Evans ◽  
Paul M. Barrett
Keyword(s):  
North America ◽  
Late Cretaceous ◽  
Generalized Least Squares ◽  
Environmental Drivers ◽  
Taxon Richness ◽  
Least Squares Regression ◽  
Genus Richness ◽  
Grande Coupure ◽  
Sampling Biases

Lepidosauria is a speciose clade with a long evolutionary history, but there have been few attempts to explore its taxon richness through time. Here we estimate patterns of terrestrial lepidosaur genus diversity for the Triassic–Palaeogene (252–23 Ma), and compare observed and sampling-corrected richness curves generated using Shareholder Quorum Subsampling and classical rarefaction. Generalized least-squares regression (GLS) is used to investigate the relationships between richness, sampling and environmental proxies. We found low levels of richness from the Triassic until the Late Cretaceous (except in the Kimmeridgian–Tithonian of Europe). High richness is recovered for the Late Cretaceous of North America, which declined across the K–Pg boundary but remained relatively high throughout the Palaeogene. Richness decreased following the Eocene–Oligocene Grande Coupure in North America and Europe, but remained high in North America and very high in Europe compared to the Late Cretaceous; elsewhere data are lacking. GLS analyses indicate that sampling biases (particularly, the number of fossil collections per interval) are the best explanation for long-term face-value genus richness trends. The lepidosaur fossil record presents many problems when attempting to reconstruct past diversity, with geographical sampling biases being of particular concern, especially in the Southern Hemisphere.

NOVEL INSECT HERBIVORY FROM THE LATE CRETACEOUS OF WESTERN NORTH AMERICA

2018 ◽  
Author(s):  
S. Augusta Maccracken ◽  
◽  
Ian M. Miller ◽  
Conrad C. Labandeira
Keyword(s):  
North America ◽  
Late Cretaceous ◽  
Insect Herbivory ◽  
Western North America

scholarly journals A comparison between generalized least squares regression and top-kriging for homogeneous cross-correlated flood regions

2021 ◽  
Author(s):  
Simone Persiano ◽  
Jose Luis Salinas ◽  
Jery Russell Stedinger ◽  
William H. Farmer ◽  
David Lun ◽  
...  
Keyword(s):  
Least Squares ◽  
Generalized Least Squares ◽  
Least Squares Regression

An early Late Cretaceous (Cenomanian) sturgeon (Acipenseriformes) from the Dunvegan Formation, northwestern Alberta, Canada

2014 ◽  
Vol 51 (7) ◽  
pp. 677-681 ◽  
Author(s):  
Matthew J. Vavrek ◽  
Alison M. Murray ◽  
Phil R. Bell
Keyword(s):  
North America ◽  
Late Cretaceous ◽  
Recent Survey ◽  
Peace River ◽  
Northern Regions ◽  
Early Late

A recent survey of the middle Cenomanian Dunvegan Formation along the Peace River, Alberta, has yielded a partial skull of a large acipenseriform fish. The fossil was from an animal approximately 5 m in length, based on comparisons with living relatives. Though incomplete, this represents an important record of mid-Cretaceous fish from northern North America, as formations of this age are virtually unexplored in northern regions. This fossil is the oldest acipenserid from North America, and one of the most northerly known.

scholarly journals International Experts’ Influence on Company Internationalization

2021 ◽  
Vol 29 (4) ◽  
Author(s):  
Grygorii Kravchenko
Keyword(s):  
Stock Exchange ◽  
Random Effect ◽  
Supervisory Board ◽  
Generalized Least Squares ◽  
Foreign Ownership ◽  
Company Performance ◽  
Least Squares Regression ◽  
Foreign Markets ◽  
Supervisory Boards ◽  
International Experts

Purpose: The article evaluates the associative relationship between international supervisory board experts and foreign ownership, along with the experts’ influence on the financial and operating performance of firms. The study was based on data collected for 257 companies listed on the Warsaw Stock Exchange in 2010–2015. Methodology: The dataset was built as a panel, and then generalized least squares regression models with a fixed or random effect were employed to test hypotheses. Findings: The findings of the study clearly show that the presence of investigated firms in foreign markets positively affects company performance. Moreover, models with dependent variables ROA and ROS show that supervisory board members with foreign experience positively affect profitability indicators of firms that do not operate on foreign markets. The data analyses reveal that international experts are more effective advisors for companies that conduct no business activities on foreign markets. Furthermore, the results show a positive moderate association between the share of international experts in supervisory boards and the share of foreign ownership in the company. Originality: The article contributes to the understanding of determinants and consequences of the presence of international experts in supervisory boards and company internationalization.

scholarly journals The Dakoticancridae (Decapoda, Brachyura) from the Late Cretaceous of North America and Mexico

1998 ◽  
Vol 67 (4) ◽  
pp. 237-255 ◽  
Author(s):  
G.A. Bishop ◽  
R.M. Feldmann ◽  
F. Vega
Keyword(s):  
North America ◽  
Functional Morphology ◽  
Late Cretaceous ◽  
Cladistic Analysis ◽  
Low Level ◽  
The Family

The podotrematous crab family Dakoticancridae includes four genera: Dakoticancer Rathbun, Tetracarcinus Weller, Avitelmessus Rathbun, and Seorsus Bishop, all known solely from the Late Cretaceous of North America. Lathelicocarcinus Bishop, originally referred to the family, must be reassigned. Fine details of anatomy, preserved on specimens of D. overanus Rathbun and A. grapsoideus Rathbun, permit description of genital openings and interpretation of functional morphology of appendages. Although one species, D. australis Rathbun, has been found associated with burrow structures, all were probably vagrant epifaunal animals on fine- to medium-grained siliciclastic substrata. Food was probably obtained by generalized low-level predation and scavenging. Results of a cladistic analysis are consistent with the stratigraphic data suggesting that T. subquadrata Weller is nearest the rootstock of the family and that other taxa within the family are derived from it.

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