Pore‐size constraints on the activity and survival of subsurface bacteria in a late cretaceous shale‐sandstone sequence, northwestern New Mexico

1997 ◽  
Vol 14 (3) ◽  
pp. 183-202 ◽  
Author(s):  
J. K. Fredrickson ◽  
J. P. McKinley ◽  
B. N. Bjornstad ◽  
P. E. Long ◽  
D. B. Ringelberg ◽  
...  
PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9251
Author(s):  
Denver W. Fowler ◽  
Elizabeth A. Freedman Fowler

Three new chasmosaurines from the Kirtland Formation (~75.0–73.4 Ma), New Mexico, form morphological and stratigraphic intermediates between Pentaceratops (~74.7–75 Ma, Fruitland Formation, New Mexico) and Anchiceratops (~72–71 Ma, Horseshoe Canyon Formation, Alberta). The new specimens exhibit gradual enclosure of the parietal embayment that characterizes Pentaceratops, providing support for the phylogenetic hypothesis that Pentaceratops and Anchiceratops are closely related. This stepwise change of morphologic characters observed in chasmosaurine taxa that do not overlap stratigraphically is supportive of evolution by anagenesis. Recently published hypotheses that place Pentaceratops and Anchiceratops into separate clades are not supported. This phylogenetic relationship demonstrates unrestricted movement of large-bodied taxa between hitherto purported northern and southern provinces in the late Campanian, weakening support for the hypothesis of extreme faunal provincialism in the Late Cretaceous Western Interior.


2018 ◽  
Vol 179 (2) ◽  
pp. 136-150 ◽  
Author(s):  
Emilio Estrada-Ruiz ◽  
Elisabeth A. Wheeler ◽  
Garland R. Upchurch ◽  
Greg H. Mack

1990 ◽  
Vol 11 (4) ◽  
pp. 343-349 ◽  
Author(s):  
Spencer G. Lucas ◽  
George Basabilvazo ◽  
Timothy F. Lawton
Keyword(s):  

2017 ◽  
Author(s):  
Holley Elane Smart ◽  
◽  
M. Ryan King ◽  
M. Ryan King ◽  
Joshua A. Smith ◽  
...  

2018 ◽  
Author(s):  
Austin Michael Deans ◽  
◽  
Amanda Hendrix ◽  
Caleb Lewis ◽  
Spencer G. Lucas ◽  
...  

1997 ◽  
Vol 16 (1) ◽  
pp. 44-49
Author(s):  
Léo Laporte

In a posthumously published work of science fiction (The Dechronization of Sam Magruder, St. Martin's Press, 1996) the American paleontologist George G. Simpson (1902-1984) tells the story of Sam Magruder, a "chronologist" living in 2162 A.D, who was experimenting on the "quantum theory of time-motion" when he suffers a "time-slip" that puts him back in the Late Cretaceous of New Mexico. Helplessly lost in time and with no hope of returning to the present, Magruder ekes out a primitive existence for some years until a fatal accident befalls him. Before his death Magruder manages to chisel out his experience and philosophy of life on eight rock slabs that are recovered many millions of years later; and so his story becomes known and discussed by several Everyman characters. Simpson spins a reasonably engaging tale, but its main interest is the degree to which Magruder's philosophy of life may reflect Simpson's own feelings toward the end of his life. Always more comfortable in expressing his views in writing than in speaking, Simpson appears to use this work of science fiction to reveal his own, mostly melancholy, views about life's meaning and purpose, the importance of adapting to the here-and-now, and how historical contingency controls subsequent outcomes. Is Simpson speaking for himself when Magruder declares "My real purpose in engraving these slabs is a search for comprehension … I am exploring my own nature"?


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