scholarly journals Transitional evolutionary forms and stratigraphic trends in chasmosaurine ceratopsid dinosaurs : evidence from the Campanian of New Mexico

2019 ◽  
Author(s):  
Denver Warwick Fowler ◽  
Elizabeth Anne Freedman Fowler
Keyword(s):  
New Mexico ◽  
Phylogenetic Relationship ◽  
Late Cretaceous ◽  
Phylogenetic Hypothesis ◽  
Stepwise Change ◽  
Horseshoe Canyon Formation

ABSTRACTThree new chasmosaurines from the Kirtland Formation (∼75.0 - 73.4 Ma), New Mexico, form morphological and stratigraphic intermediates between Pentaceratops (∼74.7 - 75Ma, Fruitland Formation, New Mexico) and Anchiceratops (∼72 - 71Ma, 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.

scholarly journals Transitional evolutionary forms in chasmosaurine ceratopsid dinosaurs: evidence from the Campanian of New Mexico

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9251
Author(s):  
Denver W. Fowler ◽  
Elizabeth A. Freedman Fowler
Keyword(s):  
New Mexico ◽  
Phylogenetic Relationship ◽  
Late Cretaceous ◽  
Phylogenetic Hypothesis ◽  
Stepwise Change ◽  
Horseshoe Canyon Formation

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.

A taxonomic assessment of the type series of Albertosaurus sarcophagus and the identity of Tyrannosauridae (Dinosauria, Coelurosauria) in the Albertosaurus bonebed from the Horseshoe Canyon Formation (Campanian–Maastrichtian, Late Cretaceous)This article is one of a series of papers published in this Special Issue on the theme Albertosaurus.

2010 ◽  
Vol 47 (9) ◽  
pp. 1213-1226 ◽  
Author(s):  
Thomas D. Carr
Keyword(s):  
Late Cretaceous ◽  
Type Specimen ◽  
Special Issue ◽  
Diagnostic Characters ◽  
Type Series ◽  
Growth Changes ◽  
Horseshoe Canyon Formation

The type series of Albertosaurus sarcophagus , consisting of a type (CMN 5600) and a paratype (CMN 5601) is inadequately established, since it has not been demonstrated that the specimens represent the same taxon. This problem has arisen because the original diagnostic characters have a wider distribution among Tyrannosauridae or they are in error, and both specimens consist of incomplete and damaged skulls. The type series was studied to test for the presence of diagnostic characters in the type specimen and, if so, to provide a rationale for referring the paratype to the taxon. Of the bones shared between the skulls, only five could be compared. One character, the enlarged posterior pneumatic recess of the palatine, is shared between the two specimens; this condition differs from the situation seen in other tyrannosaurids. This character provided the rationale for assessing the identity of the specimens collected from the Albertosaurus bonebed, from which one palatine was collected that exhibits the diagnostic recess. Isolated cranial bones from the bonebed were compared with those preserved in the type series to evaluate their referral to A. sarcophagus ; additional characters shared between the type series and the specimens from the bonebed were identified in the maxilla, lacrimal, and palatine. This evidence supports the hypothesis that A. sarcophagus is the tyrannosaurid preserved in the bonebed. A hypothesis of the principal growth changes in the skull in A. sarcophagus, which includes the type series and bonebed material, is proposed.

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 ◽  
...  
Keyword(s):  
New Mexico ◽  
Pore Size ◽  
Late Cretaceous ◽  
Size Constraints

Late Cretaceous Angiosperm Woods from the McRae Formation, South-Central New Mexico, USA: Part 2

2018 ◽  
Vol 179 (2) ◽  
pp. 136-150 ◽  
Author(s):  
Emilio Estrada-Ruiz ◽  
Elisabeth A. Wheeler ◽  
Garland R. Upchurch ◽  
Greg H. Mack
Keyword(s):  
New Mexico ◽  
Late Cretaceous ◽  
South Central

Late cretaceous dinosaurs from the ringbone formation, southwestern New Mexico, U.S.A.

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

THE INFLUENCE OF HYDRODYNAMIC FORCES ON TRACK MORPHOLOGY: TURTLE TRACKS FROM THE LATE CRETACEOUS CREVASSE CANYON FORMATION, NEW MEXICO

2017 ◽  
Author(s):  
Holley Elane Smart ◽  
◽  
M. Ryan King ◽  
M. Ryan King ◽  
Joshua A. Smith ◽  
...  
Keyword(s):  
New Mexico ◽  
Late Cretaceous ◽  
Hydrodynamic Forces
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