Results 21 to 30 of about 174 (116)

Ontogenetic changes in squamosal of Chasmosaurus.

, 2016
Increase in length/width ratio (character 12), changing outline of lateral margin (character 13), articulation (character 14) and remodeling (character 15) of episquamosals: (A) TMP 1998.128.0001 (flipped), (B) CMN 1254, (C) AMNH 5656, (D) AMNH 5401, (E)
Michael J. Ryan (326037), Claudia J. Schröder-Adams (839086), Robert B. Holmes (728268), James A. Campbell (842116)   +3 more
core   +1 more source

An exquisitely preserved young iguanodontian from the Upper Jurassic of Tanzania sheds light on skeletal fusion patterns within Archosauria

Papers in Palaeontology, Volume 12, Issue 3, May/June 2026.
Abstract Dysalotosaurus lettowvorbecki (Ornithopoda, Dinosauria) is a small‐sized dryosaurid iguanodontian known from various isolated remains collected from the Tendaguru Formation (Upper Jurassic, Tanzania). Micro‐computed tomography of a small individual encased in a block offered a unique opportunity to describe c.
Riccardo Rocchi, Filippo Maria Rotatori, Gabriel S. Ferreira, Federico Fanti   +3 more
wiley   +1 more source

Ontogenetic changes in nasal horncore of Chasmosaurus.

, 2016
Articulation of epinasal with nasals (character 2) and subsequent resorption of nasal horncore (character 3): (A) epinasal disarticulated (CMN 1254; flipped), (B) epinasal articulated with suture open (CMN 2245), (C) epinasal articulated with suture ...
Michael J. Ryan (326037), Claudia J. Schröder-Adams (839086), Robert B. Holmes (728268), James A. Campbell (842116)   +3 more
core   +1 more source

Ontogenetic changes in skull roof of Chasmosaurus.

, 2016
Articulation between: premaxillae (character 5), premaxilla-nasal (character 6), nasals (character 7), nasal-frontal (character 8), frontals (character 9), and frontal-postorbital (character 10): (A–B) CMN 1254, (C–D) UALVP 40, (E–F) AMNH 5402, (G–H ...
Michael J. Ryan (326037), Claudia J. Schröder-Adams (839086), Robert B. Holmes (728268), James A. Campbell (842116)   +3 more
core   +1 more source

Ontogenetic changes in postorbital horncores of Chasmosaurus.

, 2016
Resorption of horncores (character 4): (A) (UALVP 40) and (B) (AMNH 5401; flipped), horncore complete; (C) horncore partly resorbed (TMP 1981.019.0175; flipped); and (D) horncore resorbed to base (CMN 8800).
Michael J. Ryan (326037), Claudia J. Schröder-Adams (839086), Robert B. Holmes (728268), James A. Campbell (842116)   +3 more
core   +1 more source

Ontogenetic changes in rostral of Chasmosaurus.

, 2016
Articulation of rostral with premaxillae (character 1): (A) rostral separate and missing (UALVP 40); (B) rostral articulated, but dorsal suture open (AMNH 5402); and (C) rostral articulated with suture closed (YPM 2016).
Michael J. Ryan (326037), Claudia J. Schröder-Adams (839086), Robert B. Holmes (728268), James A. Campbell (842116)   +3 more
core   +1 more source

Ontogenetic changes in parietal of Chasmosaurus.

, 2016
Thinning of lateral bar (character 16), articulation (character 17) and reorientation (character 18) of epiparietals (character 18): (A) CMN 1254, (B) AMNH 5656, (C) TMP 1983.025.0001, and (D) CMN 2280 (flipped).
Michael J. Ryan (326037), Claudia J. Schröder-Adams (839086), Robert B. Holmes (728268), James A. Campbell (842116)   +3 more
core   +1 more source

Principal component analysis (PCA 2) of Chasmosaurus and Vagaceratops, controlling for ontogenetic differences.

, 2016
PCA of 18 specimens of Chasmosaurus belli (triangles; n = 5), Chasmosaurus russelli (inverted triangles; n = 4), Chasmosaurus sp. (diamonds; n = 7), and Vagaceratops irvinensis (circles; n = 2): (A) PC1 vs. PC2 (77.2% of variance); (B) PC2 vs. PC3 (17.2%
Michael J. Ryan (326037), Claudia J. Schröder-Adams (839086), Robert B. Holmes (728268), James A. Campbell (842116)   +3 more
core   +1 more source

Principal component analysis (PCA 1) of Chasmosaurus and Vagaceratops.

, 2016
PCA of 18 specimens of Chasmosaurus belli (triangles; n = 5), C. russelli (inverted triangles; n = 4), Chasmosaurus sp. (diamonds; n = 7), and Vagaceratops irvinensis (circles; n = 2): (A) PC1 vs. PC2 (52.5% of variance), (B) PC2 vs.
Michael J. Ryan (326037), Claudia J. Schröder-Adams (839086), Robert B. Holmes (728268), James A. Campbell (842116)   +3 more
core   +1 more source

New information on the holotype of “ Chasmosaurus ” russelli (Ornithischia: Ceratopsidae) necessitates the establishment of a new genus to receive the species

Canadian Journal of Earth Sciences
Although the holotype of Chasmosaurus russelli Sternberg, 1940, from the upper Dinosaur Park Formation of southern Alberta, shares features with other Chasmosaurus Lambe, 1914 specimens from Dinosaur Provincial Park as well as various chasmosaurine taxa from the southwest United States, it also possesses unique features of the premaxilla and frill ...
Robert B. Holmes, Jordan C. Mallon, Michael J. Ryan, David C. Evans   +3 more
openaire   +1 more source