Table 1.
List of neoceratopsian taxa for which sexual dimorphism has been previously proposed.
Fig 1.
Hypothetical large “male” at left (AMNH 6438) and hypothetical large “female” at right (AMNH 6466).
Redrawn and modified after Brown and Schlaikjer [23]. Scale equals to 10 cm.
Fig 2.
Linear measurements measured on skull.
Redrawn following the measurement standards originally in Dodson [25]. The numbers of measurements corresponds to those reported in Table B in S1 File.
Table 2.
Sexual scores for specimens of P. andrewsi unshared with Dodson’s work [25].
Fig 3.
Linear regressions of basal skull length (BSL) against the four sex-discriminant variables of the Protoceratops sample (see Table B in S1 File).
Black dot represents “male”, white dot represents “female”, gray dot represents juvenile, and red dot represents a sex-undetermined specimen. Scale of axes is logarithmic.
Fig 4.
Landmark and semi-landmark configurations.
A, landmark configuration for skull in lateral view. B, landmark configuration for skull in dorsal view. C and D are subunits of the skull configuration. Landmarks have identical definitions. See Table C in S1 File for landmark definitions.
Fig 5.
Principal Component Analysis performed on the linear measurements of skulls.
The continuous line represents “juvenile” morphospace. The dotted line represents “male” morphospace and the dashed line represents “female” morphospace. Asterisks indicate specimens shared with Dodson [25].
Fig 6.
Principal Component Analysis performed on the skulls in lateral view.
The continuous line represents “juvenile” morphospace. The dotted line represents “male” morphospace and the dashed line represents “female” morphospace. Asterisks indicate specimens shared with Dodson [25].
Fig 7.
Principal Component Analysis performed on skulls with the frill excluded.
The continuous line represents “juvenile” morphospace. The dotted line represents “male” morphospace and the dashed line represents “female” morphospace. Asterisks indicate specimens shared with Dodson [25].
Fig 8.
Principal Component Analysis performed on the frills.
The continuous line represents “juvenile” morphospace. The dotted line represents “male” morphospace and the dashed line represents “female” morphospace. Asterisks indicate specimens shared with Dodson [25].
Fig 9.
Principal Component Analysis performed on skulls in dorsal view.
The continuous line represents “juvenile” morphospace. The dotted line represents “male” morphospace and the dashed line represents “female” morphospace. Asterisks indicate specimens shared with Dodson [25].
Table 3.
Pair-wise npMANOVA performed on the shape variables per-group.
Table 4.
Pair-wise npANOVA performed on the size variables (CS) per-group.
Table 5.
Pair-wise npANOVA performed on each PCscore variable per-group.
Fig 10.
UPGMA cluster analysis performed on the four samples.
A, UPGMA cluster analysis of skulls in lateral view. B, UPGMA cluster analysis performed on skulls in dorsal view. C, UPGMA cluster analysis of skulls without frill. D, UPGMA cluster analysis performed on the frills. Asterisks indicate specimens shared with Dodson [25]. Light blue indicates a “male”, pink indicates a “female”, grey indicates a juvenile.
Fig 11.
Visualization of shape-size relationship via CCA analysis for cranial shape in lateral view and cranial shape changes associated with the increase of size.
Asterisks indicate specimens shared with Dodson [25].
Fig 12.
Visualization of shape-size relationship via CCA analysis for cranial shape in dorsal view and relative cranial shape changes associated with the increase of size.
Asterisks indicate specimens shared with Dodson [25].