Table 3 Characters that change during ontogeny in the Oviraptoridae
Feature | State (0): Immature | State (1): Mature |
|---|---|---|
1. Subnarial portion of premaxilla | Shallow | Deep |
2. Inclination of nasal process of premaxilla relative to horizontal axis of skull | Approximately 45° | More than 45° |
3. Lateral surface of premaxillary body | Bears a single fenestra | Bears a group of foramina |
4. Maxilla | Shallow | Deep |
5. Maxillary ventral margin | Horizontal | Anteroventrally inclined |
6. External antorbital fenestra | Shallow | Deep |
7. Angle between jugal process of maxilla and descending process of lacrimal | Less than 90° | Roughly 90° |
8. Anteroventral deflection of anterior part of frontal | Abrupt | Smooth |
9. Lacrimal posterodorsal process | Anteroposteriorly compressed | Stout |
10. Lacrimal anterior process | Long | Short |
11. Crest | Absent | Moderately or well developed |
12. Pneumatic quadrate | Absent | Present |
13. Neural arches and centra | Unfused | Fused |
14. Parapophyses on anterior cervicals | Protrude only slightly ventrolaterally | Extend far laterally |
15. Sacral centra | Dorsoventrally compressed | Spool-like |
16. Distal caudal vertebrae | Unossified | Ossified |
17. Furcula hypocleidium | Absent | Present |
18. Pubic peduncle | Extends further ventrally than ischial peduncle | Extends as far ventrally as ischial peduncle |
19. Brevis fossa | Absent | Present |
20. Femoral neck | Absent | Present |