Part II Introduction Outline
CHARACTERISTICS OF ORNITHISCHIA
- ALL ORNITHISCHIA
- 1 - OPISTHOPUBIC PELVIS (PUBIS ROTATED BACKWARD TO LIE CLOSE TO &
PARALLEL WITH THE ISCHIUM)
- 2 - PREDENTARY PRESENT CAPPING THE FRONT OF THE LOWER JAWS
- 3 - PALPEBRAL BONE PRESENT THAT CROSSES THE OUTSIDE OF EYE SOCKET
- 4 - OSSIFIED TENDONS ABOVE SACRAL REGION FOR STIFFENING THE BACKBONE
AT THE PELVIS
- SEE OTHER CHARACTERISTICS IN CAPTION FOR FIGURE II.3
- GENOSAURIA
- CLADE OF ORNITHISCHIA INCLUDING ALL ORNITHISCHIANS EXCEPT FOR BASAL
FORM LESOTHOSAURUS
- 1 - MUSCULAR CHEEKS (INDICATED BY POSITIONING OF TOOTH ROWS AWAY FROM
THE SIDES OF FACE)
- 2 - REDUCTION IN SIZE OF THE EXTERNAL MANDIBULAR FORAMEN
- GENOSAURS DIVIDED INTO THYREOPHORA (SHIELD BEARER) AND CERAPODA (HORN
FOOT)
- THYREOPHORA
- 1 - CHEEK BONES (JUGAL) HAVE TRANSVERSELY BROAD PROCESSES BEHIND THE
EYE
- 2 - PARALLEL ROWS OF KEELED DERMAL ARMOR SCUTES ON THE BACK SURFACE
OF THE BODY
- THYREOPHORA DIVIDED INTO BASAL FORMS ( SCUTELLOSAURUS , EMAUSAURUS
, AND SCELIDOSAURUS ) AND EURYPODA (WIDE FOOT)
- EURYPODA DIVIDED INTO STEGOSAURS (CHAPTER 6) AND ANKYLOSAURS
(CHAPTER 7)
- CERAPODA
- 1 - GAP BETWEEN THE TEETH OF THE PREMAXILLA AND MAXILLA
- 2 - FIVE OR FEWER PREMAXILLARY TEETH
- 3 - FINGER-LIKE LESSER TROCHANTER AT THE TOP OF THE FEMUR
- CERAPODS DIVIDED INTO ORNITHOPODA (CHAPTER 10) AND MARGINOCEPHALIA
(MARGIN HEAD)
- MARGINOCEPHALIA DIVIDED INTO PACHYCEPHALOSAURS (CHAPTER 8) AND
CERATOPSIANS (CHAPTER 9)