Gnathostomata Synapomorphies

Question 1

Paired Appendages

Answer 1

Origin of paired pectoral AND pelvic appendages = increased control and maneuverability of body in 3D space

Question 2

3 pairs of semicircular canals

Answer 2

Addition of horizontal

Question 3

Notochord partially/completely replaced by _______

Answer 3

Centra

Question 4

____ olfactory bulbs with _________

Answer 4

2; 2 nostrils

Question 5

Neural and hemal arches extending from notochord

Answer 5

Neural arches surround/protect SPINAL cord

Hemal arches surround/protect BLOOD vessels

Result:
-INCREASED surface area for muscle attachment = greater maneuverability

Question 6

Horizontal septum divides trunk musculature into _______ and ___________

Answer 6

epaxial (dorsal); hypaxial (ventral) portions

Result:
-Increased muscular coordination

Question 7

Gill arches _________ to gills

Answer 7

Internal

Question 8

Spiracle

Answer 8

Homologous to 1st gill slit

Located between mandibular and hyoid arches