Chapter 7

Question 1

Characteristics of chondrichyes

Answer 1

loss of bony dermatocranium, prismatic endoskeleton calcification, claspers, placoid scales

Question 2

unmovable upper jaw

Answer 2

autodisatylic jaw

Question 3

slightly movable jaw

Answer 3

amphistylic jaw

Question 4

moveable upper jaw

Answer 4

hyostylic jaw

Question 5

unmovable upper jaw

Answer 5

holostylic jaw

Question 6

what species has an autodiastylic jaw

Answer 6

chondrichthyans

Question 7

what species have amphisytlic jaw

Answer 7

Ancient elasmobranchs

Question 8

what species have hyostylic jaw

Answer 8

Crown elasmobranch

Question 9

what species have holostylic jaw

Answer 9

Holocephalians

Question 10

Hyomandibula (dorsal hyoid arch) rotates from 45°to vertical

It depresses the hinge

Allows jaw to protrude anteriorly and ventrally

Also extension (opening) of the mand. arch

Answer 10

hylostyl

Question 11

Selachii

Answer 11

sharks

Question 12

what are two major groups of Selachii

Answer 12

Geleomorpha and Squalomorpha

Question 13

what shape do selachii have

Answer 13

streamlines fusiform shape