Lecture 10

Question 1

What are the diagnostic features of bony fish?

Answer 1

Extensive endoskeletal ossification 
Rooted teeth
Primitively 4-plated sclerotic ring 
Medial adductor muscles in lower jaw
Conserve bone pattern in skull roof
Large bones in skull and pectoral girdle
Bony fin rays
Swim bladder
Operculum 
Various scale types

Question 2

What’s the different between endo and exoskeleton bones?

Answer 2

Endo -
Cartilage bone
Membrane bone

Exo-
Dermal bone

Question 3

What are rooted teeth?

Answer 3

Teeth that develop in the dermal bones lining the margins of the mouth

Question 4

What are bony fin rays?

Answer 4

Bony, bilaterally paired, segmented structures developing as part of the dermal exoskeleton and thought to originate from modified scales

Question 5

What is the operculum?

Answer 5

Protects the gill chamber

Also called Gill cover

Question 6

What are some of the types of scales osteichthyans (bony fish) possessed?

Answer 6

Ganoid
Leptoid
-cycloid
-ctenoid

Question 7

What are osteichthans?

Answer 7

Bony fish

Question 8

What are ganoid scales?

Answer 8

Heavy and infexible, often rhomboid, with peg-and-socket articulations and little or no over lap

Question 9

What are leptoid scales?

Answer 9

Found in all ray-finned fish, growth through peripheral addition of concentric layers

Scales show a head-to-tail overlap pattern like tiles on a roof

Question 10

What types of leptoid scales are there?

Answer 10

Cycloid

Ctenoid

Question 11

What’s the different between cycloid and ctenoid scales?

Answer 11

Ctenoid scales are comb-like with ‘spiked’ back end of scales

Cycloid scales are round-ish and have no comb-like aspect to them