Pinniped Evolution & Systems

Question 1

Well-Known Characteristics 1-8

Who do they belong to?

Answer 1

1) Large Infraorbital Foramen
2) Maxilla makes a significant contribution to orbital wall
3) Reduced/ Absent lacrimal bone
4) Strongly developed and rounded promineces on the proximal end of the humerus
5) Strongly developed crest on humerus shaft
6) Short & Robust humerus
7) Didget 1 on hand emphasized
8) Didget 1/5 on foot emphasized

Belong to all beginning at pinnipedia

Question 2

Well Known Characteristics 9-13

Answer 2

9) The structure between frontal and nasal bone is W shaped
10) Have a larger suborbital process
11) Secondary spine on scapula
12) pelage units spaced uniformly
13) Trachea has anterior bifunction of brochii

Belong to Otartariidae

Question 3

Well Known Characteristics 14-17

Answer 3

14) Pterygoid strut broad and thick
16) modifications in cheek teeth
17) calcaneal bone different

Belong to all except phocidae

Question 4

Well Known Characteristics 18-29

Answer 4

18
19) Large ankle bones so cant draw ankle in
20Thick and dense mastoid bone
21) Inflated typanic bulla 
22) Lack supraorbitals process
23) ilium bends outward
24) Enlarged middle ear bones
25) Testes
26) Primary hair nonmedullated
27) Thick subcutaneous fat
28) Lacking external ear pinna
29) Inflated hepatic sinus one modification of venous system

Question 5

Layers of skin

Answer 5

• Outer Layer = Epidermis
• Middle = Dermis
• Deep Layer = Blubber

Question 6

Edpidermis

Answer 6

3 layers in marine mammals:
Basale
Spinosum
Corneum

Question 7

Blubber

Answer 7

15% connective Tissue Fibers
85% Fat cells
Collagen makes it stiff and tough but still flexible

Question 8

What are to most common parasites and where are they located?

Answer 8

Sucking Lice with modified claws to hold hair, located on eyelids, nostrils, and anus. pups are more prone

Question 9

What are 2 layers of hair?

Answer 9

Guard haris= long and thick

Inner hairs= Short, fine, dense soft.

Question 10

Growth patterns

Answer 10

Otariids= uniformly

Walrus and phocids= Clusters of 2-4 in a row

Question 11

What is Lanugo?

Answer 11

First coat of pinnipeds

Question 12

What are vibrissae?

3 kinds?

Answer 12

Whiskers that can sense movement in water.

1) Rhinal= only phocids, on nose
2) Super Ciliary = above eyes
3) Mystacial= most prominant and abundant

Question 13

When does spinal Cord end in pinnipeds?

Answer 13

Ends between 8-12 thoracic vertebrae

Question 14

How do pinnipeds see in air?

Answer 14

They are near sighted