Lecture 11

Question 1

1. List the dermal components of the pectoral girdle.

Answer 1

• Cleithrum (-a)
• Clavicle
• Interclavicle

Question 2

1. List the endochondral components of the pectoral girdle.

Answer 2

• Procoracoid
• Coracoid
• Scapula

Question 3

The Cleithrum is what part of the pectoral girdle?

Answer 3

dermal

Question 4

The scapula is what component of the pectoral girdle?

Answer 4

endochondral

Question 5

The Coracoid and Procoracoid are what type of components of the pectoral girdle?

Answer 5

endochondral

Question 6

What components provide muscle attachment surfaces???

Answer 6

Dermal components provide surfaces for muscle attachment.

Question 7

Endochondral components serve as major base of

Answer 7

attachment for limb muscles.

Question 8

Why do chondricthyians only have endochondral components?

Answer 8

In the shark and other chondrichthians, the pectoral girdle only consists of endochondral components.

Question 9

Describe the coracoid bar:

Answer 9

The main component is the coracoid bar:
o Carries the fin attachment
o Is typically “U”-shaped
o Scapular processes sit on top of lateral ends of coracoid

Question 10

Describe the comparative anatomy of both dermal and endochondral components from fishes through the mammals.

Answer 10

There is a chart in the notes comparing fish, tetrapods, etc.

Question 11

Does the pelvic girdle have dermal components in vertebrates?

Answer 11

No. The pelvic girdle lacks dermal components in all vertebrates.

Question 12

The pelvic girdle consists of three paired endochondral bones: What are they?

Answer 12

Pubis, Ischium, Illum

Question 13

Where is the pubis located?

Answer 13

ventral and anterior to the other two components

Question 14

Where is the Ischium located relative to the other pelvic girdle bones?

Answer 14

posterior and ventral to the other two

Question 15

The illum is found:

Answer 15

located dorsal to the other two components

Question 16

What is the acetabular fossa?

Answer 16

Where all three bones carry limb articulation in most vertebrates

Question 17

What does the Ilium articulate with?

Answer 17

Ilium articulates with sacral vertebra(e) either directly or via sacral ribs.

Question 18

Which two bones of the pelvic girdle are used for muscle attachment?

Answer 18

Pubis and Ischium

Question 19

Describe the pelvic girdle of bony fishes.

Answer 19

In bony fishes, the pelvic girdle consists of a pair of ventral triangular plates fused along their midline. They are never articulated with the axial skeleton.

Question 20

T/F A shark pelvic girdle is entirely cartilaginous?

Answer 20

True. I’m seeing a trend here

Question 21

What is the obturator foramen?

Answer 21

The obturator foramen is an opening between the pubis and ischium which provides a passageway for a nerve (obturator nerve) supplying the limb muscles.

Question 22

The acetabulum develops

Answer 22

above the puboisciadic plate and forms from all three elements except in crocodilians.

Question 23

The ilia are attached to…

Answer 23

sacral verebrae

Question 24

Where do the pubis and ilium fuse?

Answer 24

to each other along the midline

Question 25

Why is the bony ring opening size significant?

Answer 25

in vertebrates that lay large eggs or bear live young, the bony ring must be large enough. All digestive, urinary and genital systems must be accomodated as well.

Question 26

Are frog pelvic elements ossified?

Answer 26

yes

Question 27

What the hell is the urostyle?

Answer 27

the single slender element int eh middle of the caudal vertebra in the frog

Question 28

Note that acetabulum is open in...

Answer 28

The modern alligator pelvic girdle (left) and the extinct saurischian dinosaur pelvic girdle (right) are examples of the saurischian type of pelvic girdle.

Question 29

What does teh triradiate pelvic girdle include?

Answer 29

The pubic bones fused anteriorly forming one prong, and the two ischia forming two additional prongs.

Question 30

Give an example of who has the ornithischian type pelvic girdle...

Answer 30

ornithischian dinosar

Question 31

The pubic bones are separate and in the dinosaur, the pubic bones have cranial extensions and is described as:

Answer 31

tetraradiate

Question 32

Describe the shape and orientation of the ilium in mammal like reptiles and mammals:

Answer 32

the ilium extends anteriorly rather than dorsally or posteriorly

Question 33

What supports the marsupial pouch?

Answer 33

marsupial bones that extend anteriorly from the pubic bones

Question 34

Tetrapods and turtles have a LARGE obturator foramen what might this represent?

Answer 34

may represent the pubioischiadic fenestra found in the pelvic girdles of other tetrapods such as turtles. The passageway for the obturator nerve and artery is found along a groove in the superior pubic ramus.

Question 35

Why is the obturator membrane needed?

Answer 35

It is a fibrous membrane that incrases the surface area for muscle attachment.

Question 36

What joint is formed by the sacrum and the ilium?

Answer 36

Sacroiliac joint, it has multiple sacral vertebrae connections.

Question 37

Triradiate pelvic girdle

Answer 37

Saurischians (lizard-like hip) | Like tryanysaurs rex

Question 38

Tetraradiate pelvic girdle:

Answer 38

Ornithischians (bird like) | Triceratops

Question 39

Tetrapods may have evolved from a crossopterygian ancestor called

Answer 39

♣ rhipidistian Eusthenopteron

Question 40

What is the tetrapod limb traced back to?

Answer 40

the tetrapod limb can be traced back to the crossopterygian lobe fin.

Question 41

In the rhipidistian Eusthenopteron,

Answer 41

the series of limb bones is supplied by segmental muscle slips that grow down from the somites. This has some resemblance to muscles in the limbs of tetrapods.

Question 42

The carpus and tarsus primitively consisted of twelve elements:

Answer 42

♣ Three proximal elements: radiale, intermedium, ulnare in carpus and fibulare, intermedium, and tibiale in the tarsus. ♣ Four Centralia ♣ Five distal carpalia or tarsalia

Question 43

In the forelimb, the centralia are almost always reduced:

Answer 43

♣ There are never more than two in primitive reptiles ♣ A single centrale is a common reptilian and mammalian pattern. ♣ The fifth distal carpal element is typically lost. ♣ The phalangeal formula for both primitive and mammal-like reptiles = 2-3-4-5-3. ♣ In advanced reptiles the phalangeal formula = 2-3-3-3-3.

Question 44

how many phalanges in cetaceans and extinct marine reptiles?

Answer 44

13-14

Question 45

What is hyperphalangy?

Answer 45

having 13-14 phalanges int eh phalangeal formula

Question 46

Hyperphalangy is an example of _______evolution.

Answer 46

convergent

Question 47

The calcaneus developes from

Answer 47

the fibulare

Question 48

The astragalus develops from the

Answer 48

tibiale +intermedium +centrale

Question 49

Reptiles have an intratarsal joint. Where is the joint in the crockodile?

Answer 49

Foot movement occurs between teh astragalus and the calcaneus

Question 50

Where is the intratarsal joint in dinosaurs?

Answer 50

The astragalus and calcaneus are closely attached to the fibula and the tibia, and distal tarsals are joined to the metatarsals. Birds are similar.

Question 51

What is the stylopod?

Answer 51

proximal single element: Humerus or femur, articulates with girdle.

Question 52

What the heck is the Zeugopod?

Answer 52

Two parallel elements: radius and ulna (or fibula and tibia)

Question 53

Autopod (proximal to distal):

Answer 53

♣ Carpals (tarsals) ♣ Metacarpals (metatarsals) ♣ Phalanges.

Question 54

Describe variations in phalangeal formulas

Answer 54

The tetrapod hand typically consists of five digits with varying numbers of phalanges. Phalangeal number may be indicated by listing numbers of phalanges per digit beginning with the radial side

Question 55

Human hand phalangeal formula?

Answer 55

2:3:3:3:3

Question 56

Advanced reptiles and modern mammals phalangeal formula?

Answer 56

Same as humans: | 2:3:3:3:3

Question 57

Primitive and mammal-like reptiles:

Answer 57

2:3:4:5:3 | Don't memorize this... just know that human is 2:3:3:3:3