Appendicular Skeleton

Question 1

what is the point of fins

Answer 1

Fins allow fish to continue on intended line of travel

Question 2

what do pectoral fins do

Answer 2

increase maneuverability, especially within
vegetation. Can help initiate rising or sinking (sharks).

Question 3

Gill-arch Theory of the Origin of Pectoral Fins
(Gegenbaur 1870s)

Answer 3

Suggested that the
pectoral girdle arose
from the gill arch &
the primitive
archipterygial fin
arose from the gill ray
Initially based on
anatomy of sharks &
then upon discovery of
Australian lung fish
(1872)

Question 4

what was the problem with Gill-arch Theory of the Origin of Pectoral Fins
(Gegenbaur 1870s)

Answer 4

How to explain pelvic
fins found distally, the
presence of dermal bone
in the pectoral girdle, the
embryology of the
pectoral girdles and gill
arches

Question 5

Fin folds in Early Cambrian Agnathan:
Haikouichthys

Answer 5

Fin fold = thickening
of ectoderm

Question 6

Fin folds in Early Cambrian Agnathan:
Myllokunmingia

Answer 6

Fin fold = thickening
of ectoderm

Ventrolateral fin fold was probably paired

Question 7

E Jarvisk fin fold theory

Answer 7

scales are the origin of dermal fin rays, fin ray is of dermal origin

Question 8

F Balfour, J thatcher fin fold theory evidence

Answer 8

Question 9

examples of pectoral girdles with fin endoskeleton, paired pelvic fins present

Answer 9

haikouichthys, placodermi, ostracoderms

Question 10

E. Jarvisk–
____ bone in
pectoral girdle
originated in the
___

Answer 10

dermal, skull

Question 11

Genes involved in Fin/Limb Development - Tbx gene

Answer 11

expressed along body

Question 12

Genes involved in Fin/Limb Development - Engrailed-1

Answer 12

role in
dorsal/ventral patterning, restricted
to ventral compartment of embryo

Question 13

Genes involved in Fin/Limb Development - Duplication of Tbx gene

Answer 13

within
ventral zone, Tbx4 and Tbx5
determine identity of paired
appendages

Question 14

Genes involved in Fin/Limb Development - Acquisition of Shh

Answer 14

promotes
growth away from the body

Question 15

who has the shh gene

Answer 15

absent in sharks, present in
tetrapods, promotes growth away from the body

Question 16

Hoxc8, Hoxc6

Answer 16

they are present in areas where there are no limbs, all along python, trunk of chick

Question 17

Fin rays are called ___ in bony
fishes and ___ in elasmobranchs

Answer 17

lepidotrichia, ceratotrichia

Question 18

pterygiophores derive from what

Answer 18

mesodermal

Question 19

dermal fin rays initially form at interface between ____, as do dermal scales, but sink into the ____

Answer 19

dermis and epidermis, dermis

Question 20

Basals and Radials = name + what are they made of

Answer 20

pterygiophores (cartilage or endochondral bone)

Question 21

what is lepidotrichai made of

Answer 21

Cartilage or dermal bone rods

Question 22

whoa has archipterygial fin

Answer 22

Living sarcopterygians

Question 23

who has metapterygial fins

Answer 23

Rhipidistians, and a few
other bony fish

Question 24

Primitive structure of pectoral girdle:

Answer 24

Endochrondral bones
* Scapula and coracoid
–Dermal bones (from skull)
* Postemporal, supracleithrum, cleithrum,
clavicle

Question 25

trend of pectoral girdle over time

Answer 25

Trend over time: –Loss of some dermal bones: posttemporal, supracleithrum, and cleithrum

Question 26

be able to label

Answer 26

Question 27

Pectoral girdle of Amia–

Answer 27

connected to skull, partly endochondral, but mostly dermal

Question 28

Rays of the pectoral fins articulate with a series of ___ bones which in turn articulate with the ___ and ___

Answer 28

radial, scapula, coracoid

Question 29

Rays - These bones are attached to the ___ -a large bone firmly united with body musculature and that is joined to the skull via the ___

Answer 29

cleithrum, supracleithrum

Question 30

Trend in Pectoral Girdle – loss of some dermal bones (___) – and gain in ___ bone

Answer 30

posttemporal, supracleithrum, and cleithrum, endochondral

Question 30

Australian Lungfish. PG

Answer 30

Dermal pectoral girdle = cleithrum, clavical, and postcleithrum. Endo- skeletal pectoral girdle = scapulocoracoid. Pelvic girdle is a single bar.

Question 31

coelacanth pG

Answer 31

Coelacanth. Dermal pectoral girdle lacks interclavicle. Pelvic girdle is a single bar.

Question 32

In sharks, fusion of ____ gave rise to ___ and ___ bars – fusion of separate basal girdle elements across the midline

Answer 32

pterygiophores, scapulocoracoid, pubioschiac

Question 33

Examples of modified pectoral fins in actinopterygians

Answer 33

flying fish

Question 34

Evolutionary Trends of Pelvic Girdle:

Answer 34

Pelvic girdle consists of all endochondral bones: –ilium, ischium, and pubic * Mainly changes in shape and function

Question 35

Bothriolepis, a placoderm from the Late Devonian PG

Answer 35

Pelvic girdle is exclusively endoskeletal - never joined by dermal bone

Question 36

Fused pelvic bones of birds = the

Answer 36

innominate bone

Question 37

Pelvic girdle is reduced in animals that become ___ secondarily

Answer 37

marine

Question 38

Where can you find pelvic fins in Actinopterygians

Answer 38

Question 39

Pectoral fin of primitive fish:

Answer 39

basals and radials

Question 40

Pectoral fin of rhipidistian fish:

Answer 40

humerus, radius, and ulna plus radials/radialia

Question 41

Pelvic fin of primitive fish:

Answer 41

basals and radials

Question 41

Pelvic fin of rhipidistian fish:

Answer 41

femur, tibia, and fibula plus radials/radialia

Question 42

Eusthenopteron, Pandericthys, and Tiktaalik are an example of

Answer 42

Rhipidistians

Question 43

Tiktaalik– NOTE SHOULDER GIRDLE! Looks very

Answer 43

amphibian-like

Question 44

Rhipidistian Fish PG and Pectoral girdle

Answer 44

Pelvic girdle not attached to vertebral column Pectoral girdle attached to skull

Question 45

Rhipidistian pectoral girdle and fin compared to forelimb of an early tetrapod (a labyrinthodont)

Answer 45

R; Girdle attached to skull ET: girdle not attache - loss of supracleithrum and postcleithrum, has digits

Question 46

Acanthostega, Icthyostega, and Seymouria are an example of

Answer 46

labyrinthodonts

Question 47

labyrinthodonts

Answer 47

*NOTE Pectoral (not attached to skull) and pelvic girdles (attached to vertebral column). *Note: Lack of supracleithrum and postcleithrum

Question 48

Embryological and Hox gene studies support the view that tetrapod limbs are built upon the ___ curved around to produce the ___ along its ___ margin

Answer 48

fish-fin major axis, digits, posterior

Question 49

the pandas thumb

Answer 49

elongated wrist bone

Question 50

More robust limbs and girdles in primitive tetrapods, reflecting an ____

Answer 50

increased use of limbs for terrestrial locomotion

Question 51

With sprawled limbs, propulsive forces are transferred more

Answer 51

vertically