Test 1 postcranial skeleton

Axial

grows out of notochord

• vertebrae

• ribs

• sternum

appendicular

bones added on top of that

• girdles (anchor points for limbs)

  • pectoral

  • pelvic

• limbs

myoseptum

bundle of muscles together where they are attached at the neural arch

ribs

grow out through the myoseptum and are connected to the vertebrae, providing structural support and protecting the thoracic cavity.

dorsal rib

grows up and out (seen in fish)

horizontal septum

divides the top from the bottom of the body (has an important sensory system)

ventral rib

grows down and around our coelom

epaxial

muscles located above the horizontal septum, responsible for movement of the spine and body posture.

hypaxial

muscles located below the horizontal septum, involved in body movement and respiration.

floating ribs

no connection with the sternum

false ribs

indirect connection to the sternum

true ribs

direct connection to the sternum

bony occified rib

vertebral rib

cartilagenous rib

sternal rib

uncinate processes

attachment places for muscles on a rib cage that allows more muscles to connect to the rib cage (important evolutionary characteristic for birds because it is a highly evolved skeleton)

the sternum

is frequently loseed in evolution (snakes = loss) and is the origin of chest muscles in early tetrapods

carina (keel)

a ridge (point) or projection found on the sternum of birds that supports flight muscles and enhances aerodynamic efficiency.

sternebrae

chain of sternum in mammals, that consists of several individual bones called sternebrae, which fuse together to form the complete sternum.

atlas or atlas plus axis

the first two cervical vertebrae in the spine, responsible for supporting the skull and allowing for head movements

cervical vertebrae

make the head mobile relative to the body

thoracic vertebrae

provide attachment points for the ribs

lumber vertebrae

vertebrae for the abdomen with large transverse processes

sacral vertebrae

five fused vertebrae forming the sacrum which attaches the pelvis to the axial skeleton

caudal vertebrae

form the tail (no longer have central nervous system)

What are paired fins for

maneuverability, steering, stopping, lift

what are median fins for

stability, propulsion

What are the 2 paired fins

pectoral and pelvic fins

what are the 4 median fins

dorsal, anal, caudal, and adipose fins.

what are caudal fins used for

propulstion

what are adipose, anal, and dorsal fins for

stability

paralogue

multiple different genes duplicating and growing into something different (gene sibling)

pterygiophores

supporting bones at the base of fins in fish, connecting them to the skeleton.

Types of pterygiophores

radials and basals

basal pterygiophores

few, proximal

radials

more, distal

what lays off radials

dermal fin rays

what are dermal fin rays

cartilaginous, look like the clear jelly the rods sticking through them are them, they can regrow

tiktalik

• have wrists and ankles

  • can do push ups

• first signs of a neck

• they lose the post temporal skull attachment to the pectoral girdle and gain necks (still considered fish because they have no digits)

tbox 4 and tbox 5

are associated with the evolution of limbs and the transition from aquatic to terrestrial life in vertebrates.

stylopodium

One limb or appendage as one long thin bone (humerus or femur) that serves as the primary support structure.

zeugopodium

Two paired bones attached to the stylopodium (tibia, fibia) or (radius, ulna)

Autopodium

appendage that consists of the wrist and ankle bones, including the carpals and tarsals, providing the structure for the digits. (hand and foot)

preaxial

side of the arm leading (radius, tibia)

Postaxial

side of the arm lagging (ulna, fibia)

morphogenic field

field split into postaxial and preaxial regions, influencing limb development.

Alula

synapomorphy of birds, it acts as a pointer (2nd) finger that cuts through the air leading finger when flying

Unguligrade

animal walks on the tips of its toes, typically seen in hooved animals.

plantigrade

walking pattern we use (the heel is all the way on the ground)

digitigrade

Walking on digits (tends to be carnivours)