Module 11: Avian Osteology

Question 1

Neornithes

Answer 1

Only extant subclass of birds

Question 2

Paleognathae

Answer 2

Old jaws-more primitive and reptile-like

Question 3

Paleognathae families

Answer 3

• Struthioniformes: ostriches, emus, kiwis, and allies
• Tinamiformes: tinamous

Question 4

Neognathae

Answer 4

more derived in bill, fee, function, and behavior

Question 5

Neognathae families

Answer 5

• Anseriformes—waterfowl
• Galliformes—fowl
• Charadriiformes—gulls, button-quails, plovers and allies • Gaviiformes—loons
• Podicipediformes—grebes
• Procellariiformes—albatrosses, petrels, and allies

• Sphenisciformes—penguins
• Pelecaniformes—pelicans and allies
• Phaethontiformes—tropicbirds
• Ciconiiformes—storks and allies
• Cathartiformes—New World vultures
• Phoenicopteriformes—flamingos
• Falconiformes—falcons, eagles, hawks and
allies
• Gruiformes—cranes and allies
• Pteroclidiformes—sandgrouse
• Columbiformes—doves and pigeons
• Psittaciformes—parrots and allies
• Cuculiformes—cuckoos and turacos
• Opisthocomiformes—hoatzin
• Strigiformes—owls
• Caprimulgiformes—nightjars and allies • Apodiformes—swifts and hummingbirds • Coraciiformes—kingfishers and allies
• Piciformes—woodpeckers and allies
• Trogoniformes—trogons
• Coliiformes—mousebirds
• Passeriformes—passerines, the songbirds or
perching birds

Question 6

Bone structure of birds

Answer 6

Light-weight
Highly pneumatized (esp. flight birds)
Thin cortical wall, little medullary bone
Non-compacted cancellous bone
Thin struts crossing throughout medullary cavity

Question 7

Bird skull

Answer 7

Modified to reduce weight
Less than 1% of total weight
Bones fuse very early in life-hardly found separate
Largest bone-frontal (most of cranial vault)
Frontals-contain orbital structure with interorbital septum between eyes attached to ethmoid, small lachrymal bone on anterior margin of orbits
Parietals and occipital are caudal portion
Squamosal portion-much reduced temporal bone
Basitemporal plate-triangular bone on floor of skull
Basisphenoid-anterior to plate, pair of basipterygoid process project to articulate with quadrate
Maxilla has posterior and ventral projection-maxillopalatine process
Vomer, maxilla, nasals and premaxilla-beak
Maxilla, jugal, quadratojugal bone-zygomatic arch
Mandible-5 fused bones

Question 8

Diagnostic features

Answer 8

Size, shape and location of nares or nasal aperture
Bill shape/size
Palate structure-3 groups
-schiognathous: bony palata with cleft down length separating maxillopalatines, small, pointy vomer
-aegithognathous: 2 pronged vomer anteriorly and separate maxillopalatines
-desmognathous: fused maxillopalatines, small/lacking vomer

Question 9

Furcula

Answer 9

Clavicles fused-wishbone in chickens
Furcula float free in muscle, not supportive
V/U shaped, sometimes W

Question 10

Sternum

Answer 10

Large keel to support pectorals
Articulates with coracoids at proximal end, ribs lateral margins
Size/shape highly diagnostic
Gruiformes-laryngeal box incorporated into sternum
Pelecaniformes-furcula articulates with sternum

Question 11

Coracoid

Answer 11

Separate from scapula
Struct from sternum to humerus
Somewhat triangular
Articulates with sternum, humerus, furcula, & scapula

Question 12

Scapula

Answer 12

Elongated and slender

Question 13

Humerus

Answer 13

Proximal end-spatulate, small humeral head
Lateral condyle larger than medial
Some species have pneumatic fossa, others do not

Question 14

Ulna

Answer 14

Dorsal surface tiny bony papillae for quill knobs & secondary feather attachment

Question 15

Carpometacarpus

Answer 15

Fusion of most carpals and metacarpals. Cuneiform and scapholunate only carpals remaining
Like violin bow- MC 1 and carpals=grip, MC ii=bow, MC iii=strings
Distinct appearance
Fingers reduced to 3 w 1 or 2 phalanges
1st phalanx 2nd digit shaped like scapula

Question 16

Pelvis

Answer 16

Several elements-normal 3 and fused vertebrae (synsacrum)
Flight birds-area cranial to acetabulum larger than caudal
Diving/terrestrial birds-more equal

Question 17

Femur

Answer 17

Short in comp to other hindlimb elements
Sometimes greater trochanter above the head, level in others

Question 18

Tibiotarsus

Answer 18

Like tibia on proximal end, like femur on distal with 2 condyles
Loons/grebes patella fuses to proximal end forming semilunar notch and structure like olecranon
Distal end tendinal groove or supracondylar fossa and supratendinal bridge
Fibula may be separate or fused

Question 19

Tarsometatarsus

Answer 19

Fusion of tarsals and metatarsals
Proximal end condylar facets like tibia to accommodate condyles of tibiotarsus
Distal end trochlea
-typically 3, woodpeckers 4
Males may have spur
Feet retain reptilian phalange formula 2,3,4,5 for first 4 digits. Terminal phalanges are claws

Question 20

Wild vs domestic turkey

Answer 20

Breast bone most diagnostic feature-significantly larger in domesticated turkeys
Wild turkeys more slender limb elements, particularly evident in tibiotarsus
Domestic birds harvested before mature-lack of full development of distal ends of long bones