Discovery of Mammalian Diversity

Reeder et al., 2007

Described since I last taught Mammalogy (2014)

Petrogale wilkinsi (Wilkins’ rock wallaby)

5 new species of Pithecia, includingP. rylandsi

Craseonycteris thonlongyaibumble-bee bat< 2 grams

Balaenoptera musculusblue whale200 Million grams

Thewissen et al.1994. Science, 263:210.

Simmons et al. 2008. Nature, 451:818.

Gliding species (e.g., Petaurus breviceps)

Saltatorial species (e.g., Dipodomys ordi)

Fossorial forms (e.g., Thomomys bottae)

Arboreal forms (e.g., Bradypus tridactylus)

Myrmecophagous forms (e.g., Orycteropus afer)

*Hair, *sebaceous glands, *sweat glands

Four-chambered Heart

Nucleated erythrocytes Annucleate erythrocytes

*Renal Artery and Vein

Other tetrapods have a renal portal system.

*Muscularized Diaphragm

*Facial Muscles

*Dorsal Pallium

Eleven Soft Anatomy Characters

1) *Lactation

2) Vivipary

3) *Hair

4) *Sweat/*Sebaceous Glands

5) Endothermy

6) 4-Chambered heart

7) *Annucleate RBCs

8) *Renal Artery

9) *Muscular Diaphragm

10 ) *Facial muscles

11) *Dorsal Pallium expands cerebrum

*Atlas/Axis Complex

*3 Ear Ossicles

Ancestral Mammalian

8 Cranial Characters

1) Double occipital condyle

2) *Atlas/Axis complex

3) *Tympanic bone

4) *Three ear ossicles

5) *Dentary is only bone in mandible

6) Single external naris

7) Secondary palate

8) Respiratory turbinates

Dental Characters

5 Dental Characters

1) Lack palatal teeth

2) *Diphyodont

3) Thecodont

4) Heterodont

5) Multicuspate

Axial Skeleton

7 (9)

12 or 13

Variable

Ribs only onthoracic

*Extreme Regionalization

*Limb Bones have Epiphyses

*Calcaneum (Heel bone)

Calcaneum

No anterior/posterior coracoids, No interclavicle

Pectoral Girdle

Ancestrally, there was aninterclavicle, and both anterior and posterior coracoids.

Pelvic GirdleIlium, Ischium and Pubis fusedto form the Innominate bone.

Limbs Rotate under Body(Parasagittal posture)

4 Appendicular Skeleton Characters

1) *Limb bones have epiphyses.

2) *Calcaneum.

3) *Reduction of elements in limb girdles.

4) Parasagittal limb posture.